Agronomy

10 pages, 677 KiB

Open AccessEditor’s ChoiceArticle

Seed Mineral Composition and Protein Content of Faba Beans (Vicia faba L.) with Contrasting Tannin Contents

by Hamid Khazaei and Albert Vandenberg

Agronomy 2020, 10(4), 511; https://doi.org/10.3390/agronomy10040511 - 3 Apr 2020

Cited by 46 | Viewed by 6174

Two-thirds of the world’s population are at risk of deficiency in one or more essential mineral elements. The high concentrations of essential mineral elements in pulse seeds are fundamentally important to human and animal nutrition. In this study, seeds of 25 genotypes of [...] Read more.

Two-thirds of the world’s population are at risk of deficiency in one or more essential mineral elements. The high concentrations of essential mineral elements in pulse seeds are fundamentally important to human and animal nutrition. In this study, seeds of 25 genotypes of faba bean (12 low-tannin and 13 normal-tannin genotypes) were evaluated for mineral nutrients and protein content in three locations in Western Canada during 2016–2017. Seed mineral concentrations were examined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and the protein content was determined by Near-Infrared (NIR) spectroscopy. Location and year (site-year) effects were significant for all studied minerals, with less effect for calcium (Ca) and protein content. Genotype by environment interactions were found to be small for magnesium (Mg), cobalt (Co), Ca, zinc (Zn), and protein content. Higher seed concentrations of Ca, manganese (Mn), Mg, and cadmium (Cd) were observed for low-tannin genotypes compared to tannin-containing genotypes. The protein content was 1.9% higher in low-tannin compared to tannin-containing genotypes. The high estimated heritability for concentrations of seed Mg, Ca, Mn, potassium (K), sulphur (S), and protein content in this species suggests that genetic improvement is possible for mineral elements. Full article

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22 pages, 1279 KiB

Open AccessEditor’s ChoiceReview

The Importance of Ion Homeostasis and Nutrient Status in Seed Development and Germination

by María del Carmen Martínez-Ballesta, Catalina Egea-Gilabert, Encarnación Conesa, Jesús Ochoa, María José Vicente, Jose A. Franco, Sebastián Bañon, Juan J. Martínez and Juan A. Fernández

Agronomy 2020, 10(4), 504; https://doi.org/10.3390/agronomy10040504 - 2 Apr 2020

Cited by 24 | Viewed by 5012

Abstract

Seed is the dissemination unit of plants initiating an important stage in the life cycle of plants. Seed development, comprising two phases: embryogenesis and seed maturation, may define the quality of sown seed, especially under abiotic stress. In this review we have focused [...] Read more.

Seed is the dissemination unit of plants initiating an important stage in the life cycle of plants. Seed development, comprising two phases: embryogenesis and seed maturation, may define the quality of sown seed, especially under abiotic stress. In this review we have focused on the recent advances in the molecular mechanisms underlying these complex processes and how they are controlled by distinct environmental factors regulating ion homeostasis into the seed tissues. The role of transporters affecting seed embryogenesis and first stages of germination as imbibition and subsequent radicle protrusion and extension were revised from a molecular point of view. Seed formation depends on the loading of nutrients from the maternal seed coat to the filial endosperm, a process of which the efflux is not clear and where different ions and transporters are involved. The clear interrelation between soil nutrients, presence of heavy metals and the ion capacity of penetration through the seed are discussed in terms of ion effect during different germination stages. Results concerning seed priming techniques used in the improvement of seed vigor and radicle emergence are shown, where the use of nutrients as a novel way of osmopriming to alleviate abiotic stress effects and improve seedlings yield is discussed. Novel approaches to know the re-translocation from source leaves to developing seeds are considered, as an essential mechanism to understand the biofortification process of certain grains in order to cope with nutrient deficiencies, especially in arid and semiarid areas. Finally, the role of new genes involved in hormone-dependent processes, oxidative response and water uptake into the seeds during their development or germination, have been described as plant mechanisms to deal with abiotic stresses. Full article

(This article belongs to the Special Issue GMO, New Breeding Techniques and Novel Technologies for Abiotic Stress Tolerance in Crop Plants)

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26 pages, 1082 KiB

Open AccessEditor’s ChoiceReview

Fusarium Head Blight, Mycotoxins and Strategies for Their Reduction

by Elżbieta Mielniczuk and Barbara Skwaryło-Bednarz

Agronomy 2020, 10(4), 509; https://doi.org/10.3390/agronomy10040509 - 2 Apr 2020

Cited by 83 | Viewed by 11028

Abstract

Mycotoxins are secondary metabolites of microscopic fungi, which commonly contaminate cereal grains. Contamination of small-grain cereals and maize with toxic metabolites of fungi, both pathogenic and saprotrophic, is one of the particularly important problems in global agriculture. Fusarium species are among the dangerous [...] Read more.

Mycotoxins are secondary metabolites of microscopic fungi, which commonly contaminate cereal grains. Contamination of small-grain cereals and maize with toxic metabolites of fungi, both pathogenic and saprotrophic, is one of the particularly important problems in global agriculture. Fusarium species are among the dangerous cereal pathogens with a high toxicity potential. Secondary metabolites of these fungi, such as deoxynivalenol, zearalenone and fumonisin B1 are among five most important mycotoxins on a European and world scale. The use of various methods to limit the development of Fusarium cereal head diseases and grain contamination with mycotoxins, before and after harvest, is an important element of sustainable agriculture and production of safe food. The applied strategies utilize chemical and non-chemical methods, including agronomic, physical and biological treatments. Biological methods now occupy a special place in plant protection as an element of biocontrol of fungal pathogens by inhibiting their development and reducing mycotoxins in grain. According to the literature, Good Agricultural Practices are the best line of defense for controlling Fusarium toxin contamination of cereal and maize grains. However, fluctuations in weather conditions can significantly reduce the effectiveness of plants protection methods against infection with Fusarium spp. and grain accumulation of mycotoxins. Full article

(This article belongs to the Special Issue Biocontrol of Mycotoxins Contamination of Crops)

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19 pages, 1311 KiB

Open AccessEditor’s ChoiceReview

Present Status and Perspective on the Future Use of Aflatoxin Biocontrol Products

by Juan Moral, Maria Teresa Garcia-Lopez, Boris X. Camiletti, Ramon Jaime, Themis J. Michailides, Ranajit Bandyopadhyay and Alejandro Ortega-Beltran

Agronomy 2020, 10(4), 491; https://doi.org/10.3390/agronomy10040491 - 1 Apr 2020

Cited by 62 | Viewed by 6497

Abstract

Aflatoxin contamination of important food and feed crops occurs frequently in warm tropical and subtropical regions. The contamination is caused mainly by Aspergillus flavus and A. parasiticus. Aflatoxin contamination negatively affects health and trade sectors and causes economic losses to agricultural industries. [...] Read more.

Aflatoxin contamination of important food and feed crops occurs frequently in warm tropical and subtropical regions. The contamination is caused mainly by Aspergillus flavus and A. parasiticus. Aflatoxin contamination negatively affects health and trade sectors and causes economic losses to agricultural industries. Many pre- and post-harvest technologies can limit aflatoxin contamination but may not always reduce aflatoxin concentrations below tolerance thresholds. However, the use of atoxigenic (non-toxin producing) isolates of A. flavus to competitively displace aflatoxin producers is a practical strategy that effectively limits aflatoxin contamination in crops from field to plate. Biocontrol products formulated with atoxigenic isolates as active ingredients have been registered for use in the US, several African nations, and one such product is in final stages of registration in Italy. Many other nations are seeking to develop biocontrol products to protect their crops. In this review article we present an overview of the biocontrol technology, explain the basis to select atoxigenic isolates as active ingredients, describe how formulations are developed and tested, and describe how a biocontrol product is used commercially. Future perspectives on formulations of aflatoxin biocontrol products, along with other important topics related to the aflatoxin biocontrol technology are also discussed. Full article

(This article belongs to the Special Issue Etiology and Control of Crop Diseases)

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10 pages, 1575 KiB

Open AccessEditor’s ChoiceArticle

The Microbiology of Hemp Retting in a Controlled Environment: Steering the Hemp Microbiome towards More Consistent Fiber Production

by Audrey D. Law, C. Ruth McNees and Luke A. Moe

Agronomy 2020, 10(4), 492; https://doi.org/10.3390/agronomy10040492 - 1 Apr 2020

Cited by 17 | Viewed by 4792

Abstract

Industrial hemp (Cannabis sativa L.) production is increasing dramatically in the US due to recent changes which lift restrictions on the growth and sale of hemp products; however, due to the decades-long prohibition of hemp, there is a lack of current research [...] Read more.

Industrial hemp (Cannabis sativa L.) production is increasing dramatically in the US due to recent changes which lift restrictions on the growth and sale of hemp products; however, due to the decades-long prohibition of hemp, there is a lack of current research with respect to varieties and best agricultural practices for the many uses of this versatile crop. Natural fiber production relies on retting, a microbially-mediated process necessary for the separation of fibers from the plant which can occur unevenly in the field environment and result in inconsistent fiber quality and lower processing efficiency. In this study, the microbiome of hemp stalks is investigated throughout the retting process using 16S rRNA gene amplicon sequencing using the Illumina MiSeq platform. Field retting conditions were simulated in a controlled greenhouse environment in order to determine the effects of different moisture levels and soil contact on the retting process. Samples were taken over six time points, reflecting the community of freshly cut stalks to optimally-retted material, and finally over-retted material showing degraded fibers. The results show a very consistent population throughout retting, dominated primarily by Proteobacteria, but showing an increase in the abundance of the Bacteroidetes, namely Chryseobacterium, in time points corresponding to optimally-retted and over-retted stalks in treatments receiving higher moisture levels, but not in the low-moisture treatment. Soil application did not appear to influence the microbial community throughout retting, indicating a resilient population present in and on the hemp stalks at harvest. Full article

(This article belongs to the Special Issue Drivers of Microbial Diversity and Roles in Agroecosystems)

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18 pages, 3759 KiB

Open AccessEditor’s ChoiceArticle

Exogenous Brassinolide Enhances the Growth and Cold Resistance of Maize (Zea mays L.) Seedlings under Chilling Stress

by Yujun Sun, Yunhan He, Ali Raza Irfan, Xinmeng Liu, Qiaoqiao Yu, Qian Zhang and Deguang Yang

Agronomy 2020, 10(4), 488; https://doi.org/10.3390/agronomy10040488 - 1 Apr 2020

Cited by 48 | Viewed by 3995

Abstract

This paper aims to elucidate the effects of exogenous brassinolide (BL) on maize germination and seedling growth under chilling stress. The cold-resistant maize hybrid Tiannong 9 and the cold-sensitive hybrid Tianhe 1 were soaked at the germination stage (6 °C) and leaves were [...] Read more.

This paper aims to elucidate the effects of exogenous brassinolide (BL) on maize germination and seedling growth under chilling stress. The cold-resistant maize hybrid Tiannong 9 and the cold-sensitive hybrid Tianhe 1 were soaked at the germination stage (6 °C) and leaves were sprayed at seedling stage (4 °C), with BL at concentrations of 0, 0.01, 0.1, and 1 mg/L. The germination rate of the maize seeds and the changes in seedling biomass, antioxidant, photosynthetic, and plant endogenous hormone systems and chloroplast ultrastructures were determined. The results showed that the optimum concentration of BL to alleviate chilling stress in maize seedlings was 0.1 mg/L. This rate effectively increased the germination rate and plant biomass of maize and significantly increased the superoxide dismutase (SOD) peroxidase (POD) and catalase (CAT) activities, the net photosynthetic rate (Pn), stomatal conductance (gs) and transpiration rate (Tr), and seedling auxin (IAA), gibberellin (GA₃) and trans zeatin nucleoside (t-ZR) contents under chilling stress. In addition, BL significantly reduced the malondialdehyde (MDA) content, abscisic acid (ABA) content, and intercellular carbon dioxide concentration (Ci). In the comparison of mesophyll cells, the chloroplast membrane of the treatment group was tightly attached to the stroma, and some of the plasma membranes were dissolved, but the overall structure of the chloroplast was relatively complete, and the osmiophilic granules were relatively few. The exogenous application of BL can effectively alleviate the damage caused by a low temperature in maize, maintain the normal characteristics of seedlings in chilling environments, and ensure the development and growth of plant tissue in the later stage. Full article

(This article belongs to the Special Issue The Role of Growth Regulators in Crop under Abiotic Stress)

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22 pages, 3169 KiB

Open AccessEditor’s ChoiceArticle

The Management of Agricultural Waste Biomass in the Framework of Circular Economy and Bioeconomy: An Opportunity for Greenhouse Agriculture in Southeast Spain

by Mónica Duque-Acevedo, Luis J. Belmonte-Ureña, José A. Plaza-Úbeda and Francisco Camacho-Ferre

Agronomy 2020, 10(4), 489; https://doi.org/10.3390/agronomy10040489 - 1 Apr 2020

Cited by 85 | Viewed by 11460

Abstract

For decades, non-renewable resources have been the basis of worldwide economic development. The extraction rate of natural resources has increased by 113% since 1990, which has led to overexploitation and generation of vast amounts of waste. For this reason, it is essential that [...] Read more.

For decades, non-renewable resources have been the basis of worldwide economic development. The extraction rate of natural resources has increased by 113% since 1990, which has led to overexploitation and generation of vast amounts of waste. For this reason, it is essential that a sustainable development model is adopted—one which makes it possible to produce more food and energy with fewer fossil fuels, low pollutant gas emissions and minimal solid waste. Certain management policies and approaches, such as the strategy of a circular ecocomy or bioeconomy, are oriented towards sustainable production and consumption. The present study focuses on the importance of intensive horticulture in the Mediterranean region, specifically in the province of Almería (Spain). After having conducted a study of the main crops in this area, it was determined that the waste biomass generated presented strong potential for exploitation. With the proper regulatory framework, which promotes and prioritises the circularity of agricultural waste, there are several opportunities for improving the current waste management model. In the same way, the results of the economic evaluation demonstrate that the alternative of self-management of waste biomass is profitable, specifically from tomato crops. Compost and green fertilizer production also prove to be a key strategy in the transition towards a more circular and sustainable agricultural production model. As for the said transition, government support is vital in terms of carrying out awareness campaigns and training activities and providing financing for Research and Development (R&D). Full article

(This article belongs to the Special Issue Greenhouse Technology)

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22 pages, 3415 KiB

Open AccessEditor’s ChoiceArticle

Effect of Biogas Digestate and Mineral Fertilisation on the Soil Properties and Yield and Nutritional Value of Switchgrass Forage

by Aleksandra Głowacka, Bogdan Szostak and Renata Klebaniuk

Agronomy 2020, 10(4), 490; https://doi.org/10.3390/agronomy10040490 - 1 Apr 2020

Cited by 46 | Viewed by 4316

Abstract

The aim of this study was to assess the effect of a three-year application of digestate from an agricultural biogas plant on the physicochemical properties of highly acidic pH_KCl 4.4 ± 0.23, silty loam soils with low macronutrient content and on the [...] Read more.

The aim of this study was to assess the effect of a three-year application of digestate from an agricultural biogas plant on the physicochemical properties of highly acidic pH_KCl 4.4 ± 0.23, silty loam soils with low macronutrient content and on the yield and nutritional value of switchgrass (Panicum virgatum L.) biomass harvested for green fodder. The experiment included the following treatments: (1) O (control)—no fertilisation, (2) NPK—mineral fertilisation with (in kg ha⁻¹) 150 N, 53.0 P and 105 K, (3) biogas digestate at 30 m³ ha⁻¹ and (4) biogas digestate at 60 m³ ha⁻¹. The higher application rate of biogas digestate significantly reduced soil acidity to pH_KCl 4.9 ± 0.18 and improved its sorption properties. It also increased the soil organic matter content from 5.6 ± 0.21 to 6.4 ± 0.22 g C_org kg⁻¹ and of K and Zn. The higher level of biogas digestate significantly increased switchgrass yield to 5.15 ± 0.26 t ha⁻¹. The lower application rate of biogas digestate resulted in forage yield of 4.30 ± 0.20 t ha⁻¹ comparable to that obtained after mineral fertilisation (4.33 ± 0.22 t ha⁻¹). Following application of mineral fertilisers and the higher level of biogas digestate, the number of panicles per plant (150 ± 2.49–157 ± 0.6.17), panicle height (107 ± 1.98–114 ± 2.08), crude ash content (61.2 ± 0.43–65.5 ± 0.38) and protein content (106 ± 0.59–92 ± 1.11) in the switchgrass biomass from the first cut were higher than in the case of unfertilised soil (110 ± 3.81, 93 ± 1.32, 55.5 ± 0.40, 80.3 ± 0.37). The use of mineral fertilisers and biogas digestate increased the content of protein, P and Mg in biomass from the second cut. The results suggest that the use of digestate improved the physicochemical properties of highly acidic soil and increased the yield of switchgrass forage without diminishing its nutritional value. Full article

(This article belongs to the Special Issue Soil Fertility Management for Better Crop Production)

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15 pages, 694 KiB

Open AccessEditor’s ChoiceArticle

Performance of a Set of Eggplant (Solanum melongena) Lines With Introgressions From Its Wild Relative S. incanum Under Open Field and Screenhouse Conditions and Detection of QTLs

by Giulio Mangino, Mariola Plazas, Santiago Vilanova, Jaime Prohens and Pietro Gramazio

Agronomy 2020, 10(4), 467; https://doi.org/10.3390/agronomy10040467 - 27 Mar 2020

Cited by 22 | Viewed by 4571

Abstract

Introgression lines (ILs) of eggplant (Solanum melongena) represent a resource of high value for breeding and the genetic analysis of important traits. We have conducted a phenotypic evaluation in two environments (open field and screenhouse) of 16 ILs from the first [...] Read more.

Introgression lines (ILs) of eggplant (Solanum melongena) represent a resource of high value for breeding and the genetic analysis of important traits. We have conducted a phenotypic evaluation in two environments (open field and screenhouse) of 16 ILs from the first set of eggplant ILs developed so far. Each of the ILs carries a single marker-defined chromosomal segment from the wild eggplant relative S. incanum (accession MM577) in the genetic background of S. melongena (accession AN-S-26). Seventeen agronomic traits were scored to test the performance of ILs compared to the recurrent parent and of identifying QTLs for the investigated traits. Significant morphological differences were found between parents, and the hybrid was heterotic for vigour-related traits. Despite the presence of large introgressed fragments from a wild exotic parent, individual ILs did not display differences with respect to the recipient parent for most traits, although significant genotype × environment interaction (G × E ) was detected for most traits. Heritability values for the agronomic traits were generally low to moderate. A total of ten stable QTLs scattered across seven chromosomes was detected. For five QTLs, the S. incanum introgression was associated with higher mean values for plant- and flower-related traits, including vigour prickliness and stigma length. For one flower- and four fruit-related-trait QTLs, including flower peduncle and fruit pedicel lengths and fruit weight, the S. incanum introgression was associated with lower mean values for fruit-related traits. Evidence of synteny to other previously reported in eggplant populations was found for three of the fruit-related QTLs. The other seven stable QTLs are new, demonstrating that eggplant ILs are of great interest for eggplant breeding under different environments. Full article

(This article belongs to the Special Issue Genotype× Environment Interactions in Crop Breeding)

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13 pages, 2494 KiB

Open AccessEditor’s ChoiceArticle

Pre- and Postharvest Factors Control the Disease Incidence of Superficial Scald in the New Fire Blight Tolerant Apple Variety “Ladina”

by Laura Juliana Dällenbach, Thomas Eppler, Simone Bühlmann-Schütz, Markus Kellerhals and Andreas Bühlmann

Agronomy 2020, 10(4), 464; https://doi.org/10.3390/agronomy10040464 - 27 Mar 2020

Cited by 2 | Viewed by 3582

Abstract

Superficial scald is a physiological disorder that develops during cold storage affecting apples and causes substantial market losses. Malus × domestica cv. Ladina, a new scab resistant and fire blight tolerant variety, commercialized in 2012, shows a physiological disorder similar to superficial scald [...] Read more.

Superficial scald is a physiological disorder that develops during cold storage affecting apples and causes substantial market losses. Malus × domestica cv. Ladina, a new scab resistant and fire blight tolerant variety, commercialized in 2012, shows a physiological disorder similar to superficial scald after storage. Here, we used different pre- and postharvest approaches to characterize the occurrence of these superficial scald symptoms in Malus × domestica cv. Ladina. Over a period of seven years, fruits from multiple orchards were stored for five to seven months and the occurrence of superficial scald was assessed in fruits after cold storage and controlled atmosphere (CA) storage. Apples picked at different stages of ripeness within the same year differed in superficial scald development. Additionally, superficial scald differed significantly between years and locations, strongly suggesting that maturity at harvest, weather during the growing season, and orchard management play important roles in scald occurrence. Treatment with 1-methylcyclopropene (1-MCP) after harvest, and storage in a dynamically controlled atmosphere (DCA) significantly reduced the occurrence of superficial scald, whereas storage under ultralow oxygen concentrations (ULO) showed mild but not significant effects. Low calcium concentrations in the fruit flesh and peel were associated with stronger superficial scald occurrence. Full article

(This article belongs to the Special Issue Postharvest Storage Techniques and Quality Evaluation of Fruits and Vegetables)

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26 pages, 1453 KiB

Open AccessEditor’s ChoiceReview

Integrated Weed Management in Herbaceous Field Crops

by Aurelio Scavo and Giovanni Mauromicale

Agronomy 2020, 10(4), 466; https://doi.org/10.3390/agronomy10040466 - 27 Mar 2020

Cited by 101 | Viewed by 16005

Abstract

Current awareness about the environmental impact of intensive agriculture, mainly pesticides and herbicides, has driven the research community and the government institutions to program and develop new eco-friendly agronomic practices for pest control. In this scenario, integrated pest management and integrated weed management [...] Read more.

Current awareness about the environmental impact of intensive agriculture, mainly pesticides and herbicides, has driven the research community and the government institutions to program and develop new eco-friendly agronomic practices for pest control. In this scenario, integrated pest management and integrated weed management (IWM) have become mandatory. Weeds are commonly recognized as the most important biotic factor affecting crop production, especially in organic farming and low-input agriculture. In herbaceous field crops, comprising a wide diversity of plant species playing a significant economic importance, a compendium of the specific IWM systems is missing, that, on the contrary, have been developed for single species. The main goal of this review is to fill such gap by discussing the general principles and basic aspects of IWM to develop the most appropriate strategy for herbaceous field crops. In particular, a 4-step approach is proposed: (i) prevention, based on the management of the soil seedbank and the improvement of the crop competitiveness against weeds, (ii) weed mapping, aiming at knowing the biological and ecological characteristics of weeds present in the field, (iii) the decision-making process on the basis of the critical period of weed control and weed thresholds and iv) direct control (mechanical, physical, biological and chemical). Moreover, the last paragraph discusses and suggests possible integrations of allelopathic mechanisms in IWM systems. Full article

(This article belongs to the Special Issue Herbaceous Field Crops Cultivation)

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20 pages, 1498 KiB

Open AccessEditor’s ChoiceReview

Soil Macrofauna: A key Factor for Increasing Soil Fertility and Promoting Sustainable Soil Use in Fruit Orchard Agrosystems

by Adriano Sofo, Alba Nicoletta Mininni and Patrizia Ricciuti

Agronomy 2020, 10(4), 456; https://doi.org/10.3390/agronomy10040456 - 25 Mar 2020

Cited by 64 | Viewed by 13252

Abstract

Soils and crops in orchard agrosystems are particularly vulnerable to climate change and environmental stresses. In many orchard soils, soil biodiversity and the ecosystem services it provides are under threat from a range of natural and manmade drivers. In this scenario, sustainable soil [...] Read more.

Soils and crops in orchard agrosystems are particularly vulnerable to climate change and environmental stresses. In many orchard soils, soil biodiversity and the ecosystem services it provides are under threat from a range of natural and manmade drivers. In this scenario, sustainable soil use aimed at increasing soil organic matter (SOM) and SOM-related benefits, in terms of soil quality and fertility, plays a crucial role. The role of soil macrofaunal organisms as colonizers, comminutors and engineers within soils, together with their interactions with microorganisms, can contribute to the long-term sustainability of orchard soils. Indeed, the continuous physical and chemical action of soil fauna significantly affects SOM levels. This review paper is focused on the most advanced and updated research on this argument. The analysis of the literature highlighted that a significant part of soil quality and fertility in sustainably-managed fruit orchard agrosystems is due to the action of soil macrofauna, together with its interaction with decomposing microorganisms. From the general analysis of the data obtained, it emerged that the role of soil macrofauna in orchards agrosystems should be seriously taken into account in land management strategies, focusing not exclusively on fruit yield and quality, but also on soil fertility restoration. Full article

(This article belongs to the Special Issue Irrigation Strategies and Soil Management in Orchards)

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11 pages, 1132 KiB

Open AccessEditor’s ChoiceArticle

Effect of Natural Aging of Biochar on Soil Enzymatic Activity and Physicochemical Properties in Long-Term Field Experiment

by Barbara Futa, Patryk Oleszczuk, Sylwia Andruszczak, Ewa Kwiecińska-Poppe and Piotr Kraska

Agronomy 2020, 10(3), 449; https://doi.org/10.3390/agronomy10030449 - 24 Mar 2020

Cited by 34 | Viewed by 4593

Abstract

The effect of different rates of biochar on selected soil properties and enzymatic activity 48, 60, and 72 months after biochar application to soil was investigated. Soil enzymatic activity (dehydrogenase—ADh; phosphatase—Aph; urease—AU), the organic carbon content (TOC), the total nitrogen content (N_t [...] Read more.

The effect of different rates of biochar on selected soil properties and enzymatic activity 48, 60, and 72 months after biochar application to soil was investigated. Soil enzymatic activity (dehydrogenase—ADh; phosphatase—Aph; urease—AU), the organic carbon content (TOC), the total nitrogen content (N_t), the mineral nitrogen content (NH₄⁺, NO₃⁻), and soil pH were determined. The study was conducted on Haplic Podzol originating from glaciofluvial fine-grained loamy sand. Biochar was applied to soil under winter rye (Secale cereale L.) at rates of 10 (BC₁₀), 20 (BC₂₀), and 30 t ha⁻¹ (BC₃₀). Plots with biochar-unamended soil were the control treatment (BC₀). The pH, TOC, and N_t content in the biochar-amended soil were higher compared to the control soil. A broader C:N ratio was found in the BC₀ soil compared to BC₁₀, BC₂₀, and BC₃₀. With increasing biochar rate, the content of the ammonium nitrogen form (NH₄⁺) decreased and was statistically lower than in the control soil (BC₀). The soil in the BC₂₀ and BC₃₀ treatments was characterized by the highest content of NO₃^-, whereas the lowest nitrate nitrogen content was found in the control soil (BC₀). Biochar application increased soil enzymatic activity. Dehydrogenase activity increased with increasing biochar rate. As far as phosphatase and urease activity is concerned, a similar relationship was not observed. In this case, the soil amended with biochar at a rate of 20 t ha⁻¹ (BC₂₀) was characterized by the highest phosphatase and urease activity. Full article

(This article belongs to the Special Issue Transfer of Waste to Resource in Agriculture)

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15 pages, 1696 KiB

Open AccessEditor’s ChoiceArticle

New Eco-Friendly Polymeric-Coated Urea Fertilizers Enhanced Crop Yield in Wheat

by Ricardo Gil-Ortiz, Miguel Ángel Naranjo, Antonio Ruiz-Navarro, Marcos Caballero-Molada, Sergio Atares, Carlos García and Oscar Vicente

Agronomy 2020, 10(3), 438; https://doi.org/10.3390/agronomy10030438 - 23 Mar 2020

Cited by 45 | Viewed by 6323

Abstract

Presently, there is a growing interest in developing new controlled-release fertilizers based on ecological raw materials. The present study aims to compare the efficacy of two new ureic-based controlled-release fertilizers formulated with water-soluble polymeric coatings enriched with humic acids or seaweed extracts. To [...] Read more.

Presently, there is a growing interest in developing new controlled-release fertilizers based on ecological raw materials. The present study aims to compare the efficacy of two new ureic-based controlled-release fertilizers formulated with water-soluble polymeric coatings enriched with humic acids or seaweed extracts. To this end, an experimental approach was designed under controlled greenhouse conditions by carrying out its subsequent field scaling. Different physiological parameters and crop yield were measured by comparing the new fertilizers with another non polymeric-coated fertilizer, ammonium nitrate, and an untreated ‘Control’. As a result, on the microscale the fertilizer enriched with humic acids favored a better global response in the photosynthetic parameters and nutritional status of wheat plants. A significant 1.2-fold increase in grain weight yield and grain number was obtained with the humic acid polymeric fertilizer versus that enriched with seaweed extracts; and also, in average, higher in respect to the uncoated one. At the field level, similar results were confirmed by lowering N doses by 20% when applying the humic acid polymeric-coated produce compared to ammonium nitrate. Our results showed that the new humic acid polymeric fertilizer facilitated crop management and reduced the environmental impact generated by N losses, which are usually produced by traditional fertilizers. Full article

(This article belongs to the Special Issue Physiological and Molecular Characterization of Crop Resistance to Abiotic Stresses)

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5 pages, 194 KiB

Open AccessEditor’s ChoiceEditorial

Molecular Genetics, Genomics, and Biotechnology in Crop Plant Breeding

by Søren K. Rasmussen

Agronomy 2020, 10(3), 439; https://doi.org/10.3390/agronomy10030439 - 23 Mar 2020

Cited by 10 | Viewed by 5326

Abstract

A diverse set of molecular markers techniques have been developed over the last almost 40 years and used with success for breeding a number of major crops. These have been narrowed down to a few preferred DNA based marker types, and emphasis is [...] Read more.

A diverse set of molecular markers techniques have been developed over the last almost 40 years and used with success for breeding a number of major crops. These have been narrowed down to a few preferred DNA based marker types, and emphasis is now on adapting the technologies to a wide range of crop plants and trees. In this Special Issue, the strength of molecular breeding is revealed through research and review papers that use a combination of molecular markers with other classic breeding techniques to obtain quality improvement of the crop. The constant improvement and maintenance of quality by breeding is crucial and challenged by a changing climate and molecular markers can support the direct introgression of traits into elite breeding lines. All the papers in this Special Issue “Molecular genetics, Genomics, and Biotechnology in Crop Plant Breeding” have attracted significant attention, as can be witnessed by the graphs for each paper on the Journal’s homepage. It is the hope that it will encourage others to use these tools in developing an even wider range of crop plants and trees. Full article

(This article belongs to the Special Issue Molecular Genetics, Genomics and Biotechnology of Crop Plants Breeding)

27 pages, 351 KiB

Open AccessEditor’s ChoiceReview

Durum Wheat Breeding in the Mediterranean Region: Current Status and Future Prospects

by Ioannis N. Xynias, Ioannis Mylonas, Evangelos G. Korpetis, Elissavet Ninou, Aphrodite Tsaballa, Ilias D. Avdikos and Athanasios G. Mavromatis

Agronomy 2020, 10(3), 432; https://doi.org/10.3390/agronomy10030432 - 21 Mar 2020

Cited by 95 | Viewed by 9106

Abstract

This brief historical review focuses on durum wheat domestication and breeding in the Mediterranean region. Important milestones in durum wheat breeding programs across the countries of the Mediterranean basin before and after the Green Revolution are discussed. Additionally, the main achievements of the [...] Read more.

This brief historical review focuses on durum wheat domestication and breeding in the Mediterranean region. Important milestones in durum wheat breeding programs across the countries of the Mediterranean basin before and after the Green Revolution are discussed. Additionally, the main achievements of the classical breeding methodology are presented using a comparison of old and new cultivars. Furthermore, current breeding goals and challenges are analyzed. An overview of classical breeding methods in combination with current molecular techniques and tools for cultivar development is presented. Important issues of seed quality are outlined, focusing on protein and characteristics that affect human health and are connected with the consumption of wheat end-products. Full article

(This article belongs to the Special Issue Durum Wheat Breeding and Genetics)

17 pages, 740 KiB

Open AccessEditor’s ChoiceArticle

Appraisal of Biodegradable Mulching Films and Vegetal-Derived Biostimulant Application as Eco-Sustainable Practices for Enhancing Lettuce Crop Performance and Nutritive Value

by Eugenio Cozzolino, Maria Giordano, Nunzio Fiorentino, Christophe El-Nakhel, Antonio Pannico, Ida Di Mola, Mauro Mori, Marios C. Kyriacou, Giuseppe Colla and Youssef Rouphael

Agronomy 2020, 10(3), 427; https://doi.org/10.3390/agronomy10030427 - 20 Mar 2020

Cited by 31 | Viewed by 4604

Abstract

Scientists, extensions specialists, and growers are seeking sustainable agricultural practices that are able to cope with these objectives in order to ensure global food security and minimize environmental damage. The use of mulching films and plant biostimulants in agriculture seems to be a [...] Read more.

Scientists, extensions specialists, and growers are seeking sustainable agricultural practices that are able to cope with these objectives in order to ensure global food security and minimize environmental damage. The use of mulching films and plant biostimulants in agriculture seems to be a valid solution for tackling these rising concerns. A greenhouse experiment was conducted in order to elucidate the morpho-physiological and nutritive characteristics of lettuce (Lactuca sativa L.) in response to foliar application of a tropical plant extract (PE) biostimulant and the use of plastic mulches. Two biodegradable mulch treatments (Mater-Bi^® 1 and Mater-Bi^® 2) were compared to black polyethylene (LDPE) and bare soil. Biodegradable mulch film Mater-Bi^® 1 produced a comparable marketable fresh yield to the commercial standard polyethylene (LDPE), whereas Mater-Bi^® 2 exhibited the highest crop productivity. When averaged over biostimulant application, lettuce plants grown with biodegradable film Mater-Bi^® 2 exhibited superior quality traits in terms of K, Ca, total ascorbic acid, and carotenoids content. The combination of film mulching (LDPE, Mater-Bi^® 1 or Mater-Bi^® 2) with the tropical plant extract biostimulant exhibited a positive and significant synergistic effect (+30%) on yield. The PE-biostimulant induced higher values of SPAD index and total chlorophyll content when compared to untreated greenhouse lettuce. The mineral content of leaf tissues was greater by 10% and 17% (for P and Ca, respectively) when compared to the untreated lettuce (no PE application). Nitrate content was significantly reduced by 23% in greenhouse lettuce plants receiving PE as compared to the untreated control. The positive effect of Mater-Bi^® 2 film on the ascorbic acid content has also been highlighted when combined with the biostimulant application, where a major amplification of total ascorbic acid (+168%) was recorded in comparison to the untreated lettuce. Overall, our work can assist leafy vegetables growers in adopting good agricultural practices, such as biodegradable plastic mulches and vegetal-derived biostimulants, to improve the sustainability of greenhouse production. Full article

(This article belongs to the Special Issue Toward a Sustainable Agriculture Through Plant Biostimulants: From Experimental Data to Practical Applications)

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18 pages, 1661 KiB

Open AccessEditor’s ChoiceArticle

Effect of Pterocladia capillacea Seaweed Extracts on Growth Parameters and Biochemical Constituents of Jew’s Mallow

by Mohamed Ashour, Ahmed A. El-Shafei, Hanan M. Khairy, Doaa Y. Abd-Elkader, Mohamed A. Mattar, Abed Alataway and Shimaa M. Hassan

Agronomy 2020, 10(3), 420; https://doi.org/10.3390/agronomy10030420 - 19 Mar 2020

Cited by 31 | Viewed by 4182

Abstract

We performed field experiments to evaluate the influence of two extraction treatments, seaweed (Pterocladia capillacea S.G. Gmelin) water extraction (WE) and ultrasound-assisted water extraction (USWE) at three concentrations (5%, 10%, and 15%), as well as control NPK traditional mineral fertilizer on the [...] Read more.

We performed field experiments to evaluate the influence of two extraction treatments, seaweed (Pterocladia capillacea S.G. Gmelin) water extraction (WE) and ultrasound-assisted water extraction (USWE) at three concentrations (5%, 10%, and 15%), as well as control NPK traditional mineral fertilizer on the growth, yield, minerals, and antioxidants of Jew’s Mallow (Corchorus olitorius L.) during the two seasons of 2016 and 2017 in Egypt. Plant height, number of leaves, and fresh weight of WE10 treatment were the highest (p < 0.05) as 59.67 cm, 10.67 and 2.41 kg m⁻² in 2016, respectively, and 57.33 cm, 11.00 and 2.32 kg m⁻² in 2017, respectively. WE10 and USWE5 treatments produced the highest dry matter (17.07%) in 2016 and (16.97%) in 2017, respectively. WE10 plants had an increased water productivity of 41.2% relative to control plants in both seasons. The highest chlorophyll ‘a’ was recorded after the WE10 treatment in 2016 and 2017 (17.79 μg g⁻¹ and 17.84 μg g⁻¹, respectively). The highest levels of total antioxidant capacity, total phenolics, and total flavonoids were also recorded after the WE10 treatment. Application of WE10 boosted growth, yield, minerals, and antioxidants of Jew’s Mallow. The CROPWAT model was used to estimate the evapotranspiration, irrigation water requirements, and yield response to irrigation scheduling. Our data showed a yield reduction in the initial growth stage if a limited amount of water was provided. Therefore, irrigation water should be provided during the most important stages of crop development with the choice of effective irrigation practices to avoid water losses, as this helps to maximize yield. Full article

(This article belongs to the Special Issue Toward a Sustainable Agriculture Through Plant Biostimulants: From Experimental Data to Practical Applications)

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32 pages, 817 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Chilling and Heat Requirements of Temperate Stone Fruit Trees (Prunus sp.)

by Erica Fadón, Sara Herrera, Brenda I. Guerrero, M. Engracia Guerra and Javier Rodrigo

Agronomy 2020, 10(3), 409; https://doi.org/10.3390/agronomy10030409 - 18 Mar 2020

Cited by 84 | Viewed by 8800

Abstract

Stone fruit trees of genus Prunus, like other temperate woody species, need to accumulate a cultivar-specific amount of chilling during endodormancy, and of heat during ecodormancy to flower properly in spring. Knowing the requirements of a cultivar can be critical in determining [...] Read more.

Stone fruit trees of genus Prunus, like other temperate woody species, need to accumulate a cultivar-specific amount of chilling during endodormancy, and of heat during ecodormancy to flower properly in spring. Knowing the requirements of a cultivar can be critical in determining if it can be adapted to a particular area. Growers can use this information to anticipate the future performance of their orchards and the adaptation of new cultivars to their region. In this work, the available information on chilling- and heat-requirements of almond, apricot, plum, peach, and sweet cherry cultivars is reviewed. We pay special attention to the method used for the determination of breaking dormancy, the method used to quantify chilling and heat temperatures, and the place where experiments were conducted. The results reveal different gaps in the information available, both in the lack of information of cultivars with unknown requirements and in the methodologies used. The main emerging challenges are the standardization of the conditions of each methodology and the search for biological markers for dormancy. These will help to deal with the growing number of new cultivars and the reduction of winter cold in many areas due to global warming. Full article

(This article belongs to the Special Issue Fruit and Nut Tree Phenology in a Warming World)

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26 pages, 4943 KiB

Open AccessEditor’s ChoiceArticle

Pear Flower Cluster Quantification Using RGB Drone Imagery

by Yasmin Vanbrabant, Stephanie Delalieux, Laurent Tits, Klaas Pauly, Joke Vandermaesen and Ben Somers

Agronomy 2020, 10(3), 407; https://doi.org/10.3390/agronomy10030407 - 17 Mar 2020

Cited by 24 | Viewed by 5995

Abstract

High quality fruit production requires the regulation of the crop load on fruit trees by reducing the number of flowers and fruitlets early in the growing season, if the bearing is too high. Several automated flower cluster quantification methods based on proximal and [...] Read more.

High quality fruit production requires the regulation of the crop load on fruit trees by reducing the number of flowers and fruitlets early in the growing season, if the bearing is too high. Several automated flower cluster quantification methods based on proximal and remote imagery methods have been proposed to estimate flower cluster numbers, but their overall performance is still far from satisfactory. For other methods, the performance of the method to estimate flower clusters within a tree is unknown since they were only tested on images from one perspective. One of the main reported bottlenecks is the presence of occluded flowers due to limitations of the top-view perspective of the platform-sensor combinations. In order to tackle this problem, the multi-view perspective from the Red–Green–Blue (RGB) colored dense point clouds retrieved from drone imagery are compared and evaluated against the field-based flower cluster number per tree. Experimental results obtained on a dataset of two pear tree orchards (N = 144) demonstrate that our 3D object-based method, a combination of pixel-based classification with the stochastic gradient boosting algorithm and density-based clustering (DBSCAN), significantly outperforms the state-of-the-art in flower cluster estimations from the 2D top-view (R² = 0.53), with R² > 0.7 and RRMSE < 15%. Full article

(This article belongs to the Special Issue Application of Remote Sensing in Orchard Management)

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14 pages, 1815 KiB

Open AccessEditor’s ChoiceArticle

Sesquiterpenes-Rich Essential Oil from Above Ground Parts of Pulicaria somalensis Exhibited Antioxidant Activity and Allelopathic Effect on Weeds

by Abdulaziz Assaeed, Abdelsamed Elshamy, Abd El-Nasser El Gendy, Basharat Dar, Saud Al-Rowaily and Ahmed Abd-ElGawad

Agronomy 2020, 10(3), 399; https://doi.org/10.3390/agronomy10030399 - 14 Mar 2020

Cited by 42 | Viewed by 3449

Abstract

Pulicaria genus (fleabane) is characterized by its fragrant odor due to the presence of essential oil (EO). According to the literature reviews, the EO of Pulicaria somalensis O.Hoffm. (Shie) is still unexplored. For the first time, 71 compounds were characterized in EO derived [...] Read more.

Pulicaria genus (fleabane) is characterized by its fragrant odor due to the presence of essential oil (EO). According to the literature reviews, the EO of Pulicaria somalensis O.Hoffm. (Shie) is still unexplored. For the first time, 71 compounds were characterized in EO derived from above-ground parts of P. somalensis collected from Saudi Arabia. Sesquiterpenes represented the main components (91.8%), along with minor amounts of mono-, diterpenes, and hydrocarbons. Juniper camphor (24.7%), α-sinensal (7.7%), 6-epi-shyobunol (6.6%), α-zingiberene (5.8%), α-bisabolol (5.3%), and T-muurolol (4.7%) were characterized as main constituents. The correlation analysis between different Pulicaria species showed that P. somalensis has a specific chemical pattern of the EO, thereby no correlation was observed with other reported Pulicaria species. The EO showed significant allelopathic activity against the weeds of Dactyloctenium aegyptium (L.) Willd. (crowfoot grass) and Bidens pilosa L. (hairy beggarticks). The IC₅₀ value on the germination of D. aegyptium was double that of B. pilosa. The IC₅₀ values on the root growth of B. pilosa and D. aegyptium were 0.6 mg mL⁻¹ each, while the shoot growths were 1.0 and 0.7 mg mL⁻¹, respectively. This variation in the activity could be attributed to the genetic characteristics of the weeds. Moreover, the EO exhibited significant antioxidant effects compared to ascorbic acid. Further studies are necessary to verify if these biological activities of the EO could be attributable to its major compounds. Full article

(This article belongs to the Section Weed Science and Weed Management)

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16 pages, 1886 KiB

Open AccessEditor’s ChoiceArticle

Effect of Digestate on Soil Organic Carbon and Plant-Available Nutrient Content Compared to Cattle Slurry and Mineral Fertilization

by Przemysław Barłóg, Lukáš Hlisnikovský and Eva Kunzová

Agronomy 2020, 10(3), 379; https://doi.org/10.3390/agronomy10030379 - 10 Mar 2020

Cited by 64 | Viewed by 7256

Abstract

Digestate contains many valuable nutrients, including nitrogen (N), phosphorus (P), and potassium (K); however, it is characterized by relatively little organic matter. The objective of this study was to assess the four-year impact of digestate (Dig) application, digestate + straw (Dig + St), [...] Read more.

Digestate contains many valuable nutrients, including nitrogen (N), phosphorus (P), and potassium (K); however, it is characterized by relatively little organic matter. The objective of this study was to assess the four-year impact of digestate (Dig) application, digestate + straw (Dig + St), cattle slurry (Csl), and mineral fertilization (NPK) on soil organic carbon (SOC), total nitrogen (TN), mineral N (N_min), and the content of plant-available P and K. Fertilization did not have any significant influence on SOC, TN, and SOC/TN parameters. Yet, in comparison with control, there was an upward trend in the concentration of SOC and TN in the topsoil, where fertilizers were applied. In contrast to SOC and TN, fertilizer treatment significantly affected the content of P, K, and N_min, and the differences depended on the soil depth and the fertilizer used. On average, the highest content of P was obtained in Csl treatment, but the highest content of K was observed in Dig + St. The effect of treatment on N_min in spring was as follows: NPK = control < Csl = Dig + St < Dig. Straw plowing increased the bio-immobilization of N with digestate and, at the same time, lowered the content level of nitrates in soil. Full article

(This article belongs to the Special Issue Soil Carbon Sequestration for Food Security, Climate Change Adaptation and Mitigation)

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13 pages, 1029 KiB

Open AccessEditor’s ChoiceArticle

Screening of Nematicides against the Lotus Root Nematode, Hirschmanniella diversa Sher (Tylenchida: Pratylenchidae) and the Efficacy of a Selected Nematicide under Lotus Micro-Field Conditions

by Motonori Takagi, Maki Goto, David Wari, Mina Saito, Roland N. Perry and Koki Toyota

Agronomy 2020, 10(3), 373; https://doi.org/10.3390/agronomy10030373 - 8 Mar 2020

Cited by 8 | Viewed by 4038

Abstract

In Japan, Hirschmanniella diversa is an important pest in lotus cultivation in paddy fields and only lime nitrogen is registered for its control. Therefore, additional nematicides are required to control the nematode. The objective of this study was to screen for an effective [...] Read more.

In Japan, Hirschmanniella diversa is an important pest in lotus cultivation in paddy fields and only lime nitrogen is registered for its control. Therefore, additional nematicides are required to control the nematode. The objective of this study was to screen for an effective nematicide. Fourth-stage juveniles and adults of H. diversa sampled from a lotus field were tested in in vitro solution experiments against 37 pesticides that are registered for the pest control of crops in Japan. Carbamate-based benfuracarb, organophosphate-based fenthion, nereistoxin-based cartap hydrochloride and cyanamide showed nematicidal effects against H. diversa. Benfuracarb at 1 μg/mL showed a nematostatic effect on H. diversa in an agar plate assay. Further, H. diversa treated with benfuracarb did not resume activity 7 days post nematicide treatment when transferred to distilled water. Benfuracarb was tested in micro-field experiments, in which H. diversa density and lotus tuber damage levels were monitored. Results showed that benfuracarb reduced H. diversa densities in the roots during the cultivation period in 2012 and consistently reduced damage levels during a five year study period. Thus, benfuracarb is recommended as an effective nematicide to be used for H. diversa control in lotus cultivation. Full article

(This article belongs to the Special Issue Effects of Nematodes on Crops)

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17 pages, 2829 KiB

Open AccessEditor’s ChoiceArticle

Impact of Growth Stage and Biomass Fractions on Cannabinoid Content and Yield of Different Hemp (Cannabis sativa L.) Genotypes

by Lisa Burgel, Jens Hartung, Annegret Pflugfelder and Simone Graeff-Hönninger

Agronomy 2020, 10(3), 372; https://doi.org/10.3390/agronomy10030372 - 8 Mar 2020

Cited by 23 | Viewed by 6546

Abstract

The medicinal use of cannabinoids renewed the interest in industrial hemp (Cannabis sativa L.). The aim of this study was to evaluate the impact of growth stage and biomass fractions of seven industrial hemp genotypes. The study focused on biomass yield, content [...] Read more.

The medicinal use of cannabinoids renewed the interest in industrial hemp (Cannabis sativa L.). The aim of this study was to evaluate the impact of growth stage and biomass fractions of seven industrial hemp genotypes. The study focused on biomass yield, content of cannabidiolic acid/cannabidiol (CBDA/CBD), cannabigerolic acid/cannabigerol (CBGA/CBG), and tetrahydrocannabinolic acid (THCA). The experiment was conducted in 2017 and 2018. The biomass samples were taken at the vegetative (S1), bud (S2), full-flowering (S3) and seed maturity stage (S4). Plants were fractionated into inflorescence, upper and lower leaves. The average inflorescence dry yield of genotypes Futura75, Fédora17, Félina32 and Ferimon ranged between 257.28 g m⁻² to 442.00 g m⁻², resulting in a maximum yield of CBDA at S4, with 4568.26 mg m⁻², 6011.20 mg m⁻², 4975.60 mg m⁻² and 1929.60 mg m⁻², respectively. CBGA was exclusively found in genotype Santhica27, with a maximum CBGA yield of 5721.77 mg m⁻² in inflorescence at growth stage S4 and a dry weight yield of 408.99 g m⁻². Although these industrial hemp genotypes are mainly cultivated for fibre and seed production, however, cannabinoids offer an additional value. For an optimized harvest result, yield of extractable material and overall yield of cannabinoids must be considered. Full article

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14 pages, 1427 KiB

Open AccessEditor’s ChoiceArticle

The Use of a Plant-Based Biostimulant Improves Plant Performances and Fruit Quality in Tomato Plants Grown at Elevated Temperatures

by Silvana Francesca, Carmen Arena, Bruno Hay Mele, Carlo Schettini, Patrizia Ambrosino, Amalia Barone and Maria Manuela Rigano

Agronomy 2020, 10(3), 363; https://doi.org/10.3390/agronomy10030363 - 6 Mar 2020

Cited by 67 | Viewed by 7695

Abstract

Abiotic stresses can cause a substantial decline in fruit quality due to negative impacts on plant growth, physiology and reproduction. The objective of this study was to verify if the use of a biostimulant based on plant and yeast extracts, rich in amino [...] Read more.

Abiotic stresses can cause a substantial decline in fruit quality due to negative impacts on plant growth, physiology and reproduction. The objective of this study was to verify if the use of a biostimulant based on plant and yeast extracts, rich in amino acids and that contains microelements (boron, zinc and manganese) can ensure good crop yield and quality in tomato plants grown at elevated temperatures (up to 42 °C). We investigated physiological responses of four different tomato landraces that were cultivated under plastic tunnel and treated with the biostimulant CycoFlow. The application of the biostimulant stimulated growth (plants up to 48.5% taller) and number of fruits (up to 105.3%). In plants treated with the biostimulant, antioxidants contents were higher compared to non-treated plants, both in leaves and in fruits. In particular, the content of ascorbic acid increased after treatments with CycoFlow. For almost all the traits studied, the effect of the biostimulant depended on the genotype it was applied on. Altogether, the use of the biostimulant on tomato plants led to better plant performances at elevated temperatures, that could be attributed also to a stronger antioxidant defence system, and to a better fruit nutritional quality. Full article

(This article belongs to the Special Issue Toward a Sustainable Agriculture Through Plant Biostimulants: From Experimental Data to Practical Applications)

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20 pages, 1730 KiB

Open AccessEditor’s ChoiceReview

An Overview of the Oil Palm Industry: Challenges and Some Emerging Opportunities for Nanotechnology Development

by Farhatun Najat Maluin, Mohd Zobir Hussein and Abu Seman Idris

Agronomy 2020, 10(3), 356; https://doi.org/10.3390/agronomy10030356 - 4 Mar 2020

Cited by 54 | Viewed by 19587

Abstract

The increase in the world’s oil demand due to the rise of the global population urges more research into the production of sustainable vegetable oilseeds, among which palm oil is the most suitable candidate as it is the most efficient oilseed crop in [...] Read more.

The increase in the world’s oil demand due to the rise of the global population urges more research into the production of sustainable vegetable oilseeds, among which palm oil is the most suitable candidate as it is the most efficient oilseed crop in the world. In an effort to drive the oil palm industry in the areas of food safety and security nanotechnology could offer a sustainable alternative. However, the utilization of nanotechnology in the oil palm industry is still limited. In this review, we aim to encourage the researchers to fully utilize nanotechnology as an alternative solution to tackle the challenges faced by the oil palm industry. Moreover, we also aim to highlight the opportunities for nanotechnology development in oil palm-based related research. The major points are as follows: (1) Nanosensing enables real-time monitoring of plantation status and crop progression, including soil, water and nutrient management, early pest/disease detection, and the spreading of pests/diseases. The use of nanosensing conveniently extends into advanced breeding topics, such as the development of disease-tolerant plants; (2) Nanotechnology could be the answer for the development of integrated management of pest and disease. Active agricultural ingredients can be entrapped or encapsulated into nanocarrier systems to improve their solubility, stability, enhance their efficient delivery to site-specific targets, with longer shelf life, and consequently improved efficacy; (3) Valuable nanomaterials can be isolated and generated from oil palm biomass waste. The utilization of oil palm biomass waste could overcome the issue of the massive production of waste in the oil palm industry and palm oil mills, where oil only accounts for 10% of the biomass, while 90% is comprised of the generated biowastes. (4) Palm oil can be utilized as a green alternative as a capping and stabilizing agent in the biosynthesis of metallic and non-metallic nanoparticles. In addition, nanoemulsion formulations using palm oil in drug delivery systems offer advantages such as low toxicity, enhance bioavailability and solubility of the drugs, apart from being inexpensive and environmentally friendly. Full article

(This article belongs to the Special Issue Nanotechnology Applications in Agriculture System)

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13 pages, 3581 KiB

Open AccessEditor’s ChoiceArticle

Ozone Induced Loss of Seed Protein Accumulation Is Larger in Soybean than in Wheat and Rice

by Malin C. Broberg, Sara Daun and Håkan Pleijel

Agronomy 2020, 10(3), 357; https://doi.org/10.3390/agronomy10030357 - 4 Mar 2020

Cited by 12 | Viewed by 2715

Abstract

We investigated the effects of ozone (O₃) on seed protein accumulation in soybean, rice, and wheat based on existing literature. We identified 30, 10, and 32 datasets meeting the requirements for soybean, rice, and wheat, respectively. Data for each crop were [...] Read more.

We investigated the effects of ozone (O₃) on seed protein accumulation in soybean, rice, and wheat based on existing literature. We identified 30, 10, and 32 datasets meeting the requirements for soybean, rice, and wheat, respectively. Data for each crop were combined in response regressions for seed protein concentration, seed protein yield, and seed yield. Although seed yield in rice was less sensitive to O₃ than in wheat, there was a significant positive effect of O₃ on the seed protein concentration of the same magnitude in both crops. Soybean, an N-fixing high-protein crop, responded differently. Even though the effect on seed yield was similar to wheat, there was no indication of any effect of O₃ on seed protein concentration in soybean. The negative influence of O₃ on seed protein yield was statistically significant for soybean and wheat. The effect was larger for soybean (slope of response function: −0.58% per ppb O₃) than for wheat (slope: −0.44% per ppb) and especially compared to rice (slope: −0.08% per ppb). The different response of protein concentration in soybean, likely to be associated with adverse O₃ effects on N fixation, has large implications for global protein production because of the much higher absolute protein concentration in soybean. Full article

(This article belongs to the Special Issue Agronomy and Agroecology in a Polluted Atmosphere)

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18 pages, 1104 KiB

Open AccessEditor’s ChoiceArticle

Biochar, Vermicompost, and Compost as Soil Organic Amendments: Influence on Growth Parameters, Nitrate and Chlorophyll Content of Swiss Chard (Beta vulgaris L. var. cycla)

by Angela Libutti, Vincenzo Trotta and Anna Rita Rivelli

Agronomy 2020, 10(3), 346; https://doi.org/10.3390/agronomy10030346 - 3 Mar 2020

Cited by 35 | Viewed by 6825

Abstract

Soil addition with organic amendments is an issue that receives growing attention in the agricultural sector. However, the effects of such materials on plant growth and crop yield are highly variable in the literature. This study aims to evaluate the influence of soil [...] Read more.

Soil addition with organic amendments is an issue that receives growing attention in the agricultural sector. However, the effects of such materials on plant growth and crop yield are highly variable in the literature. This study aims to evaluate the influence of soil addition with biochar (from vine pruning residues), vermicompost (from cattle manure), and three different composts (from olive pomace or cattle anaerobic digestate), on the quali-quantitative response of Swiss chard (Beta vulgaris L. var. cycla) grown in pots. The organic amendments were applied to the soil in two doses to provide 140 and 280 kg N ha⁻¹, respectively. Two growth cycles were considered, and, at each leaf cut, plants were analyzed for growth parameters (height, fresh weight, leaf number, and leaf area) and qualitative characteristics (nitrogen, nitrate, and pigment leaf content). Swiss chard responded positively to organic amendment and, particularly when the soil was treated with compost from animal wastes, higher plant growth and pigment leaf content were observed. Nitrate leaf content was always well below the NO₃⁻ thresholds established by the European Commission Regulations. Biochar application did not show a positive effect on the quali-quantitative characteristics of Swiss chard, likely due to benefits that may be achieved over time. Full article

(This article belongs to the Special Issue Applications of Biochar and Other Organic Amendments within a Sustainable Agriculture and Circular Economy)

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14 pages, 1098 KiB

Open AccessEditor’s ChoiceArticle

Divergent Genomic Selection for Herbage Accumulation and Days-To-Heading in Perennial Ryegrass

by Marty J. Faville, Mingshu Cao, Jana Schmidt, Douglas L. Ryan, Siva Ganesh, M. Z. Zulfi Jahufer, Soon Won Hong, Richard George and Brent A. Barrett

Agronomy 2020, 10(3), 340; https://doi.org/10.3390/agronomy10030340 - 2 Mar 2020

Cited by 9 | Viewed by 2927

Abstract

Increasing the rate of genetic gain for dry matter (DM) yield in perennial ryegrass (Lolium perenne L.), which is a key source of nutrition for ruminants in temperate environments, is an important goal for breeders. Genomic selection (GS) is a strategy used [...] Read more.

Increasing the rate of genetic gain for dry matter (DM) yield in perennial ryegrass (Lolium perenne L.), which is a key source of nutrition for ruminants in temperate environments, is an important goal for breeders. Genomic selection (GS) is a strategy used to improve genetic gain by using molecular marker information to predict breeding values in selection candidates. An empirical assessment of GS for herbage accumulation (HA; proxy for DM yield) and days-to-heading (DTH) was completed by using existing genomic prediction models to conduct one cycle of divergent GS in four selection populations (Pop I G1 and G3; Pop III G1 and G3), for each trait. G1 populations were the offspring of the training set and G3 populations were two generations further on from that. The HA of the High GEBV selection group (SG) progenies, averaged across all four populations, was 28% higher (p < 0.05) than Low GEBV SGs when assessed in the target environment, while it did not differ significantly in a second environment. Divergence was greater in Pop I (43%–65%) than Pop III (10%–16%) and the selection response was higher in G1 than in G3. Divergent GS for DTH also produced significant (p < 0.05) differences between High and Low GEBV SGs in G1 populations (+6.3 to 9.1 days; 31%–61%) and smaller, non-significant (p > 0.05) responses in G3. This study shows that genomic prediction models, trained from a small, composite reference set, can be used to improve traits with contrasting genetic architectures in perennial ryegrass. The results highlight the importance of target environment selection for training models, as well as the influence of relatedness between the training set and selection populations. Full article

(This article belongs to the Special Issue Breeding Strategies for Improving Yield of Forage Crops and Energy Grasses)

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25 pages, 2784 KiB

Open AccessEditor’s ChoiceArticle

The Integration of Bio and Organic Fertilizers Improve Plant Growth, Grain Yield, Quality and Metabolism of Hybrid Maize (Zea mays L.)

by Canhong Gao, Ahmed M. El-Sawah, Dina Fathi Ismail Ali, Yousef Alhaj Hamoud, Hiba Shaghaleh and Mohamed S. Sheteiwy

Agronomy 2020, 10(3), 319; https://doi.org/10.3390/agronomy10030319 - 26 Feb 2020

Cited by 122 | Viewed by 18577

Abstract

Expanding eco-friendly approaches to improve plant growth and crop productivity is of great important for sustainable agriculture. Therefore, a field experiment was carried out at the Faculty of Agriculture Farm, Mansoura University, Egypt during the 2018 and 2019 growing seasons to study the [...] Read more.

Expanding eco-friendly approaches to improve plant growth and crop productivity is of great important for sustainable agriculture. Therefore, a field experiment was carried out at the Faculty of Agriculture Farm, Mansoura University, Egypt during the 2018 and 2019 growing seasons to study the effects of different bio- and organic fertilizers and their combination on hybrid maize growth, yield, and grain quality. Seeds were treated with Azotobacter chrocoocum, arbuscular mycorrhizal fungi (AMF), Bacillus circulans, biogas slurry, humic acid (HA), and their combination aiming to increase the growth and yield of maize and to reduce the need for chemical fertilizers. The results showed that combined application of the biofertilizer mixture (Azotobacter chrocoocum, AMF, and Bacillus circulans) with organic fertilizers enhanced maize growth, yield, and nutrient uptake. Moreover, the bio-organic fertilization has improved the soluble sugars, starch, carbohydrates, protein, and amino acid contents in maize seeds. Additionally, the bio-organic fertilization caused an obvious increase in the microbial activity by enhancing acid phosphatase and dehydrogenase enzymes, bacterial count, and mycorrhizal colonization levels in maize rhizosphere as compared with the chemical fertilization. Additionally, the bio-organic fertilizers has improved α-amylase and gibberellins (GA) activities and their transcript levels, as well as decreased the abscisic acid (ABA) level in the seeds as compared to the chemical fertilizers. The obtained results of bio-organic fertilization on the growth parameters and yield of maize recommend their use as an alternative tool to reduce chemical fertilizers. Full article

(This article belongs to the Section Soil and Plant Nutrition)

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14 pages, 1818 KiB

Open AccessEditor’s ChoiceArticle

Droplet Deposition and Control of Planthoppers of Different Nozzles in Two-Stage Rice with a Quadrotor Unmanned Aerial Vehicle

by Pengchao Chen, Yubin Lan, Xiaoyu Huang, Haixia Qi, Guobin Wang, Juan Wang, Linlin Wang and Hanxiang Xiao

Agronomy 2020, 10(2), 303; https://doi.org/10.3390/agronomy10020303 - 20 Feb 2020

Cited by 41 | Viewed by 6125

Abstract

Previous studies have confirmed that choosing nozzles that produce coarser droplets could reduce the risk of pesticide spray drift, but this conclusion is based on a large volume of application, and it is easy to ignore how this impacts the control effect. The [...] Read more.

Previous studies have confirmed that choosing nozzles that produce coarser droplets could reduce the risk of pesticide spray drift, but this conclusion is based on a large volume of application, and it is easy to ignore how this impacts the control effect. The difference from the conventional spray is that the carrier volume of Unmanned Aerial Vehicle (UAV) is very limited. Little was known about how to choose suitable nozzles with UAV’s limited volume to ensure appropriate pest control. Droplet deposition with the addition of adjuvant and the LU110-010, LU110-015, and LU110-020 nozzles and control of planthoppers within nozzles treatments were studied by a quadrotor UAV in rice (Tillering and Flowering stages). Allura Red (10 g/L) was used as a tracer and Kromekote cards were used to collect droplet deposits. The results indicate that the density of the droplets covered by the LU110-01 nozzle is well above other treatments, while the differences in droplet deposition and coverage are not significant. The deposition and coverage were improved with the addition of adjuvant, especially in LU110-01 nozzles’ treatment. The control effects of rice planthoppers treated by LU110-01 nozzle were 89.4% and 90.8% respectively, which were much higher than 67.6% and 58.5% of LU110-020 nozzle at 7 days in the Tillering and Flowering stage. The results suggest that selecting a nozzle with a small atomizing particle size for UAV could improve the control effect of planthoppers. Full article

(This article belongs to the Section Agricultural Biosystem and Biological Engineering)

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21 pages, 2630 KiB

Open AccessEditor’s ChoiceArticle

Effect of Drought Stress at Reproductive Stages on Growth and Nitrogen Metabolism in Soybean

by Yanli Du, Qiang Zhao, Liru Chen, Xingdong Yao and Futi Xie

Agronomy 2020, 10(2), 302; https://doi.org/10.3390/agronomy10020302 - 20 Feb 2020

Cited by 58 | Viewed by 7335

Abstract

This study aims to determine variability among soybean (Glycine max (L.) Merr.) cultivars under drought conditions and how nitrogen metabolites, metabolism-related enzymes, and gene expression vary during soybean growth. Three soybean cultivars, Shennong17 (CV.SN17), Shennong8 (CV.SN8), and Shennong12 (CV.SN12), were grown in [...] Read more.

This study aims to determine variability among soybean (Glycine max (L.) Merr.) cultivars under drought conditions and how nitrogen metabolites, metabolism-related enzymes, and gene expression vary during soybean growth. Three soybean cultivars, Shennong17 (CV.SN17), Shennong8 (CV.SN8), and Shennong12 (CV.SN12), were grown in pot culture and subjected to drought stress at reproductive stages for 45 days. The results showed that long-term drought stress decreased biomass allocation to reproductive organs, weakened antioxidant capacity, and reduced seed weight, effects that were less pronounced in CV.SN12 compared with those in CV.SN8 and CV.SN17. Drought stress decreased the concentrations of nitrogen and soluble protein but increased nitrate concentration in leaves. This was related to the significantly reduction of nitrogen metabolism efficiency, including decreased activities of nitrogen metabolism enzymes, and downregulated expression of GmNR, GmNiR, GmGS, and GmGOGAT. Drought stress increased the concentrations of free amino acid, proline, and soluble sugar in leaves to enhance the osmotic adjustment ability. Furthermore, soybean seed weight showed significantly correlation (p < 0.05) with nitrogen-metabolism-related parameters. Based on the performance of growth, nitrogen metabolism, and yield attributes, CV.SN12 showed the highest tolerance to drought, followed by CV.SN8 and CV.SN17. In addition, these nitrogen-metabolism-related parameters could be used in soybeans to select for drought tolerance. Full article

(This article belongs to the Special Issue Functional Metabolism in Crops/Agronomy)

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25 pages, 5686 KiB

Open AccessEditor’s ChoiceArticle

Genome-Wide Identification, Structure Characterization, and Expression Profiling of Dof Transcription Factor Gene Family in Wheat (Triticum aestivum L.)

by Zhengwu Fang, Wenqiang Jiang, Yiqin He, Dongfang Ma, Yike Liu, Shuping Wang, Yingxin Zhang and Junliang Yin

Agronomy 2020, 10(2), 294; https://doi.org/10.3390/agronomy10020294 - 19 Feb 2020

Cited by 35 | Viewed by 4369

Abstract

DNA binding with one finger (Dof) proteins are plant-specific transcription factors with crucial roles in plant growth and stress response. Even so, little is known about them in wheat. In this study, 108 wheat Dof (TaDof) genes across 21 chromosomes were detected. Although [...] Read more.

DNA binding with one finger (Dof) proteins are plant-specific transcription factors with crucial roles in plant growth and stress response. Even so, little is known about them in wheat. In this study, 108 wheat Dof (TaDof) genes across 21 chromosomes were detected. Although variable in sequence length, molecular weight, and isoelectric point, all TaDof proteins contained conserved zinc-finger structures and were phylogenetically divided into 7 sub-groups. Exon/intron and motif analyses suggested that TaDof structures and conserved motifs were similar within sub-groups but diverse among sub-groups. Many segmental duplications were identified and Ka/Ks and inter-species synthetic analyses indicated that polyploidization was main reason for increased number of TaDofs. Prediction and experimental confirmation revealed that TaDofs functioned as transcription factors in the nucleus. Expression pattern profiling showed that TaDofs specifically affected growth and development, and biotic and abiotic stress responses. Wheat miRNAs and cis-regulator were predicted as essential players in molding TaDofs expression patterns. qRT-PCR analysis revealed that TaDofs were induced by salt and drought stresses. Customized annotation revealed that TaDofs were widely involved in phytohormone response, defense, growth and development, and metabolism. Our study provided a comprehensive understanding to wheat TaDofs. Full article

(This article belongs to the Special Issue Bioinformatics Applied to Genetic Improvement of Crop Species)

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15 pages, 624 KiB

Open AccessEditor’s ChoiceArticle

Nitrogen Use and Uptake Efficiency and Crop Performance of Baby Spinach (Spinacia oleracea L.) and Lamb’s Lettuce (Valerianella locusta L.) Grown under Variable Sub-Optimal N Regimes Combined with Plant-Based Biostimulant Application

by Ida Di Mola, Eugenio Cozzolino, Lucia Ottaiano, Sabrina Nocerino, Youssef Rouphael, Giuseppe Colla, Christophe El-Nakhel and Mauro Mori

Agronomy 2020, 10(2), 278; https://doi.org/10.3390/agronomy10020278 - 15 Feb 2020

Cited by 56 | Viewed by 5133

Abstract

An optimized nitrogen (N) fertilization may have a positive effect on leafy vegetables by increasing growth, yield and nutrient content of plants. Nevertheless, crop performance must be coupled with an increase in Nitrogen Use Efficiency (NUE) in order to limit external N inputs [...] Read more.

An optimized nitrogen (N) fertilization may have a positive effect on leafy vegetables by increasing growth, yield and nutrient content of plants. Nevertheless, crop performance must be coupled with an increase in Nitrogen Use Efficiency (NUE) in order to limit external N inputs and to avoid N surpluses associated with environmental and health problems. The aim of the current study was to assess the effects of a legume-derived plant hydrolysates (LDPH; Trainer^®) and N fertilization levels (0, 2.25 and 4.5 g N m⁻² for spinach and 0, 2.5 and 5.0 g N m⁻² for lamb’s lettuce; N0%, N50%, N100%, respectively) on agronomical, biochemical, qualitative responses and NUE of these two important greenhouse leafy vegetables. Spinach and lamb’s lettuce were sprayed four times during the growing period (at a concentration of 4 mL L⁻¹ of LDPH). In baby spinach, the LDPH application elicited a significant increase at the three levels of N fertilization: +16.8%, +14.2%, and 39.4% at 0, 2.25 and 4.5 g N m⁻², respectively. Interestingly, in lamb’s lettuce, the N50% plants treated with LDPH reached similar values of marketable yield in comparison to treated and non-treated plants under N100% conditions. The presumed mechanism involved in the enhancement of yield response in the two leafy greens could be associated to a better activity of the photosystem II (higher SPAD index), biochemical (higher content of chlorophyll a, b and total) and leaf nitrate status. The foliar application of LDPH produced a major fortification in lipophilic and hydrophilic antioxidant activities (+11.6 and 6.3% for spinach and lamb’s lettuce, respectively). The biostimulant application also improved N-use efficiency and N-uptake efficiency compared to untreated plants: +17.8% and +18.8%, and +50% and +73.3%, for spinach and lamb’s lettuce, respectively. Full article

(This article belongs to the Special Issue Toward a Sustainable Agriculture Through Plant Biostimulants: From Experimental Data to Practical Applications)

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20 pages, 3606 KiB

Open AccessEditor’s ChoiceArticle

Phenotypic Characterization of 183 Turkish Common Bean Accessions for Agronomic, Trading, and Consumer-Preferred Plant Characteristics for Breeding Purposes

by Muhammad Azhar Nadeem, Tolga Karaköy, Mehmet Zahit Yeken, Ephrem Habyarimana, Ruştu Hatipoğlu, Vahdettin Çiftçi, Muhammad Amjad Nawaz, Ferit Sönmez, Muhammad Qasim Shahid, Seung Hwan Yang, Gyuhwa Chung and Faheem Shehzad Baloch

Agronomy 2020, 10(2), 272; https://doi.org/10.3390/agronomy10020272 - 14 Feb 2020

Cited by 39 | Viewed by 6298

Abstract

Plant landraces represent a repository of a gene pool, local adaptation of their domestic species, and thereby are considered a great source of genetic variations. Such genetic variation can be helpful to mitigate the current and future food challenges. A total of 183 [...] Read more.

Plant landraces represent a repository of a gene pool, local adaptation of their domestic species, and thereby are considered a great source of genetic variations. Such genetic variation can be helpful to mitigate the current and future food challenges. A total of 183 common bean accessions including three commercial varieties collected from 19 Turkish provinces were grown to record their morpho-agronomic variations and to evaluate the best performing accessions under multi-environmental conditions. Plant height, days to maturity, pods weight, seed length, and 100-seed weight were used to evaluate the best performing accessions under different environmental conditions. A wide range of variations for traits like days to maturity (99–161), plant height (21–168.7 cm), seed length (7.41–16.4 mm), seeds per plant (17.8–254.4), and 100-seeds weight (24.97–73.8 g) were observed and can be useful for breeding purposes. The analytic results derived from the first three eigenvectors suggested that plant height, plant weight, 100-seed weight, and days to flowering were biologically significant bean traits. Seed yield per plant was positively and significantly correlated with plant weight and pods weight. Genotype × environment biplot discriminated the studied common bean accessions based on their plant height and growth habit. Plant height, days to maturity, seed width, and first pod height were found highly heritable traits and were least affected by environmental forces. Among 19 provinces, accessions of Bilecik showed maximum pods per plant, seed yield per plant and 100-seed weight, while Erzincan and Sivas provinces reflected the prevalence of bushy and early maturing accessions. Information provided herein comprehensively explored the occurrence of genotypic variations which can be used for the development of candidate varieties responding to breeder, farmer, and consumer preferences. Full article

(This article belongs to the Section Crop Breeding and Genetics)

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22 pages, 762 KiB

Open AccessEditor’s ChoiceReview

Grafting Tomato as a Tool to Improve Salt Tolerance

by Hira Singh, Pradeep Kumar, Ashwani Kumar, Marios C. Kyriacou, Giuseppe Colla and Youssef Rouphael

Agronomy 2020, 10(2), 263; https://doi.org/10.3390/agronomy10020263 - 12 Feb 2020

Cited by 62 | Viewed by 9300

Abstract

Salinity in soil or water is a serious threat to global agriculture; the expected acreage affected by salinity is about 20% of the global irrigated lands. Improving salt tolerance of plants through breeding is a complex undertaking due to the number of traits [...] Read more.

Salinity in soil or water is a serious threat to global agriculture; the expected acreage affected by salinity is about 20% of the global irrigated lands. Improving salt tolerance of plants through breeding is a complex undertaking due to the number of traits involved. Grafting, a surgical mean of joining a scion and rootstock of two different genotypes with the desired traits, offers an alternative to breeding and biotechnological approaches to salt tolerance. Grafting can also be used to circumvent other biotic and abiotic stresses. Increasing salinity tolerance in tomato (Solanum lycopresicum L.), a highly nutritious and economical vegetable, will have greater impact on the vegetable industry, especially in (semi) arid regions where salinity in soil and water are more prevalent. Besides, plants also experience salt stress when water in hydroponic system is recycled for tomato production. Grafting high yielding but salt-susceptible tomato cultivars onto salt-resistant/tolerant rootstocks is a sustainable strategy to overcome saline stress. Selection of salt-tolerant rootstocks though screening of available commercial and wild relatives of tomato under salt stress conditions is a pre-requisite for grafting. The positive response of grafting exerted by tolerant rootstocks or scion-rootstock interactions on yield and fruit characteristics of tomato under saline conditions is attributed to several physiological and biochemical changes. In this review, the importance of tomato grafting, strategies to select appropriate rootstocks, scion-rootstock interaction for growth, yield and quality characteristics, as well as the tolerance mechanisms that (grafted) plants deploy to circumvent or minimize the effects of salt stress in root zones are discussed. The future challenges of grafting tomato are also highlighted. Full article

(This article belongs to the Special Issue Grafting as a Sustainable Means for Securing Yield Stability and Quality in Vegetable Crops)

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18 pages, 2495 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Absence of Yield Reduction after Controlled Water Stress during Prehaverst Period in Table OliveTrees

by María José Martín-Palomo, Mireia Corell, Ignacio Girón, Luis Andreu, Alejandro Galindo, Ana Centeno, David Pérez-López and Alfonso Moriana

Agronomy 2020, 10(2), 258; https://doi.org/10.3390/agronomy10020258 - 11 Feb 2020

Cited by 10 | Viewed by 3252

Abstract

Deficit irrigation scheduling is becoming increasingly important under commercial conditions. Water status measurement is a useful tool in these conditions. However, the information about water stress levels for olive trees is scarce. The aim of this experiment was to evaluate the effect on [...] Read more.

Deficit irrigation scheduling is becoming increasingly important under commercial conditions. Water status measurement is a useful tool in these conditions. However, the information about water stress levels for olive trees is scarce. The aim of this experiment was to evaluate the effect on yield of a moderate controlled water stress level at the end of the irrigation season. The experiment was conducted in the experimental farm of La Hampa (Coria del Río, Seville, Spain) during three years. A completely randomized block design was performed using three different irrigation treatments. Deficit irrigation was applied several (4 or 2) weeks before harvest. Irrigation was controlled using the midday stem water potential, with a threshold value of −2 MPa and compared with a full irrigated treatment. This water stress did not reduced gas exchange during the deficit period. The effect on yield was not significant in any of the three seasons. In the high-fruit load season, fruit volume was slightly affected (around 10%), but this was not significant at harvest. Results suggest an early affection of fruit growth with water stress, but with a slow rate of decrease. Moderate water stress could be useful for the management of deficit irrigation in table olive trees. Full article

(This article belongs to the Special Issue Optimizing Plant Water Use Efficiency for a Sustainable Environment)

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16 pages, 1565 KiB

Open AccessEditor’s ChoiceReview

Non-Chemical Weed Management in Vegetables by Using Cover Crops: A Review

by Husrev Mennan, Khawar Jabran, Bernard H. Zandstra and Firat Pala

Agronomy 2020, 10(2), 257; https://doi.org/10.3390/agronomy10020257 - 11 Feb 2020

Cited by 62 | Viewed by 10725

Abstract

Vegetables are a substantial part of our lives and possess great commercial and nutritional value. Weeds not only decrease vegetable yield but also reduce their quality. Non-chemical weed control is important both for the organic production of vegetables and achieving ecologically sustainable weed [...] Read more.

Vegetables are a substantial part of our lives and possess great commercial and nutritional value. Weeds not only decrease vegetable yield but also reduce their quality. Non-chemical weed control is important both for the organic production of vegetables and achieving ecologically sustainable weed management. Estimates have shown that the yield of vegetables may be decreased by 45%–95% in the case of weed–vegetable competition. Non-chemical weed control in vegetables is desired for several reasons. For example, there are greater chances of contamination of vegetables by herbicide residue compared to cereals or pulse crops. Non-chemical weed control in vegetables is also needed due to environmental pollution, the evolution of herbicide resistance in weeds and a strong desire for organic vegetable cultivation. Although there are several ways to control weeds without the use of herbicides, cover crops are an attractive choice because these have a number of additional benefits (such as soil and water conservation) along with the provision of satisfactory and sustainable weed control. Several cover crops are available that may provide excellent weed control in vegetable production systems. Cover crops such as rye, vetch, or Brassicaceae plants can suppress weeds in rotations, including vegetables crops such as tomato, cabbage, or pumpkin. Growers should also consider the negative effects of using cover crops for weed control, such as the negative allelopathic effects of some cover crop residues on the main vegetable crop. Full article

(This article belongs to the Special Issue Ecologically Sustainable Weed Management in Cropping Systems)

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17 pages, 4674 KiB

Open AccessEditor’s ChoiceArticle

RNA-Binding Proteins as Targets to Improve Salt Stress Tolerance in Crops

by Sara Rosa Téllez, Rodoldphe Kanhonou, Carlos Castellote Bellés, Ramón Serrano, Paula Alepuz and Roc Ros

Agronomy 2020, 10(2), 250; https://doi.org/10.3390/agronomy10020250 - 8 Feb 2020

Cited by 9 | Viewed by 3431

Abstract

Salt stress drastically reduce crop productivity. In order to identify genes that could improve crop salt tolerance, we randomly expressed a cDNA library of the halotolerant sugar beet in a sodium-sensitive yeast strain. We identified six sugar beet genes coding for RNA binding [...] Read more.

Salt stress drastically reduce crop productivity. In order to identify genes that could improve crop salt tolerance, we randomly expressed a cDNA library of the halotolerant sugar beet in a sodium-sensitive yeast strain. We identified six sugar beet genes coding for RNA binding proteins (RBP) able to increase the yeast Na⁺-tolerance. Two of these genes, named Beta vulgaris Salt Tolerant 3 (BvSATO3) and BvU2AF35b, participate in RNA splicing. The other four BvSATO genes (BvSATO1, BvSATO2, BvSATO4 and BvSATO6) are putatively involved in other processes of RNA metabolism. BvU2AF35b improved the growth of a wild type yeast strain under salt stress, and also in mutant backgrounds with impaired splicing, thus confirming that splicing is a target of salt toxicity. To validate the yeast approach, we characterized BvSATO1 in sugar beet and Arabidopsis. BvSATO1 expression was repressed by salt treatment in sugar beet, suggesting that this gene could be a target of salt toxicity. Expression of BvSATO1 in Arabidopsis increased the plant salt tolerance. Our results suggest that not only RNA splicing, but RNA metabolic processes such as such as RNA stability or nonsense-mediated mRNA decay may also be affected by salt stress and could be biotechnological targets for crop improvement. Full article

(This article belongs to the Special Issue GMO, New Breeding Techniques and Novel Technologies for Abiotic Stress Tolerance in Crop Plants)

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17 pages, 2502 KiB

Open AccessEditor’s ChoiceArticle

Adaptive Response of a Native Mediterranean Grapevine Cultivar Upon Short-Term Exposure to Drought and Heat Stress in the Context of Climate Change

by Nikolaos Tzortzakis, Antonios Chrysargyris and Aziz Aziz

Agronomy 2020, 10(2), 249; https://doi.org/10.3390/agronomy10020249 - 7 Feb 2020

Cited by 31 | Viewed by 4051

Abstract

The impact of climate change on viticulture is of major importance. Several international and indigenous grapevine cultivars have been examined for their adaptive performance to drought and heat stresses. However, the underlying physiological mechanisms are not well known. In the present study we [...] Read more.

The impact of climate change on viticulture is of major importance. Several international and indigenous grapevine cultivars have been examined for their adaptive performance to drought and heat stresses. However, the underlying physiological mechanisms are not well known. In the present study we examined the short-term effects of light and moderate drought stress (DS) as well as heat stress (HS) on physiological and biochemical attributes in two grapevine cultivars: Chardonnay (international) and Xynisteri, an indigenous adapted to the specific Cypriot microclimate. Xynisteri plants exhibited decreasing leaf stomatal conductance and photosynthetic rate as well as increasing total phenols and antioxidant capacity under DS conditions. These reactions were concomitant to a rapid accumulation of hydrogen peroxide and lipid peroxidation in leaves, associated to an increase of the antioxidant superoxide dismutase activity. However, Chardonnay plants did not exhibit the same responses as Xynisteri against DS (i.e., stomatal closure, total phenolics and antioxidants) over the first four days. Additionally, Chardonnay showed leaf damage with increased lipid peroxidation levels and activation of catalase and peroxidase. Interestingly, HS increased leaf stomatal conductance and decreased total phenolic content, flavonoids and antioxidant capacity in Chardonnay after 20 d of stress. In both cultivars, HS had milder effects compared to DS, and again Xynisteri showed better performance than Chardonnay in terms of damage index and antioxidative activities. Overall, Xynisteri adaptation to DS and HS was higher than that of Chardonnay, and both cultivars reacted more to the short-term DS than to HS. Although the Xynisteri performances under stress conditions provide an important resource for adaptation to stressful conditions, the impacts on earliness, yield and grape quality remain to be explored. Full article

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20 pages, 1855 KiB

Open AccessFeature PaperEditor’s ChoiceReview

A Conceptual Framework for Winter Dormancy in Deciduous Trees

by Erica Fadón, Eduardo Fernandez, Helen Behn and Eike Luedeling

Agronomy 2020, 10(2), 241; https://doi.org/10.3390/agronomy10020241 - 6 Feb 2020

Cited by 90 | Viewed by 11875

Abstract

The perennial life strategy of temperate trees relies on establishing a dormant stage during winter to survive unfavorable conditions. To overcome this dormant stage, trees require cool (i.e., chilling) temperatures as an environmental cue. Numerous approaches have tried to decipher the physiology of [...] Read more.

The perennial life strategy of temperate trees relies on establishing a dormant stage during winter to survive unfavorable conditions. To overcome this dormant stage, trees require cool (i.e., chilling) temperatures as an environmental cue. Numerous approaches have tried to decipher the physiology of dormancy, but these efforts have usually remained relatively narrowly focused on particular regulatory or metabolic processes, recently integrated and linked by transcriptomic studies. This work aimed to synthesize existing knowledge on dormancy into a general conceptual framework to enhance dormancy comprehension. The proposed conceptual framework covers four physiological processes involved in dormancy progression: (i) transport at both whole-plant and cellular level, (ii) phytohormone dynamics, (iii) genetic and epigenetic regulation, and (iv) dynamics of nonstructural carbohydrates. We merged the regulatory levels into a seasonal framework integrating the environmental signals (i.e., temperature and photoperiod) that trigger each dormancy phase. Full article

(This article belongs to the Special Issue Fruit and Nut Tree Phenology in a Warming World)

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21 pages, 5509 KiB

Open AccessEditor’s ChoiceArticle

Effect of Agronomic Practices on Yield and Quality of Borage at Harvest and During Storage as Minimally-Processed Produce

by Claudia Miceli, Alessandra Moncada, Filippo Vetrano, Giovanni Iapichino, Fabio D’Anna and Alessandro Miceli

Agronomy 2020, 10(2), 242; https://doi.org/10.3390/agronomy10020242 - 6 Feb 2020

Cited by 6 | Viewed by 4331

Abstract

Borage (Borago officinalis L.) is a hairy pubescent herb known throughout the world for its folk medicinal uses, as well as for many culinary uses. There is still little information on the cultivation needs of this species, especially for its use as [...] Read more.

Borage (Borago officinalis L.) is a hairy pubescent herb known throughout the world for its folk medicinal uses, as well as for many culinary uses. There is still little information on the cultivation needs of this species, especially for its use as vegetable crop and as fresh-cut produce. Hence, the aim of the research was to study the effects of agronomic practices on yield and quality of borage and on the storability as minimally-processed product. Two experiments were carried out in two consecutive years in order to evaluate the effect of plant density and plastic mulching on yield and quality of two borage accessions at harvest and during storage as minimally-processed produce for 14 days at 4 °C. The highest plant density (8 plants m²) determined the highest yield of plants and minimally-processed leaves with good quality retention during storage. Mulching had a positive effect on earliness, yield, and shelf life of minimally-processed leaves but also increased nitrate accumulation and reduced ascorbic acid content. Borage plants with lower spacing grown on mulched soil showed the best yield of plants and minimally-processed leaves irrespective of the borage accession tested. Borage plants can be used to produce minimally-processed entire leaves with good quality characteristics. Full article

(This article belongs to the Special Issue Germplasm Exploitation and Product Innovation of Vegetable, Aromatic and Medicinal Plants)

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25 pages, 6598 KiB

Open AccessEditor’s ChoiceReview

Local Solutions for Sustainable Food Systems: The Contribution of Orphan Crops and Wild Edible Species

by Teresa Borelli, Danny Hunter, Stefano Padulosi, Nadezda Amaya, Gennifer Meldrum, Daniela Moura de Oliveira Beltrame, Gamini Samarasinghe, Victor W. Wasike, Birgül Güner, Ayfer Tan, Yara Koreissi Dembélé, Gaia Lochetti, Amadou Sidibé and Florence Tartanac

Agronomy 2020, 10(2), 231; https://doi.org/10.3390/agronomy10020231 - 5 Feb 2020

Cited by 50 | Viewed by 11225

Abstract

Calls for a global food system transformation and finding more sustainable ways of producing healthier, safe and nutritious food for all have spurred production approaches such as sustainable intensification and biofortification with limited consideration of the copious amounts of orphan crops, traditional varieties [...] Read more.

Calls for a global food system transformation and finding more sustainable ways of producing healthier, safe and nutritious food for all have spurred production approaches such as sustainable intensification and biofortification with limited consideration of the copious amounts of orphan crops, traditional varieties and wild edible species readily available in many countries, mostly in and around smallholder farmers’ fields. This paper explores the potential role of locally available; affordable and climate-resilient orphan crops, traditional varieties and wild edible species to support local food system transformation. Evidence from Brazil, Kenya, Guatemala, India, Mali, Sri Lanka and Turkey is used to showcase a three-pronged approach that aims to: (i) increase evidence of the nutritional value and biocultural importance of these foods, (ii) better link research to policy to ensure these foods are considered in national food and nutrition security strategies and actions, and (iii) improve consumer awareness of the desirability of these alternative foods so that they may more easily be incorporated in diets, food systems and markets. In the seven countries, this approach has brought about positive changes around increasing community dietary diversity and increasing market opportunities for smallholder growers, as well as increased attention to biodiversity conservation. Full article

(This article belongs to the Special Issue Wild Crop Relatives and Associated Biocultural and Traditional Agronomic Practices for Food and Nutritional Security)

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15 pages, 1918 KiB

Open AccessEditor’s ChoiceArticle

Wheat Grain Composition, Dough Rheology and Bread Quality as Affected by Nitrogen and Sulfur Fertilization and Seeding Density

by Lorenzo Guerrini, Marco Napoli, Marco Mancini, Piernicola Masella, Alessio Cappelli, Alessandro Parenti and Simone Orlandini

Agronomy 2020, 10(2), 233; https://doi.org/10.3390/agronomy10020233 - 5 Feb 2020

Cited by 42 | Viewed by 6232

Abstract

Flour from old varieties are usually considered very weak flours, and thus difficult to use in breadmaking especially when processed as Italian “Tipo 2” flour. Hence, the aim of our study was to understand if agronomic treatments can be used to improve flour [...] Read more.

Flour from old varieties are usually considered very weak flours, and thus difficult to use in breadmaking especially when processed as Italian “Tipo 2” flour. Hence, the aim of our study was to understand if agronomic treatments can be used to improve flour processability and the quality of three old wheat varieties. An experimental strip-plot scheme was used: three old wheat varieties (Andriolo, Sieve, Verna), two seeding densities, three levels of nitrogen fertilization (N35, N80, and N135), and two levels of foliar sulfur fertilization. Analyzed parameters related to kernel composition, dough rheology and bread quality. Sulfur and nitrogen treatments significantly affected protein composition and dough alveograph strength, which increased by about 34% with nitrogen fertilization, and by about 14% with the sulfur treatment. However, only nitrogen fertilization affected bread characteristics. Crumb density significantly decreased from N35 to N135, while springiness and cohesiveness increased. On the other hand, sulfur did not improve breads. This highlight the importance of performing breadmaking tests in addition to the rheological determinations. The poor technological performance of old wheat flours can be improved with agronomical treatments designed to obtain higher-quality bread. Full article

(This article belongs to the Section Soil and Plant Nutrition)

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21 pages, 3459 KiB

Open AccessEditor’s ChoiceReview

From Smart Farming towards Agriculture 5.0: A Review on Crop Data Management

by Verónica Saiz-Rubio and Francisco Rovira-Más

Agronomy 2020, 10(2), 207; https://doi.org/10.3390/agronomy10020207 - 3 Feb 2020

Cited by 440 | Viewed by 53895

Abstract

The information that crops offer is turned into profitable decisions only when efficiently managed. Current advances in data management are making Smart Farming grow exponentially as data have become the key element in modern agriculture to help producers with critical decision-making. Valuable advantages [...] Read more.

The information that crops offer is turned into profitable decisions only when efficiently managed. Current advances in data management are making Smart Farming grow exponentially as data have become the key element in modern agriculture to help producers with critical decision-making. Valuable advantages appear with objective information acquired through sensors with the aim of maximizing productivity and sustainability. This kind of data-based managed farms rely on data that can increase efficiency by avoiding the misuse of resources and the pollution of the environment. Data-driven agriculture, with the help of robotic solutions incorporating artificial intelligent techniques, sets the grounds for the sustainable agriculture of the future. This paper reviews the current status of advanced farm management systems by revisiting each crucial step, from data acquisition in crop fields to variable rate applications, so that growers can make optimized decisions to save money while protecting the environment and transforming how food will be produced to sustainably match the forthcoming population growth. Full article

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21 pages, 365 KiB

Open AccessEditor’s ChoiceReview

Extension of Avocado Fruit Postharvest Quality Using Non-Chemical Treatments

by Karen Munhuweyi, Semakaleng Mpai and Dharini Sivakumar

Agronomy 2020, 10(2), 212; https://doi.org/10.3390/agronomy10020212 - 2 Feb 2020

Cited by 40 | Viewed by 14429

Abstract

Developing postharvest management techniques using environmentally friendly and non-chemical approaches is key to extending the shelf life of avocados in a safer and health conscious manner. Avocados are prone to postharvest deterioration caused by mechanical damage, chilling injury, soft landing, uneven ripening and [...] Read more.

Developing postharvest management techniques using environmentally friendly and non-chemical approaches is key to extending the shelf life of avocados in a safer and health conscious manner. Avocados are prone to postharvest deterioration caused by mechanical damage, chilling injury, soft landing, uneven ripening and decay. Among the different cultivars of avocados commercially grown worldwide, the ‘Hass’ variety continues to be the most predominant due to its nutty flavour and functional properties. Most of the literature on postharvest decay and disorders affecting avocado fruit quality during storage and marketing is dedicated to the Hass avocado. Some of these postharvest problems are unique to the ‘Hass’ avocado can possibly be controlled by simply investing more research into other cultivars. These postharvest losses can be significantly controlled using eco-friendly technologies, such as modified atmosphere, physical heat treatments and most importantly investing in natural biodegradable products with naturally inherent antimicrobial properties. Thus, this review includes the recent research-based information on the use of non-chemical treatments on the improvement of fruit health and quality. Full article

(This article belongs to the Special Issue Postharvest Storage Techniques and Quality Evaluation of Fruits and Vegetables)

22 pages, 1060 KiB

Open AccessEditor’s ChoiceArticle

Appraisal of Combined Applications of Trichoderma virens and a Biopolymer-Based Biostimulant on Lettuce Agronomical, Physiological, and Qualitative Properties under Variable N Regimes

by Youssef Rouphael, Petronia Carillo, Giuseppe Colla, Nunzio Fiorentino, Leo Sabatino, Christophe El-Nakhel, Maria Giordano, Antonio Pannico, Valerio Cirillo, Edris Shabani, Eugenio Cozzolino, Nadia Lombardi, Mauro Napolitano and Sheridan L. Woo

Agronomy 2020, 10(2), 196; https://doi.org/10.3390/agronomy10020196 - 1 Feb 2020

Cited by 54 | Viewed by 4384

Abstract

The current research elucidated the agronomical, physiological, qualitative characteristics and mineral composition of lettuce (Lactuca sativa L. var. longifolia) after treatments with a beneficial fungus Trichoderma virens (TG41) alone or in combination with a vegetal biopolymer-based biostimulant (VBP; ‘Quik-link’). The experiment [...] Read more.

The current research elucidated the agronomical, physiological, qualitative characteristics and mineral composition of lettuce (Lactuca sativa L. var. longifolia) after treatments with a beneficial fungus Trichoderma virens (TG41) alone or in combination with a vegetal biopolymer-based biostimulant (VBP; ‘Quik-link’). The experiment consisted of lettuce plants grown in three N conditions: sub-optimal (0N kg ha⁻¹), optimal (70N kg ha⁻¹), and supra-optimal (140N kg ha⁻¹) N levels. Lettuce grown under 0N fertilization showed a significant increase in fresh yield when inoculated with TG41 alone (45%) and a greater increase with TG41 + VBP biostimulant (67%). At 48 days after transplanting, both the TG41 alone or TG41+VBP biostimulant induced higher values of CO₂ assimilation in comparison to the control. The mineral concentrations in leaf tissues were greater by 10% for K and 12% for Mg with the TG41+VBP treatments compared to the untreated lettuce. The lettuce plants receiving either TG41 alone or TG41+VBP biostimulants had a significantly lower nitrate content than any of the untreated controls. In non-fertilized conditions, plants treated with TG41+VBP biostimulants produced lettuce of higher premium quality as indicated by the higher antioxidant activity, total ascorbic acid (+61%–91%), total phenols (+14%) and lower nitrate content when compared to the untreated lettuce. Full article

(This article belongs to the Special Issue Toward a Sustainable Agriculture Through Plant Biostimulants: From Experimental Data to Practical Applications)

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32 pages, 1070 KiB

Open AccessEditor’s ChoiceReview

Towards a Sustainable Agriculture: Strategies Involving Phytoprotectants against Salt Stress

by José Ramón Acosta-Motos, Consuelo Penella, José A. Hernández, Pedro Díaz-Vivancos, María Jesús Sánchez-Blanco, Josefa María Navarro, María José Gómez-Bellot and Gregorio Barba-Espín

Agronomy 2020, 10(2), 194; https://doi.org/10.3390/agronomy10020194 - 1 Feb 2020

Cited by 38 | Viewed by 6611

Abstract

Salinity is one of the main constraints for agriculture productivity worldwide. This important abiotic stress has worsened in the last 20 years due to the increase in water demands in arid and semi-arid areas. In this context, increasing tolerance of crop plants to [...] Read more.

Salinity is one of the main constraints for agriculture productivity worldwide. This important abiotic stress has worsened in the last 20 years due to the increase in water demands in arid and semi-arid areas. In this context, increasing tolerance of crop plants to salt stress is needed to guarantee future food supply to a growing population. This review compiles knowledge on the use of phytoprotectants of microbial origin (arbuscular mycorrhizal fungi and plant growth-promoting rhizobacteria), osmoprotectants, melatonin, phytohormones and antioxidant metabolism-related compounds as alleviators of salt stress in numerous plant species. Phytoprotectants are discussed in detail, including their nature, applicability, and role in the plant in terms of physiological and phenotype effects. As a result, increased crop yield and crop quality can be achieved, which in turn positively impact food security. Herein, efforts from academic and industrial sectors should focus on defining the treatment conditions and plant-phytoprotectant associations providing higher benefits. Full article

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15 pages, 4096 KiB

Open AccessEditor’s ChoiceArticle

Effect of Droplet Size Parameters on Droplet Deposition and Drift of Aerial Spraying by Using Plant Protection UAV

by Shengde Chen, Yubin Lan, Zhiyan Zhou, Fan Ouyang, Guobin Wang, Xiaoyu Huang, Xiaoling Deng and Shengnan Cheng

Agronomy 2020, 10(2), 195; https://doi.org/10.3390/agronomy10020195 - 1 Feb 2020

Cited by 80 | Viewed by 8596

Abstract

In the field of pesticide spraying, droplet size is one of the most important factors affecting droplet deposition and drift. In order to study the effect of different droplet size parameters on droplet deposition distribution and drift of aerial spraying by using plant [...] Read more.

In the field of pesticide spraying, droplet size is one of the most important factors affecting droplet deposition and drift. In order to study the effect of different droplet size parameters on droplet deposition distribution and drift of aerial spraying by using plant protection UAV, an aerial spraying test with the same spraying rate and different size droplets in rice canopy was carried out by using multi-rotor unmanned aerial vehicles (UAV) and four TEEJET nozzles with different orifice sizes (these droplets with a volume median diameter (VMD) of 95.21, 121.43, 147.28, and 185.09 μm, respectively), and the deposition distribution and penetration of droplets in the target area and the drift distribution of droplets in the non-target area were compared and analyzed. The results showed that the deposition distribution and penetration of droplets in the target area and the drift distribution of droplets in the non-target area were influenced by the droplet size. The droplet deposition rate in the upper and lower rice canopies were increased in the target area with the increase of droplet size. The penetration results of droplets also increased with the increase of droplet size, and that of droplets with a VMD of 185.09 μm was the best, reaching 38.13%. The average values of the cumulative drift rate of droplets in the rice canopy in the four tests were 73.87%, 50.26%, 35.91%, and 23.06%, respectively, and the cumulative drift rate and the drift distance of droplets decreased with the increase of droplet size, which indicated that the increase of droplet size can effectively reduce droplet drift. It demonstrated that the droplet size is one of the most important factors affecting droplet deposition and drift for pesticide spraying by plant protection UAV, and for the application of plant protection UAV with extra-low volume spraying, the use of droplets with VMD less than 160 μm should be avoided and a more than 10 m buffer zone should be considered downwind of the spraying field to avoid drug damage caused by pesticide drift. The results have fully revealed the effect of droplet size parameters on droplet deposition and drift of aerial spraying. Moreover, the influence of the wind field below the rotors on the distribution of droplet deposition was surmised and analyzed from the perspective of plant protection UAV. It is important for optimizing the droplet parameters of aerial spraying, increasing the spraying efficiency, and realizing precision agricultural aviation spray. Full article

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26 pages, 2021 KiB

Open AccessEditor’s ChoiceArticle

Biostimulants Application Alleviates Water Stress Effects on Yield and Chemical Composition of Greenhouse Green Bean (Phaseolus vulgaris L.)

by Spyridon A. Petropoulos, Ângela Fernandes, Sofia Plexida, Antonios Chrysargyris, Nikos Tzortzakis, João C. M. Barreira, Lillian Barros and Isabel C. F. R. Ferreira

Agronomy 2020, 10(2), 181; https://doi.org/10.3390/agronomy10020181 - 27 Jan 2020

Cited by 39 | Viewed by 5158

Abstract

The increasing scarcity of water demands proper water management practices to ensure crop sustainability. In this study, the effect of drought stress and biostimulants application on the yield and chemical composition of green pods and seeds of common bean (Phaseolus vulgaris L.) [...] Read more.

The increasing scarcity of water demands proper water management practices to ensure crop sustainability. In this study, the effect of drought stress and biostimulants application on the yield and chemical composition of green pods and seeds of common bean (Phaseolus vulgaris L.) was evaluated. For this purpose, four commercially available biostimulant products, namely Nomoren (G), EKOprop (EK), Veramin Ca (V), and Twin-Antistress (TW), were tested under two irrigation regimes: normal irrigation (W+) and water-holding (W-) conditions. The highest increase (20.8%) of pods total yield was observed in EKW+ treatment due to the formation of more pods of bigger size compared to control treatment (CW+). In addition, the highest yield under drought stress conditions was recorded for the GW- treatment (5691 ± 139 kg/ha). Regarding the effects of biostimulants on the protein and ash content of pods, the application of VW+ treatment (first harvest of pods; 201 ± 1 and 79 ± 1 g/kg dw for proteins and ash content, respectively) and GW+ (second harvest of pods; 207.1 ± 0.1 and 68.4 ± 0.5 g/kg dw for proteins and ash content, respectively) showed the best results. For seeds, the application of GW+ treatment resulted in the highest content for fat, protein, and ash content (52.7 ± 0.1, 337 ± 1, 56 ± 1 g/kg dw) and energetic value (5474 ± 3 kcal/kg dw). γ-tocopherol was the main detected tocopherol in pods and seeds, and it was significantly increased by the application of TWW- (first harvest of pods; 6410 ± 40 μg/kg dw), VW- (second harvest of pods; 3500 ± 20 μg/kg dw), and VW+ (seeds; 39.8 ± 0.1 g/kg dw) treatments. EKW- treatment resulted in the lowest oxalic acid content for both pod harvests (26.3 ± 0.1 g/kg dw and 22.7 ± 0.2 g/kg dw for the first and second harvest of pods, respectively) when compared with the rest of the treatments where biostimulants were applied, although in all the cases, the oxalic acid content was considerably low. Fructose and sucrose were the main sugars detected in pods and seeds, respectively, while the highest content was recorded for the TWW- (first harvest of pods) and GW- (second harvest of pods and seeds) treatments. The main detected fatty acids in pods and seeds were α-linolenic, linoleic, and palmitic acid, with a variable effect of the tested treatments being observed. In conclusion, the application of biostimulants could be considered as an eco-friendly and sustainable means to increase the pod yield and the quality of common bean green pods and seeds under normal irrigation conditions. Promising results were also recorded regarding the alleviation of negative effects of drought stress, especially for the application of arbuscular mycorrhizal fungi (AMF; G treatment), which increased the total yield of green pods. Moreover, the nutritional value and chemical composition of pods and seeds was positively affected by biostimulants application, although a product specific effect was recorded depending on the irrigation regime and harvesting time (pods and seeds). Full article

(This article belongs to the Special Issue Toward a Sustainable Agriculture Through Plant Biostimulants: From Experimental Data to Practical Applications)

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