Research

25 pages, 2848 KiB

Open AccessArticle

Fertigation Management and Growth-Promoting Treatments Affect Tomato Transplant Production and Plant Growth after Transplant

by Alessandra Moncada, Filippo Vetrano, Alessandro Esposito and Alessandro Miceli

Agronomy 2020, 10(10), 1504; https://doi.org/10.3390/agronomy10101504 - 03 Oct 2020

Cited by 15 | Viewed by 3248

Abstract

Plant biostimulants are of interest as they can stimulate plant growth and increase resource utilization. There is still no information on the use of plant growth-promoters under variable nutritional conditions in the nursery and the effects on tomato seedling growth and plant performance [...] Read more.

Plant biostimulants are of interest as they can stimulate plant growth and increase resource utilization. There is still no information on the use of plant growth-promoters under variable nutritional conditions in the nursery and the effects on tomato seedling growth and plant performance after transplant. This study aimed to evaluate the suitability of gibberellic acid (GA₃) or bacterial biostimulant treatments to enhance the growth and quality of greenhouse-grown tomato (Solanum lycopersicum ‘Marmande’) seedlings, fertigated with increasing nutrient rates and to assess the efficacy of these treatments on the early growth of tomato plants. During autumn 2019, tomato seedlings were inoculated with 1.5 g L⁻¹ of TNC Bactorr^S13 (a commercial biostimulant containing 1.3 × 10⁸ CFU g⁻¹ of Bacillus spp.) or sprayed with 10⁻⁵ M GA₃ and fertigated with a nutrient solution containing 0, 1, 2 and 4 g L⁻¹ of NPK fertilizer (20-20-20) when they reached the 11th BBCH growth stage for tomato. Subsequently, the seedlings were evaluated in greenhouse cultivation for 60 days until at least the 61st BBCH growth stage (January 2020). The growth of the tomato seedlings increased curvilinearly in relation to the fertigation rates. The GA₃-treated seedlings showed similar or even higher growth parameters than the control seedlings fed with 4 g L⁻¹ of fertilizer but with half of the nutrients. The inoculation of the substrate with Bacillus spp. had negative effects in the absence of fertigation but determined a greater growth at the highest fertigation rate. The bacterial inoculum of seedlings had longer-term effects than the GA₃ treatment during the plant growth, but these effects were noticeable mainly when the bacterial biostimulant was associated with the highest fertigation rate. Full article

(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)

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17 pages, 999 KiB

Open AccessArticle

Response of Soybean (Glycine max (L.) Merrill) to Mineral Nitrogen Fertilization and Bradyrhizobium japonicum Seed Inoculation

by Janusz Prusiński, Anna Baturo-Cieśniewska and Magdalena Borowska

Agronomy 2020, 10(9), 1300; https://doi.org/10.3390/agronomy10091300 - 01 Sep 2020

Cited by 13 | Viewed by 3086

Abstract

A growing interest in soybean cultivation in Poland has been observed in the recent years, however it faces a lot of difficulties resulting from a poorly understood effectiveness of plant nitrogen fertilization and from the introduction of Bradyrhizobium japonicum to the environment. The [...] Read more.

A growing interest in soybean cultivation in Poland has been observed in the recent years, however it faces a lot of difficulties resulting from a poorly understood effectiveness of plant nitrogen fertilization and from the introduction of Bradyrhizobium japonicum to the environment. The aim of the study was to evaluate the consistency of response of two soybean cultivars to three different rates of mineral N fertilization and two seed inoculation treatments with B. japonicum in field conditions over four years regardless of previous B. japonicum presence in the soil. A highly-diversified-over-years rainfall and temperature in the growing season do not allow for a definite statement of the differences resulting from seed inoculation and mineral N fertilization applied separately or jointly in soybean. A high sensitivity of the nodulation process to rainfall deficits was noted, which resulted in a decreased amount of B. japonicum DNA measured in qPCR and dry matter of nodules. ‘Annushka’ demonstrated a higher yield of seeds and protein, higher plants and the 1st pod setting. ‘Aldana’, due to a significant decrease in plant density, produced a higher number of pods, seeds per pod and the 1000 seed weight per plant. Both cultivars responded with an increase in the seed yield after seed inoculation with HiStick, also with an application of 30 and 60 kg N, as well as with Nitragina with 60 kg N. Full article

(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)

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12 pages, 1030 KiB

Open AccessArticle

Effect of N Fertilization on the Content of Phenolic Compounds in Jerusalem Artichoke (Helianthus tuberosus L.) Tubers and Their Antioxidant Capacity

by Ryszard Amarowicz, Bożena Cwalina-Ambroziak, Michał A. Janiak and Bożena Bogucka

Agronomy 2020, 10(8), 1215; https://doi.org/10.3390/agronomy10081215 - 18 Aug 2020

Cited by 30 | Viewed by 4183

Abstract

Three cultivars of Jerusalem artichoke Albik, Rubik and Gute Gelbe were grown under different nitrogen fertilization regimens: 0, 80 and 120 kg N·ha⁻¹. Phenolic compounds were extracted from tubers using 80% (v/v) methanol. The total phenolics were determined with [...] Read more.

Three cultivars of Jerusalem artichoke Albik, Rubik and Gute Gelbe were grown under different nitrogen fertilization regimens: 0, 80 and 120 kg N·ha⁻¹. Phenolic compounds were extracted from tubers using 80% (v/v) methanol. The total phenolics were determined with the Folin–Ciocâlteu reagent and antioxidant activity was assessed using the ABTS (2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)), FRAP (ferric-reducing antioxidant power), and DPPH (2,2-diphenyl-1-picrylhydrazyl) assays. The content of individual phenolic compounds was determined by HPLC. The effect of nitrogen fertilization on the total phenolics content was observed for the Albik cultivar. In the Rubik variety the lowest content was recorded at fertilization zero, and in the Gute Gelbe variety at this fertilization level the content of phenols was the highest. At fertilization 120 kg N·ha⁻¹, the highest ABTS test results were noted for all cultivars. For the Albik variety no effect of fertilization on the FRAP test results was noted; for the Rubik variety at zero nitrogen fertilization, the value for FRAP was the lowest, and it was the highest Gute Gelbe. The results of the DPPH test in the Gute Gelbe variety did not depend on the fertilization used. In the other two varieties, the lowest DPPH results were obtained at zero nitrogen regimen. Three main phenolic compounds were determined using HPLC. One of them was chlorogenic acid and the other two were derivatives of caffeic acid. The content of chlorogenic acid in tubers of the Gute Gelbe variety depended on nitrogen fertilization; the highest content of this compound was found in the case of fertilization zero. Statistical analysis showed a correlation between the content of phenolic compounds in tubers and their antioxidant potential. The results of this study suggest great potential for using Jerusalem artichoke tubers as a rich source of phenolic compounds with high antioxidant capacity. Full article

(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)

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13 pages, 1247 KiB

Open AccessArticle

Combining Green Manuring and Fertigation Maximizes Tomato Crop Yield and Minimizes Nitrogen Losses

by Michela Farneselli, Paolo Benincasa, Giacomo Tosti, Marcello Guiducci and Francesco Tei

Agronomy 2020, 10(7), 977; https://doi.org/10.3390/agronomy10070977 - 08 Jul 2020

Cited by 7 | Viewed by 2201

Abstract

The aim of this experiment was to evaluate the effect of fertilizing processing tomato by coupling the green manuring of fall-winter cover crops with fertigation in spring-summer. In a two-year experiment, seven fertilization treatments were compared: green manuring of pure barley (B100) and [...] Read more.

The aim of this experiment was to evaluate the effect of fertilizing processing tomato by coupling the green manuring of fall-winter cover crops with fertigation in spring-summer. In a two-year experiment, seven fertilization treatments were compared: green manuring of pure barley (B100) and pure vetch (V100) sown at 100% of their ordinary seeding rates, green manuring of a barley-vetch mixture at a ratio of 75:25 of their own seed rates (B75V25), fertigation with drip irrigation at a rate of 200 kg ha⁻¹ of nitrogen (N) (Fert_N200), fertigation combined with B100 and B75V25 at a N rate complementary to 200 kg N ha⁻¹ (B100 + Fert and B75V25 + Fert, respectively), and an unfertilized control (N0) with no cover crops for green manuring prior to tomato transplanting or fertigation. The Fert_N200 treatment resulted in maximum tomato N uptake, growth and yield, but caused high N leaching, especially during the no-cover fall-winter period, as was also the case for N0. The V100 treatment promoted quite good tomato N status and yield, but did not reduce N leaching. The B100 and B75V25 treatments reduced N leaching but decreased tomato N uptake, growth and yield. The B100 + Fert and B75V25 + Fert treatments reduced N leaching, likely increased soil N stock, and facilitated optimal tomato N nutrition and maximum yields. Combining fertigation with green manuring of cover crops composed of pure grass or grass-legume mixtures appears to be a very effective and environmentally sound practice for fertilizing high N-demanding spring-summer crops like processing tomato. Full article

(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)

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16 pages, 900 KiB

Open AccessArticle

Agronomic Performance of Different Open-Pollinated Beetroot Genotypes Grown Under Organic Farming Conditions

by Khadijeh Yasaminshirazi, Jens Hartung, René Groenen, Thomas Heinze, Michael Fleck, Sabine Zikeli and Simone Graeff-Hoenninger

Agronomy 2020, 10(6), 812; https://doi.org/10.3390/agronomy10060812 - 08 Jun 2020

Cited by 6 | Viewed by 4620

Abstract

Due to the increase of the organic cultivation of beetroot and its growing importance as a functional food, the potential advantages of open-pollinated genotypes as an alternative for F1 hybrid genotypes has been investigated. In this regard, six field experiments were carried out [...] Read more.

Due to the increase of the organic cultivation of beetroot and its growing importance as a functional food, the potential advantages of open-pollinated genotypes as an alternative for F1 hybrid genotypes has been investigated. In this regard, six field experiments were carried out in 2017 and 2018 in three different locations to investigate the agronomic potential of new and existing open-pollinated genotypes of beetroot and their performance under the specific conditions of organic agriculture. Fifteen beetroot genotypes, including one F1 hybrid as a commercial control and one breeding line, were compared regarding their total and marketable yield, individual beet weight, diameter of beet, and leaves-growth-base width. Furthermore, five randomly selected beetroots meeting common marketable criteria were evaluated optically with regard to skin smoothness, corky surface, root tail, scab incidence, and uniformity. Results of this study indicated a significant impact of genotype on eight of the assessed traits. The cylindrical-shaped genotype, Carillon RZ, demonstrated significantly higher total and marketable yields, with 53.28 ± 3.34 t ha⁻¹ and 44.96 ± 3.50 t ha⁻¹, respectively, compared to the yellow-colored genotype, Burpees Golden, which obtained the lowest total yield, 36.06 ± 3.38 t ha⁻¹, and marketable yield, 27.92 ± 3.55 t ha⁻¹. Moreover, the comparison of the open-pollinated genotypes with the F1 hybrid, Monty RZ F1, revealed that except for the traits yield, scab, and uniformity, the open-pollinated genotypes indicated desirable competitive outcomes and thus offer suitable alternatives for organic cropping systems. Overall, the observed genetic variability can be beneficial for breeding and food product development. Full article

(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)

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17 pages, 1324 KiB

Open AccessArticle

Recovery of ¹⁵N Labeled Nitrogen Fertilizer by Fertigated and Drip Irrigated Greenhouse Vegetable Crops

by Carolina Martínez-Gaitán, María Rosa Granados, María Dolores Fernández, Marisa Gallardo and Rodney B. Thompson

Agronomy 2020, 10(5), 741; https://doi.org/10.3390/agronomy10050741 - 21 May 2020

Cited by 8 | Viewed by 2927

Abstract

The stable isotope ¹⁵N was used to assess the recovery of mineral N fertilizer applied to fertigated and drip-irrigated spring muskmelon and autumn-winter sweet pepper crops grown in greenhouse soil plots. They received 92–96% of mineral N fertilizer as NO₃⁻ [...] Read more.

The stable isotope ¹⁵N was used to assess the recovery of mineral N fertilizer applied to fertigated and drip-irrigated spring muskmelon and autumn-winter sweet pepper crops grown in greenhouse soil plots. They received 92–96% of mineral N fertilizer as NO₃⁻. ¹⁵N-labeled Ca (NO₃)₂ fertilizer was applied to crops during vegetative growth and fruit production phases. Crops were grown with either conventional management or combined improved N and irrigation management. Improved management for both irrigation and N was based on the combined use of models, to estimate crop requirements, and of monitoring of soil parameters. In sweet pepper, from conventional management, ¹⁵N recoveries from the ¹⁵N applications made during vegetative growth and fruit production were 66% and 58%, respectively. With improved management in sweet pepper, the corresponding ¹⁵N recoveries were 82% and 77%. In muskmelon, ¹⁵N recoveries from conventional management from the ¹⁵N applications made during vegetative growth and fruit production were 71% and 42%, respectively. With improved management, the corresponding ¹⁵N recoveries were 68% and 44%, respectively. The results demonstrated that combined drip irrigation and fertigation systems with frequent irrigation and N fertilizer application can have very high recovery of applied N fertilizer, of 77–82%. Full article

(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)

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19 pages, 383 KiB

Open AccessArticle

The Optimization of Nitrogen Fertilization Regulates Crop Performance and Quality of Processing Tomato (Solanum lycopersicum L. cv. Heinz 3402)

by Spyridon A. Petropoulos, Ângela Fernandes, Eustratios Xyrafis, Nikolaos Polyzos, Vasileios Antoniadis, Lillian Barros and Isabel C.F.R. Ferreira

Agronomy 2020, 10(5), 715; https://doi.org/10.3390/agronomy10050715 - 16 May 2020

Cited by 22 | Viewed by 5216

Abstract

In this study, we evaluated the effect of various fertilization regimes on processing tomato (Solanum lycopersicum L. cv. Heinz 3402) yield and quality by applying the following treatments: (i) control (C), (ii) conventional fertilizer (21-0-0, N-P-K) (CF), (iii) slow release nitrogen fertilizer [...] Read more.

In this study, we evaluated the effect of various fertilization regimes on processing tomato (Solanum lycopersicum L. cv. Heinz 3402) yield and quality by applying the following treatments: (i) control (C), (ii) conventional fertilizer (21-0-0, N-P-K) (CF), (iii) slow release nitrogen fertilizer 46-0-0 (SR), (iv) conventional fertilizer (21-0-0, N-P-K) + Zeolite (CFZ), and v) composted sheep manure (M). The results of the study showed that the SR and CFZ treatments resulted in the highest fruit yield per hectare compared to the rest of the fertilizer and the control treatments. Fruit firmness was higher for the treatments C, M and SR, while color parameters (chroma and hue angle) were higher for the C and M treatments, respectively. Moreover, the total soluble solids content (TSS; °Brix) was higher when manure (M) was applied. In terms of chemical composition, the total and individual tocopherols and sugars were the highest for the M and C treatments, respectively, whereas the oxalic, malic and total organic acid contents were the highest for the CFZ treatment. Moreover, the tested treatments showed a varied response in different antioxidant assays, although the M treatment exhibited a high antioxidant capacity in most of the assays, except for the β-carotene/linoleate assay. The carotenoid and chlorophyll contents were the highest for the control treatment. The main detected fatty acid was linoleic acid, followed by palmitic, oleic and α-linolenic acid, while the CFZ treatment had the highest content of polyunsaturated fatty acids (PUFA) due to its high content of linoleic acid. In conclusion, although the application of fertilizers increased yield, the quality parameters and chemical composition showed a varied response to the fertilization regime, especially the TSS content and juice pH and electric conductivity (EC), which are significant for the marketability of the final product. Full article

(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)

23 pages, 1026 KiB

Open AccessFeature PaperArticle

Use of Gibberellic Acid to Increase the Salt Tolerance of Leaf Lettuce and Rocket Grown in a Floating System

by Filippo Vetrano, Alessandra Moncada and Alessandro Miceli

Agronomy 2020, 10(4), 505; https://doi.org/10.3390/agronomy10040505 - 02 Apr 2020

Cited by 20 | Viewed by 4435

Abstract

Hydroponics need water of good quality to prepare a balanced nutrient solution that could allow plants to reach their maximum yield potential. The rising difficulties in finding water with good quality have led to the compelling necessity of identifying sustainable ways to use [...] Read more.

Hydroponics need water of good quality to prepare a balanced nutrient solution that could allow plants to reach their maximum yield potential. The rising difficulties in finding water with good quality have led to the compelling necessity of identifying sustainable ways to use saline water, limiting its negative effect on crop yield and quality. The exogenous supplementation of plant growth regulators, such as gibberellic acid (GA₃), can be effective in increasing plant growth and vigor, thus helping plants to better cope with salt stress. The aim of this study was to evaluate the feasibility to increase the salt tolerance of leaf lettuce and rocket grown in a floating system by adding GA₃ (10⁻⁶ M) to mineral nutrient solutions (MNS) with increasing salinity (0, 10, and 20 mM NaCl). Leaf lettuce and rocket plants suffered a significant reduction of growth and yield, determined by the reduction of biomass, leaf number, and leaf area, even with moderate salt stress (10 mM NaCl). The supplementation of exogenous GA₃ through the MNS allowed plants to substantially counterbalance salt stress by enhancing various morphological and physiological traits, such as biomass accumulation, leaf expansion, stomatal conductance and water and nitrogen use efficiency. The effects of salt stress and GA₃ treatment varied according to the species, thus indicating that this interaction may improve salt tolerance by activating different adaptation systems. Full article

(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)

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18 pages, 762 KiB

Open AccessArticle

The Impact of Fertilization Regime on the Crop Performance and Chemical Composition of Potato (Solanum tuberosum L.) Cultivated in Central Greece

by Spyridon A. Petropoulos, Ângela Fernandes, Nikolaos Polyzos, Vasileios Antoniadis, Lillian Barros and Isabel C.F.R. Ferreira

Agronomy 2020, 10(4), 474; https://doi.org/10.3390/agronomy10040474 - 30 Mar 2020

Cited by 16 | Viewed by 4892

Abstract

Potato cultivation is quite demanding in inorganic nutrients and adequate fertilization is a key factor for maximizing yield and producing tubers of high quality. In the present study, a field experiment was carried out to evaluate the effect of various forms of fertilization [...] Read more.

Potato cultivation is quite demanding in inorganic nutrients and adequate fertilization is a key factor for maximizing yield and producing tubers of high quality. In the present study, a field experiment was carried out to evaluate the effect of various forms of fertilization on crop performance and the nutritional value and chemical composition of two potato varieties (cv. Spunta and cv. Kennebec). For this purpose, five different fertilizer treatments were applied namely: control (C), standard fertilizer (T1), standard fertilizer + zeolite (T2), manure (T3) and slow release nitrogen fertilizer (T4). According to the results, it was observed that slow release treatment (T4) achieved the highest yield for both varieties, while the control treatment presented significantly lower yield compared to the studied fertilization regimes. The dry matter of leaves and shoots was higher in T1 treatment for cv. Kennebec and in T2 and T4 treatments for cv. Spunta, whereas the control treatment presented the highest dry matter content in tubers for cv. Kennebec and T2 and T3 treatments for cv. Spunta. A significant effect of the fertilization regime was also observed on the nutritional value of tubers and more specifically the protein, ash and fat content was increased by treatments T1 and T4, while carbohydrate content was also increased by T3 and T4 treatments for both varieties. Similarly, the total sugars, organic acids, β-carotene and lycopene content was increased in T3 treatment for the Spunta variety, while the antioxidant capacity showed a varied response depending on the fertilizer regime and the tested variety. In conclusion, the fertilization regime has a significant effect not only on the tuber yield but also on the quality of the final product and should be considered as an effective tool to increase the added value of potato crop. Full article

(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)

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11 pages, 245 KiB

Open AccessArticle

Nitrogen Fertilizer Management and Maize Straw Return Modulate Yield and Nitrogen Balance in Sweet Corn

by Lei Gao, Wu Li, Umair Ashraf, Wenjia Lu, Yuliang Li, Chunyan Li, Guangyu Li, Gaoke Li and Jianguang Hu

Agronomy 2020, 10(3), 362; https://doi.org/10.3390/agronomy10030362 - 05 Mar 2020

Cited by 27 | Viewed by 3888

Abstract

Nitrogen fertilizer is an important component of crop production; however, its excessive application could result in N loss that could have serious environmental concerns. Straw incorporation in the soil after crop harvest is one of the most feasible straw management techniques, however, the [...] Read more.

Nitrogen fertilizer is an important component of crop production; however, its excessive application could result in N loss that could have serious environmental concerns. Straw incorporation in the soil after crop harvest is one of the most feasible straw management techniques, however, the optimization of nitrogen (N) fertilizer management and maize straw incorporation to modulate the crop yield and to maintain N balance in sweet corn is necessary to get better yields on a sustained basis. The present study was comprised of two straw management treatments i.e., (i) no straw return (S0), and (ii) incorporation of crushed corn ears by into the soil using rotary tiller (S100) and four N fertilizer management treatments i.e., (i) common farmer practice with total N applied at 300 kg ha⁻¹ with 50%, 5%, 30%, and 15% splits at basal, 3-leaf stage (V3), at hilling stage (V8) and at tasseling/flowering stage (RT), respectively (FM); (ii) application of total N at 225 kg ha⁻¹ with 40%, 10% and 50% at basal, 3-leaf stage (V3) and at hilling stage (V8), respectively (OMI); (iii) application of total N at 150 kg ha⁻¹ with 40%, 10% and 50% at basal, 3-leaf stage (V3), and at hilling stage (V8), respectively (OMII); and (iv) the treatment without any fertilizer application (N0). The hybrid sweet corn cultivar ‘Yuetian 28’ was grown during the spring and autumn growing seasons of 2016 and 2017. The results showed that the N management treatments substantially improved the fresh ear yield, ear number and ear weight, partial factor productivity from nitrogen (PFP_N), recovery efficiency from nitrogen (RE_N), and agronomic efficiency from nitrogen (AE_N). Compared with FM, the OMI and OMII treatments significantly increased the AE_N and PFP_N whilst decreased the apparent N loss, however, the fresh ear yield, ear number and ear weight in OMI treatment were found to be statistically similar (p ˃ 0.05) to FM. Moreover, the S100 treatment did not affect the fresh ear yield and yield components significantly. Overall, straw return combined with an optimized N fertilizer application could improve the yield of sweet corn on a sustained basis with minimum and/or negligible N loss. Full article

(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)

16 pages, 634 KiB

Open AccessArticle

Can Trichoderma-Based Biostimulants Optimize N Use Efficiency and Stimulate Growth of Leafy Vegetables in Greenhouse Intensive Cropping Systems?

by Donato Visconti, Nunzio Fiorentino, Eugenio Cozzolino, Sheridan Lois Woo, Massimo Fagnano and Youssef Rouphael

Agronomy 2020, 10(1), 121; https://doi.org/10.3390/agronomy10010121 - 14 Jan 2020

Cited by 28 | Viewed by 3631

Abstract

The present study addresses the effects of Trichoderma-based biostimulants and nitrogen (N) fertilization levels on agronomic performance and functional quality of two important greenhouse leafy vegetables: lettuce and rocket. A factorial analysis of the relative effects of Trichoderma-based biostimulants (Trichoderma [...] Read more.

The present study addresses the effects of Trichoderma-based biostimulants and nitrogen (N) fertilization levels on agronomic performance and functional quality of two important greenhouse leafy vegetables: lettuce and rocket. A factorial analysis of the relative effects of Trichoderma-based biostimulants (Trichoderma harzianum strain T22 and Trichoderma virens strain GV41) and N fertilization levels (sub-optimal, optimal, and supra-optimal) was carried out to evaluate crop productive behavior (marketable and unmarketable yields, leaf dry matter content, and biomass production), nitrogen nutrition (N uptake, apparent N recovery, and nitrogen use efficiency (NUE)) as well as phytochemical qualitative components (antioxidant activity and total polyphenols). The soil plant analysis development (SPAD) index in both leafy vegetables and leaf colorimetry only in rocket were mainly affected by N fertilization levels but not by Trichoderma-based biostimulants. The contribution of native mineral N was 60 and 100 kg N ha⁻¹ of the total uptake in lettuce and rocket, respectively, and N surpluses were observed in both crops, even under optimal fertilization conditions. Trichoderma virens GV41-based biostimulant increased lettuce marketable yield and biomass production, both under optimal and sub-optimal fertilization. In addition, the same treatment increased NUE up to 116% under recommended N fertilization, that was also associated to an increase in phenol content and antioxidant activity. Rocket showed a clear effect of the Trichoderma virens GV41 treatment, only in absence of fertilization, demonstrating an increase in marketable yield and N uptake. Thus, the inoculation of rocket with this Trichoderma biostimulant can be considered as a useful management tool in leafy vegetable cropping systems for the efficient use of residual fertilizers from previous crops, enhancing NUE within the crop rotations. Nevertheless, the application of microbial biostimulant treatments requires good monitoring of soil N fertility in order to avoid an overexploitation of soil N supplying potential. Full article

(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)

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16 pages, 3779 KiB

Open AccessArticle

Effects of Nitrogen Management on Biomass Production and Dry Matter Distribution of Processing Tomato Cropped in Southern Italy

by Domenico Ronga, Mario Parisi, Alfonso Pentangelo, Mauro Mori and Ida Di Mola

Agronomy 2019, 9(12), 855; https://doi.org/10.3390/agronomy9120855 - 05 Dec 2019

Cited by 30 | Viewed by 4159

Abstract

Processing tomato is an important worldwide horticultural crop. It is generally grown in high-input systems; nevertheless, plant responses to nitrogen fertilization, in terms of the effects on dry matter production and allocation to different plant organs, have yet to be investigated in depth. [...] Read more.

Processing tomato is an important worldwide horticultural crop. It is generally grown in high-input systems; nevertheless, plant responses to nitrogen fertilization, in terms of the effects on dry matter production and allocation to different plant organs, have yet to be investigated in depth. Moreover, information on the crop marginal net return and global warming potential (as an index of the environmental impact of crop cultivation) at different nitrogen rates is still scarce. Therefore, the aim of this work was to study the effects of different nitrogen rates (0, 50, 100, 150, 200, and 250 kg of N ha⁻¹) on the agronomic, economic, and environmental aspects of processing tomato grown under conventional management in the Mediterranean area. The results of the two-year trials indicated 200 kg of nitrogen ha⁻¹ as the best rate, ensuring the highest values of marketable and total yields, brix ton ha⁻¹, and marginal net return and the lowest global warming potential per ton of marketable yield. However, since plants fertilized with 200 kg of N ha⁻¹ did not record the highest values of nitrogen use efficiency and nitrogen uptake efficiency, our finding suggest the possibility to select better-performing cultivars for these physiological parameters by adopting specific tomato breeding programs. Full article

(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)

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21 pages, 775 KiB

Open AccessArticle

Nitrogen Nutrition Optimization in Organic Greenhouse Tomato Through the Use of Legume Plants as Green Manure or Intercrops

by Anastasios Gatsios, Georgia Ntatsi, Luisella Celi, Daniel Said-Pullicino, Anastasia Tampakaki, Ioannis Giannakou and Dimitrios Savvas

Agronomy 2019, 9(11), 766; https://doi.org/10.3390/agronomy9110766 - 17 Nov 2019

Cited by 14 | Viewed by 3922

Abstract

In the present study, in addition to farmyard manure (FYM), cowpea was applied as green manure and faba bean as an intercrop in an organic greenhouse tomato crop, aiming to increase the levels of soil N. Three experiments (E1, E2, E3) were carried [...] Read more.

In the present study, in addition to farmyard manure (FYM), cowpea was applied as green manure and faba bean as an intercrop in an organic greenhouse tomato crop, aiming to increase the levels of soil N. Three experiments (E1, E2, E3) were carried out, in which legumes were either noninoculated or inoculated with rhizobia alone or together with plant growth, promoting rhizobacteria. Inoculation of legumes with rhizobia considerably increased N₂ fixation in E1 but had no impact on N₂ fixation in E2 and E3. In E1, the application of cowpea decreased yield because it imposed a stronger nematode infection as the cowpea plants acted as a good host for Meloidogyne. However, in E2 and E3 the nematode infection was successfully controlled and the legumes significantly increased the tomato yield when inoculated in E2, irrespective of legume inoculation in E3. The total N concentration in the tomato plant tissues was significantly increased by legume application in E2 and E3, but not in E1. These results show that legumes applied as green manure can successfully complement N supply via FYM in organic greenhouse tomato, while legume inoculation with rhizobia can increase the amounts of nitrogen provided to the crop via green manure. Full article

(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)

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18 pages, 5091 KiB

Open AccessArticle

Distillery Anaerobic Digestion Residues as Fertilizers for Field Vegetable Crops: Performance and Efficiency in Mid-term Successions

by Carlo Nicoletto, Luisa Dalla Costa, Paolo Sambo and Giampaolo Zanin

Agronomy 2019, 9(8), 463; https://doi.org/10.3390/agronomy9080463 - 17 Aug 2019

Cited by 4 | Viewed by 3006

Abstract

Understanding nitrogen use efficiency (NUE) of crops plays an important role in achieving sustainable production. Intensive agriculture has adversely affected social and environmental issues worldwide over the past few decades. Anaerobic digested residues from the distillery industry (DADRs) can be used in agriculture, [...] Read more.

Understanding nitrogen use efficiency (NUE) of crops plays an important role in achieving sustainable production. Intensive agriculture has adversely affected social and environmental issues worldwide over the past few decades. Anaerobic digested residues from the distillery industry (DADRs) can be used in agriculture, thereby recycling valuable organic materials that can supply organic N. An experiment using DADRs in horticulture was conducted to evaluate the performance of different treatments on yield and NUE. The experiment was conducted for five years, growing lettuce, cauliflower, chicory, potato, Swiss chard, catalogna chicory, tomato, pepper, and melon in two different succession schemes. Five fertilization treatments were designed, including a mineral fertilization control, in which nitrogen (N) was supplied according to standard recommendations in the area. The other treatments were an unfertilized control and three treatments in which 50%, 75%, and 100% of the N were supplied by DADRs and the remaining with common chemical fertilizer. Major findings were: (1) Spring–summer crops showed the lowest N-uptake and N recovery, during this period high chemical fertilization can cause environmental problems such as N leaching, and fertilization with 100% DADRs is a viable alternative; (2) fall–winter crops can be fertilized by combining 50% mineral N and 50% organic N, supplying the nutrients required by the crops during the growing cycle. Full article

(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)

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22 pages, 1689 KiB

Open AccessArticle

Morphological and Physiological Responses Induced by Protein Hydrolysate-Based Biostimulant and Nitrogen Rates in Greenhouse Spinach

by Petronia Carillo, Giuseppe Colla, Giovanna Marta Fusco, Emilia Dell’Aversana, Christophe El-Nakhel, Maria Giordano, Antonio Pannico, Eugenio Cozzolino, Mauro Mori, Hélène Reynaud, Marios C. Kyriacou, Mariateresa Cardarelli and Youssef Rouphael

Agronomy 2019, 9(8), 450; https://doi.org/10.3390/agronomy9080450 - 14 Aug 2019

Cited by 89 | Viewed by 7215

Abstract

Plant-derived protein hydrolysates (PHs) are gaining prominence as biostimulants due to their potential to improve yield and nutritional quality even under suboptimal nutrient regimens. In this study, we investigated the effects of foliar application of a legume-derived PH (0 or 4 mL L [...] Read more.

Plant-derived protein hydrolysates (PHs) are gaining prominence as biostimulants due to their potential to improve yield and nutritional quality even under suboptimal nutrient regimens. In this study, we investigated the effects of foliar application of a legume-derived PH (0 or 4 mL L⁻¹) on greenhouse baby spinach (Spinacia oleracea L.) under four nitrogen (N) fertilization levels (0, 15, 30, or 45 kg ha⁻¹) by evaluating morphological and colorimetric parameters, mineral composition, carbohydrates, proteins, and amino acids. The fresh yield in untreated and biostimulant-treated spinach plants increased in response to an increase in N fertilization from 1 up to 30 kg ha⁻¹, reaching a plateau thereafter indicating the luxury consumption of N at 45 kg ha⁻¹. Increasing N fertilization rate, independently of PH, lead to a significant increase of all amino acids with the exception of alanine, GABA, leucine, lysine, methionine, and ornithine but decreased the polyphenols content. Interestingly, the fresh yield at 0 and 15 kg ha⁻¹ was clearly greater in PH-treated plants compared to untreated plants by 33.3% and 24.9%, respectively. This was associated with the presence in of amino acids and small peptides PH ‘Trainer^®’, which act as signaling molecules eliciting auxin- and/or gibberellin-like activities on both leaves and roots and thus inducing a “nutrient acquisition response” that enhances nutrients acquisition and assimilation (high P, Ca, and Mg accumulation) as well as an increase in the photochemical efficiency and activity of photosystem II (higher SPAD index). Foliar applications of the commercial PH decreased the polyphenols content, but on the other hand strongly increased total amino acid content (+45%, +82%, and +59% at 0, 15, and 30 kg ha⁻¹, respectively) but not at a 45-kg ha⁻¹-rate. Overall, the use of PH could represent a sustainable tool for boosting yield and nitrogen use efficiency and coping with soil fertility problems under low input regimens. Full article

(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)

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15 pages, 1766 KiB

Open AccessArticle

Effect of Fertilization on Yield and Quality of Sisymbrium officinale (L.) Scop. Grown as Leafy Vegetable Crop

by Marta Guarise, Gigliola Borgonovo, Angela Bassoli and Antonio Ferrante

Agronomy 2019, 9(7), 401; https://doi.org/10.3390/agronomy9070401 - 19 Jul 2019

Cited by 4 | Viewed by 3588

Abstract

Sisymbrium officinale is a wild Brassicaceae species that is known for its use in the alleviation of vocal inflammatory states. Since this species is particularly rich in bioactive compounds, there is an interest for developing cultivation protocols to use this plant as a [...] Read more.

Sisymbrium officinale is a wild Brassicaceae species that is known for its use in the alleviation of vocal inflammatory states. Since this species is particularly rich in bioactive compounds, there is an interest for developing cultivation protocols to use this plant as a leafy vegetable harvested at the 13th BBCH growth stage. Two wild populations of S. officinale (L.) Scop., denominate MI (Milan) and BG (Bergamo), have been used, and three different levels of nutrients (g/m²) have been provided such as 13 N, 7 P₂O₅, 8 K₂O (100%); 9 N, 5 P₂O₅, 5.5 K₂O (70%); and 6.5 N, 3.5 P₂O₅, 4.0 K₂O (50%). The effects of different fertilization levels were evaluated on the yield, leaf pigments (chlorophylls, carotenoids), nitrate concentration, sugars content, and on the antioxidant compounds such as anthocyanins, total phenols and glucosinolates (GLS). Plant stress monitoring was performed by measuring the chlorophyll a fluorescence. Results indicated that yield was not affected and ranged from 0.18 to 0.47 kg/m², and differences were not statistically significant for chlorophylls, carotenoids, and total sugars content. Nitrate concentrations were higher in the BG wild population (4388.65 mg/kg FW) during the second cultivation cycle and lower (1947.21 mg/kg FW) in the same wild population during the first cultivation cycle, both at the 100% fertilization level. Total phenols and anthocyanins were higher in the highest fertilization rate in the MI wild population during the second cycle. The GLS were higher in the lowest fertilization rate in the BG wild population (19 µmol/g FW) grown at the fertilization level of the 50%, and significant differences were observed in the second cycle. In conclusion, the 50% fertilization level can be considered the most suitable for our experimental conditions. Full article

(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)

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