Agronomy

24 pages, 754 KiB

Open AccessReview

Facing Heavy Metal Stress, What Are the Positive Responses of Melatonin in Plants: A Review

by Xianghan Cheng, Xiaolei Liu, Feifei Liu, Yuantong Yang and Taiji Kou

Agronomy 2024, 14(9), 2094; https://doi.org/10.3390/agronomy14092094 - 13 Sep 2024

With the growth of the population and the development of modern industry and the economy, the problem of heavy metal pollution in cultivated soil has become increasingly prominent. Moreover, heavy metal poses a serious threat to plant growth due to its characteristics of [...] Read more.

With the growth of the population and the development of modern industry and the economy, the problem of heavy metal pollution in cultivated soil has become increasingly prominent. Moreover, heavy metal poses a serious threat to plant growth due to its characteristics of difficult degradation, high mobility, easy enrichment, and potential toxicity and has become a social topic. Melatonin is a new type of plant hormone widely present in animals, plants, fungi, and bacteria, and its biological role has begun investigated in the last dozen years. Facing heavy metal stress, melatonin can play a pleiotropic role in the physiological processes of plants, such as stress resistance and growth regulation, mitigate the damage caused by stress on plants, and provide a new research idea for alleviating heavy metal stress in plants. From the aspects of the plant phenotype, physiology, element absorption, and molecular structure, this paper, therefore, mainly reviews the effects of melatonin on plants subjected to heavy metal stress and the mechanism of melatonin alleviating heavy metal stress and then puts forward future research directions. This information may be of great significance to the normal growth of crops under heavy metal stress and will provide an important theoretical basis for the genetic improvement of crop resistance in the future. Full article

(This article belongs to the Section Plant-Crop Biology and Biochemistry)

16 pages, 5469 KiB

Open AccessArticle

Agronomic Performance and Yield Stability of Elite White Guinea Yam (Dioscorea rotundata) Genotypes Grown in Multiple Environments in Nigeria

by Alice Adenike Olatunji, Andrew Saba Gana, Kehinde D. Tolorunse, Paterne A. Agre, Patrick Adebola and Asrat Asfaw

Agronomy 2024, 14(9), 2093; https://doi.org/10.3390/agronomy14092093 - 13 Sep 2024

Abstract

Yam (Dioscorea spp.) is a main staple tuber crop in Nigeria and the West African region. Its performance is determined by genotypes and also the environment of growth. This study assessed the agronomic performance and yield stability of elite white yam (Dioscorea [...] Read more.

Yam (Dioscorea spp.) is a main staple tuber crop in Nigeria and the West African region. Its performance is determined by genotypes and also the environment of growth. This study assessed the agronomic performance and yield stability of elite white yam (Dioscorea rotundata) genotypes across diverse Nigerian environments. A total of 25 genotypes were evaluated at three locations in two consecutive growing seasons, 2022 and 2023, for fresh tuber yield, disease resistance, and tuber quality traits. The genotype’s performance and stability for the measured traits were assessed using various analytical tools such as additive main effects and multiplicative interaction (AMMI) and multi-trait stability index (MTSI). The AMMI analysis revealed significant differences among the genotypes and across the environments for all traits (p < 0.001, p < 0.01). The PCA revealed that the first two principal components (PC1 and PC2) explained a substantial portion of the total variation (49.84%). The MTSI identified four clones: G18, G19, G24, and G16 as promising candidates for improved yam production in Nigeria with high and stable performance for the multiple traits. Full article

(This article belongs to the Section Horticultural and Floricultural Crops)

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17 pages, 3639 KiB

Open AccessArticle

The Effect of Drip Irrigation and Nitrogen Levels on the Oil and Fatty Acid Composition of Sesame and Its Economic Analysis

by Ismail Tas, Sevim Akcura, Mahmut Kaplan, Barbara Jagosz, Atılgan Atılgan, Joanna Kocięcka, Roman Rolbiecki, Daniel Liberacki and Stanisław Rolbiecki

Agronomy 2024, 14(9), 2092; https://doi.org/10.3390/agronomy14092092 - 13 Sep 2024

Abstract

One of the oldest oilseed crops is sesame, which is mainly cultivated due to its valuable oleic/linolenic fatty acid ratio. The application of precise irrigation and fertilisation is crucial to ensure the continuity and productivity of sesame production, especially in arid and semi-arid [...] Read more.

One of the oldest oilseed crops is sesame, which is mainly cultivated due to its valuable oleic/linolenic fatty acid ratio. The application of precise irrigation and fertilisation is crucial to ensure the continuity and productivity of sesame production, especially in arid and semi-arid regions. This study aimed to determine the effect of drip irrigation and nitrogen levels on sesame’s oil and fatty acid composition. For this purpose, four nitrogen doses (N₀: 0 kg ha⁻¹, N₃₀: 30 kg ha⁻¹, N₆₀: 60 kg ha⁻¹ and N₉₀: 90 kg ha⁻¹) and three different irrigation water levels (I₅₀, I₇₅ and I₁₀₀, which correspond to 50, 75 and 100% evaporation levels from the evaporation of the Class A pan) were applied. The highest oleic acid content (43.06%) was obtained for the I₇₅N₉₀ treatment. In the case of linoleic fatty acid, the greatest value (43.66%) was for I₅₀N₀ treatment. The effects of irrigation and nitrogen doses on oleic acid and linoleic acid content were inverse of each other. An increase in applied irrigation water increased the linoleic acid content. However, it caused a decrease in oleic acid content. Increasing the nitrogen dose increased the oleic acid content and caused a decrease in linoleic acid content. Furthermore, this study showed that the I₅₀N₆₀ treatment (50% Epan and a rate of 60 kg N ha⁻¹) is the most effective for achieving high grain and oil yields in sesame cultivation. The results obtained provide practical guidance for farmers in sesame cultivation. Full article

(This article belongs to the Special Issue Optimal Water Management and Sustainability in Irrigated Agriculture—2nd Edition)

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18 pages, 5197 KiB

Open AccessArticle

Composting of Cow-Dung-Amended Soil by the Dung Beetle Catharsius molossus L. Improves Bacterial Ecological Functions Related to Nitrogen Mineralization and Human and Plant Pathogenesis

by Abdul Rasheed Kaleri, Jiahua Ma, Ali Murad Jakhar, Awais Ahmed, Yahya Faqir, Chengjia Tan, Slaviša Stanković and Martin Raspor

Agronomy 2024, 14(9), 2091; https://doi.org/10.3390/agronomy14092091 - 13 Sep 2024

Abstract

The Asian dung beetle (Catharsius molossus L.; Coleoptera: Scarabeidae) has been shown to positively affect soil bacterial diversity and the agronomic features of crop plants. In this study, we used bioinformatic tools to investigate the differences in bacterial functional phenotypes and ecological [...] Read more.

The Asian dung beetle (Catharsius molossus L.; Coleoptera: Scarabeidae) has been shown to positively affect soil bacterial diversity and the agronomic features of crop plants. In this study, we used bioinformatic tools to investigate the differences in bacterial functional phenotypes and ecological functions between control soil, cow dung-amended soil (CD), and cow dung-amended soil composted by dung beetles (DB). The soil bacterial metagenomes were sequenced and analyzed with the bioinformatic packages BugBase, PICRUSt2, Tax4Fun, and FAPROTAX to evaluate the effects of dung beetle-mediated composting on bacterial functions such as human and plant pathogenicity, trophic strategies, and soil nutrient transformation. BugBase proved useful for the determination of differences in major functional phenotypes, whereas FAPROTAX was effective at identifying differences in bacterial ecological functions between the treatments. Both tools suggested a relative decrease in human pathogens in the DB soil. This was corroborated by the pairwise comparison of abundances in bacterial species, which showed a significant reduction in the abundance of the broad-host-range pathogen Pseudomonas aeruginosa in the DB soil. In addition, FAPROTAX suggested a decrease in plant pathogens and an increase in chitinolytic bacteria, meaning that the DB treatment might be beneficial to the plant-growth-promoting bacteria involved in biological control. Finally, FAPROTAX revealed an array of ecological functions related to trophic strategies and macro- and micronutrient metabolism. According to these results, the activity of C. molossus beetles enhanced methanotrophy, ammonification, nitrification, sulfate reduction, and manganese oxidation, whereas iron respiration was decreased in the DB-treated soil. Our results represent a collection of general insights into the effects of C. molossus beetles on soil bacterial functions, which also reflect on the nutrient composition of dung beetle-composted soil. Full article

(This article belongs to the Special Issue The Role of Livestock Manure in Sustainable Agricultural Land Management (Soil Health) in the Context of Climate Change)

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15 pages, 12378 KiB

Open AccessArticle

Induction of Tetraploids in Phellodendron amurense Rupr. and Its Effects on Morphology and Alkaloid Content

by Jing Li, Ning Yu, Can-Can Lv, Long Tie, Jia-Ju Pang, Jin-Wang Zhang and Jun Wang

Agronomy 2024, 14(9), 2090; https://doi.org/10.3390/agronomy14092090 - 13 Sep 2024

Abstract

Phellodendron amurense Rupr. is a precious medicinal tree species in northeast China. However, P. amurense resources have been severely destroyed due to uncontrolled overharvest and the limited innovation of new germplasms by traditional cross-breeding. In this study, polyploid breeding was introduced to the [...] Read more.

Phellodendron amurense Rupr. is a precious medicinal tree species in northeast China. However, P. amurense resources have been severely destroyed due to uncontrolled overharvest and the limited innovation of new germplasms by traditional cross-breeding. In this study, polyploid breeding was introduced to the improvement program of P. amurense. Fifty-four tetraploid plants of P. amurense were first produced by colchicine-induced adventitious bud chromosome doubling in stem segment explants. The induction frequency reached 36.16% (1.0 g L⁻¹ colchicine solution for 48 h treatment) and 50.00% (2.0 g L⁻¹ colchicine solution for 24 h treatment), respectively, showing the high efficiency of the somatic chromosome doubling based on the organogenesis system. Tetraploidization resulted in significant phenotypic variation, such as larger and thicker leaves, thicker stems, and bigger stomata. Ultra-performance liquid chromatography–mass spectrometry (UPLC–MS/MS) analysis identified 59 differentially accumulated alkaloids (DAAs) between the leaf and stem samples of tetraploids, including 32 upregulated and 27 downregulated in stems. For both leaf and stem samples, 18 DAAs were identified between diploids and tetraploids, with 16 DAAs upregulated in tetraploid leaves and 8 upregulated in tetraploid stems, suggesting that polyploidization caused significant alterations in alkaloid contents in leaves and stems of P. amurense. The contents of the main medicinal compounds, such as berberine, jatrorrhizine, phellodendrine, and palmatine, increased significantly in the leaf and/or stem samples after polyploidization. This finding implied that polyploid breeding might be an effective approach for improving P. amurense, beneficial to preserving and exploiting natural resources. Full article

(This article belongs to the Special Issue Breeding, Propagation and Cultivation Techniques of Medicinal and Aromatic Plants)

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14 pages, 3236 KiB

Open AccessArticle

Determinants and Pathways of Nitrous Oxide Emissions from Soil Irrigated with Reclaimed Water

by Yanbing Chi, Chenchen Wei, Peiling Yang and Ning Ma

Agronomy 2024, 14(9), 2089; https://doi.org/10.3390/agronomy14092089 - 13 Sep 2024

Abstract

Reclaimed water (RW), as a reliable and renewable secondary water source, has become a crucial strategy for many countries to supplement agricultural water usage and alleviate water scarcity. However, despite the increasing use of RW, there has been limited research on the factors [...] Read more.

Reclaimed water (RW), as a reliable and renewable secondary water source, has become a crucial strategy for many countries to supplement agricultural water usage and alleviate water scarcity. However, despite the increasing use of RW, there has been limited research on the factors affecting soil nitrous oxide (

N_{2} O

) emissions under RW irrigation. Understanding these factors is essential for guiding RW irrigation practices and controlling greenhouse gas emissions. This research, conducted from 2014 to 2015, includes field experiments designed to systematically assess the effects of soil chemistry properties and temperature on soil

N_{2} O

emissions under RW irrigation. Subsequent to these field studies, soil samples were collected for ¹⁵N isotope trials to examine the impact of RW on the soil

N_{2} O

production process, including autotrophic nitrification, heterotrophic nitrification, and denitrification. The results showed that RW irrigation influenced soil

N_{2} O

emissions by affecting soil pH, but not through changes in soil total nitrogen (TN) or soil organic carbon (SOC) content. Moreover, compared to groundwater (UW) irrigation, RW irrigation significantly reduced the temperature sensitivity of soil

N_{2} O

emissions. The ¹⁵N isotope labeling trial indicated that autotrophic nitrification was the primary pathway for soil

N_{2} O

production under RW irrigation, contributing 60.46%—significantly higher than that observed with UW irrigation. Primary treated sewage (PW) significantly increased soil

N_{2} O

emissions through the heterotrophic nitrification process compared to RW, with contributions rising from 11.31% to 13.23%. Additionally, RW, compared to UW, significantly increased the copy numbers of soil nitrification genes (ammonia-oxidizing archaea [AOA-amoA]) and denitrification genes (nitrite reductase [nirK and nirS]). Therefore, it is important to appropriately control the nitrification process and balance soil pH to manage soil

N_{2} O

emissions under RW irrigation. Full article

(This article belongs to the Section Water Use and Irrigation)

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25 pages, 4117 KiB

Open AccessArticle

Modeling the Effects of Irrigation and Its Interaction with Silicon on Quinoa Seed Yield and Water Use Efficiency in Arid Regions

by Amira M. El-Tahan, Mohamed Emran, Fatmah A. Safhi, Asal M. Wali, Sherien E. Sobhy and Omar M. Ibrahim

Agronomy 2024, 14(9), 2088; https://doi.org/10.3390/agronomy14092088 - 12 Sep 2024

Abstract

Despite quinoa (Chenopodium quinoa Willd.) gaining international popularity in the early 21st century for its nutritional benefits, there remains a critical need to optimize its cultivation practices in arid regions. Current research often overlooks the combined effects of supplemental irrigation and foliar [...] Read more.

Despite quinoa (Chenopodium quinoa Willd.) gaining international popularity in the early 21st century for its nutritional benefits, there remains a critical need to optimize its cultivation practices in arid regions. Current research often overlooks the combined effects of supplemental irrigation and foliar treatments on quinoa’s yield and water efficiency, particularly under challenging environmental conditions like those in Borg El-Arab, Egypt. Field studies were conducted in Borg El-Arab, Alexandria, Egypt, during the winter seasons of 2021/2022 and 2022/2023 to determine the influence of supplemental irrigation (rainfed, 2000, and 4000 m³/hectare, respectively) and foliar spraying of sodium silicate (control, 200, and 400 ppm) on yield, yield components, seed quality, and water usage efficiency in quinoa cv. Chibaya grown in arid lands. Three replications were used in a split-plot design. The main plots were designated for irrigation, while the subplots were designated for foliar spraying. The results indicate that applying irrigation at a rate of 4000 m³/hectare significantly increased leaf dry weight per plant by 23.5%, stem dry weight per plant by 18.7%, total dry weight per 25 plants by 21.4%, leaf area per plant by 19.2%, and straw yield by 26.8% compared to the control treatment. There were no significant differences between irrigation with the rate of 4000 m³ or 2000 m³/hectare on biological yield kg/hectare, N (%), P (mg/100 g), and protein (%). The utilization of sodium silicate had no significance on all studied features except for straw yield kg ha⁻¹ at the rate of 200 or 400 ppm. The results regarding the RAPD1 primer revealed that the 2000+0 silicon treatment was the only treatment that resemble the control with no up- or downregulated fragment. Moreover, 20 upregulated fragments were observed in all treatments, while 19 DNA fragments were downregulated. Furthermore, the results obtained regarding the RAPD2 primer revealed that 53 fragments were upregulated and 19 downregulated. Additionally, the RAPD3 primer demonstrated that 40 DNA fragments were upregulated, whereas 18 downregulated DNA fragments were detected. It may be inferred that the application of irrigation at a rate of 4000 m3 ha⁻¹ might serve as a supplemental irrigation method. Spraying sodium silicate at a 400 mg L⁻¹ concentration could alleviate the dry climate on the Egyptian shore. Full article

(This article belongs to the Special Issue The Effects of Irrigation and Fertilization Management on Cropping Systems—2nd Edition)

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18 pages, 1589 KiB

Open AccessArticle

Reducing Nitrogen Application Rates and Straw Mulching Can Alleviate Greenhouse Gas Emissions from Wheat Field Soil and Improve Soil Quality

by Mengyin Du, Yao Yao, Shuainan Liu, Guang Li and Jianyu Yuan

Agronomy 2024, 14(9), 2087; https://doi.org/10.3390/agronomy14092087 - 12 Sep 2024

Abstract

Sustainable agriculture faces challenges balancing the need for increasing crop production with environmental protection. Straw mulching is widely used to improve crop productivity, while reducing nitrogen application is an effective strategy to reduce greenhouse gas (GHG) emissions. However, the comprehensive evaluation of soil [...] Read more.

Sustainable agriculture faces challenges balancing the need for increasing crop production with environmental protection. Straw mulching is widely used to improve crop productivity, while reducing nitrogen application is an effective strategy to reduce greenhouse gas (GHG) emissions. However, the comprehensive evaluation of soil properties, GHG emissions, and soil quality under straw mulching conditions with different N application rates has not been extensively studied, especially in the Loess Plateau region of Central Gansu. Therefore, a two-year field experiment was conducted, involving two tillage practices (CT: conventional tillage, CTS: conventional tillage + straw mulching) and three fertilization levels (LN: low nitrogen fertilizer, 55 kg N ha⁻¹; MN: medium nitrogen fertilizer, 110 kg N ha⁻¹ HN: high nitrogen fertilizer, 220 kg N ha⁻¹). Based on the greenhouse gas emission intensity (GHGI), the minimum data set (MDS) was constructed by principal component analysis, correlation analysis, and Norm value, and the weighted index method was applied to comprehensively evaluate the soil quality. Our results showed that compared with CT, CTS significantly increased crop yields and improved the content of soil nutrients, and it was more effective when applying moderate amounts of nitrogen fertilizer. Wheat field soil behaves as a nitrous oxide (N₂O) emission source and a methane (CH₄) absorption sink. CTS–MN and CTS–LN reduced N₂O emission by 52.95–87.76%, increased total CH₄ uptake by 16.69–43.60%, and slowed down global warming potential (GWP) by 35.70–48.17% compared with CTS–HN in 2021–2022. They also reduced GHGI. Furthermore, CTS enhanced soil quality at different nitrogen application levels compared with CT, with CTS–MN exhibiting the highest Soil Quality Index (SQI) over the two years. Consequently, considering both economic and environmental benefits, CTS–MN can be regarded as a key practice for the sustainable development of agroecosystems in the Loess Plateau region of Central Gansu. Full article

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

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17 pages, 10212 KiB

Open AccessArticle

YOLOv9s-Pear: A Lightweight YOLOv9s-Based Improved Model for Young Red Pear Small-Target Recognition

by Yi Shi, Zhen Duan, Shunhao Qing, Long Zhao, Fei Wang and Xingcan Yuwen

Agronomy 2024, 14(9), 2086; https://doi.org/10.3390/agronomy14092086 - 12 Sep 2024

Abstract

With the advancement of computer vision technology, the demand for fruit recognition in agricultural automation is increasing. To improve the accuracy and efficiency of recognizing young red pears, this study proposes an improved model based on the lightweight YOLOv9s, termed YOLOv9s-Pear. By [...] Read more.

With the advancement of computer vision technology, the demand for fruit recognition in agricultural automation is increasing. To improve the accuracy and efficiency of recognizing young red pears, this study proposes an improved model based on the lightweight YOLOv9s, termed YOLOv9s-Pear. By constructing a feature-rich and diverse image dataset of young red pears and introducing spatial-channel decoupled downsampling (SCDown), C2FUIBELAN, and the YOLOv10 detection head (v10detect) modules, the YOLOv9s model was enhanced to achieve efficient recognition of small targets in resource-constrained agricultural environments. Images of young red pears were captured at different times and locations and underwent preprocessing to establish a high-quality dataset. For model improvements, this study integrated the general inverted bottleneck blocks from C2f and MobileNetV4 with the RepNCSPELAN4 module from the YOLOv9s model to form the new C2FUIBELAN module, enhancing the model’s accuracy and training speed for small-scale object detection. Additionally, the SCDown and v10detect modules replaced the original AConv and detection head structures of the YOLOv9s model, further improving performance. The experimental results demonstrated that the YOLOv9s-Pear model achieved high detection accuracy in recognizing young red pears, while reducing computational costs and parameters. The detection accuracy, recall, mean precision, and extended mean precision were 0.971, 0.970, 0.991, and 0.848, respectively. These results confirm the efficiency of the SCDown, C2FUIBELAN, and v10detect modules in young red pear recognition tasks. The findings of this study not only provide a fast and accurate technique for recognizing young red pears but also offer a reference for detecting young fruits of other fruit trees, significantly contributing to the advancement of agricultural automation technology. Full article

(This article belongs to the Topic Intelligent Agriculture: Perception Technologies and Agricultural Equipment for Crop Production Processes)

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17 pages, 3984 KiB

Open AccessArticle

Utilizing Hydrophobic Sand to Construct an Air-Permeable Aquiclude to Enhance Rice Yield and Lodging Resistance

by Xiaoyan Ma, Jing Wu, Yuming Su, Shengyi Qin and Francesco Pilla

Agronomy 2024, 14(9), 2085; https://doi.org/10.3390/agronomy14092085 - 12 Sep 2024

Abstract

Global climate change and persistent droughts lead to soil desertification, posing significant challenges to food security. Desertified lands, characterized by high permeability, struggle to retain water, thereby hindering ecological restoration. Sand, a natural resource abundant in deserts, inspired our proposal to design hydrophobic [...] Read more.

Global climate change and persistent droughts lead to soil desertification, posing significant challenges to food security. Desertified lands, characterized by high permeability, struggle to retain water, thereby hindering ecological restoration. Sand, a natural resource abundant in deserts, inspired our proposal to design hydrophobic sand and construct Air-permeable Aquicludes (APAC) using this material. This approach aims to address issues related to the ecological restoration of desertified lands, food security, and the utilization of sand resources. Reclamation of desertified land and sandy areas can simultaneously address ecological restoration and ensure food security, with soil reconstruction being a critical step. This study investigated the effects of constructing an Air-permeable Aquiclude (APAC) using hydrophobic sand on rice yield and lodging resistance, using clay aquitard (CAT) and plastic aquiclude (PAC) as control groups. The APAC enhanced soil oxygen content, increased internode strength, and improved vascular bundle density, substantially reducing the lodging index and increasing yield. This research finds that the APAC (a) increased internode outer diameter, wall thickness, fresh weight, and filling degree; (b) enhanced the vascular bundle area by 11.11% to 27.66% and increased density; (c) reduced the lodging index by 37.54% to 36.93% (p < 0.01); and (d) increased yield to 8.09 t·hm⁻², a rise of 12.05% to 14.59% (p < 0.05), showing a negative correlation with lodging index. These findings suggest that APAC has very good potential for desertified land reclamation and food security. In conclusion, the incorporation of hydrophobic sand in APAC construction considerably strengthens rice stem lodging resistance and increases yield, demonstrating considerable application potential for the reclamation of desertified and sandy land and ensuring food security. Full article

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

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16 pages, 2123 KiB

Open AccessArticle

The Microbiological Activity of Soil in Response to Gliotoxin, the “Lethal Principle” of Trichoderma

by Anastasia V. Teslya, Elena V. Gurina, Artyom A. Stepanov, Aleksandr V. Iashnikov and Alexey S. Vasilchenko

Agronomy 2024, 14(9), 2084; https://doi.org/10.3390/agronomy14092084 - 12 Sep 2024

Abstract

Trichoderma is a soil-dwelling microorganism that has many benefits for plants and is therefore widely used in agriculture. Among the secondary metabolites produced by Trichoderma, gliotoxin (GT) is one of the most studied. The antagonistic effect of GT on other fungi was [...] Read more.

Trichoderma is a soil-dwelling microorganism that has many benefits for plants and is therefore widely used in agriculture. Among the secondary metabolites produced by Trichoderma, gliotoxin (GT) is one of the most studied. The antagonistic effect of GT on other fungi was first discovered by R. Weindling in 1934. He referred to it as the “lethal principle” of Trichoderma. Despite the long history of studying GT, its impact on the soil microbial community has remained largely unexplored. In our work, we investigated the response of the soil microbial community to different doses of GT (10–500 µM per kg) and different durations (7–56 days) of exposure. We measured microbiological parameters (CO₂ emission, microbial biomass (MB)), calculated the eco-physiological indices and determined the activity of soil enzymes involved in the C, N, P and S cycles. We identified three types of microbial responses to GT: inhibition, stress and stimulation. The inhibitory effect developed only by day 56 and in the samples treated with 500 μM GT. The stress effect (increased CO₂ emission and decreased MB) of GT on microbial communities was predominant. Soil extracellular enzymes also responded to GT to varying degrees. A stimulating effect of GT on enzyme activity was noted for β-D-1,4-cellobiosidase and β-1,4-glucosidase. The activity of arylsulfatase and leucine aminopeptidase decreased under the influence of GT up to day 28, but by the end of the experiment, there was a restoration of activity. We did not observe any significant changes in the activity of β-1,4-xylosidase, β-1,4-N-acetyl-glucosaminidase or acid phosphatase. The results obtained showed that GT at high, “man-made” doses can inhibit the microbiological activity of soil, but at naturally occurring concentrations, it can have a stimulating effect on soil microbiome functionality. Full article

(This article belongs to the Special Issue Effects of Agrotechnical Factors and Farming Systems on Soil Properties and Plant Productivity)

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20 pages, 8922 KiB

Open AccessArticle

Investigation of the Composting Process of Mongolian Horse Manure Utilizing Intelligent Composting Equipment

by Jian Wang, Kailin Ren, Yong Zhang, Longfei Zhang and Zhe Li

Agronomy 2024, 14(9), 2083; https://doi.org/10.3390/agronomy14092083 - 12 Sep 2024

Abstract

The Inner Mongolia Autonomous Region, known for its famous Mongolian horses, faces significant environmental challenges due to the large-scale rearing of these animals, which produces a substantial amount of manure. If not managed effectively, this manure can lead to severe environmental pollution. The [...] Read more.

The Inner Mongolia Autonomous Region, known for its famous Mongolian horses, faces significant environmental challenges due to the large-scale rearing of these animals, which produces a substantial amount of manure. If not managed effectively, this manure can lead to severe environmental pollution. The aim of this study was to investigate whether a small-scale intelligent aeration and heating composting system is effective in treating Mongolian horse manure, with the objective of enhancing composting efficiency and resource utilization to support sustainable agricultural development in the region. The equipment was utilized to treat a compost mixture of Mongolian horse manure and corn stover, allowing for an analysis of the changes in key indicators throughout the composting process. The results demonstrated that the equipment maintained high temperatures for up to eight days during the composting process, effectively inactivating pathogens and promoting the efficient decomposition of organic matter. The system also successfully controlled humidity to 12.7% and maintained oxygen concentration within the optimal range. Post-composting analysis revealed that the final compost contained 2.3% nitrogen, 1.3% phosphorus, and 1.2% potassium, with a pH of 6.4 and conductivity of approximately 5.2 mS/cm. Additionally, the carbon-to-nitrogen ratio decreased significantly from 27.3 to 15.9, indicating substantial organic matter degradation. Seed germination tests showed germination rates of 80%, 86%, and 75% for corn, mung bean, and wheat, respectively, with a final seed germination index of 104%. This study concluded that the small aeration and heating composting equipment is highly effective in treating Mongolian horse manure, producing high-quality organic fertilizers that significantly enhance soil fertility and demonstrate considerable potential for supporting sustainable agricultural practices and improving environmental management in the Inner Mongolia Autonomous Region. Full article

(This article belongs to the Topic Waste Management through Composting: Benefits, New Insights and Challenges)

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16 pages, 5661 KiB

Open AccessArticle

Genotype and Nitrogen Source Influence Drought Stress Response in Oil Palm Seedlings

by Rodrigo Ruiz-Romero, Marlon De la Peña, Iván Ayala-Díaz, Carmenza Montoya and Hernán Mauricio Romero

Agronomy 2024, 14(9), 2082; https://doi.org/10.3390/agronomy14092082 - 12 Sep 2024

Abstract

As a significant global source of vegetable oil, the oil palm’s ability to withstand abiotic stresses, particularly drought, is crucial for sustainable agriculture. This is especially significant in tropical regions, where water scarcity is becoming more common. Nitrogen, a vital nutrient, plays an [...] Read more.

As a significant global source of vegetable oil, the oil palm’s ability to withstand abiotic stresses, particularly drought, is crucial for sustainable agriculture. This is especially significant in tropical regions, where water scarcity is becoming more common. Nitrogen, a vital nutrient, plays an essential role in various physiological and biochemical processes in plants, directly influencing growth and stress tolerance. This study investigates the interaction between nitrogen sources (ammonium vs. nitrate) and drought stress in oil palm (Elaeis guineensis) seedlings, which is critical in enhancing productivity in this economically important crop. The experiment evaluated five commercial oil palm genotypes, which were supplied with nitrogen solutions (15 mM NH₄⁺ or NO₃⁻) for 46 days, followed by 30 days of progressive drought. The results showed that drought conditions universally reduced the biomass, with ammonium-fed plants exhibiting greater shoot biomass sensitivity than nitrate-fed plants. Drought also significantly decreased the chlorophyll a, PhiPS2, and root-reducing sugar levels—critical indicators of photosynthetic efficiency and overall plant health. The effects on the root architecture were complex, with ammonium nutrition differentially influencing the lateral root length under well-watered versus drought conditions, highlighting nitrogen forms’ nuanced role in root development. Importantly, substantial genotypic variability was observed in most traits, affecting the responses to both the nitrogen source and drought stress. This variability suggests that certain genotypes may be better suited to cultivation in specific environmental conditions, particularly drought-prone areas. In conclusion, this study underscores the intricate interplay between nitrogen nutrition, genotypic variability, and drought tolerance in oil palm seedlings. These findings highlight the need to integrate these factors into agricultural management strategies to improve resilience and productivity in oil palm plantations. Full article

(This article belongs to the Section Plant-Crop Biology and Biochemistry)

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13 pages, 1455 KiB

Open AccessArticle

Echinacea Species Cultivated in Bulgaria as a Source of Chicoric and Caftaric Acids

by Maria Vlasheva, Mariana Katsarova, Ana Dobreva, Anatolii Dzhurmanski, Petko Denev and Stela Dimitrova

Agronomy 2024, 14(9), 2081; https://doi.org/10.3390/agronomy14092081 - 11 Sep 2024

Abstract

The trend towards alternative medicine and naturopathy increases the interest in the use of natural products. This requires larger quantities of qualitative raw material of medicinal plants, including the well-known genus Echinacea. The purpose of this study was to evaluate the quality [...] Read more.

The trend towards alternative medicine and naturopathy increases the interest in the use of natural products. This requires larger quantities of qualitative raw material of medicinal plants, including the well-known genus Echinacea. The purpose of this study was to evaluate the quality of E. purpurea and pallida cultivated in Kazanlak, Bulgaria. We developed and validated a rapid, reliable, and inexpensive HPLC method for the quantitative determination of chicoric, caftaric, and caffeic acids, and of cynarin, echinacoside, quercetin, and apigenin. The amount of chicoric and caftaric acids was monitored in different phases of plant development in aerial parts and roots. Maximal concentrations of chicoric acid (3.4%) were reported in roots in the seed-formation phase, and a concentration of 2.8% was reported in aerial parts in the vegetative phase. Caftaric acid was 0.9% in aerial parts in the vegetative and flowering phases and 0.5% in roots in the vegetative and seeding phases. Their amounts significantly exceed the requirements of the European Pharmacopoeia 8.0. Therefore, Kazanlak-grown E. purpurea could be a reliable raw material for the formulation of phytopreparations. In addition, the proposed method was applied to the detection and determination of the above-described substances in phytopreparations containing Echinacea from commercial sources. The amounts of the tested substances were found to vary widely. Full article

(This article belongs to the Special Issue Planting Production, Identification and Quality Control of Medicinally Agricultural Products)

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23 pages, 3564 KiB

Open AccessArticle

Assessing the Impacts of Climate Change on Geographical Distribution of Tea (Camellia sinensis L.) in Kenya with Maximum Entropy Model

by Goitom Tesfay, Yuncheng Zhao, Mingyue Zhao, Kuo Li, Tsedale Demelash and Yinlong Xu

Agronomy 2024, 14(9), 2080; https://doi.org/10.3390/agronomy14092080 - 11 Sep 2024

Abstract

Climate change has been disturbing the present species distribution ranges, resulting in the shifting of cultivation areas and decreases in production and quality. Tea (Camellia sinensis L.), which seeks optimum climatic resources, is a key cash crop economically in Kenya. In this [...] Read more.

Climate change has been disturbing the present species distribution ranges, resulting in the shifting of cultivation areas and decreases in production and quality. Tea (Camellia sinensis L.), which seeks optimum climatic resources, is a key cash crop economically in Kenya. In this study, the shifting of tea suitability was projected with the MaxEnt model under the SSP (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) climate scenarios for the 2050s and 2090s relative to the 1970–2000 distribution. Analysis under the current climatic condition showed that the proportions of optimal and medium- and marginal-suitable areas were 2%, 3%, and 24% of the total area, respectively, and located in south-western (SW), central, and north-eastern (NE) Kenya and, to some extent, in the Rift Valley. It was projected that the potential suitable tea-growing areas would migrate from the western areas to the central, eastern, and north-eastern highlands in Kenya. It was detected that the precipitation of the driest period (July), precipitation of the wettest quarter (April, May, and June), and annual temperature range could be the main climatic factors determining the shift in tea distribution. Compared to the current distribution (29%), the climatically suitable areas for tea production could reach 32.58% of Kenya’s land area under the SSP1-2.6 scenarios in the 2050s and 35.08% in the 2090s under the SSP5-8.5 scenario. On the contrary, it was found that the optimal climate-suitable habitats were projected to shrink by 2% and 1% in the 2050s and 2090s under all scenarios on the west side of the Great Rift Valley compared to the current distribution. In comparison, the sizes of medium- and marginal-suitable habitats would increase by 1% and 3%, respectively. The findings indicated that unless adaptive climate actions are taken, climate change could reduce the tea planting areas in western Kenya. Meanwhile, climate suitability was projected to expand upward on the east side of the Rift Valley, enhancing the potential distribution of tea. The developed climate information could be used to design and implement adaptation interventions in the lower elevation areas. Finally, we highlight that the available scientific literature on the climate suitability of tea in Kenya should be broadened by adding non-climatic factors. Full article

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

36 pages, 2357 KiB

Open AccessArticle

The Impact of Suspension Fertilizers Based on Waste Phosphorus Salts from Polyol Production on the Content of Macronutrients in Maize Grown for Green Fodder

by Paulina Bogusz, Marzena Sylwia Brodowska and Paweł Muszyński

Agronomy 2024, 14(9), 2079; https://doi.org/10.3390/agronomy14092079 - 11 Sep 2024

Abstract

Mineral phosphorus is a non-renewable resource that is constantly decreasing due to intensive fertilizer production. In total, 90% of mined phosphate ore is used for fertilizer purposes, so the demand for phosphorus is the highest in this sector. In this respect, it is [...] Read more.

Mineral phosphorus is a non-renewable resource that is constantly decreasing due to intensive fertilizer production. In total, 90% of mined phosphate ore is used for fertilizer purposes, so the demand for phosphorus is the highest in this sector. In this respect, it is advisable to strive to close the phosphorus cycle. In addition, economically viable phosphate-bearing deposits are concentrated in just a few locations worldwide. This comes down to the fact that most countries are simply dependent on imports of this raw material. This and the growing amount of waste have contributed to the search for alternative sources of phosphorus. One example of such phosphorus-containing waste that has fertilizer potential is sodium–potassium phosphate waste from polyol production. This article describes the effect of suspension fertilizers based on polyol production waste on the content of macronutrients in maize intended for green fodder. Fertilizers containing only basic nutrients (NPK) and fertilizers enriched with secondary components (S, Mg) and micronutrients (Zn, Mn, B) were evaluated. The conducted studies confirmed the effectiveness of the tested suspension fertilizers. The content of macronutrients in the dry mass of maize was at a similar level compared with the results obtained in the control, in which Fosdar was used for fertilization, which confirms the suitability of these products for agricultural use. Full article

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

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19 pages, 4454 KiB

Open AccessArticle

Effects of Phosphorus Application Levels on Its Uptake and Utilization in Foxtail Millet

by Junwei Ma, Guo Wang, Xiaojie Liu, Biao Lei and Guofang Xing

Agronomy 2024, 14(9), 2078; https://doi.org/10.3390/agronomy14092078 - 11 Sep 2024

Abstract

Foxtail millet is a traditional minor crop in China, known for its strong resistance to stress, tolerance to barren lands, and wide adaptation. Phosphorus is an essential element for crop growth and development, and the appropriate application of phosphorus can enhance crop yield [...] Read more.

Foxtail millet is a traditional minor crop in China, known for its strong resistance to stress, tolerance to barren lands, and wide adaptation. Phosphorus is an essential element for crop growth and development, and the appropriate application of phosphorus can enhance crop yield and quality. However, the optimal phosphorus fertilization levels for the growth of foxtail millet have yet to be determined. This study aims to explore the effects of different phosphorus application levels (T₁, T₂, T₃, and T₄), on phosphorus accumulation and use efficiency and crop yield and quality in the foxtail millet cultivars ‘B376’ and ‘B27’, which have different phosphorus efficiencies. Additionally, we investigated the effects of phosphorus accumulation and use efficiency on the heading and filling stages of these cultivars. The results show that the total phosphorus content and accumulation levels in the ‘B376’ and ‘B27’ cultivars vary at different developmental stages and in different plant parts. Furthermore, crop yield and quality in both cultivars vary in response to the different phosphorus application levels. In terms of yield, the phosphorus-tolerant variety ‘B376’ reaches its highest at T₂, while the phosphorus-sensitive variety ‘B27’ achieves its maximum yield at T₃. For quality, ‘B376’ exhibits the highest moisture and crude fat content under T₄, and the highest protein and the lowest amylose content under T₃. On the other hand, ‘B27’ achieves its highest moisture content under T₄, its highest crude fat and protein levels under T₃, and its lowest amylose content under T₂. Therefore, the response to different phosphorus application levels differs between the two cultivars with different phosphorus use efficiencies. Moreover, under different phosphorus fertilization levels, the average crop yield, moisture, fat, and amylose content averages of the phosphorus-tolerant ‘B376’ cultivar are 16.1%, 1.2%, 7.0%, and 4.1% higher than those of the phosphorus-sensitive ‘B27’ cultivar. Additionally, phosphorus use efficiency is positively correlated with the moisture and crude fat contents of foxtail millet. In conclusion, the phosphorus-tolerant cultivar demonstrates superior phosphorus accumulation, absorption, and utilization capacities compared to the phosphorus-sensitive cultivar. These results suggest that in the phosphorus-tolerant ‘B376’, optimal phosphorus fertilization levels enhance the development of roots, stems, and leaves at the T₂ (P₉₀) level, and promote the accumulation of moisture and crude fat in foxtail millet grains, thereby improving their taste and quality. Our findings provide a theoretical basis for phosphorus fertilizer utilization in foxtail millet cultivation and will help determine the optimal fertilization levels for foxtail millet growth. Full article

(This article belongs to the Section Plant-Crop Biology and Biochemistry)

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13 pages, 928 KiB

Open AccessArticle

Valorization of Mediterranean Species of Thyme for the Formulation of Bio-Herbicides

by Rym Boukhalfa, Claudia Ruta, Saida Messgo-Moumene, Generosa J. Calabrese, Maria Pia Argentieri and Giuseppe De Mastro

Agronomy 2024, 14(9), 2077; https://doi.org/10.3390/agronomy14092077 - 11 Sep 2024

Abstract

This study focused on the evaluation of the phytotoxic activity of four essential oils (EOs) from the Mediterranean species of Thymus sp. pl., namely Thymus algeriensis Boiss. et Reut., T. ciliatus Desf. subspecies coloratus (Boiss. et Reut.) Batt., T. vulgaris L. ecotype Fasano [...] Read more.

This study focused on the evaluation of the phytotoxic activity of four essential oils (EOs) from the Mediterranean species of Thymus sp. pl., namely Thymus algeriensis Boiss. et Reut., T. ciliatus Desf. subspecies coloratus (Boiss. et Reut.) Batt., T. vulgaris L. ecotype Fasano and T. vulgaris cultivar L. Varico 3, to identify new biomolecules with herbicide potential. The chemical characterization of EOs was performed by GC-MS. The evaluation of the phytotoxicity of the EOs was conducted under in vitro conditions, and the inhibition of germination and seedling growth of Lolium perenne L. and Amaranthus retroflexus L. were assessed. Five concentrations (100, 250, 500, 750 and 1000 µL/100 mL) were considered. Phytochemical analysis revealed a great diversity of compounds. T. algeriensis and T. ciliatus EOs were characterized by the absence of carvacrol and a low content of thymol in T. ciliatus. On the contrary, T. vulgaris ecotype Fasano and T. vulgaris cultivar Varico 3 were characterized by an important content of p-cymene, thymol and carvacrol. All the EOs expressed a potent phytotoxic activity against the tested species. The total inhibition of seed germination and seedling growth were recorded for the highest concentrations of all the EOs. T. vulgaris ecotype Fasano expressed the most effective activity. Full article

(This article belongs to the Special Issue Agro-Environmental Sustainable Exploitation of Halophyte, Medicinal and Aromatic Species from Marginal Areas)

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26 pages, 25701 KiB

Open AccessArticle

Key Factors Controlling Cadmium and Lead Contents in Rice Grains of Plants Grown in Soil with Different Cadmium Levels from an Area with Typical Karst Geology

by Long Li, Lijun Ma, Lebin Tang, Fengyan Huang, Naichuan Xiao, Long Zhang and Bo Song

Agronomy 2024, 14(9), 2076; https://doi.org/10.3390/agronomy14092076 - 11 Sep 2024

Abstract

Cadmium (Cd) is a naturally occurring element often associated with lead (Pb) in the Earth’s crust, particularly in karst regions, posing significant safety hazards for locally grown rice. Identifying the key factors controlling Cd and Pb content in local rice is essential under [...] Read more.

Cadmium (Cd) is a naturally occurring element often associated with lead (Pb) in the Earth’s crust, particularly in karst regions, posing significant safety hazards for locally grown rice. Identifying the key factors controlling Cd and Pb content in local rice is essential under the natural soil condition, as this will provide a crucial theoretical foundation for implementing security intervention measures within the local rice-growing industry. This study collected three types of paddy field soils with varying Cd concentrations from karst areas for pot experiments. The rice varieties tested included a low-Cd-accumulating variety, a high-Cd-accumulating variety, and a locally cultivated variety. Soil physicochemical properties and plant physiological indices were monitored throughout the rice growth stages. These data were used to construct a segmented regression model of Cd and Pb levels in rice grains based on the plant’s metabolic pathways and the structure of polynomial regression equations. Stepwise regression identified the key factors controlling Cd and Pb accumulation in rice grains. In conclusion, the key factors controlling Cd and Pb levels in rice grains should be classified into two categories: (i) factors influencing accumulation in roots and (ii) factors regulating transport from roots to grains. The aboveground translocation abilities for Cd, Pb, zinc (Zn), iron (Fe), manganese (Mn), calcium (Ca), and magnesium (Mg) in soil among the three rice varieties showed no significant interspecific differences under identical soil conditions. Soil Mg uptake by rice roots may represent a key mechanism for inhibiting soil Cd uptake by rice roots. In karst areas with high background soil Cd, increased soil organic matter (SOM) levels enhance Pb bioavailability. Additionally, the rice YXY may possess a potential for low Cd accumulation. Full article

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

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