Agronomy

15 pages, 6132 KiB

Open AccessArticle

Evaluation of Soil Quality of Pingliang City Based on Fuzzy Mathematics and Cluster Analysis

by Zhenhua Zhao, Yifei Yang, Bo Dong, Rui Zhang, Guangrong Chen, Zhandong Pan and Dandan Du

Agronomy 2024, 14(6), 1205; https://doi.org/10.3390/agronomy14061205 (registering DOI) - 2 Jun 2024

Pingliang City has a complex topography and diverse soil types. To realize the improvement of soil according to local conditions and the reasonable and sustainable use of soil resources, an evaluation of soil quality in Pingliang City was carried out, based on the [...] Read more.

Pingliang City has a complex topography and diverse soil types. To realize the improvement of soil according to local conditions and the reasonable and sustainable use of soil resources, an evaluation of soil quality in Pingliang City was carried out, based on the soil distribution situation in Pingliang City, adopting a method combining fuzzy mathematics and cluster analysis of the main evaluation factors, such as soil organic matter, topsoil depth, soil erosion intensity, soil moisture regime, effective soil thickness, soil texture, soil profile structure, soil nutrient status and topographical parts, to carry out a comprehensive evaluation. A comprehensive evaluation of soil quality was conducted in seven counties under the jurisdiction of Pingliang City, and the evaluation results were compared and analyzed against the national standard, “Cultivated land quality grade”, to provide a basis for the selection of scientific soil improvement methods. The results of the arable land quality grades indicate that the quality of farmland in Pingliang City is divided into three to ten grades, and the average quality grade of farmland is 6.83, which is in the middle–lower level, and the overall grade distribution shows the characteristics of low in the middle and high in the east and west. The results of fuzzy mathematics combined with cluster analysis indicated the following trends in soil quality for the 12 soil genera: Chuan black gunny soil > yellow moist soil > sandy soil > silt soil > mulching helilu soil> loessal soil> loamy soil > slope loessal soil > arenosol > tillage leaching gray cinnamon soil > calcareous gray cinnamon soil > red clay soil. The results of the combination of fuzzy mathematics and clustering were significantly correlated with the results of the evaluation of the soil quality of arable land; the correlation coefficient was 0.884. This indicates that the method can accurately and objectively review the advantages and disadvantages of arable land soil and can be effectively applied to the evaluation of the soil quality of agricultural soils in other regions. It is a complement to the existing evaluation of the soil quality of arable land and at the same time provides a reference for the improvement of soil quality in agricultural regions. Full article

(This article belongs to the Special Issue Soil Evolution, Management, and Sustainable Utilization)

► Show Figures

Figure 1

19 pages, 12253 KiB

Open AccessArticle

Rapid pH Value Detection in Secondary Fermentation of Maize Silage Using Hyperspectral Imaging

by Yang Yu, Haiqing Tian, Kai Zhao, Lina Guo, Jue Zhang, Zhu Liu, Xiaoyu Xue, Yan Tao and Jinxian Tao

Agronomy 2024, 14(6), 1204; https://doi.org/10.3390/agronomy14061204 (registering DOI) - 2 Jun 2024

Abstract

As pH is a key factor affecting the quality of maize silage, its accurate detection is essential to ensuring product quality. Although traditional methods for testing the pH of maize silage feed are widely used, the procedures are often complex and time-consuming and [...] Read more.

As pH is a key factor affecting the quality of maize silage, its accurate detection is essential to ensuring product quality. Although traditional methods for testing the pH of maize silage feed are widely used, the procedures are often complex and time-consuming and may damage the sample. This study presents a non-destructive hyperspectral imaging (HSI) technology that provides a more efficient and cost-effective method of monitoring pH by capturing the spectral information of samples and analyzing their chemical and physical properties rapidly and without contact. We applied four spectral preprocessing methods, among which the multiplicative scatter correction (MSC) preprocessing method yielded the best results. To minimize model redundancy and enhance predictive performance, we utilized six feature extraction methods for characteristic wavelength extraction, integrating these with partial least squares (PLS), non-linear support vector machine regression (SVR), and extreme learning machine (ELM) algorithms to construct a quantitative pH value prediction model. The results showed that the model based on the bootstrapping soft shrinkage (BOSS) feature wavelength extraction method outperformed the other feature extraction methods, selecting 20 pH value-related feature wavelengths from 256 bands and building a stable BOSS–ELM model with prediction set determination coefficient

(R_{P}^{2}

), root-mean-square error of prediction (RMSEP), and relative percentage deviation (RPD) values of 0.9241, 0.4372, and 3.6565, respectively. To further optimize the model for precisely predicting pH at each pixel in hyperspectral images, we employed three algorithms: the genetic algorithm (GA), whale optimization algorithm (WOA), and bald eagle search (BES). These algorithms optimized and compared the BOSS–ELM model to obtain the best model for predicting maize silage pH: the BOSS–BES–ELM model. This model achieved a determination coefficient (

R_{P}^{2})

of 0.9598, an RMSEP of 0.3216, and an RPD of 5.1448. We generated a visualized distribution map of pH value variation in maize silage using the BOSS–BES–ELM model. This study provides strong technical support and a reference for the rapid, non-destructive detection of maize silage pH from an image, an advancement of great significance to ensuring the quality of maize silage. Full article

(This article belongs to the Section Precision and Digital Agriculture)

► Show Figures

Figure 1

4 pages, 158 KiB

Open AccessEditorial

Agricultural Unmanned Systems: Empowering Agriculture with Automation

by Mengke Zhang and Shubo Wang

Agronomy 2024, 14(6), 1203; https://doi.org/10.3390/agronomy14061203 (registering DOI) - 2 Jun 2024

Abstract

Automation is crucial for the advancement of modern agriculture [...] Full article

(This article belongs to the Special Issue Agricultural Unmanned Systems: Empowering Agriculture with Automation)

17 pages, 871 KiB

Open AccessArticle

The Effect of Foliar Application with Naphthalene Acetic Acid and Potassium Nitrate on the Growth, Sex Ratio, and Productivity of Cucumbers (Cucumis sativas L.) under High Temperatures in Semi-Arid Areas

by Mashael M. Alotaibi, Mohamed M. M. El Nagy, Makhdora Almuziny, Moodi S. Alsubeie, Amero A. I. Abo-Zeid, Fahad Mohammed Alzuaibr, Abdulrahman Alasmari, Bedur Faleh Albalawi, Ahmed H. M. Abd-Elwahed, Khadiga Ahmed Ismail and Mamdouh M. A. Awad-Allah

Agronomy 2024, 14(6), 1202; https://doi.org/10.3390/agronomy14061202 (registering DOI) - 1 Jun 2024

Abstract

High temperatures in late spring, summer, and autumn are one of the main elements limiting cucumber production. Heat stress in cucumber plants leads to significant changes in sex expression and negative effects at the physiological stage, including decreased absorption of water and nutrients, [...] Read more.

High temperatures in late spring, summer, and autumn are one of the main elements limiting cucumber production. Heat stress in cucumber plants leads to significant changes in sex expression and negative effects at the physiological stage, including decreased absorption of water and nutrients, decreased photosynthetic functions, and increased respiration, which in turn affects growth and production. Therefore, it is very difficult for cucumber plants exposed to heat stress to improve their productivity, especially in arid and semi-arid regions. Cucumber plants bear a variety of flower forms, including staminate, pistillate, and hermaphrodites that occur in different arrangements. In addition, maleness is considered the main problem in cucumber production, as it significantly reduces fruit yield. Recently, the growth, flowering, and productivity of plants have been controlled with the help of growth-regulating substances, and one of these substances is naphthalene acetic acid (NAA), which is of great importance in modifying sex in cucumber and various cucurbit crops. Two experiments were conducted during 2022 and 2023 during the summer season to study the effect of foliar spraying of two levels of potassium nitrate, 500 mg/L and 1000 mg/L, and two levels of NAA, 50 mg/L and 100 mg/L, individually and together, and the comparison treatment in nine treatments on growth traits, sex ratio, fruit traits and yield of cucumber (Cucumis sativas L.) plants in three replicates in a completely randomized block design. The results indicated that applying the treatment containing 1000 mg/L KNO₃ + 100 mg/L NAA led to obtaining the highest value in most vegetable growth, flowering, and production parameters, with a significant increase compared to the control and all other treatments. Followed by treatments consisting of potassium nitrate and NAA, which gave high values in the traits of sex ratio %, fruit setting %, fruit yield, and most other traits. This study showed the importance of spraying with both NAA and potassium nitrate, individually or in combination, and the high combined effect of both in the treatments that contained each of them in the vegetative growth traits and floral traits such as the number of female flowers, the sexual ratio, fruit set percentage, weight fruit, length fruit, and the fruit yield in cucumber plants grown in the summer season with high temperatures Full article

(This article belongs to the Special Issue Regulatory Mechanism of Growth Regulators on Crop Growth and Development)

► Show Figures

Figure 1

30 pages, 1798 KiB

Open AccessReview

Genetic and Genomic Pathways to Improved Wheat (Triticum aestivum L.) Yields: A Review

by Zaid Chachar, Lina Fan, Sadaruddin Chachar, Nazir Ahmed, Mehar-un-Nisa Narejo, Naseer Ahmed, Ruiqiang Lai and Yongwen Qi

Agronomy 2024, 14(6), 1201; https://doi.org/10.3390/agronomy14061201 (registering DOI) - 1 Jun 2024

Abstract

Wheat (Triticum aestivum L.) is a fundamental crop essential for both human and animal consumption. Addressing the challenge of enhancing wheat yield involves sophisticated applications of molecular genetics and genomic techniques. This review synthesizes current research identifying and characterizing pivotal genes that [...] Read more.

Wheat (Triticum aestivum L.) is a fundamental crop essential for both human and animal consumption. Addressing the challenge of enhancing wheat yield involves sophisticated applications of molecular genetics and genomic techniques. This review synthesizes current research identifying and characterizing pivotal genes that impact traits such as grain size, number, and weight, critical factors influencing overall yield. Key genes including TaSPL17, ABP7, TaGNI, TaCKX6, TaGS5, TaDA1, WAPO1, TaRht1, TaTGW-7A, TaGW2, TaGS5-3A, TaSus2-2A, TaSus2-2B, TaSus1-7A, and TaSus1-7B are examined for their roles in these traits. The review also explores genes responsive to environmental changes, which are increasingly significant under current climate variability. Multi-trait regulatory genes and quantitative trait loci (QTLs) that contribute to these traits are discussed, highlighting their dual influences on grain size and yield. Furthermore, the paper underscores the utility of emerging technologies such as CRISPR/Cas9, Case13, and multi-omics approaches. These innovations are instrumental for future discoveries and are poised to revolutionize wheat breeding by enabling precise genetic enhancements. Facing unprecedented challenges from climate change, the identification and utilization of these candidates is crucial. This review aims to be a comprehensive resource for researchers, providing an integrative understanding of complex traits in wheat and proposing new avenues for research and crop improvement strategies. Full article

(This article belongs to the Special Issue Genetic Dissection and Improvement of Crop Traits)

16 pages, 1533 KiB

Open AccessArticle

Camelina Intercropping with Pulses a Sustainable Approach for Land Competition between Food and Non-Food Crops

by Elena Pagani, Federica Zanetti, Federico Ferioli, Erika Facciolla and Andrea Monti

Agronomy 2024, 14(6), 1200; https://doi.org/10.3390/agronomy14061200 (registering DOI) - 1 Jun 2024

Abstract

With increasing global attention toward the need for mitigating climate change, the transition to sustainable energy sources has become an essential priority. Introducing alternative oilseed crops, such as camelina (Camelina sativa L.), into intercropping systems with staple food crops can mitigate ILUC [...] Read more.

With increasing global attention toward the need for mitigating climate change, the transition to sustainable energy sources has become an essential priority. Introducing alternative oilseed crops, such as camelina (Camelina sativa L.), into intercropping systems with staple food crops can mitigate ILUC (indirect land use change) and their negative impact on biofuel production. The present study compared camelina + field pea intercropping (ICw + IP, winter sowing) and camelina + lentil intercropping (ICs + IL, spring sowing) with their respective single crops regarding weed control, soil coverage, yields, and camelina seed quality (1000-seed weight, oil, and fatty acid composition). The comparison between different cropping systems was conducted using a one-way ANOVA. Both intercropping improved weed control at an early stage but no differences in soil coverage were found. Camelina seed yield was negatively affected by the presence of peas, whereas the pulse was unaffected. Conversely, camelina seed yield was not affected when intercropped with lentils while lentils reduced their yield in the intercropping. Furthermore, when camelina was intercropped with lentils, a significant increase was reported in 1000-seed weight and α -linolenic acid (C18:3) compared with the sole-camelina. However, both intercropping systems had a land equivalent ratio (LER, based on total seed yield at maturity) higher than one. Defining the best combination of crops and the optimal sowing and harvesting settings remain key to increasing the adoption of intercropping systems by farmers. Full article

(This article belongs to the Special Issue Promoting Intercropping Systems in Sustainable Agriculture)

► Show Figures

Figure 1

34 pages, 10443 KiB

Open AccessArticle

Development of Tetramycin-Loaded Core–Shell Beads with Hot-/Wet-Responsive Release Properties for Control of Bacterial Wilt Disease

by Juntao Gao, Guan Lin, Xinmin Deng, Junxian Zou, Yong Liu, Xingjiang Chen and Shiwang Liu

Agronomy 2024, 14(6), 1199; https://doi.org/10.3390/agronomy14061199 (registering DOI) - 1 Jun 2024

Abstract

Plant bacterial wilt is caused by Ralstonia solanacearum, a soilborne pathogen that infects plant conduits, leading to wilt disease. It is extremely difficult to cure plants infected with Ralstonia solanacearum; however, bactericide-loaded beads with hot-/wet-responsive properties may be able to release [...] Read more.

Plant bacterial wilt is caused by Ralstonia solanacearum, a soilborne pathogen that infects plant conduits, leading to wilt disease. It is extremely difficult to cure plants infected with Ralstonia solanacearum; however, bactericide-loaded beads with hot-/wet-responsive properties may be able to release a biocide in line with the increase in the hot-/wet-associated activity of Ralstonia solanacearum, effectively killing the pathogenic cells and providing high levels of plant protection. A biopesticide, Tetramycin, was embedded in corn kernel powder (CKP)-based cores. An oil-phase mixture was sprayed onto the core surface to form a hot-/wet-responsive intermediate shell (IMS). Subsequently, a layer of ethyl cellulose (EC) and hydroxypropyl methyl cellulose (HPMC) was coated onto the IMS to create a single wet-responsive outer shell (OTS). The ratios of the components in the cores, including the corn kernel powder (CKP), xanthan gum (XG), and Tetramycin, were optimized, as well as those of the IMS, including pentaerythrityl tetrastearate (PETS), pentaerythrityl tetraoleate (PETO), polyethylene glycol stearate (PEG400MS), and polyethylene glycol monooleate (PEG400MO), and those of the outer shell (OTS), including ethyl cellulose (EC) and hydroxypropyl methyl cellulose (HPMC). A texture performance analysis, differential scanning calorimetry (DSC) analysis, thermogravimetric analysis (TGA), temperature and humidity response performance tests, scanning electron microscope (SEM) observations, and a field effectiveness test were conducted to characterize the Tetramycin-loaded beads. The results indicated that the optimal formula for the bead cores comprised a mass ratio of CKP/Tetramycin solution/XG = 13.5:23:2. The preferred mass ratio for IMS was PETS/PETO/PEG400MO = 10:30:10, and the formula for the applicable OTS consisted of a mass ratio of EC/HPMC = 5:1. In soil with a temperature of 30–35 °C and humidity of 30%, the release period of the Tetramycin-loaded beads, with a cumulative release rate of over 95%, could last up to 35 days. Furthermore, the Tetramycin-loaded beads exhibited a gradual and multi-cyclic release process under alternating hot/wet and dry/cold environments. The relative preventive efficacy of 54.74% on tobacco was revealed at a field-testing scale. A significant reduction in the abundance of Ralstonia solanacearum was also observed under treatment with the Tetramycin-loaded beads. The early fungal community structure exhibited higher consistency compared to the control. However, in the later stage, the diversity differences between the soil layers were restored. In conclusion, Tetramycin-loaded beads that could effectively respond to temperature and humidity fluctuations were developed, resulting in enhanced disease prevention efficacy and offering broad prospects for the prevention and control of Ralstonia solanacearum in agricultural settings. Full article

(This article belongs to the Section Pest and Disease Management)

18 pages, 3106 KiB

Open AccessArticle

Comparative Gene Expression following 2,4-D Treatment in Two Red Clover (Trifolium pratense L.) Populations with Differential Tolerance to the Herbicide

by Lucas Pinheiro de Araujo, Michael Barrett and Randy D. Dinkins

Agronomy 2024, 14(6), 1198; https://doi.org/10.3390/agronomy14061198 (registering DOI) - 1 Jun 2024

Abstract

Incorporation of red clover (Trifolium pratense L.) into grass pastures can reduce the need for nitrogen fertilizer applications and increase the nutritional value of the forage. However, red clover cultivars available for Kentucky producers are highly susceptible to herbicides, such as 2,4-D [...] Read more.

Incorporation of red clover (Trifolium pratense L.) into grass pastures can reduce the need for nitrogen fertilizer applications and increase the nutritional value of the forage. However, red clover cultivars available for Kentucky producers are highly susceptible to herbicides, such as 2,4-D (2,4-dichlorophenoxy acetic acid), used for pasture broadleaf weed control. To overcome this problem, ‘UK2014’ red clover was selected for increased tolerance to 2,4-D. We employed a transcriptome analysis approach to compare the gene expression response following 2,4-D treatment of ‘UK2014’ to that of ‘Kenland’, a 2,4-D sensitive red clover and one of the parents of ‘UK2014’. The objectives were to first determine if the increased 2,4-D tolerance in ‘UK2014’ is reflected in a change of transcription response and/or a quicker recovery of a transcriptional response following 2,4-D treatment, and second, to identify genes, whether constitutively expressed or induced by 2,4-D, which could be the basis for the increased 2,4-D tolerance. Leaf tissue from the two red clovers grown in the field was collected at 4, 24, and 72 h after 2,4-D (1.12 kg 2,4-amine a.e. ha⁻¹) treatment from both untreated and treated plants. Global gene expression was determined with reads from Illumina Hiseq 2500 mapped against the red clover draft genome, Tpv2.1 (GenBank Accession GCA_900079335.1). Genes that displayed differential expression (DEGs) following 2,4-D treatment were selected for further analysis. The number of DEGs was higher for ‘Kenland’ than for ‘UK2014’, suggesting that a lower transcriptional response corresponds with the higher 2,4-D tolerance in the ‘UK2014’ line. Similarly, gene ontology enrichment analysis revealed that expression of photosynthesis-related genes was less affected by 2,4-D in the ‘UK2014’ line than ‘Kenland’. Although we were not able to identify any specific genes that are the basis for the increased 2,4-D tolerance of ‘UK2014’, we concluded that the increased 2,4-D tolerance of ‘UK2014’ correlates with a decreased transcription response to 2,4-D. Additionally, expression of several cytochrome P450 genes that had different isoforms between ‘UK2014’ and ‘Kenland’ increased significantly in both following 2,4-D treatment, one or more of these P450s could be mediators of 2,4-D metabolism and tolerance in red clover. Full article

(This article belongs to the Special Issue Integrated Ways to Improve Forage Production and Nutritional Value)

► Show Figures

Figure 1

22 pages, 43859 KiB

Open AccessArticle

Enhanced Tomato Pest Detection via Leaf Imagery with a New Loss Function

by Lufeng Mo, Rongchang Xie, Fujun Ye, Guoying Wang, Peng Wu and Xiaomei Yi

Agronomy 2024, 14(6), 1197; https://doi.org/10.3390/agronomy14061197 (registering DOI) - 1 Jun 2024

Abstract

Pests have caused significant losses to agriculture, greatly increasing the detection of pests in the planting process and the cost of pest management in the early stages. At this time, advances in computer vision and deep learning for the detection of pests appearing [...] Read more.

Pests have caused significant losses to agriculture, greatly increasing the detection of pests in the planting process and the cost of pest management in the early stages. At this time, advances in computer vision and deep learning for the detection of pests appearing in the crop open the door to the application of target detection algorithms that can greatly improve the efficiency of tomato pest detection and play an important technical role in the realization of the intelligent planting of tomatoes. However, in the natural environment, tomato leaf pests are small in size, large in similarity, and large in environmental variability, and this type of situation can lead to greater detection difficulty. Aiming at the above problems, a network target detection model based on deep learning, YOLONDD, is proposed in this paper. Designing a new loss function, NMIoU (Normalized Wasserstein Distance with Mean Pairwise Distance Intersection over Union), which improves the ability of anomaly processing, improves the model’s ability to detect and identify objects of different scales, and improves the robustness to scale changes; Adding a Dynamic head (DyHead) with an attention mechanism will improve the detection ability of targets at different scales, reduce the number of computations and parameters, improve the accuracy of target detection, enhance the overall performance of the model, and accelerate the training process. Adding decoupled head to Head can effectively reduce the number of parameters and computational complexity and enhance the model’s generalization ability and robustness. The experimental results show that the average accuracy of YOLONDD can reach 90.1%, which is 3.33% higher than the original YOLOv5 algorithm and is better than SSD, Faster R-CNN, YOLOv7, YOLOv8, RetinaNet, and other target detection networks, and it can be more efficiently and accurately utilized in tomato leaf pest detection. Full article

(This article belongs to the Special Issue Pests, Pesticides, Pollinators and Sustainable Farming)

► Show Figures

Figure 1

22 pages, 3571 KiB

Open AccessArticle

Straw Returning Proves Advantageous for Regulating Water and Salt Levels, Facilitating Nutrient Accumulation, and Promoting Crop Growth in Coastal Saline Soils

by Rui Liu, Min Tang, Zhenhai Luo, Chao Zhang, Chaoyu Liao and Shaoyuan Feng

Agronomy 2024, 14(6), 1196; https://doi.org/10.3390/agronomy14061196 (registering DOI) - 1 Jun 2024

Abstract

Saline soils limit plant growth due to high salinity. Straw returning has proven effective in enhancing soil adaptability and agricultural stability on saline lands. This study evaluates the effects of different straw-returning methods—straw mulching (SM), straw incorporation (SI), and straw biochar (BC)—on soil [...] Read more.

Saline soils limit plant growth due to high salinity. Straw returning has proven effective in enhancing soil adaptability and agricultural stability on saline lands. This study evaluates the effects of different straw-returning methods—straw mulching (SM), straw incorporation (SI), and straw biochar (BC)—on soil nutrients, water dynamics, and salinity in a barley–cotton rotation system using field box experiments. SM improved soil water retention during barley’s jointing and heading stages, while SI was more effective in its filling and maturation stages. BC showed lesser water storage capacity. During cotton’s growth, SI enhanced early-stage water retention, and SM benefited the flowering and boll opening stages. Grey relational analysis pinpointed significant water relationships at 10 cm and 20 cm soil depths, with SM regulating water across layers. SM and BC notably reduced soil conductivity, primarily within the top 20 cm, and their effectiveness decreased with depth. SI significantly lowered soil conductivity at barley’s jointing stage. SM effectively reduced salinity at 10 cm and 20 cm soil depths, whereas BC decreased soil conductivity throughout barley’s jointing, filling, and heading stages. For cotton, SI lowered soil conductivity at the seedling and boll opening stages. SM consistently reduced salinity across all stages, and BC decreased conductivity in the top 30 cm of soil during all growth stages. Both SM and BC significantly enhanced the total nutrient availability for barley and cotton, especially improving soil organic carbon and available potassium, with BC showing notable improvements. At barley’s heading stage, SI maximized dry matter accumulation, while SM boosted accumulation in leaves, stems, and spikes during the filling and maturation stages. Straw returning increased barley yield, particularly with SM and BC, and improved water use efficiency by 11.60% and 5.74%, respectively. For cotton, straw returning significantly boosted yield and water use efficiency, especially with SI and SM treatments, enhancing the total bolls and yield. In conclusion, straw returning effectively improves saline soils, enhances fertility, boosts crop yields, and supports sustainable agriculture. These results provide a robust scientific foundation for adopting efficient soil improvement strategies on saline lands, with significant theoretical and practical implications for increasing agricultural productivity and crop resilience to salt stress. Full article

(This article belongs to the Special Issue Nutrient Cycling and Environmental Effects on Farmland Ecosystems)

► Show Figures

Figure 1

18 pages, 6217 KiB

Open AccessReview

Toward an Environmentally Friendly Future: An Overview of Biofuels from Corn and Potential Alternatives in Hemp and Cucurbits

by Jelena Visković, Dušan Dunđerski, Boris Adamović, Goran Jaćimović, Dragana Latković and Đorđe Vojnović

Agronomy 2024, 14(6), 1195; https://doi.org/10.3390/agronomy14061195 (registering DOI) - 1 Jun 2024

Abstract

Increased energy consumption and climate change, driven by greenhouse gas emissions, pose significant risks to global sustainability. Concerns about using agricultural land for fuel production and its competition with food production have made feedstocks like corn (Zea mays) highly controversial. This [...] Read more.

Increased energy consumption and climate change, driven by greenhouse gas emissions, pose significant risks to global sustainability. Concerns about using agricultural land for fuel production and its competition with food production have made feedstocks like corn (Zea mays) highly controversial. This study explores the potential of alternative feedstocks, such as hemp (Cannabis sativa) and cucurbits (family Cucurbitaceae), for biofuel production amidst environmental concerns linked to fossil fuel usage. Hemp is widely acknowledged as a promising feedstock for sustainable biorefinery due to its agricultural adaptability and its ability to produce oil and carbohydrates. Cucurbits seeds are characterized by a high oil content, which can be utilized in the food industry or for energy production as biofuel. As a byproduct of cucurbits processing, a significant number of seeds often remains, which constitutes waste. By examining hemp and cucurbit byproducts and waste, which are suitable for bioenergy production, this research highlights the promise these alternative feedstocks hold for the biofuel industry. Utilizing these resources presents a viable route to diminish dependence on fossil fuels and transition toward a more environmentally sustainable energy future. Full article

(This article belongs to the Special Issue Transforming AgriFood Systems under a Changing Climate)

► Show Figures

Figure 1

18 pages, 13836 KiB

Open AccessArticle

The Performance of Agronomic and Quality Traits of Quinoa under Different Altitudes in Northwest of China

by Hongliang Cui, Qing Yao, Bao Xing, Bangwei Zhou, Syed Sadaqat Shah and Peiyou Qin

Agronomy 2024, 14(6), 1194; https://doi.org/10.3390/agronomy14061194 (registering DOI) - 1 Jun 2024

Abstract

Quinoa is a resilient crop known for its adaptability to diverse environmental conditions. This study examined the agronomic performance and ecological adaptability of quinoa across four distinct altitudes in the northwestern regions of China. Six quinoa genotypes were assessed for agronomic traits, phenology [...] Read more.

Quinoa is a resilient crop known for its adaptability to diverse environmental conditions. This study examined the agronomic performance and ecological adaptability of quinoa across four distinct altitudes in the northwestern regions of China. Six quinoa genotypes were assessed for agronomic traits, phenology and yield performances, and nutritional quality characteristics in Yining city, Nilka County, Tekes County and Zhaosu County under varied environmental conditions. Our findings demonstrate significant variations in all measured traits, including agronomic and nutritional quality traits, across the various altitudes and genotypes. In Yining city, a warmer and lower altitude area, genotypes exhibit superior traits for fodder production, including increased branches, longer panicles, robust stems, and high seed protein content. Genotypes Jinli 1 and Beijing 2 achieve yields exceeding 3 tons per hectare (t/ha), highlighting the region’s productivity. The Nilka and Tekes counties boasted the shortest quinoa crop cycles, with Jinli 1 yielding 4.05 t/ha seeds in Tekes County, exhibiting high protein and fat content alongside low saponins, making it a prime location for yield production. Zhaosu County, with its cooler climate and fertile chernozem soil, elicited high 1000 seed weight and more robust protein response than Nilka and Tekes counties, illustrating the impact of soil fertility on nutritional composition. Correlation analyses further elucidated that the plants characterized by shorter flowering times, crop cycles, compact inflorescence, and taller heights exhibited superior seed yields. Our study contributes significant insights into the ecological adaptability and nutritional dynamics of quinoa, with implications for sustainable crop production and food security in diverse agroecosystems. Full article

(This article belongs to the Special Issue Adaptation of Crops to the Environment under Climate Change: Physiological and Agronomic Strategies—Volume III)

► Show Figures

Figure 1

14 pages, 2826 KiB

Open AccessArticle

Comparison of Oil Extraction and Density Extraction Method to Extract Microplastics for Typical Agricultural Soils in China

by Xiaoli Zhao, Zihan Liu, Jichao Zuo, Lu Cai, Yihang Liu, Jianqiao Han and Man Zhang

Agronomy 2024, 14(6), 1193; https://doi.org/10.3390/agronomy14061193 (registering DOI) - 1 Jun 2024

Abstract

Microplastic pollution in agricultural soil threatens soil quality and human health which has attracted extensive attention worldwide. However, there is no uniform standard for microplastic extraction methods and the identification of microplastic component in different typical agricultural soils. In this study, an artificial [...] Read more.

Microplastic pollution in agricultural soil threatens soil quality and human health which has attracted extensive attention worldwide. However, there is no uniform standard for microplastic extraction methods and the identification of microplastic component in different typical agricultural soils. In this study, an artificial simulation adding experiment was used in eight typical agricultural soil samples in China. The aim of the study was to use different methods for extraction, comparing the extraction rates of four microplastics and their influence on polymer identification using ATR- FTIR. The two separate methods were oil extraction (water + oil and saturated NaCl solution + oil), and density method (saturated NaCl solution). The four types of microplastics include polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), and polyethylene (PE). We found that the oil extraction method effectively extracted four types of microplastics in agricultural soils, which varied from 83.33% to 100.00%. However, the extraction rate of PET under the oil extraction method and PP under the density method from Southern laterite area was lower than other soils. The presence of iron and aluminum ions influenced the extraction rates of microplastics in the Southwest laterite area. With the increase in microplastic density, the extraction rates of the density method decrease. The oil extraction methods with the cleaning of residual oil were recommended for the higher density microplastics. The density method was recommended for the lighter microplastics in agricultural soils. However, these two extraction methods were not ideal to extract the microplastics from the Southern laterite area and the appropriate extraction methods for laterite need to be further studied in the future. Our results can provide technical support for the extraction treatment and scientific microplastic pollution control of typical agricultural soils with different erosion areas. Full article

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

► Show Figures

Figure 1

11 pages, 678 KiB

Open AccessReview

The Potential of Three Summer Legume Cover Crops to Suppress Weeds and Provide Ecosystem Services—A Review

by Stavros Zannopoulos, Ioannis Gazoulis, Metaxia Kokkini, Nikolaos Antonopoulos, Panagiotis Kanatas, Marianna Kanetsi and Ilias Travlos

Agronomy 2024, 14(6), 1192; https://doi.org/10.3390/agronomy14061192 (registering DOI) - 1 Jun 2024

Abstract

Recently, there has been growing interest in the use of summer cover crops that can be grown during summer fallow periods of crop rotation. This study evaluates the potential of sunn hemp (Crotalaria juncea L.), velvetbean [Mucuna pruriens (L.) DC.] and [...] Read more.

Recently, there has been growing interest in the use of summer cover crops that can be grown during summer fallow periods of crop rotation. This study evaluates the potential of sunn hemp (Crotalaria juncea L.), velvetbean [Mucuna pruriens (L.) DC.] and cowpea [Vigna unguiculata (L.) Walp.]. as three annual legumes summer cover crops. The main objective of this review was to conduct global research comparing these summer cover crops to investigate the benefits, challenges, and trade-offs among ecosystems services when implementing these summer cover crops. In European agriculture, there are three main windows in crop rotation when these summer legumes can be grown: Around mid-spring after winter fallow, early summer after harvest of a winter crop, and mid- to late summer after harvest of an early-season crop. All three legumes can suppress weeds while they are actively growing. After termination, their mulch can create unfavorable conditions for weed emergence. Sunn hemp and velvetbean cover crops can cause a reduction in weed biomass of more than 50%. In addition to their ability to suppress weeds, sunn hemp, velvetbean, and cowpea provide a variety of ecosystem services, such as improving soil health, quality, and fertility, controlling pests, and sequestering carbon. The review highlights their promising role in weed suppression and their contribution to sustainable agricultural practices. However, further research is needed to evaluate their performance in weed management and their environmental impact in field trials under different soil-climatic conditions, as cover cropping is an effective practice but highly context-specific. Full article

(This article belongs to the Special Issue Weed Biology and Ecology: Importance to Integrated Weed Management)

► Show Figures

Figure 1

22 pages, 5557 KiB

Open AccessArticle

Low-Cadmium Wheat Cultivars Limit the Enrichment, Transport and Accumulation of Cadmium

by Liyong Bai, Suo Ding, Xiaoli Li, Chuanli Ning, He Liu, Mei Sun, Dongmei Liu, Ke Zhang, Shuangshuang Li, Xiaojing Yu and Jiulan Dai

Agronomy 2024, 14(6), 1191; https://doi.org/10.3390/agronomy14061191 (registering DOI) - 1 Jun 2024

Abstract

Low-cadmium (Cd) accumulating wheat cultivars (LAWC-Cds) can effectively reduce the total Cd content in wheat grains (Grain-Cd). Thirteen LAWC-Cds were planted in three fields to study the enrichment, transport, and accumulation patterns of Cd in LAWC-Cds. Compared with the soil properties before planting, [...] Read more.

Low-cadmium (Cd) accumulating wheat cultivars (LAWC-Cds) can effectively reduce the total Cd content in wheat grains (Grain-Cd). Thirteen LAWC-Cds were planted in three fields to study the enrichment, transport, and accumulation patterns of Cd in LAWC-Cds. Compared with the soil properties before planting, the soil pH and the total Cd content in the soil decreased, while the Cd content in the diethylenetriaminepentaacetic acid extract, soil conductivity, and soil organic matter increased at wheat maturity. The Cd enrichment capacity of the different organs of wheat decreased in the following order: root > leaf > rachis > stem > glume > grain. The dynamics of Cd accumulation in roots affected Grain-Cd, and these factors were negatively correlated. The Cd content and Cd accumulation in all organs of LAWC-Cds showed strong negative correlations with the lengths of the first and second internodes and highly significant positive correlations with both grains per spike and awn length. Structural equation modeling showed that the Cd content of wheat organs had the most direct effect (0.639) in determining Grain-Cd, and soil properties had the largest effect (0.744) in influencing Grain-Cd. This study is important for screening wheat cultivars with stable low Cd-accumulation characteristics. Full article

(This article belongs to the Section Agroecology Innovation: Achieving System Resilience)

► Show Figures

Figure 1

11 pages, 2984 KiB

Open AccessArticle

Effects of Salt Water on Growth and Quality of Raphanus sativus L. and Physiological Responses against Salt Stress

by Haiyan Zhu, Mingyu Liu, Haoyi Xu, Di Feng and Xiaoan Sun

Agronomy 2024, 14(6), 1190; https://doi.org/10.3390/agronomy14061190 (registering DOI) - 1 Jun 2024

Abstract

To determine the optimal salinity of irrigation water for fruit radish cultivated in peat, five levels of salinized water were used to evaluate their effect on the growth and quality of fruit radish (Raphanus sativus L.). Results showed that with an increase [...] Read more.

To determine the optimal salinity of irrigation water for fruit radish cultivated in peat, five levels of salinized water were used to evaluate their effect on the growth and quality of fruit radish (Raphanus sativus L.). Results showed that with an increase in salinity, the leaf growth was somehow inhibited, but the fleshy root growth increased, and quality improved with more soluble solids, sugar, protein, and Vitamin C substances in fleshy roots. With an increase in water salinity up to 4.2 dS/m, the weight of fleshy roots increased by 51.10% with a high increment in the root/shoot ratio. With the same salt concentration, the content of soluble solids in both root peal and pulp was the highest and improved by 11.06% and 6.70%, respectively. The soluble sugar content was the highest in root peals with the 4.2 dS/m treatment and in fleshy roots with the 7.4 dS/m treatment, with a 55.85% and 32.30% increase, respectively. The content of both soluble protein and vitamin C with the 4.2 dS/m treatment increased by 11.99% and 113.36%, respectively. Strong evidence derived from the study has indicated that 4.2 dS/m salinized irrigation water is optimal for growing ‘ice-cream’ fruit radishes and maintaining ultimate root weight and quality. Full article

(This article belongs to the Special Issue Saline Water Irrigation in Agriculture)

► Show Figures

Figure 1

19 pages, 722 KiB

Open AccessArticle

Comparative Study of Vermicomposting: Apple Pomace Alone and in Combination with Wheat Straw and Manure

by Jasna M. Kureljušić, Slavica M. Vesković Moračanin, Dragutin A. Đukić, Leka Mandić, Vesna Đurović, Branislav I. Kureljušić and Marina T. Stojanova

Agronomy 2024, 14(6), 1189; https://doi.org/10.3390/agronomy14061189 - 31 May 2024

Abstract

Considering the sporadic number of scientific studies on vermicomposting apple pomace waste, this research conducts a comparative analysis of vermicomposting processes using Eisenia fetida, focusing on apple pomace both independently and in combination with wheat straw and/or manure (experiment 1: 60% apple [...] Read more.

Considering the sporadic number of scientific studies on vermicomposting apple pomace waste, this research conducts a comparative analysis of vermicomposting processes using Eisenia fetida, focusing on apple pomace both independently and in combination with wheat straw and/or manure (experiment 1: 60% apple pomace and 40% cattle manure; experiment 2: 60% wheat straw and 40% cattle manure; experiment 3: 80% apple pomace, 10% wheat straw, and 10% cattle manure; and experiment 4: 100% apple pomace). After a 240-day substrate transformation period, all four variations of vermicompost produced demonstrated favorable sensory properties, along with high microbiological and physicochemical quality. Throughout the vermicomposting process, the pH of all vermicomposting mixtures changed, converging towards approximately neutral values by the process’s conclusion. There was an increase in dry matter content, as well as total N, P, K, Ca, and Mg, along with organic matter. Notably, the levels of heavy metals (Zn, Cu, Cd, and Pb) in both the vermicomposting materials and resulting vermicomposts remained significantly below the maximum permissible levels stipulated by Republic of Serbia and European Union legislation, which is directly linked to the ecological origin of the raw materials used. The microbiological quality of the final vermicomposts was deemed satisfactory. Over time, there was a decrease in the counts of aerobic mesophilic bacteria as well as Escherichia coli. The counts of sulfite-reducing clostridia in all substrates remained below 10² CFU/g, while Salmonella spp. and Listeria monocytogenes were not detected in either the composting materials or the resulting composts. The vermiculture of apple pulp exhibited advantageous characteristics, notably a shortened vermicomposting period (150 days) compared to other agricultural waste. This reduction in processing time contributes an additional layer of advantage to the overall quality and efficiency of the resulting vermicompost. Full article

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

13 pages, 2937 KiB

Open AccessArticle

Variability of Root and Shoot Traits under PEG-Induced Drought Stress at an Early Vegetative Growth Stage of Soybean

by Miroslav Bukan, Snježana Kereša, Ivan Pejić, Aleksandra Sudarić, Ana Lovrić and Hrvoje Šarčević

Agronomy 2024, 14(6), 1188; https://doi.org/10.3390/agronomy14061188 - 31 May 2024

Abstract

The performance of a soybean genotype under water deficit stress at an early vegetative stage might be related to its general tolerance to drought. To investigate the plasticity of root and shoot seedling traits in response to drought at an early vegetative stage, [...] Read more.

The performance of a soybean genotype under water deficit stress at an early vegetative stage might be related to its general tolerance to drought. To investigate the plasticity of root and shoot seedling traits in response to drought at an early vegetative stage, a set of 32 soybean genotypes adapted to southeast European growing conditions was grown under polyethylene glycol (PEG) 8000-induced drought stress and well-watered control conditions. Under drought, mean tap root length (RL), shoot length (SL), root fresh weight (RFW) and shoot fresh weight (SFW) decreased significantly by 11, 17, 38 and 34%, respectively, while root dry matter (RDM) and shoot dry matter (SDM) increased significantly by 13 and 11%, respectively. Of the four derived traits, the ratios of RL/SL, RL/RFW and SL/SFW increased significantly by 8, 45 and 28%, respectively, under drought, while the ratio of RFW/SFW decreased significantly by 4%. However, a wide variation between genotypes was observed for all 10 studied seedling traits under both control and drought conditions. Broad sense heritability ranged from 0.53 (RL) to 0.97 (SL) under control conditions and from 0.56 (RL/RFW) to 0.96 (SL) under drought conditions. The correlation coefficients between the traits were either weak or moderate, indicating that the studied traits can be modified independently by selection. Full article

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

23 pages, 1425 KiB

Open AccessArticle

Analysis of an Evaporative Cooling Pad Connected to an Air Distribution System of Perforated Polyethylene Tubes in a Greenhouse

by Sofía Pardo-Pina, Javier Ferrández-Pastor, Francisco Rodríguez and José M. Cámara-Zapata

Agronomy 2024, 14(6), 1187; https://doi.org/10.3390/agronomy14061187 - 31 May 2024

Abstract

The increase in ambient temperature decreases crop yields. Therefore, greenhouse cooling techniques can be considered adaptation strategies to climate change. To improve the efficiency of crop production, semi-closed greenhouses are utilized, which reduce the mass and energy transfer from the greenhouse. Frequently, these [...] Read more.

The increase in ambient temperature decreases crop yields. Therefore, greenhouse cooling techniques can be considered adaptation strategies to climate change. To improve the efficiency of crop production, semi-closed greenhouses are utilized, which reduce the mass and energy transfer from the greenhouse. Frequently, these types of structures include an evaporative panel and a distribution system through perforated inflated ducts. To further improve the management of this type of installation, the present work models its behavior. The proper functioning of these installations greatly depends on temperature, as well as the relative humidity of the exterior air. The results show how the exterior climate conditions affect the values of temperature and relative humidity inside the greenhouse due to its effect on the value of evaporative cooling. The cooling capacity of the air per unit mass of evaporated water is reduced when the temperature and/or humidity of the air to be treated in the evaporative panel increases. Thus, when the exterior air is at 40 °C and its relative humidity is 75%, its temperature after passing through the evaporative panel is 15 °C higher than when the initial state of the exterior air is 30 °C and 30%. The effect of the use of frequency drivers in the fans on energy consumption has also been evaluated. A reduction of 8% in the frequency value causes a 22% decrease in the power consumed and a 15% pressure drop in the circuit. Therefore, reducing the frequency of electrical energy can contribute to energy savings without affecting the climate inside the greenhouse. Full article

14 pages, 2037 KiB

Open AccessArticle

Characteristics of the Soil Microbial Community Structure under Long-Term Chemical Fertilizer Application in Yellow Soil Paddy Fields

by Yehua Yang, Xingcheng Huang, Yu Li, Yanling Liu, Yarong Zhang, Huaqing Zhu, Han Xiong, Song Zhang and Taiming Jiang

Agronomy 2024, 14(6), 1186; https://doi.org/10.3390/agronomy14061186 - 31 May 2024

Abstract

To compare the differences in the soil microbial community structure in yellow soil paddy fields after the long-term application of chemical fertilizer, the role and mechanism of chemical fertilizer in maintaining soil microbial diversity were analyzed, and a theoretical basis for fertilization management [...] Read more.

To compare the differences in the soil microbial community structure in yellow soil paddy fields after the long-term application of chemical fertilizer, the role and mechanism of chemical fertilizer in maintaining soil microbial diversity were analyzed, and a theoretical basis for fertilization management in farmlands was provided. In this study, long-term experiments were conducted at the Scientific Observation and Experimental Station of the Arable Land Conservation and Agricultural Environment (Guizhou), Ministry of Agriculture and Rural Affairs. Soil samples were collected from five treatments: fertilizer N, P, and K (NPK); fertilizer P and K (PK); fertilizer N and K (NK); fertilizer N and P (NP); and no fertilizer (CK). High-throughput sequencing technology was used to analyze the microbial composition and diversity of the colonies, and the influencing factors are discussed. An analysis of the soil bacterial α diversity indices under the different fertilization treatments revealed that the long-term application of NPK fertilizers had less of an effect on the soil bacterial α diversity indices than did the CK. The long-term application of chemical fertilizers significantly reduced the soil bacterial Chao1, Shannon, and Simpson indices, while there was no significant difference in the bacterial Pielou e index among the treatments. The long-term application of chemical fertilizers significantly increased the soil fungal Chao1 index, but the effects on the other indices were not significant (p < 0.05). An analysis of the bacterial and fungal species under different fertilization treatments showed found that compared with CK, the long-term application of chemical fertilizer increased the relative abundance of Proteobacteria to varying degrees while reducing the relative abundance of Chloroflexi. The impact of other phyla was relatively small, and the difference in the relative abundance of fungi was not significant (p < 0.05). Principal component analysis revealed that, at the genus level, the bacterial and fungal community structures in the CK and NK treatments were relatively independent, while those in the NPK, PK, and NP treatments were similar. Random forest analysis revealed that OM, TP, and TK are the dominant factors that affect soil bacteria α diversity. The dominant factors affecting fungi α diversity are pH, OM, and AK. Redundancy analysis indicated that AK and TP were the main factors affecting bacterial community structure, while AP, AK, and pH were the main factors affecting fungal community structure. The conclusion drawn from this study is that the long-term application of nitrogen, phosphorus, and potassium fertilizer; phosphorus and potassium fertilizer; and nitrogen and phosphorus fertilizer can improve soil fertility, alter the soil environment, enhance microbial diversity, and improve the microbial community structure in yellow soil paddy fields, promoting soil ecosystem stability and health. Full article

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

► Show Figures

Figure 1

20 pages, 1702 KiB

Open AccessArticle

Effects of Rotating Rice with Upland Crops and Adding Organic Amendments, and of Related Soil Quality on Rice Yield in the Vietnamese Mekong Delta

by Nguyen Van Qui, Le Van Khoa, Nguyen Minh Phuong, Duong Minh Vien, Tran Van Dung, Tran Ba Linh, Tran Huynh Khanh, Bui Trieu Thuong, Vo Thi Thu Tran, Nguyen Khoi Nghia, Tran Minh Tien, Emmanuel Abatih, Ann Verdoodt, Steven Sleutel and Wim Cornelis

Agronomy 2024, 14(6), 1185; https://doi.org/10.3390/agronomy14061185 - 31 May 2024

Abstract

In the Vietnamese Mekong Delta, soil quality and crop yield are steadily declining under rice monocultures with three crops per year. The objective of this study was to evaluate the medium-term effects of rotating rice with upland crops and adding organic amendments on [...] Read more.

In the Vietnamese Mekong Delta, soil quality and crop yield are steadily declining under rice monocultures with three crops per year. The objective of this study was to evaluate the medium-term effects of rotating rice with upland crops and adding organic amendments on rice yield, and to relate this to soil quality. A field trial with split-plot design including two factors and three replicates was carried out from 2017 to 2020, over the course of nine consecutive cropping seasons. Crop rotations and organic amendments were applied as main-plot and subplot factors, respectively. The rotations were (1) rice–rice–rice (R–R–R), (2) soybean–rice–rice (So–R–R), and (3) sesame–rice–rice (Se–R–R), while organic amendment treatments included (i) no amendment (NO-AM), (ii) compost of rice straw and cow manure (RS+CM), and (iii) sugarcane compost (SGC); the composts were applied at a rate of 2.0 t ha⁻¹. The rotation cycle started with the so-called spring–summer (SS) season, followed by the summer–autumn (SA) season and ending with the winter–spring (WS) season. Rice yield significantly (p < 0.05) increased under organic amendments after nine growing seasons (2019–2020 WS), with an increment of 5.1% for RS+CM (7.07 ton/ha) and 6.1% for SGC (7.14 ton/ha). Contrary to our expectation, rotations with upland crops did not significantly increase rice yield. Rice yield significantly and positively correlated with an integrated soil quality index–SQI (r = 0.85) for the topsoil (0–15 cm), but not for the subsoil (15–30 cm). The increased availability of soil nutrients (Si and marginally also P) and improved soil physical properties probably induced by organic amendments, along with other soil properties under study, cumulatively attributed to enhanced rice yield. Repeated organic amendments thus becomes an effective management practice in improving soil quality under rice-based systems and could be applied to sustain rice yield in rice-producing regions with similar soil types and climatic conditions. Use of a SQI involving several soil quality indicators enables us to quantify the overall importance of soil fertility for rice yield versus other factors, and it provides an effective means of quantifying the integrated effect of improved management. Moreover, integrating a wide range of soil quality indicators in a SQI ensures its applicability across diverse settings, including different crop rotations and various soil types. Full article

(This article belongs to the Section Agroecology Innovation: Achieving System Resilience)

► Show Figures

Figure 1

15 pages, 2030 KiB

Open AccessArticle

Foliar Application of Selenium Enhances Drought Tolerance in Tomatoes by Modulating the Antioxidative System and Restoring Photosynthesis

by Yuan Zhong, Haixue Cui, Huanhuan Li, Xiaoman Qiang, Qisheng Han and Hao Liu

Agronomy 2024, 14(6), 1184; https://doi.org/10.3390/agronomy14061184 - 31 May 2024

Abstract

Drought stress can impact the physiological and biochemical properties of crops. However, selenium (Se) can effectively alleviate the abiotic stress experienced by plants. This study aims to investigate how applying selenium to tomato leaves affects their antioxidant system and photosynthetic traits when subjected [...] Read more.

Drought stress can impact the physiological and biochemical properties of crops. However, selenium (Se) can effectively alleviate the abiotic stress experienced by plants. This study aims to investigate how applying selenium to tomato leaves affects their antioxidant system and photosynthetic traits when subjected to drought conditions. The experiment used four different foliar selenium concentrations and three different irrigation levels. The investigation scrutinized the effects of foliar spraying employing different selenium concentrations on the antioxidant system, osmotic adjustment substances, photosynthetic performance, and growth indices of tomatoes under drought stress. The findings indicated that drought stress led to cellular oxidative damage, significantly elevating peroxide, MDA, proline, and soluble sugar content (p < 0.001). Under severe drought stress, malondialdehyde (MDA) and proline levels increased by 21.2% and 110.0% respectively, compared to well-watered conditions. Concurrently, the net photosynthetic rate exhibited a reduction of 26.0% and dry matter accumulation decreased by 35.5%. However, after spraying with a low concentration of selenium, selenium reduced oxidative damage and malondialdehyde content by reducing the content of peroxide in leaves, restoring photosynthesis, and promoting the normal growth of tomato. Compared to the control group, spraying with 2.5 mg·L⁻¹ selenium resulted in a 21.5% reduction in MDA content, a 111.8% increase in net photosynthetic rate, and a 29.0% increase in dry matter accumulation. When subjected to drought stress conditions, foliar spraying of low concentrations of selenium (2.5 mg·L⁻¹) can effectively reduce oxidative damage caused by drought stress and alleviate growth constraints in tomatoes. In addition, treatments with high selenium concentrations exhibited specific toxic effects. These findings offer valuable insights into the mechanisms governing selenium-induced drought tolerance in tomatoes, thus advancing our comprehension of standard tomato production practices. Full article

(This article belongs to the Special Issue Crop Management in Water-Limited Cropping Systems)

► Show Figures

Figure 1

16 pages, 2464 KiB

Open AccessArticle

Genome-Wide Association Study and Candidate Gene Mining of Seed Size Traits in Soybean

by Pu Zhang, Zhiya Yang, Shihao Jia, Guoliang Chen, Nannan Li, Benjamin Karikari and Yongce Cao

Agronomy 2024, 14(6), 1183; https://doi.org/10.3390/agronomy14061183 - 30 May 2024

Abstract

Seed size traits, including seed length (SL), seed width (SW), and seed thickness (ST), are crucial appearance parameters that determine soybean seed weight, yield, and ultimate utilization. However, there is still a large gap in the understanding of the genetic mechanism of these [...] Read more.

Seed size traits, including seed length (SL), seed width (SW), and seed thickness (ST), are crucial appearance parameters that determine soybean seed weight, yield, and ultimate utilization. However, there is still a large gap in the understanding of the genetic mechanism of these traits. Here, 281 soybeans were utilized to analyze the genetic architecture of seed size traits in different years through multiple (single-locus and multi-locus) genome-wide association study (GWAS) models, and candidate genes were predicted by integrating information on gene function and transcriptome sequencing data. As a result, two, seven, and three stable quantitative trait nucleotides (QTNs) controlling SL, SW, and ST were detected in multiple environments using the single-locus GWAS model, and concurrently detected by the results of the multi-locus GWAS models. These stable QTNs are located on 10 linkage disequilibrium blocks, with single genome regions ranging in size from 20 to 440 kb, and can serve as the major loci controlling soybean seed size. Furthermore, by combining gene functional annotation and transcriptome sequencing data of seeds at different developmental stages from two extreme soybean accessions, nine candidate genes, including Glyma.05G038000, Glyma.05G244100, Glyma.05G246900, Glyma.07G070200, Glyma.11G010000, Glyma.11G012400, Glyma.17G165500, Glyma.17G166500, and Glyma.20G012600 within the major loci that may regulate soybean seed size, were mined. Overall, these findings offer valuable insights for molecular improvement breeding as well as gene functional studies to unravel the mechanism of soybean seed size. Full article

(This article belongs to the Special Issue New Insights in Soybean Germplasm Resources, Genetic Breeding and Production)

14 pages, 1487 KiB

Open AccessArticle

Temporal Analysis of the Relationship between Black Bean Aphid (Aphis fabae) Infestation and Meteorological Conditions in Faba Bean (Vicia faba)

by Mohammad Almogdad, Karolina Lavrukaitė and Roma Semaškienė

Agronomy 2024, 14(6), 1182; https://doi.org/10.3390/agronomy14061182 - 30 May 2024

Abstract

Faba beans (Vicia faba L.) face threats from pests like the black bean aphid (Aphis fabae S.). By understanding the intricate interactions between environmental factors and pest dynamics, we aim to enhance pest management practices in leguminous crop production for improved [...] Read more.

Faba beans (Vicia faba L.) face threats from pests like the black bean aphid (Aphis fabae S.). By understanding the intricate interactions between environmental factors and pest dynamics, we aim to enhance pest management practices in leguminous crop production for improved efficiency and sustainability. A field experiment spanning three growing seasons (2021–2023) explored the link between meteorological parameters and A. fabae abundance in V. faba. Weekly field inspections documented aphid levels alongside concurrent meteorological data. Correlation and multiple linear regression were used to evaluate these relationships. Aphid infestation varied annually, appearing in 2021 and 2023 but not in 2022. Peak density aligned with specific growth stages, indicating temporal variability. In 2023, a significant surge of 1157.4% to 2126.0% compared to 2021 levels highlighted population dynamics in response to environmental factors. Negative correlations with total rainfall were consistent in both years, while positive correlations with maximum temperature and relative humidity were observed. Multiple linear regression attributed 67.1% to 99.9% of aphid abundance variance to the meteorological parameters, emphasizing their role in predicting aphid populations. Our study sheds light on the complex relationship between meteorological parameters and A. fabae dynamics, offering valuable insights into factors impacting aphid abundance in V. faba. Full article

(This article belongs to the Section Pest and Disease Management)

► Show Figures

Figure 1

17 pages, 1643 KiB

Open AccessArticle

Soybean Canopy Stress Classification Using 3D Point Cloud Data

by Therin J. Young, Shivani Chiranjeevi, Dinakaran Elango, Soumik Sarkar, Asheesh K. Singh, Arti Singh, Baskar Ganapathysubramanian and Talukder Z. Jubery

Agronomy 2024, 14(6), 1181; https://doi.org/10.3390/agronomy14061181 - 30 May 2024

Abstract

Automated canopy stress classification for field crops has traditionally relied on single-perspective, two-dimensional (2D) photographs, usually obtained through top-view imaging using unmanned aerial vehicles (UAVs). However, this approach may fail to capture the full extent of plant stress symptoms, which can manifest throughout [...] Read more.

Automated canopy stress classification for field crops has traditionally relied on single-perspective, two-dimensional (2D) photographs, usually obtained through top-view imaging using unmanned aerial vehicles (UAVs). However, this approach may fail to capture the full extent of plant stress symptoms, which can manifest throughout the canopy. Recent advancements in LiDAR technologies have enabled the acquisition of high-resolution 3D point cloud data for the entire canopy, offering new possibilities for more accurate plant stress identification and rating. This study explores the potential of leveraging 3D point cloud data for improved plant stress assessment. We utilized a dataset of RGB 3D point clouds of 700 soybean plants from a diversity panel exposed to iron deficiency chlorosis (IDC) stress. From this unique set of 700 canopies exhibiting varying levels of IDC, we extracted several representations, including (a) handcrafted IDC symptom-specific features, (b) canopy fingerprints, and (c) latent feature-based features. Subsequently, we trained several classification models to predict plant stress severity using these representations. We exhaustively investigated several stress representations and model combinations for the 3-D data. We also compared the performance of these classification models against similar models that are only trained using the associated top-view 2D RGB image for each plant. Among the feature-model combinations tested, the 3D canopy fingerprint features trained with a support vector machine yielded the best performance, achieving higher classification accuracy than the best-performing model based on 2D data built using convolutional neural networks. Our findings demonstrate the utility of color canopy fingerprinting and underscore the importance of considering 3D data to assess plant stress in agricultural applications. Full article

(This article belongs to the Special Issue Advances in Data, Models, and Their Applications in Agriculture)

► Show Figures

Figure 1

3 pages, 154 KiB

Open AccessEditorial

AI, Sensors, and Robotics for Smart Agriculture

by Baohua Zhang and Yongliang Qiao

Agronomy 2024, 14(6), 1180; https://doi.org/10.3390/agronomy14061180 - 30 May 2024

Abstract

Agriculture plays a crucial role in development, especially in low-income countries where the sector is large in terms of both aggregate income and total labor force [...] Full article

(This article belongs to the Special Issue AI, Sensors and Robotics for Smart Agriculture)

16 pages, 6428 KiB

Open AccessArticle

Effect of Agroforestry Systems on Soil NPK and C Improvements in Karst Graben Basin of Southwest China

by Long Wan, Jiaqi Yang, Chenghao Zheng, Jianbin Guo, Jinxing Zhou, Yuguo Han and Ansa Rebi

Agronomy 2024, 14(6), 1179; https://doi.org/10.3390/agronomy14061179 - 30 May 2024

Abstract

Agroforestry systems can fully exploit the ecological benefits of an ecosystem’s component plants, and improve the ecological environment, soil quality, and land use efficiency, all of which have recently attracted the attention of many scholars. Southwest China’s karst graben basins have barren soil [...] Read more.

Agroforestry systems can fully exploit the ecological benefits of an ecosystem’s component plants, and improve the ecological environment, soil quality, and land use efficiency, all of which have recently attracted the attention of many scholars. Southwest China’s karst graben basins have barren soil that needs immediate improvement. The karst graben basin in southwest China was used for this study to examine the impacts of several forest–grass composite systems of Bingtang orange–alfalfa–ryegrass on soil improvement, which is located in Jianshui County, Honghe Prefecture, Yunnan Province. The experiment had four treatments, Bingtang orange–alfalfa sowing (B2), Bingtang orange–ryegrass × alfalfa mixed sowing (A), Bingtang orange–ryegrass × alfalfa intercropping (R), and Bingtang orange monocropping (CK). The results showed that different forest–grass composite patterns had noticeable effects on improving the soil’s organic carbon (SOC), total nutrients, and available nutrients, especially in the rainy season when plants grew vigorously. Forage grass intercropping under forest exerted the best effect on soil improvement in the surface layer, and the effect decreased with the increase in soil depth. Alfalfa intercropping under Bingtang orange forest had the strongest effect on improving SOC, total N, ammonia nitrogen, and nitrate nitrogen, whose content increased by 30.7%, 27.3%, 35%, and 36.3%, respectively, in the dry season and 38%, 46.7%, 48.7%, and 55.3%, in the rainy season. However, the effect of alfalfa–ryegrass intercropping under the Bingtang orange forest on soil total P, total K, and available P was better than that of the Bingtang orange–alfalfa intercropping system. The C:N ratio is more suitable in the Bingtang orange–ryegrass-alfalfa composite system. Forage grass intercropping under the Bingtang orange forest effectively improved the soil NPK and C status, and the results of this study provided a basis for the selection of forest–grass composite patterns for soil improvement. Full article

(This article belongs to the Section Agroecology Innovation: Achieving System Resilience)

► Show Figures

Figure 1

17 pages, 6257 KiB

Open AccessArticle

HPPEM: A High-Precision Blueberry Cluster Phenotype Extraction Model Based on Hybrid Task Cascade

by Rongli Gai, Jin Gao and Guohui Xu

Agronomy 2024, 14(6), 1178; https://doi.org/10.3390/agronomy14061178 - 30 May 2024

Abstract

Blueberry fruit phenotypes are crucial agronomic trait indicators in blueberry breeding, and the number of fruits within the cluster, maturity, and compactness are important for evaluating blueberry harvesting methods and yield. However, the existing instance segmentation model cannot extract all these features. And [...] Read more.

Blueberry fruit phenotypes are crucial agronomic trait indicators in blueberry breeding, and the number of fruits within the cluster, maturity, and compactness are important for evaluating blueberry harvesting methods and yield. However, the existing instance segmentation model cannot extract all these features. And due to the complex field environment and aggregated growth of blueberry fruits, the model is difficult to meet the demand for accurate segmentation and automatic phenotype extraction in the field environment. To solve the above problems, a high-precision phenotype extraction model based on hybrid task cascade (HTC) is proposed in this paper. ConvNeXt is used as the backbone network, and three Mask RCNN networks are cascaded to construct the model, rich feature learning through multi-scale training, and customized algorithms for phenotype extraction combined with contour detection techniques. Accurate segmentation of blueberry fruits and automatic extraction of fruit number, ripeness, and compactness under severe occlusion were successfully realized. Following experimental validation, the average precision for both bounding boxes (bbox) and masks stood at 0.974 and 0.975, respectively, with an intersection over union (IOU) threshold of 0.5. The linear regression of the extracted value of the fruit number against the true value showed that the coefficient of determination (R²) was 0.902, and the root mean squared error (RMSE) was 1.556. This confirms the effectiveness of the proposed model. It provides a new option for more efficient and accurate phenotypic extraction of blueberry clusters. Full article

(This article belongs to the Section Precision and Digital Agriculture)

► Show Figures

Figure 1

14 pages, 2853 KiB

Open AccessArticle

Whole-Genome Evolutionary Analyses of Non-Endosymbiotic Organelle-Targeting Nuclear Genes Reveal Their Genetic Evolution in 12 Representative Poaceae Species

by Yanan Yu, Yue Yu, Yuefan Dong, Guo Li, Ning Li, Bao Liu, Tianya Wang, Lei Gong and Zhibin Zhang

Agronomy 2024, 14(6), 1177; https://doi.org/10.3390/agronomy14061177 - 30 May 2024

Abstract

Chloroplasts and mitochondria, descendants of ancient prokaryotes via endosymbiosis, occupy a pivotal position in plant growth and development due to their intricate connections with the nuclear genome. Genes encoded by the nuclear genome but relocated to or being functional within these organelles are [...] Read more.

Chloroplasts and mitochondria, descendants of ancient prokaryotes via endosymbiosis, occupy a pivotal position in plant growth and development due to their intricate connections with the nuclear genome. Genes encoded by the nuclear genome but relocated to or being functional within these organelles are commonly referred as organelle-targeting nuclear genes (ONGs). These genes are essential for maintaining cytonuclear coordination, thereby determining the stability of the life cycle. While molecular function and cytonuclear coordination of some endosymbiosis-derived ONGs (E-ONGs) have been extensively studied, the evolutionary history and characteristics from a more widespread range of non-endosymbiosis-derived ONGs (NE-ONGs) remain largely enigmatic. In this study, we focused on 12 representative species within the Poaceae family to systematically identify NE-ONGs and investigated their evolutionary history and functional significance on a phylogenetic timescale. Upon aligning these 12 species’ evolutionary histories, we observed the following phenomena: (i) an exploration of NE-ONGs between the BOP and PACMAD clades unveiled dynamic compositions, potentially influencing their photosynthetic divergence; (ii) the majority of the abundant species-specific NE-ONGs exist in a single-copy status, and functional enrichment analysis further underscored their specialized roles, which could be crucial for species adaptation; and (iii) comparative analyses between plasmid- and mitochondria-related NE-ONGs (pNE-ONGs and mNE-ONGs) revealed a prevalence of pNE-ONGs, indicating tighter control for chloroplast function in Poaceae. In summary, this study offers novel insights into the cytonuclear co-evolutionary dynamics in Poaceae speciation and draws attention to crop improvement by using NE-ONGs. Full article

(This article belongs to the Special Issue Recognition and Utilization of Natural Genetic Resources for Advances in Plant Biology through Genomics and Biotechnology—Volume II)

► Show Figures

Figure 1

14 pages, 1558 KiB

Open AccessArticle

Silicon Improves Heat and Drought Stress Tolerance Associated with Antioxidant Enzyme Activity and Root Viability in Creeping Bentgrass (Agrostis stolonifera L.)

by Xunzhong Zhang, Mike Goatley, Kehua Wang, Ben Goddard, Rose Harvey, Isabel Brown and Kelly Kosiarski

Agronomy 2024, 14(6), 1176; https://doi.org/10.3390/agronomy14061176 - 30 May 2024

Abstract

Creeping bentgrass (Agrostis stolonifera L.) is an important cool-season turfgrass species widely used for golf course putting greens; however, it experiences summer stress and quality decline in the U.S. transition zone and other regions with similar climates. Silicon (Si) may improve the [...] Read more.

Creeping bentgrass (Agrostis stolonifera L.) is an important cool-season turfgrass species widely used for golf course putting greens; however, it experiences summer stress and quality decline in the U.S. transition zone and other regions with similar climates. Silicon (Si) may improve the abiotic stress of creeping bentgrass, but the mechanism of its impact on plant drought and heat tolerance is not well understood, and a few studies have reported on the effects of Si on creeping bentgrass drought and heat tolerance. The objectives of this study were to determine the effects of Ortho-silicic acid (Ortho-Si) on antioxidant metabolism and root growth characteristics and viability in creeping bentgrass under drought and heat-stress conditions. The three treatments, including control, Ortho-Si at 0.16 mL m⁻² and 0.32 mL m⁻², were applied biweekly to creeping bentgrass. Foliar application of the Ortho-Si exhibited beneficial effects on turf quality, physiological fitness, and root growth in creeping bentgrass. The Ortho-Si application at 0.16 mL m⁻² and 0.32 mL m⁻² improved turf quality ratings by 9.5% and 11.1%, respectively, photochemical efficiency (PE) by 6.9% and 8.5%, respectively, chlorophyll content by 27.1% and 29.9%, and carotenoids content by 25.5% and 27.2%, respectively, when compared to the control at the end of the trial. The Ortho-Si treatments enhanced antioxidant enzyme activity; the highest amount, in particular, increased superoxide dismutase (SOD) activity by 32.8%, catalase (CAT) by 12.8%, and ascorbate peroxidase (APX) activity by 37.4%, as compared to the control. The Ortho-Si application reduced leaf hydrogen peroxide (H₂O₂) concentration relative to the control. In addition, exogenous Ortho-Si improved leaf Si concentration. The Ortho-Si application at 0.32 mL m⁻² increased root biomass by 52.7% and viability by 89.3% relative to the control. Overall, Ortho-Si at 0.32 mL m⁻² had greater beneficial effects than the low rate (0.16 mL m⁻²). Exogenous Si may improve drought and heat tolerance by protecting photosynthetic function, enhancing the activities of leaf antioxidant enzymes, and stimulating root growth, viability, and Si uptake. The results of this study suggest that foliar application of Ortho-Si at 0.32 mL m⁻² may be considered to be an effective approach to improve turf quality and physiological fitness of creeping bentgrass during the summer months in the U.S. transition zone and other regions with similar climates. Full article

(This article belongs to the Section Grassland and Pasture Science)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Agronomy, Volume 14, Issue 6 (June 2024) – 119 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI