Agronomy

15 pages, 1297 KiB

Open AccessArticle

Construction of Bacillus–Pseudomonas Synthetic Communities and Development of Bio-Nursery Substrates

by Qisheng Li, Qing Li, Xiaodong Yin, Yanyan Jia, Kai Yang, Jiamin Song, Yang Che, Ke Li, Zhangrong Wen, Dalu Gu, Xiaofeng Du and Wenfei Yang

Agronomy 2024, 14(9), 2179; https://doi.org/10.3390/agronomy14092179 - 23 Sep 2024

Viewed by 506

Abstract

With the rapid development of ecological agriculture and organic products, there is an urgent need to reduce the use of fertilizers and pesticides by producing bio-nursery substrates containing multifunctional microbial communities. In this study, beneficial Pseudomonas strains were screened from the rhizosphere of [...] Read more.

With the rapid development of ecological agriculture and organic products, there is an urgent need to reduce the use of fertilizers and pesticides by producing bio-nursery substrates containing multifunctional microbial communities. In this study, beneficial Pseudomonas strains were screened from the rhizosphere of muskmelon (Cucumis melo L.) pre-inoculated with Bacillus velezensis R1-3. The ability of the strain to dissolve phosphorus and produce indole-3-acetic acid (IAA), the effect of the strain on seed germination rate, and the antagonism with R1-3 were determined. Four strains of beneficial Pseudomonas strains that had no antagonistic effect against R1-3 were obtained and formed a Bacillus–Pseudomonas community. The seedling effect of biological substrates containing the Bacillus–Pseudomonas community was evaluated using a seedling pot experiment and a pot experiment. The results showed that the phosphorus solubilization range of all Pseudomonas strains was 86.32–459.48 mg L⁻¹ and the IAA production range was 2.98–11.86 mg L⁻¹. There was a significant negative correlation between the amount of phosphorus dissolved in the fermentation solution and pH. Combined with the results of the seed germination rate and antagonism test, the strains R1-3 + HY-S7, R1-3 + HY-S25, R1-3 + HY-S36, and R1-3 + HY-S70 were selected for the seedling pot experiment and the pot experiment. The results of the two-season seedling culture and two-season pot experiments showed that the bio-nursery substrates containing the bacterial community R1-3 + HY-S70 significantly promoted the growth of muskmelon seedlings, improved plant height, maximum leaf length, and fresh weight, and were significantly better than single bacterial and control treatments at increasing plant height and fresh weight. Finally, the bacterial community R1-3 + HY-S70 was established as the optimal combination for developing biological seedling substrates. Based on 16S rDNA gene sequence analysis, the strain HY-S70 was preliminarily identified as Pseudomonas moraviensis. Full article

(This article belongs to the Special Issue Molecular Regulatory Network of Plant Nutrition Signaling)

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12 pages, 2454 KiB

Open AccessArticle

Variation in Starch Properties in Ratoon Rice and Their Relationship with Rice Quality

by Chenqian Jiang, Shuaijun Dai, Dingguo Yang, Liying Huang, Xiaohai Tian, Zhaoqiang Jin, Shijie Shi, Ke Liu and Yunbo Zhang

Agronomy 2024, 14(9), 2178; https://doi.org/10.3390/agronomy14092178 - 23 Sep 2024

Viewed by 384

Abstract

Ratoon rice is characterized by higher production combined with enhanced rice quality. However, the relationship between the differences in the structure and properties of the starch and variations in the ratoon season and rice quality is still unclear. In this study, we conducted [...] Read more.

Ratoon rice is characterized by higher production combined with enhanced rice quality. However, the relationship between the differences in the structure and properties of the starch and variations in the ratoon season and rice quality is still unclear. In this study, we conducted a field experiment in 2023 to assess the relationship between rice quality differences and starch characteristics of four different hybrid rice varieties (Longjingyou1212: LJY1212; Taoyouxiangzhan: TYXZ; Liangyou6326: LY6326; Fengliangyouxiang1: FLYX1) in the ratoon season. In terms of appearance, the chalkiness degrees and chalky grain percentage of LJY1212 (0.6%, 2.3%) and TYXZ (1.2%, 6.0%) were 53.5% and 53.9% lower than those of LY6326 (2.4%, 10.0%) and FLYX1 (1.6%, 7.8%), indicating that the appearances of LJY1212 and TYXZ were better than those of LY6326 and FLYX1. The average amylose contents of LJY1212 (18.5%) and TYXZ (19.0%) were 10.8% higher than those of LY6326 (17.7%) and FLYX1 (15.7%), and there was no significant difference in protein content between the varieties in the ratoon season. Regarding the starch microstructure, the starch granules of LJY1212 and TYXZ in the ratoon season were arranged more closely. The average ratios of 1045/1022 cm⁻¹ of LJY1212 (0.77) and TYXZ (0.76) were 7.0% higher than those of LY6326 (0.71) and FLYX1 (0.72), indicating that the internal orders of LJY1212 and TYXZ’s starch were better than those of LY6326 and FLYX1. The average relative crystallinities of LJY1212 (24.8%) and TYXZ (24.5%) were 5.2% lower than those of LY6326 (25.7%) and FLYX1 (26.6%). The relative crystallinity of starch decreased with the increase in amylose content, while the short-range order degree, gelatinization temperature, and gelatinization enthalpy increased with the increase in amylose content. Therefore, the LJY1212 and TYXZ varieties, with better rice qualities, are recommended for planting in southern China. Full article

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

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13 pages, 1510 KiB

Open AccessArticle

Seed Dormancy and Germination Responses to Different Temperatures of Leptochloa chinensis (L.) Nees: A Case Study with 242 Populations Collected from Rice Fields in East China

by Kai An, Ling Chen, Yiyang Liu, Haiyan Wei and Guoqi Chen

Agronomy 2024, 14(9), 2177; https://doi.org/10.3390/agronomy14092177 - 23 Sep 2024

Viewed by 306

Abstract

Leptochloa chinensis (L.) Nees is a troublesome rice weed. We collected 242 L. chinensis populations from rice fields in eastern China and studied the duration of seed dormancy and the seed germination ability at different temperatures. All L. chinensis populations studied exhibited seed [...] Read more.

Leptochloa chinensis (L.) Nees is a troublesome rice weed. We collected 242 L. chinensis populations from rice fields in eastern China and studied the duration of seed dormancy and the seed germination ability at different temperatures. All L. chinensis populations studied exhibited seed dormancy. The periods required to reach 50% germination under optimal conditions were 31–235 days, with an average of 96 days. None of the populations germinated at 15 °C. Under constant temperatures of 20, 25, 30, and 35 °C, the average germination percentages of 242 populations were 0%, 71%, 79%, and 60% at 2 days after treatment (DAT), and were 56%, 84%, 88%, and 88% at 14 DAT, respectively. The duration of seed dormancy, as well as the germination ability of seeds, were significantly (p < 0.05) influenced by the agricultural region and the longitude and latitude of the collection locations. Under constant temperatures of 20 to 35 °C, the average germination percentages of seeds collected from transplanted rice fields were significantly higher than those collected from direct-seeded fields. This is the first study on seed germination biology of L. chinensis with multiple populations systematically collected from rice fields on a regional scale. Full article

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

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15 pages, 4907 KiB

Open AccessArticle

Biochar and Straw Amendments over a Decade Divergently Alter Soil Organic Carbon Accumulation Pathways

by Kunjia Lei, Wenxia Dai, Jing Wang, Zhenwang Li, Yi Cheng, Yuji Jiang, Weiqin Yin, Xiaozhi Wang, Xiaodong Song and Quan Tang

Agronomy 2024, 14(9), 2176; https://doi.org/10.3390/agronomy14092176 - 23 Sep 2024

Viewed by 519

Abstract

Exogenous organic carbon (C) inputs and their subsequent microbial and mineral transformation affect the accumulation process of soil organic C (SOC) pool. Nevertheless, knowledge gaps exist on how different long-term forms of crop straw incorporation (direct straw return or pyrolyzed to biochar) modifies [...] Read more.

Exogenous organic carbon (C) inputs and their subsequent microbial and mineral transformation affect the accumulation process of soil organic C (SOC) pool. Nevertheless, knowledge gaps exist on how different long-term forms of crop straw incorporation (direct straw return or pyrolyzed to biochar) modifies SOC composition and stabilization. This study investigated, in a 13-year long-term field experiment, the functional fractions and composition of SOC and the protection of organic C by iron (Fe) oxide minerals in soils amended with straw or biochar. Under the equal C input, SOC accumulation was enhanced with both direct straw return (by 43%) and biochar incorporation (by 85%) compared to non-amended conventional fertilization, but by different pathways. Biochar had greater efficiency in increasing SOC through stable exogenous C inputs and inhibition of soil respiration. Moreover, biochar-amended soils contained 5.0-fold greater SOCs in particulate organic matter (POM) and 1.2-fold more in mineral-associated organic matter (MAOM) relative to conventionally fertilized soils. Comparatively, although the magnitude of the effect was smaller, straw-derived OC was preserved preferentially the most in the MAOM. Straw incorporation increased the soil nutrient content and stimulated the microbial activity, resulting in greater increases in microbial necromass C accumulation in POM and MAOM (by 117% and 43%, respectively) compared to biochar (by 72% and 18%). Moreover, straw incorporation promoted poorly crystalline (Feo) and organically complexed (Fep) Fe oxides accumulation, and both were significantly and positively correlated with MAOM and SOC. The results address the decadal-scale effects of biochar and straw application on the formation of the stable organic C pool in soil, and understanding the causal mechanisms can allow field practices to maximize SOC content. These results are of great implications for better predicting and accurately controlling the response of SOC pools in agroecosystems to future changes and disturbances and for maintaining regional C balance. Full article

(This article belongs to the Special Issue The Interaction between the Type of Fertilizer and Soil Carbon Cycling)

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37 pages, 4412 KiB

Open AccessReview

Traditional Strategies and Cutting-Edge Technologies Used for Plant Disease Management: A Comprehensive Overview

by Hira Akhtar, Muhammad Usman, Rana Binyamin, Akhtar Hameed, Sarmad Frogh Arshad, Hafiz Muhammad Usman Aslam, Imran Ahmad Khan, Manzar Abbas, Haitham E. M. Zaki, Gabrijel Ondrasek and Muhammad Shafiq Shahid

Agronomy 2024, 14(9), 2175; https://doi.org/10.3390/agronomy14092175 - 23 Sep 2024

Viewed by 1089

Abstract

Agriculture plays a fundamental role in ensuring global food security, yet plant diseases remain a significant threat to crop production. Traditional methods to manage plant diseases have been extensively used, but they face significant drawbacks, such as environmental pollution, health risks and pathogen [...] Read more.

Agriculture plays a fundamental role in ensuring global food security, yet plant diseases remain a significant threat to crop production. Traditional methods to manage plant diseases have been extensively used, but they face significant drawbacks, such as environmental pollution, health risks and pathogen resistance. Similarly, biopesticides are eco-friendly, but are limited by their specificity and stability issues. This has led to the exploration of novel biotechnological approaches, such as the development of synthetic proteins, which aim to mitigate these drawbacks by offering more targeted and sustainable solutions. Similarly, recent advances in genome editing techniques—such as meganucleases (MegNs), zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPR)—are precise approaches in disease management, but are limited by technical challenges and regulatory concerns. In this realm, nanotechnology has emerged as a promising frontier that offers novel solutions for plant disease management. This review examines the role of nanoparticles (NPs), including organic NPs, inorganic NPs, polymeric NPs and carbon NPs, in enhancing disease resistance and improving pesticide delivery, and gives an overview of the current state of nanotechnology in managing plant diseases, including its advantages, practical applications and obstacles that must be overcome to fully harness its potential. By understanding these aspects, we can better appreciate the transformative impact of nanotechnology on modern agriculture and can develop sustainable and effective strategies to mitigate plant diseases, ensuring enhanced agricultural productivity. Full article

(This article belongs to the Special Issue Innovative Research on Soil Microbial Ecosystem and Its Interaction with Crop Plants)

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23 pages, 1432 KiB

Open AccessArticle

The Effect of Herbicides and Biostimulant Application on the Seed Yield and Seed Quality of Soybean (Glycine max (L.) Merr.)

by Dorota Gawęda, Małgorzata Haliniarz, Sylwia Andruszczak and Roman Wacławowicz

Agronomy 2024, 14(9), 2174; https://doi.org/10.3390/agronomy14092174 - 23 Sep 2024

Viewed by 385

Abstract

The profitability of growing soybean (Glycine max (L.) Merr.) is largely determined by the successful elimination of weeds and the weather conditions, the adverse effect of which can be minimized by the use of biostimulants. This study aims to evaluate the effect [...] Read more.

The profitability of growing soybean (Glycine max (L.) Merr.) is largely determined by the successful elimination of weeds and the weather conditions, the adverse effect of which can be minimized by the use of biostimulants. This study aims to evaluate the effect of several herbicides and biostimulants on the seed yield and contents of protein, fat, amino acids, and fatty acids in soybean seeds. The results demonstrate that the yield and quality of soybean seeds were most beneficially affected by the use of prosulfocarb immediately after sowing in combination with a subsequent foliar application of bentazone and imazamox with an adjuvant containing methyl oleate and fatty alcohol. This treatment ensured the highest seed yield (3.32 t ha⁻¹⁾, the highest contents in seeds of protein (342.4 g kg⁻¹ DM), phenylalanine (15.65 g kg⁻¹ DM), leucine (23.54 g kg⁻¹ DM), and most of the endogenous amino acids. All herbicide treatments increased the contents of tryptophan, serine, and glutamic acid compared to the seeds without herbicide treatment. The study results indicate that soybean responded positively to all biostimulants, as indicated by a higher seed yield (from 5.3% to 11.3%), plant height, and contents of tryptophan, serine, glutamic acid, cysteine, tyrosine, and C18:1n9c + C18:1n9t acids in the seeds. Full article

(This article belongs to the Section Farming Sustainability)

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15 pages, 2753 KiB

Open AccessArticle

Effects of Various Levels of Water Stress on Morpho-Physiological Traits and Spectral Reflectance of Maize at Seedling Growth Stage

by Xuemin Li, Yayang Feng, Xiulu Sun, Wentao Liu, Weiyue Yang, Xiaoyang Ge and Yanhui Jia

Agronomy 2024, 14(9), 2173; https://doi.org/10.3390/agronomy14092173 - 23 Sep 2024

Viewed by 459

Abstract

Water stress (drought and waterlogging) is one highly important factor affecting food security in China. Investigating the effects of soil moisture stress on the morphological and physiological characteristics of maize seedlings is crucial for ensuring food production. The use of spectral monitoring to [...] Read more.

Water stress (drought and waterlogging) is one highly important factor affecting food security in China. Investigating the effects of soil moisture stress on the morphological and physiological characteristics of maize seedlings is crucial for ensuring food production. The use of spectral monitoring to observe crop phenotypic traits and assess crop health has become a focal point in field crop research. However, studies exploring the contribution of crop phenotypic and physiological data to the Normalized Difference Vegetation Index (NDVI) are still limited. In this study, a 35-day pot experiment was conducted with seven soil moisture gradients: 50%, 60%, 70%, 80% (control group, CK), 90%, 100%, and 110% treatment. In order to investigate the effects of soil moisture stress on seedling phenotypes, antioxidant enzyme activities, and NDVI, an ASD FieldSpec 4 Hi-Res NG portable spectrometer was used to collect spectral data from maize (Zea mays L. B73) leaves. The contributions of maize phenotypic and physiological traits to NDVI were also examined. The results indicated that (1) the 50% and 110% treatments significantly affected maize seedling phenotypes compared to the CK group; (2) the activities of superoxide dismutase (SOD) and peroxidase (POD) in the leaves increased under water stress, while the activities of glutathione peroxidase (GSH-PX) and ascorbate peroxidase (APX) decreased; (3) soil moisture stress (drought and waterlogging) reduced photosynthetic pigments, chlorophyll content (SPAD), and NDVI, with inhibitory effects intensifying as the stress level increased; (4) Redundancy analysis showed that antioxidant enzymes explained 69.87% of the variation in seedling height, leaf area, and NDVI. Soil moisture stress, chlorophyll, and SPAD explained 58.14% of the variation in these parameters. The results demonstrated that maize seedlings were highly sensitive to soil moisture changes, and the SPAD value contributed significantly to NDVI (p < 0.01). This study provides valuable insights for future research in precision agriculture management Full article

(This article belongs to the Special Issue Influence of Irrigation and Water Use on Agronomic Traits of Crop)

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20 pages, 3143 KiB

Open AccessArticle

Unveiling Microbial Dynamics and Gene Expression in Legume–Buffel Grass Coculture Systems for Sustainable Agriculture

by Xipeng Ren, Sung J. Yu, Philip B. Brewer, Nanjappa Ashwath, Yadav S. Bajagai, Dragana Stanley and Tieneke Trotter

Agronomy 2024, 14(9), 2172; https://doi.org/10.3390/agronomy14092172 - 23 Sep 2024

Viewed by 579

Abstract

Legumes enhance pasture health and soil productivity by fixing atmospheric nitrogen and boosting soil microbiota. We investigated the effects of tropical pasture legumes, including butterfly pea (Clitoria ternatea), seca stylo (Stylosanthes scabra), desmanthus (Desmanthus virgatus), lablab ( [...] Read more.

Legumes enhance pasture health and soil productivity by fixing atmospheric nitrogen and boosting soil microbiota. We investigated the effects of tropical pasture legumes, including butterfly pea (Clitoria ternatea), seca stylo (Stylosanthes scabra), desmanthus (Desmanthus virgatus), lablab (Lablab purpureus), and Wynn cassia (Chamaecrista rotundifolia), on the soil microbial community and buffel grass (Cenchrus ciliaris) gene expression. Additionally, we explored the impact of a phytogenic bioactive product (PHY) in the coculture system. A pot trial using soil enriched with cow paunch compost included four treatments: monoculture of buffel grass and five legume species with and without PHY supplementation and coculture of buffel grass with each legume species with and without PHY supplementation. Actinobacteriota and Firmicutes were the dominant bacterial phyla. Regardless of PHY application, the coculture of buffel grass with legumes positively influenced microbial composition and diversity. Transcriptomic analysis revealed significant gene expression changes in buffel grass shoots and roots, with each legume uniquely affecting nitrogen metabolism. Lablab and Wynn cassia exhibited similarities in modulating metabolic processes, butterfly pea contributed to mycotoxin detoxification, and desmanthus balanced cell death and growth. Seca stylo enhanced root cell growth and regeneration. These findings offer insights for optimizing legume–grass coculture systems, enhancing soil activity and promoting sustainable agriculture. Full article

(This article belongs to the Special Issue Effect of Agricultural Management Practices on Soil Microbial Community Composition, Diversity and Function)

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15 pages, 1928 KiB

Open AccessArticle

Genome-Wide Association Study Reveals Marker–Trait Associations for Heat-Stress Tolerance in Sweet Corn

by Quannv Yang, Zifeng Guo, Jianan Zhang, Yunbo Wang, Yunbi Xu and Hai Nian

Agronomy 2024, 14(9), 2171; https://doi.org/10.3390/agronomy14092171 - 23 Sep 2024

Viewed by 620

Abstract

Sweet corn (Zea mays var. rugosa Bonaf.) is a crop with a high economic benefit in tropical and subtropical regions. Heat tolerance analysis and heat-tolerant gene mining are of great significance for breeding heat-resistant varieties. By combining improved genotyping using targeted [...] Read more.

Sweet corn (Zea mays var. rugosa Bonaf.) is a crop with a high economic benefit in tropical and subtropical regions. Heat tolerance analysis and heat-tolerant gene mining are of great significance for breeding heat-resistant varieties. By combining improved genotyping using targeted sequencing (GBTS) with liquid chip (LC) technology, a high-density marker array containing 40 K multiple single polynucleotide polymorphisms (mSNPs) was used to genotype 376 sweet corn inbred lines and their heat-stress tolerance was evaluated in the spring and summer of 2019. In general, plant height, ear height and the number of lateral branches at the first level of the male flowers were reduced by 24.0%, 36.3%, and 19.8%, respectively. High temperatures in the summer accelerated the growth process of the sweet corn, shortening the days to shedding pollen by an average of 21.6% compared to the spring. A genome-wide association study (GWAS) identified 85 significant SNPs distributed on 10 chromosomes. Phenotypes in the spring and summer were associated with the 21 and 15 loci, respectively, and significant phenotypic differences between the two seasons caused by the temperature change were associated with the 49 SNP loci. The seed setting rate (SSR) was more susceptible to heat stress. An annotation analysis identified six candidate genes, which are either heat shock transcription factors (Hsfs) or heat shock proteins (Hsps) in Arabidopsis and rice (Oryza sativa), and these candidate genes were directly and indirectly involved in the heat-resistant response in the sweet corn. The current findings provide genetic resources for improving the heat-stress tolerance of sweet corn by molecular breeding. Full article

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

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11 pages, 766 KiB

Open AccessArticle

A Synthesis Analysis of the Relationship between Main and Ratoon Crop Grain Yields in Ratoon Rice

by Bin Liu, Shen Yuan and Shaobing Peng

Agronomy 2024, 14(9), 2170; https://doi.org/10.3390/agronomy14092170 - 23 Sep 2024

Viewed by 373

Abstract

Ratoon rice represents a viable means to enhance rice production efficiency in terms of both area and time. Nonetheless, the development of specific varieties tailored for ratoon rice has been hindered by the complexity of trait considerations required during breeding/screening processes. A pivotal [...] Read more.

Ratoon rice represents a viable means to enhance rice production efficiency in terms of both area and time. Nonetheless, the development of specific varieties tailored for ratoon rice has been hindered by the complexity of trait considerations required during breeding/screening processes. A pivotal step towards advancing ratoon rice breeding programs involves reducing the dimensionality of selection traits. In this study, we performed a comprehensive analysis exploring whether the yield of the main crop could serve as a predictor for ratoon crop yield, thereby simplifying the selection process. Our findings revealed significant variability in the rice yields of both main and ratoon crops, with the ratoon crop yield averaging 51% of the main crop. Importantly, the correlation between grain yields of the main and ratoon crops did not deviate from the identity line, substantiating the feasibility of predicting ratoon crop yield based on the main crop yield. The number of panicles in the ratoon crops was found to be closely linked to that of the main crop; however, the size values of the panicles in the ratoon crops exhibited less of a dependency on the main crop’s panicle size. Additionally, a general decrease in grain weight was observed in the ratoon crops compared to the main crop. In summary, this study elucidates a pathway for the simplification of selection traits, thereby enhancing the efficiency of breeding high-yielding ratoon rice varieties, with the ultimate aim of fostering the sustainable development of ratoon rice. Full article

(This article belongs to the Section Innovative Cropping Systems)

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17 pages, 3432 KiB

Open AccessArticle

Reducing the Sodium Adsorption Ratio Improves the Soil Aggregates and Organic Matter in Brackish-Water-Irrigated Cotton Fields

by Yucai Xie, Huifeng Ning, Xianbo Zhang, Wang Zhou, Peiwen Xu, Yinping Song, Nanfang Li, Xingpeng Wang and Hao Liu

Agronomy 2024, 14(9), 2169; https://doi.org/10.3390/agronomy14092169 - 23 Sep 2024

Viewed by 492

Abstract

The assessment of soil health relies on key parameters such as soil aggregates and organic matter content. Therefore, examining the impact of irrigation water ion composition and variations in salinity on soil aggregates and organic matter is imperative, which is key to developing [...] Read more.

The assessment of soil health relies on key parameters such as soil aggregates and organic matter content. Therefore, examining the impact of irrigation water ion composition and variations in salinity on soil aggregates and organic matter is imperative, which is key to developing a theoretical basis for the sustainable utilization of saline water resources, particularly in extremely arid regions. This experiment was conducted to investigate the impact of different irrigation water salinity treatments (T3: 3 g/L, T5: 5 g/L, and T7: 7 g/L) on the root zone soil of cotton fields. Each salinity treatment included three variations of the sodium adsorption ratio (SAR) at S10: 10 (mmol/L)^1/2, S15: 15 (mmol/L)^1/2, and S20: 20 (mmol/L)^1/2. Local freshwater irrigation served as the control, resulting in a total of 10 treatments. Our findings show that the soil Ca²⁺ and Mg²⁺ content increased with higher irrigation water salinity but decreased with increasing irrigation water SAR. The relative macroaggregate stability and the content of water-stable macroaggregates and soil organic matter (SOM) decreased as the irrigation water salinity and SAR increased. In comparison to T3S20, T5S10 did not improve the soil Na⁺ content but significantly increased the soil Ca²⁺ content by 147.76%, while the water-stable aggregate and SOM saw a notable increase of 7.66% and 9.86%, respectively. Reducing the SAR in brackish water lessens its negative impact on soil aggregates in cotton fields. This is primarily because Ca²⁺ counteracts the dispersive effect of high Na⁺ concentrations and promotes aggregate formation. Irrigation water with a salinity of 3 g/L and an SAR of 10 (mmol/L)^1/2 positively affected the stabilization of soil aggregates and organic matter. Full article

(This article belongs to the Section Farming Sustainability)

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17 pages, 1744 KiB

Open AccessArticle

Spatio-Temporal Dynamics of Soil Penetration Resistance Depending on Different Conservation Tillage Systems

by Danijel Jug, Irena Jug, Dorijan Radočaj, Edward Wilczewski, Boris Đurđević, Mladen Jurišić, Jozsef Zsembeli and Bojana Brozović

Agronomy 2024, 14(9), 2168; https://doi.org/10.3390/agronomy14092168 - 22 Sep 2024

Viewed by 774

Abstract

As conservation tillage becomes one of the foundations of sustainable crop production, important questions arise about its value, which needs to be defined and evaluated. One of the most important indicators of soil compaction is penetration resistance (PR), which comes as a short-term [...] Read more.

As conservation tillage becomes one of the foundations of sustainable crop production, important questions arise about its value, which needs to be defined and evaluated. One of the most important indicators of soil compaction is penetration resistance (PR), which comes as a short-term response to the state of soil physics. The objective of this work is to compare different tillage treatments (TT) on soil compaction on silty clay loam Stagnosol and silt Gleysol in the continental part of Croatia. The research included three tillage treatments: ST—conventional tillage, CTD—deep conservation tillage, and CTS—shallow conservation tillage. PR was determined on each soil depth of 5 cm up to 80 cm, and measuring was provided on two measuring dates. The obtained results showed a higher influence of the year factor than TT. In the upper layers (up to 35 cm), PR values between TT were with significant differences, but in most cases below root-limiting critical values, while in deeper soil layers (35–80 cm), we found that penetration values on each tillage treatment begin to stabilize and smooth out in most cases, with similar dynamics on both soil types and measurement dates. In most of the cases, the highest PR was measured for conservation treatments in wetter soil conditions. 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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22 pages, 5103 KiB

Open AccessArticle

Combined Effects of Nitrogen Addition and Warming on Shrub Growth and Nutrient Uptake through Microbially Mediated Soil Fertility

by Zhuxin Mao, Yang Li, Siyu Chen, Yuchao Wang, Guanghua Jing, Ying Wei, Huiying Shang and Ming Yue

Agronomy 2024, 14(9), 2167; https://doi.org/10.3390/agronomy14092167 - 22 Sep 2024

Viewed by 404

Abstract

Plant restoration strategies are ubiquitously employed for the purposes of soil and water conservation and ecological improvement in forest ecosystems. Despite N and temperature being acknowledged as pivotal factors affecting plant restoration outcomes, their effects on soil fertility, microbial communities, and shrub biomass [...] Read more.

Plant restoration strategies are ubiquitously employed for the purposes of soil and water conservation and ecological improvement in forest ecosystems. Despite N and temperature being acknowledged as pivotal factors affecting plant restoration outcomes, their effects on soil fertility, microbial communities, and shrub biomass remain underexplored, particularly in the loess hilly regions of China. Here, we examined the growth patterns and nutrient acquisition abilities of three shrub species, Periploca sepium, Amorpha fruticosa, and Vitex negundo, along with the attendant alterations in soil properties and microbial community composition under controlled greenhouse conditions. Specifically, we imposed three levels of N fertilization (200, 400, and 600 kg ha⁻¹; designated as N1, N2, and N3, respectively) and temperature regimes (18–23, 25–30, and 32–37 °C; labeled T1, T2, and T3, respectively). The results indicated a significant interplay between the combination of N fertilization and temperature significantly affecting shrub growth. Optimal growth conditions, as evidenced by the highest dry biomass accumulation, were identified as N3T1 for A. fruticosa, N1T1 for P. sepium, and N2T2 for V. negundo, with these conditions differentially influencing roots, stems, and leaves. Furthermore, soil microorganisms also responded significantly to the N fertilization and temperature. However, this was largely dependent on shrub species and soil nutrients. For A. fruticosa under N3T1 conditions, Actinobacteria and Basidiomycota abundances correlated strongly with soil C, N, and P contents, while leaf N uptake significantly correlated with the structure of both bacterial and fungal communities. For P. sepium at N1T1, Acidobacteriota was dominant in response to soil N and C, while leaf C uptake and leaf and stem N uptake positively correlated with bacterial and fungal communities, respectively. For V. negundo at N2T2, Chloroflexi had the greatest abundance, responding to the greatest variation in soil N and C, while its stem N uptake was significantly related to the structure of the fungal communities. Thus, our findings underscored the intricate interplay between abiotic factors, shrub growth, soil fertility, and microbial community dynamics, providing insights into the optimization of plant restoration efforts in ecologically sensitive regions. Full article

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

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24 pages, 5311 KiB

Open AccessArticle

Study on the Natural Ventilation Model of a Single-Span Plastic Greenhouse in a High-Altitude Area

by Youyu Li, Shumei Zhao, Anguo Dai, Jingfu Zhang, Zilong Fan and Tao Ding

Agronomy 2024, 14(9), 2166; https://doi.org/10.3390/agronomy14092166 - 22 Sep 2024

Viewed by 452

Abstract

The natural ventilation model plays a crucial role in greenhouse environmental control. It has been extensively studied by previous researchers, but it is limited to low-altitude areas. This study established a numerical model of single-span plastic greenhouses in high-altitude areas. The model was [...] Read more.

The natural ventilation model plays a crucial role in greenhouse environmental control. It has been extensively studied by previous researchers, but it is limited to low-altitude areas. This study established a numerical model of single-span plastic greenhouses in high-altitude areas. The model was validated using measured data, showing a good agreement between the measured and simulated values. By setting boundary conditions based on on-site monitoring data, ventilation rates were extracted under different conditions for numerical simulations. Through nonlinear fitting, an empirical formula for natural ventilation rates, with a determination coefficient (R²) of 0.9724, was derived. The formula was validated through an energy balance analysis of indoor air. Different ventilation opening sizes were simulated to derive an empirical formula for natural ventilation rates based on opening size. Building on this, the relationship between plant height and ventilation rate was analyzed. As the dominant factors of natural ventilation change with environmental fluctuations, this study also proposed the threshold wind speed for wind pressure ventilation, thermal pressure ventilation, and coupled ventilation, filling the knowledge gap in relevant ventilation rate calculations. This is the first time that a natural ventilation model of single-span plastic greenhouses in high-altitude areas has been proposed, providing the basis in terms of modeling for the further development of local facility agriculture. Full article

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

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26 pages, 3009 KiB

Open AccessArticle

Phenotypic Diversity and Seed Germination of Elaeagnus angustifolia L. in Relation to the Geographical Environment in Gansu Province, China

by Kaiqiang Zhang, Zhu Zhu, Rongrong Shi, Ningrui Shi, Qing Tian and Xuemei Lu

Agronomy 2024, 14(9), 2165; https://doi.org/10.3390/agronomy14092165 - 22 Sep 2024

Viewed by 418

Abstract

Elaeagnus angustifolia L. is a highly adaptable urban ornamental plant, playing a key role in dry land and saline-alkali protective forests. The diverse geographical and climatic conditions in Gansu Province have resulted in variations in its distribution and growth. This study assesses the [...] Read more.

Elaeagnus angustifolia L. is a highly adaptable urban ornamental plant, playing a key role in dry land and saline-alkali protective forests. The diverse geographical and climatic conditions in Gansu Province have resulted in variations in its distribution and growth. This study assesses the phenotypic diversity of fruits and seeds, and the seed germination characteristics of 82 E. angustifolia plants from nine populations in Gansu Province, exploring their relationship with geographical and climatic factors. We measured 12 phenotypic traits and five germination indices. This study included germination tests under standard conditions, statistical analysis of phenotypic differences, and Pearson and Spearman correlation analyses to examine relationships between traits and geo-climatic factors. Principal component and cluster analyses were also performed to identify key traits and classify populations. The findings were as follows: (1) Significant differences were observed in phenotypic traits and germination characteristics among populations. Single fruit weight showed the highest variation (27.56%), while seed transverse diameter had the lowest (8.76%). The Lanzhou population exhibited the greatest variability (14.27%), while Linze had the lowest (6.29%). (2) A gradient change pattern in traits was observed, primarily influenced by longitude and a combination of geographical and climatic factors. Seed germination was positively correlated with altitude, annual precipitation, and relative humidity, but negatively affected by latitude and traits such as fruit weight. (3) Principal component analysis identified germination rate, germination index, seed shape index, and fruit shape index as primary factors, contributing 27.4%, 20.6%, and 19.9% to the variation, respectively. Cluster analysis grouped the 82 plants into four clusters, not strictly based on geographical distance, suggesting influence from factors such as genotype or environmental conditions. In conclusion, this study lays a foundation for understanding the genetic mechanisms behind the phenotypic diversity and germination characteristics of E. angustifolia. It offers insights into how geo-climatic factors influence these traits, providing valuable information for the species’ conservation, cultivation, and management. Full article

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

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19 pages, 12861 KiB

Open AccessArticle

Optimization of Clamping and Conveying Parameters for Spinach Orderly Harvesting with Low Damage by Simulation and Experiment

by Huankun Wang, Chong Qi, Qiaojun Luo, Minglin Chen, Yidong Ma and Xianlong Wang

Agronomy 2024, 14(9), 2164; https://doi.org/10.3390/agronomy14092164 - 22 Sep 2024

Viewed by 308

Abstract

The leaves of spinach are delicate and easily injured during harvesting. To reduce the spinach damage rate and increase the conveyance success rate, an orderly harvester was designed and manufactured, and the key conveying parameters of the harvester were optimized by simulation and [...] Read more.

The leaves of spinach are delicate and easily injured during harvesting. To reduce the spinach damage rate and increase the conveyance success rate, an orderly harvester was designed and manufactured, and the key conveying parameters of the harvester were optimized by simulation and experiments. The compression damage stress of spinach was determined by compression tests. Then, a finite element simulation model for spinach clamping was established, and the influence of different clamping heights on the spinach deformation and equivalent stress were simulated and analyzed. Finally, response surface Box–Behnken experiments were conducted to optimize the combinations of the twisting angle, clamping distance, and height difference. The results of the compression tests showed that the compression damage stresses of spinach leaves, stems, and their connection points were 8.04 × 10⁻² MPa, 7.85 × 10⁻² MPa, and 11.63 × 10⁻² MPa, respectively. The optimal clamping height of spinach for orderly conveyance was obtained to be 20 mm according to the finite element simulation. The response surface experimental results indicated that the significance order of factors affecting the extrusion force was the clamping distance, the height difference, and the twisting angle. The significance order of factors affecting the conveyance success rate was the clamping distance, the twisting angle, and the height difference. The optimal parameter combination was ae twisting angle of 60°, clamping distance of 24 mm, and a height difference of 20 cm. The experimental validation of the optimization results from the finite element simulation and response surface tests demonstrated that the extrusion force and conveyance success rate were 2.37 N and 94%, respectively, with a conveying damage rate of 3% for spinach, meeting the requirements for the low-damage and orderly harvesting of spinach. Full article

(This article belongs to the Special Issue Agricultural Automation and Innovative Agricultural Systems—2nd Edition)

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21 pages, 41502 KiB

Open AccessReview

Recent Advances in Biomimetic Methods for Tillage Resistance Reduction in Agricultural Soil-Engaging Tools

by Xuezhen Wang, Shihao Zhang, Ruizhi Du, Hanmi Zhou and Jiangtao Ji

Agronomy 2024, 14(9), 2163; https://doi.org/10.3390/agronomy14092163 - 22 Sep 2024

Viewed by 356

Abstract

The high tillage resistance of agricultural soil-engaging tools (TASTs) in farmland operations (e.g., tillage, sowing, crop management, and harvesting) increases fuel consumption and harmful gas emissions, which negatively affect the development of sustainable agriculture. Biomimetic methods are promising and effective technologies for reducing [...] Read more.

The high tillage resistance of agricultural soil-engaging tools (TASTs) in farmland operations (e.g., tillage, sowing, crop management, and harvesting) increases fuel consumption and harmful gas emissions, which negatively affect the development of sustainable agriculture. Biomimetic methods are promising and effective technologies for reducing the TASTs and have been developed in the past few years. This review comprehensively summarizes the typical agricultural soil-engaging tools (ASETs) and their characteristics and presents existing biomimetic methods for decreasing TASTs. The introduction of TAST reduction was performed on aspects of tillage, sowing, crop management, and harvesting. The internal mechanisms and possible limitations of current biomimetic methods for various ASETs were investigated. The tillage resistance reduction rates of ASETs, as affected by various biomimetic methods, were quantitatively compared under different soil conditions with statistical analyses. Additionally, three future research directions were recommended in the review to further reduce TASTs and encourage the development of sustainable agriculture. Full article

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

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13 pages, 2462 KiB

Open AccessArticle

Medium-Term Monitoring of Greenhouse Gases above Rice-Wheat Rotation System Based on Mid-Infrared Laser Heterodyne Radiometer

by Zhengyue Xue, Jun Li, Fengjiao Shen, Sheng Zhang, Xueyou Hu and Tu Tan

Agronomy 2024, 14(9), 2162; https://doi.org/10.3390/agronomy14092162 - 22 Sep 2024

Viewed by 435

Abstract

The rice-wheat rotation system is a major agricultural practice in China as well as an important source of greenhouse gas (GHG) emissions. In this study, the developed mid-infrared laser heterodyne radiometer (MIR-LHR) was used for the remote sensing of atmospheric CH₄ and [...] Read more.

The rice-wheat rotation system is a major agricultural practice in China as well as an important source of greenhouse gas (GHG) emissions. In this study, the developed mid-infrared laser heterodyne radiometer (MIR-LHR) was used for the remote sensing of atmospheric CH₄ and N₂O concentrations above the rice-wheat rotation system. From April 2019 to May 2022, the atmospheric column concentrations of CH₄ and N₂O above the rice-wheat rotation system were continuously observed in Hefei, China. The peak values of the N₂O column concentration appeared 7~10 days after wheat seasonal fertilization, with additional peaks during the drainage period of rice cultivation. During the three-year rice-wheat crop rotation cycle, a consistent trend was observed in the CH₄ column concentrations, which increased during the rice-growing season and subsequently decreased during the wheat-growing season. The data reveal different seasonal patterns and the impact of agricultural activities on their emissions. During the observation period, the fluctuations in the CH₄ and N₂O column concentrations associated with the rice-wheat rotation system were about 40 ppbv and 6 ppbv, respectively. The MIR-LHR developed for this study shows great potential for analyzing fluctuations in atmospheric column concentrations caused by GHG emissions in the rice-wheat rotation system. 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—2nd Edition)

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23 pages, 4458 KiB

Open AccessArticle

A Comprehensive Benefit Evaluation of the Model of Salt-Tolerant Crops Irrigated by Mariculture Wastewater Based on a Field Plot Experiment

by Dan Chen, Huimin Lu, Ze Fu, Zhaohui Luo and Jiaming Duan

Agronomy 2024, 14(9), 2161; https://doi.org/10.3390/agronomy14092161 - 22 Sep 2024

Viewed by 464

Abstract

The intensified development of aquaculture and excessive use of agricultural fertilizers pose a threat to natural resource availability and deteriorate the environment. Utilizing aquaculture wastewater from mariculture for agricultural irrigation can mitigate pollution and alleviate the pressure on natural resources. This study investigated [...] Read more.

The intensified development of aquaculture and excessive use of agricultural fertilizers pose a threat to natural resource availability and deteriorate the environment. Utilizing aquaculture wastewater from mariculture for agricultural irrigation can mitigate pollution and alleviate the pressure on natural resources. This study investigated the comprehensive benefits of using freshwater and mariculture wastewater for irrigation, employing two concentration levels of mariculture wastewater in a pot experiment with saline-tolerant rice. Furthermore, we quantitively assessed the integrated benefits for farmland by utilizing an ecosystem service function value assessment and emergy value theory. The results indicate a significant enhancement in the growth and yield of saline-tolerant rice when irrigated with mariculture wastewater. Specifically, the theoretical yield increased by 9.01% relative to freshwater irrigation. Irrigation using aquaculture wastewater significantly enhanced the nutrient concentrations in the soil, including soil organic carbon (SOC), avail-K (AK), Olsen-P (OP), and alkali-N (AN). Additionally, the uptake of these nutrients by salt-tolerant crops during their late reproductive stage effectively mitigated the rise in soil salinity induced by the wastewater irrigation practice. Under experimental conditions, wastewater irrigation conferred superior ecological benefits compared with freshwater irrigation. The comprehensive benefits of wastewater irrigation, valued at 104,439.10 RMB/hm², exceeded those of freshwater irrigation by 188.8%. The utilization of mariculture wastewater effectively enhances the coastal environment, augments crop yields, and diminishes treatment costs. From the perspectives of revenue enhancement, environmental compatibility, and sustainability, the model of utilizing salt-tolerant crops irrigated with mariculture wastewater holds substantial promotional and practical significance. Full article

(This article belongs to the Special Issue Agricultural Water Management Strategies for Sustainable Crop Production)

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10 pages, 1038 KiB

Open AccessArticle

Combined Application of Chemical Fertilizer and Organic Amendment Improved Soil Quality in a Wheat–Sweet Potato Rotation System

by Hui Zhang, Xiang Li, Jiayi Zhou, Jidong Wang, Lei Wang, Jie Yuan, Cong Xu, Yue Dong, Yahua Chen, Yuchun Ai and Yongchun Zhang

Agronomy 2024, 14(9), 2160; https://doi.org/10.3390/agronomy14092160 - 22 Sep 2024

Viewed by 682

Abstract

The long-term excessive use of chemical fertilizers may result in soil degradation, but manure and straw application is considered to be an effective approach for alleviating this problem. The aim of this study is to examine the long-term impacts of different fertilization patterns [...] Read more.

The long-term excessive use of chemical fertilizers may result in soil degradation, but manure and straw application is considered to be an effective approach for alleviating this problem. The aim of this study is to examine the long-term impacts of different fertilization patterns on soil quality variables in a wheat–sweet potato rotation system. Four treatments were conducted in a field trial for a duration of twelve years, including (1) no fertilizer (control, CK); (2) application of mineral fertilizers (NPK) alone; (3) NPK with crop straw return (NPKs); (4) combined use of NPK and farmyard manure (NPKm). Thirteen physical, chemical, and biological soil parameters were measured. The results showed that the NPKm and NPKs significantly improved the proportion of macroaggregates (>0.25 mm) by 24.7% and 21.9% compared to the NPK alone, respectively. The proportion of microaggregates (0.053–0.25 mm) under the NPKm was 47.4% significantly higher than the NPKs. Additionally, the NPKm resulted in a 22.2% and 19.6% increase in the SOC content than the NPK and NPKs, respectively. In terms of soil-available K, the NPKs resulted in levels that were 42.1% and 49.6% higher than the NPKm and NPK alone, respectively. Long-term fertilization significantly decreased soil pH by 0.95–1.85 units compared to the control, whereas manure application could alleviate soil acidification, as shown when the pH increased by 10.6–18.7%. The NPKm and NPKs resulted in significantly increased soil pHs by 10.6% and 18.7% compared to the NPK alone, respectively. In addition, the NPKm and NPKs increased N-acetyl-β-D-glucosaminidase activity by 52.6% and 60.3% compared to the NPK alone. Determined by the minimum data set method, the NPKm treatment exhibited the highest soil quality index, followed by the NPKs and NPK. Our findings suggested that the combined use of chemical fertilizers with organic amendments proved beneficial for enhancing soil quality. Full article

(This article belongs to the Section Innovative Cropping Systems)

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21 pages, 3387 KiB

Open AccessArticle

Biochar Increases Rice Yield in Soda Saline-Alkali Paddy Fields by Improving Saline-Alkali Stress and Phosphorus Use Efficiency

by Xuebin Li, Weikang Che, Junlong Piao, Yang Song, Xudong Wang, Yue Zhang, Shihao Miao, Hongyue Wang, Liming Xie, Jiayi Sun and Feng Jin

Agronomy 2024, 14(9), 2159; https://doi.org/10.3390/agronomy14092159 - 21 Sep 2024

Viewed by 667

Abstract

Soda saline-alkali significantly hinders rice growth, phosphorus utilization efficiency, and yield formation. The application of biochar can alleviate the adverse effects of saline-alkali stress on crops. However, there is limited research on the interaction between biochar and phosphorus fertilizer concerning ionic accumulation, phosphorus [...] Read more.

Soda saline-alkali significantly hinders rice growth, phosphorus utilization efficiency, and yield formation. The application of biochar can alleviate the adverse effects of saline-alkali stress on crops. However, there is limited research on the interaction between biochar and phosphorus fertilizer concerning ionic accumulation, phosphorus utilization efficiency, and rice yield in soda saline-alkali soils. A two-year field experiment was conducted to study the combined effects of biochar and phosphate fertilizer on ionic accumulation, physiological status, phosphorus utilization efficiency, and rice yield in soda saline-alkali soil. Four treatments were established for the study: NK (225 kg N, 75 kg K ha⁻¹ year⁻¹), NPK (225 kg N, 70 kg P, 75 kg K ha⁻¹ year⁻¹), NK + B [225 kg N, 75 kg K ha⁻¹ year⁻¹, 1.5% biochar (w/w)], and NPK + B [225 kg N, 70 kg P, 75 kg K ha⁻¹ year⁻¹, 1.5% biochar (w/w)]. The findings indicated that the combined application of biochar and phosphorus fertilizer (NPK + B) significantly reduced the Na⁺ concentration, Na⁺/K⁺ ratio, malondialdehyde (MDA), superoxide anion (O₂⁻), and hydrogen peroxide (H₂O₂) levels in rice plants. Furthermore, it resulted in a significant increase in K⁺ concentration and elevated the levels of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), proline (Pro), soluble protein (SP), soluble sugar (SS), and acid phosphatase (ACP). The NPK + B treatment exhibited a significant difference compared to the other treatments (p < 0.05). Compared with NK, phosphorus accumulation and phosphorus utilization efficiency under NPK + B were significantly increased (p < 0.05). The average of biomass yield, grain yield, and harvest index of NPK + B, NK + B, and NPK significantly surpassed those of NK by 6.28–12.25%, 19.80–42.13%, and 11.59–24.64%, respectively. Moreover, a significant difference was observed between NPK + B and the other treatments (p < 0.05). Principal component analysis of the two-year mean data revealed a strong positive correlation of 89.5% for PC1 and a minor negative correlation of 4.4% for PC2. Our research findings demonstrate that the combination of biochar and phosphorus fertilizer effectively enhances salt and alkali tolerance in rice plants, resulting in increased yield through improved ionic balance and physiological status. Full article

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

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6 pages, 217 KiB

Open AccessEditorial

Sustainable Strategies for the Control of Crop Diseases and Pests to Reduce Pesticides

by Carmenza E. Góngora and Maria do Céu Silva

Agronomy 2024, 14(9), 2158; https://doi.org/10.3390/agronomy14092158 - 21 Sep 2024

Viewed by 1119

Abstract

Crop diseases and pests may cause considerable yield losses and threaten food supply and security [...] Full article

(This article belongs to the Special Issue Sustainable Strategies for the Control of Crop Diseases and Pests to Reduce Pesticides)

12 pages, 7615 KiB

Open AccessArticle

Infection Process of Alfalfa Root Rot Caused by Fusarium acuminatum

by Le Wang, Jianfeng Yang, Ruifang Jia, Zhengqiang Chen, Na Wang, Jie Wu, Fangqi Chen, Yuanyuan Zhang and Kejian Lin

Agronomy 2024, 14(9), 2157; https://doi.org/10.3390/agronomy14092157 - 21 Sep 2024

Viewed by 536

Abstract

Fusarium spp. can cause root rot in alfalfa, leading to the death of the whole plant, which seriously affects the yield and quality of alfalfa. This study used a Fusarium acuminatum strain labeled with green fluorescent protein (GFP) to observe the infection process [...] Read more.

Fusarium spp. can cause root rot in alfalfa, leading to the death of the whole plant, which seriously affects the yield and quality of alfalfa. This study used a Fusarium acuminatum strain labeled with green fluorescent protein (GFP) to observe the infection process of F. acuminatum on alfalfa by confocal fluorescence microscopy. The aim of this study was to reveal the infection mechanism of alfalfa Fusarium root rot at the cellular histological level. The results showed that conidia of F. acuminatum attached to the surface of the root and germinated at one day post-inoculation, the mycelium then entered the vascular bundle tissue of the alfalfa root at 5 days post-inoculation, reached the base of the plant stem at 14 days post-inoculation, and colonized the stem of the first and second compound leaf at 28 and 49 days post-inoculation, respectively. Moreover, the experiment, which sprayed a spore suspension, showed that the conidia of F. acuminatum could spread through the air to infect the pericarp and seed coat tissue of the pod. For the first time, we report the infection process of alfalfa Fusarium root rot caused by F. acuminatum and clarify that F. acuminatum can initially infect the root tissue of alfalfa, colonize the bottom stem of the plant through systematic infection, and eventually cause the plant to wilt and die. The results reveal the infection mechanism of F. acuminatum at the cell level via histology and provide theoretical support for the development of control strategies and key control technologies for alfalfa root rot. Full article

(This article belongs to the Special Issue Grass and Forage Diseases: Etiology, Epidemic and Management)

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18 pages, 2293 KiB

Open AccessArticle

Nodules of Medicago spp. Host a Diverse Community of Rhizobial Species in Natural Ecosystems

by Andrei Stefan, Jannick Van Cauwenberghe, Craita Maria Rosu, Catalina Stedel, Crystal Chan, Ellen L. Simms, Catalina Iticescu, Daniela Tsikou, Emmanouil Flemetakis and Rodica Catalina Efrose

Agronomy 2024, 14(9), 2156; https://doi.org/10.3390/agronomy14092156 - 21 Sep 2024

Viewed by 436

Abstract

Biological nitrogen fixation by rhizobia-nodulated legumes reduces the dependence on synthetic nitrogen fertilizers. Identification of locally adapted rhizobia may uncover economically valuable strains for sustainable agriculture. This study investigated the diversity and symbiotic potential of rhizobia associated with three Medicago species from Eastern [...] Read more.

Biological nitrogen fixation by rhizobia-nodulated legumes reduces the dependence on synthetic nitrogen fertilizers. Identification of locally adapted rhizobia may uncover economically valuable strains for sustainable agriculture. This study investigated the diversity and symbiotic potential of rhizobia associated with three Medicago species from Eastern Romania’s ecosystems. Phenotypic screening ensured that only rhizobial species were retained for molecular characterization. 16S rDNA sequencing clustered the isolates into four distinct groups: Sinorhizobium meliloti, Sinorhizobium medicae, Rhizobium leguminosarum, and Mesorhizobium spp. The chromosomal genes (atpD, glnII, recA) and nifH phylogenies were congruent, while the nodA phylogeny grouped the Mesorhizobium spp. isolates with R. leguminosarum. Medicago sativa was the most sampled plant species, and only S. meliloti and R. leguminosarum were found in its nodules, while Medicago falcata nodules hosted S. meliloti and Mesorhizobium spp. Medicago lupulina was the only species that hosted all four identified rhizobial groups, including S. medicae. This study provides the first report on the Mesorhizobium spp. associated with M. falcata nodules. Additionally, R. leguminosarum and two Mesorhizobium genospecies were identified as novel symbionts for Medicago spp. Comparative analysis of Medicago-associated rhizobia from other studies revealed that differences in 16S rDNA sequence type composition were influenced by Medicago species identity rather than geographic region. Full article

(This article belongs to the Special Issue Functional Diversity of Soil Microbial Communities in Environments Shaped by Anthropogenic Activities)

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14 pages, 1821 KiB

Open AccessArticle

The Influence of X-ray Radiation on the Morphological, Biochemical, and Molecular Changes in Copiapoa tenuissima Seedlings

by Piotr Licznerski, Emilia Michałowska, Alicja Tymoszuk, Janusz Winiecki and Justyna Lema-Rumińska

Agronomy 2024, 14(9), 2155; https://doi.org/10.3390/agronomy14092155 - 21 Sep 2024

Viewed by 304

Abstract

Cactaceae are a significant group of ornamental plants in the horticultural market. In the present study, X-rays were used for the first time to induce mutational changes in the cactus Copiapoa tenuissima. The aim of this study was to assess the genetic [...] Read more.

Cactaceae are a significant group of ornamental plants in the horticultural market. In the present study, X-rays were used for the first time to induce mutational changes in the cactus Copiapoa tenuissima. The aim of this study was to assess the genetic variability in seedlings exposed to in vitro X-ray irradiation at doses of 0, 15, 20, 25, and 50 Gy (radiation time from 5 min 13 s to 17 min 22 s) by morphological analysis, a spectrophotometric evaluation of plant pigment content, and the confirmation of changes at the genetic level using SCoT (start codon targeted) markers. The results showed that the percentage of colorful seedlings increased with the radiation dose and was the highest for the 50 Gy dose (4.89%). The radiation doses of 25 and 50 Gy generated seedlings with a new color (orange-brown), which had not yet been observed in C. tenuissima. With the increase in the radiation dose, as compared to control seedlings, brown seedlings showed an increase in the concentrations of carotenoids, chlorophyll a, and chlorophyll b, while green seedlings showed an increase in the concentrations of anthocyanins and chlorophyll b and a decrease in the concentrations of carotenoids and chlorophyll a. The unweighted pair group method analysis showed a very large genetic distance among the tested genotypes exposed to X-rays. The results of the present study provide a novel direction for using X-rays to breed new cultivars of C. tenuissima. Full article

(This article belongs to the Special Issue Plant Tissue Culture and Plant Somatic Embryogenesis–2nd Edition)

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17 pages, 5116 KiB

Open AccessArticle

Determination of Critical Crop Water Stress Index of Tea under Drought Stress Based on the Intercellular CO₂ Concentration

by Yongzong Lu, Jialiang Zheng, Huijie Hu, Qingmin Pan, Longfei Cui and Yongguang Hu

Agronomy 2024, 14(9), 2154; https://doi.org/10.3390/agronomy14092154 - 21 Sep 2024

Viewed by 274

Abstract

Climatic changes have caused seasonal drought to occur frequently in tea fields of low-mountain and hill regions over the past decades. This leads to huge losses in the quality and yields of famous tea, which restricts the economic development of the tea industry. [...] Read more.

Climatic changes have caused seasonal drought to occur frequently in tea fields of low-mountain and hill regions over the past decades. This leads to huge losses in the quality and yields of famous tea, which restricts the economic development of the tea industry. It is crucial to implement suitable irrigation scheduling. The crop water stress index (CWSI) is the main index to assess the water status of the crop. When the crop suffers irreversible drought stress, its critical water status cannot be easily evaluated using the CWSI. The change from stomatal limitations (SLs) to non-stomatal limitations (NSLs) of photosynthesis is vital for accurately recognizing crop drought stress. Thus, the objective of this research is to determine the critical crop water stress index of tea based on intercellular CO₂ concentration (C_i) dynamic responses to drought stress. During two sensitive periods of water stress (famous tea harvest season and summer drought season, which are from March to April and July to August, respectively), the dynamic changes in the CWSI in tea were calculated and analyzed based on the CWSI theoretical model. The upper and lower baselines were determined on a daily basis and during a certain period. A critical value of the CWSI represents irreversible drought damage. This was determined by the characteristic response of the C_i of tea leaves during extreme drought stress. The results showed the following: (1) during the famous tea harvest season and summer drought season, the daily variation in CWSI was similar. During a certain period, the former maintained a stable fluctuation, while the latter increased in fluctuation. (2) The C_i showed a trend of fluctuating downward to a low point and then upward during extreme drought stress. After reaching the low point, it quickly increased in the former and stabilized for a day in the latter. When the C_i reached the low point, the upper benchmark of this critical point was 13.9 μmol·mol⁻¹, the lower benchmark was 3.4, and the CWSI was 0.27. This critical CWSI could be used as an irrigation threshold point to ensure normal production for tea fields. Full article

(This article belongs to the Special Issue Agricultural Water Management in Arid, Semi-arid and Drought Prone Areas—2nd Edition)

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18 pages, 9680 KiB

Open AccessArticle

Are Water Use Efficiency and Effectiveness Relatively Lower in Arid Zones? Comparative Analyses of the Water Productivity of Typical Crops

by Yanfei Zhang, Aihua Long, Pei Zhang, Xiaoya Deng and Xinchen Gu

Agronomy 2024, 14(9), 2153; https://doi.org/10.3390/agronomy14092153 - 21 Sep 2024

Viewed by 416

Abstract

Agriculture is the largest water user of all sectors. In arid regions in particular, achieving efficient water use in agriculture is an important way to solve water scarcity. However, the difference in water use efficiency between arid and humid regions has long been [...] Read more.

Agriculture is the largest water user of all sectors. In arid regions in particular, achieving efficient water use in agriculture is an important way to solve water scarcity. However, the difference in water use efficiency between arid and humid regions has long been a focus of academic debate. Many studies consider water use efficiency to be higher in humid areas due to the abundance of water resources. This view is based on the fact that less irrigation in humid areas may lead to higher crop yields and better conditions for agricultural production; however, it ignores the efforts of researchers and agricultural workers in arid zones who have attempted to develop efficient water-saving technologies, as well as the effect of natural conditions on agricultural production. Correctly evaluating the efficiency of agricultural water use in arid zones is important for achieving efficient use of water resources, as well as for water management decisions. This study calculates the yield structure and water productivity of typical crops in both arid and humid regions in China based on the footprint theory and other methodologies. This approach allows for an accurate assessment of irrigation water benefits in various regions, providing a scientific basis for improving agricultural water use efficiency under different climatic conditions. The study results indicate that the average reliance on blue water for wheat and cotton gradually increases from 49.9% to 93.6% as regional aridity intensifies, ranging from the Central China Humid Region to the Northwest China Arid Region. Similarly, the average contribution of blue water to crop yield rises from 31.0% to 100%, while irrigation water productivity increases from 0.27 kg·m⁻³ to 0.53 kg·m⁻³. Finally, this study concludes that, in arid zones with lower precipitation and more hours of sunshine, a higher dependence on blue water for crop growth and development leads to a higher productivity of irrigation water. In addition, in arid zones, the focus should be on optimizing the use of irrigation water and improving irrigation technology and efficiency, while, in humid zones, there should be more use of natural precipitation to efficiently reduce dependence on irrigation water. Full article

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

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20 pages, 4457 KiB

Open AccessReview

From Field to Building: Harnessing Bio-Based Building Materials for a Circular Bioeconomy

by Monica C. M. Parlato and Andrea Pezzuolo

Agronomy 2024, 14(9), 2152; https://doi.org/10.3390/agronomy14092152 - 21 Sep 2024

Viewed by 776

Abstract

The transition from a linear to circular economy is driving a growing emphasis on utilizing bio-based materials for bioenergy and construction purposes. This literature review seeks to offer a thorough bibliometric and critical analysis of bio-based building materials, particularly those that incorporate agricultural [...] Read more.

The transition from a linear to circular economy is driving a growing emphasis on utilizing bio-based materials for bioenergy and construction purposes. This literature review seeks to offer a thorough bibliometric and critical analysis of bio-based building materials, particularly those that incorporate agricultural residues. A selection of pertinent articles was analyzed using text-mining techniques, revealing a substantial increase in research output on this topic, from 74 publications in 2000 to 1238 in 2023. Key areas such as sustainability, sources of bio-based materials, building applications, design and analysis, material properties, and processes have been extensively examined. The cluster “Sustainability” was the most frequently discussed topic, comprising 28.85% of the content, closely followed by “Building Materials and Techniques” at 28.07%. Given the critical role of life cycle assessment (LCA) in sustainability, an additional analysis was conducted focusing on existing research addressing this subject. The findings of this study are aimed at advancing the incorporation of waste-derived bio-based materials into a circular economy framework, thereby supporting the broader objectives of sustainability and resource efficiency. Full article

(This article belongs to the Special Issue Sustainable Cropping Systems and Biomasses for Energy and Biorefinery Applications)

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13 pages, 1438 KiB

Open AccessArticle

Effects of Successive Top-Dressing Application of Lime on a Sweet Cherry Orchard in Southern Chile

by Pamela Artacho, Daniel Schwantes, Pablo Martabit and Claudia Bonomelli

Agronomy 2024, 14(9), 2151; https://doi.org/10.3390/agronomy14092151 - 21 Sep 2024

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Abstract

Annual top-dressing application of agricultural lime is a common practice in fruit orchards on acidic soils in southern Chile, which could result in surface over-liming and base imbalances. A trial was performed in a cherry orchard with an 8-year history of surface liming [...] Read more.

Annual top-dressing application of agricultural lime is a common practice in fruit orchards on acidic soils in southern Chile, which could result in surface over-liming and base imbalances. A trial was performed in a cherry orchard with an 8-year history of surface liming to evaluate the effectiveness of lime materials in neutralizing acidity in the soil profile and the effect on the tree nutritional status. No-lime (NL), calcitic (AgL), hydrated (HL), and liquid (LL) lime treatments were applied on soil surface at commercial rates, and soil acidity variables were measured at depths of 0–5, 5–10, and 10–20 cm in samples collected at 0, 15, 30, 60, and 225 days after application. Tree nutritional status was evaluated through foliar analysis. Top-dressing application of AgL was ineffective in ameliorating subsoil acidity at depths >5 cm, even in high-rainfall conditions. HL did not exhibit greater alkalinity mobility compared to AgL, although it had a faster but shorter-lived reaction. At the manufacturer-recommended rates, LL application was ineffective. After 8 years of top-dressing liming with AgL, a significant stratification of soil pH, Al, and Ca was observed. However, foliar concentration of bases did not reflect the surface Ca accumulation in soil, discarding an antagonistic cation competition for tree uptake. Full article

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

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17 pages, 3548 KiB

Open AccessArticle

Effect of Organic Fertilizer Application on Microbial Community Regulation and Pollutant Accumulation in Typical Red Soil in South China

by Qinghong Sun, Qiao Zhang, Zhijie Huang, Chang Wei, Yongtao Li and Huijuan Xu

Agronomy 2024, 14(9), 2150; https://doi.org/10.3390/agronomy14092150 - 21 Sep 2024

Viewed by 640

Abstract

Returning livestock manure to the cropland as organic fertilizer is a sustainable and environmentally friendly treatment method, but its application also alters the soil microenvironment. However, the impact of soil microbial community disturbance and pollutant accumulation from different types of organic fertilizers remains [...] Read more.

Returning livestock manure to the cropland as organic fertilizer is a sustainable and environmentally friendly treatment method, but its application also alters the soil microenvironment. However, the impact of soil microbial community disturbance and pollutant accumulation from different types of organic fertilizers remains largely unknown in South China. To fill this gap, we investigated the effects of organic fertilizers, including chicken manure, pig manure and vermicompost on the soil bacterial and fungal communities and environmental risks. The results show that applying organic fertilizer effectively increases the soil nutrient content. High-throughput sequencing of bacteria and fungi showed that the application of different organic fertilizers had differential effects on microbial community structure, with the highest number of microbe-specific OTUs in the vermicomposting treatment. Additionally, this study found no risk of heavy metal (Cu, Zn, Pb, Cr and Cd) contamination from short-term organic fertilizer application, but there was a risk of antibiotic (ENR and CHL) contamination. Functional microorganisms regulating heavy metals and antibiotics were identified by RDA analysis. This study facilitates the screening of types of organic fertilizers that can be safely returned to the field as well as developing strategies to regulate functional microbes. Full article

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

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Agronomy, Volume 14, Issue 9 (September 2024) – 304 articles

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