Rice-wheat Rotation Research Articles

Seasonal alternation of soil phosphorus saturation in rice-wheat rotation systems under multiple fertilization strategies

The rice-wheat rotation system has been shown to improve agricultural productivity with associated economic benefits. The degree of phosphorus saturation (DPS) refers to saturation of soil sorption sites with phosphorus (P), and reflects the tendency of soil P fixation or release. A current knowledge gap is to investigate how a rice-wheat rotation system affects soil DPS, which is closely related to P loss to the environment. In the present field study, a rice-wheat rotation was established and different fertilization treatments were implemented, and the Anthrosol soils collected from the rice season and the wheat season, were evaluated. Sequential extraction, Langmuir model, and structural equation modeling were used to reveal the proportion of P fractions, P sorption capacity, and the relationships between the degree of P saturation and soil properties, in order to reveal the geochemical mechanisms of P transformation. A higher degree of P saturation is always found in the rice season soils rather than in the wheat season soils, which should be attributed to the lower P retention capacity and the higher presence of P in forms with greater mobility potential in the rice season soils. The reduction of the proportion of residual P fraction coupled with the enhancement of NaHCO3-P/NaOH-P/HCl-P fractions indicated a prevalence of P mobilization due to flooding during the rice planting period. Simultaneously, lower P sorption capacity was also found in the rice season soils. Structural equation modelling was able to confirm that the change of P sorption capacity together with the enhancement proportion labile P in total P, and mobilization of soil residual P combined to affect the degree of P saturation. Management interventions, such as flooding, induced changes from crystalline iron oxides to amorphous iron oxides and this may have enhanced the release of P retained by crystalline iron oxides, which contributed to the mobilization of P in the soils after the rice season. This knowledge can be utilized to avoid P losses to the environment, while still achieving efficient P utilization.

Optimizing phosphate application to improve soil quality and reduce phosphorus loss in rice-wheat rotation

How to determine the optimal dosage of phosphorus (P) fertilizer input for an agricultural field is important to maintain soil quality and crop production while minimizing environmental impact. In this study, we set up a 5-year rice-wheat rotation with contrasting P fertilization treatments (0, 25, 50, 75, 100, and 150 kg P2O5 ha−1, hereafter, P0, P25, P50, P75, P100, and P150, respectively) per season to explore the relationship between the amount of P input and crop yield, P use efficiency (PUE), balance of P accumulation and loss, ecosystem multifunctionality (EMF), and soil quality. Our results indicate that increased P amounts significantly boosted rice and wheat production of both straw and grain, but the tendency slowed down when the input was over 75 kg P2O5 ha−1. The PUE declined with increased P input and soil P balance of 50 kg P2O5 ha−1 for wheat and 100 kg P2O5 ha−1 for rice. Runoff emerges as the main pathway for soil P loss and escalates with higher P application rates. We emphasize increasing ridge height and controlling water input for basal fertilizer to minimize P loss. The application of P fertilizer increased the soil P pool, with labile P (L-P) and moderately labile P (M-P) increasing by 13–114 % and 23–111 %, respectively, compared to P0. The transformation of M-P to L-P in paddy soil is associated with an increased abundance of Actinobacteria. Low P applications (P25 and P50) increased EMF by 3.27 and 3.58 times, while high P applications (P75, P100, and P150) decreased EMF. Furthermore, P application significantly improved the soil quality index (SQI) compared to P0. The impact of abiotic factors on yield and P loss is more significant than that of biotic elements, with the SQI serving as a dependable indicator for predicting yield. Central to minimizing P loss while maximizing yield is the reduction of Resin-P content and the maintenance of NaOH-Pi levels, suggesting that organic materials may be a good alternative strategy. These findings provide valuable data and theoretical support for optimizing P application in rice-wheat cropping systems, promoting a mutually beneficial scenario for agricultural production and ecological protection.

Responses of Soil Macro-Porosity, Nutrient Concentrations and Stoichiometry Following Conversion of Rice–Wheat Rotation to Organic Greenhouse Vegetable System

Responses of Soil Macro-Porosity, Nutrient Concentrations and Stoichiometry Following Conversion of Rice–Wheat Rotation to Organic Greenhouse Vegetable System

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

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.

Investigation of the effects of polyethylene microplastics at environmentally relevant concentrations on the plant-soil-microbiota system: A two-year field trial

Microplastics are a potential threat to agricultural sustainability. However, the effects of microplastics at environmentally relevant concentrations on the plant-soil-microbiota system in realistic field conditions are largely unknown. Herein, we conducted a two-year field trial to study the effects of polyethylene (PE) microplastics at 0, 100, and 600 mg/kg on crop growth, soil properties, and the composition and function of microbial communities in a farmland with rice-wheat rotation. PE did not affect wheat growth but it increased the rice grain weight by 42.5 % at 600 mg/kg, and enhanced rice height by 35.4 % and 30.2 % at 100 and 600 mg/kg, respectively. The presence of PE significantly decreased soil available phosphorus during the wheat season, while it reduced soil total nitrogen, NH4+-N and available phosphorus during the rice season. There were five and sixteen bacterial orders identified changed by PE in wheat and rice soils, respectively. Specifically, PE at different concentrations differentially altered the abundances of sulfate-reducing bacteria Thermodesulfovibrionia, Thermoactinomycetales and Syntrophobacterales, and further modified soil sulfate respiration in wheat soils. During the rice season, PE (100 mg/kg) increased the abundance of Xanthomonadales by 98.0 % and enriched the functional groups of intracellular parasites, while PE (600 mg/kg) inhibited twelve cluster of orthologous group function classes and disturbed bacterial metabolism. This study suggests that PE exhibits a greater impact on the plant-soil-microbiota system during the rice season compared to the previous year's wheat season, highlighting the importance of crop type and cultivation practices in determining the environmental risks of microplastics in agroecosystems.

Carbon Farming of Main Staple Crops: A Systematic Review of Carbon Sequestration Potential

Carbon farming has become increasingly popular as it integrates agriculture, forestry, and diverse land use practices, all crucial for implementing European strategies aimed at capturing 310 million tons of carbon dioxide from the atmosphere. These farming methods were proven to reliably increase the amount of carbon stored in the soil. However, there is a lack of discussion and consensus regarding the standards used to report these values and their implications. This article analyzes carbon sequestration rates, calculation methodologies, and communication procedures, as well as potential co-benefits and best practices. The average carbon sequestration rates in major staple crops range from very low values (0–0.5 Mg/ha/yr) to medium values (1–5 Mg/ha/yr). Scientific agricultural experiments in key global staple crops demonstrate positive rates of 4.96 Mg C ha−1 yr−1 in wheat–maize rotations and 0.52–0.69 Mg C ha−1 yr−1 in rice–wheat rotations. In agriculture, carbon sequestration rates are reported using different terms that are not consistent and pose communication challenges. This assessment involves a systematic review of the scientific literature, including articles, reviews, book chapters, and conference papers indexed in Scopus from 2001 to 2022. Specifically, this review focuses on long-term experiments, meta-analyses, and reviews that report an increase in soil carbon stock. The research trends observed, through a VOSviewer 1.6.18 analysis, show a steadily increasing interest in the field of carbon sequestration.

In-situ prediction of soil organic carbon contents in wheat-rice rotation fields via visible near-infrared spectroscopy

Visible near-infrared (VNIR) spectroscopy is a reliable method for estimating soil properties. However, its effectiveness in accurately predicting soil organic carbon (SOC) contents, particularly in wheat-rice rotation fields, remains uncertain. In this study, we collected 202 samples from wheat-rice fields (0–20 ​cm) in southeastern China and measured in-situ spectra of the vertical surface of the soil cores and the laboratory spectra of the dried and sieved soil samples. Our study focused on evaluating three algorithms - external parameter orthogonalization (EPO), direct standardization (DS), and piecewise direct standardization (PDS) - to address the influence of external factors, particularly soil moisture. To carry out our analysis, the dataset was divided into calibration (141 samples) and validation (61 samples) sets via the Kennard-Stone algorithm. A subset of the corresponding in-situ and laboratory spectra in the calibration set (transfer set) was used to derive the transfer matrix for EPO, DS, and PDS, enabling the conversion of in-situ spectra to laboratory spectra by characterizing their differences. Four machine learning models, including cubist, partial least squares regression (PLSR), random forest (RF), and memory-based learning (MBL), were used to predict the SOC, particulate organic carbon (POC), and mineral-associated organic carbon (MAOC) contents based on the laboratory, in-situ, and corrected in-situ spectra. The results revealed that the laboratory spectra outperformed the non-corrected in-situ spectra, with coefficients of determination (R2) of 0.91, 0.75, and 0.80 for SOC, POC, and MAOC, respectively. Among the models, MBL and PLSR exhibited the highest average R2 at 0.85–0.86. EPO marginally improved the prediction accuracy (R2 increased from 0.85 to 0.87 for SOC, 0.64 to 0.69 for POC, and 0.75 to 0.82 for MAOC). These promising prediction accuracies underscore the potential of VNIR spectra for in-situ predictions in wheat-rice fields in Southeast China, offering insights for predicting SOC contents via in-situ spectroscopy.

The mutation Asp-376-Glu in the ALS gene confers resistance to mesosulfuron-methyl in Beckmannia syzigachne

Understanding the mechanisms by which weeds develop herbicide resistance is crucial for managing resistance effectively and optimizing herbicide use. Beckmannia syzigachne, a harmful grass weed prevalent in wheat and rice-wheat rotation areas, poses a significant threat to crop productivity. A field herbicide resistance survey identified a resistant population with a new ALS mutation (Asp-376-Glu). The Glu-376-Asp population displayed varying resistance levels to seven ALS herbicides, verified using the dCAPS method. qRT-PCR analysis showed that no significant difference existed in the ALS gene expression between the Asp-376-Glu and S populations. P450 and GST inhibitors failed to reverse resistance to mesosulfuron-methyl, suggesting no involvement of P450- and GST-based metabolic resistance. Molecular docking indicated that the Asp-376-Glu mutation reduces the binding affinity between ALS-inhibitors and BsALS. The findings provide valuable insights into herbicide resistance mechanisms for weed resistance control.

A holistic investigation of potentially toxic element flow in the soil-root-straw-grain continuum of a typical rice–wheat rotation system

Rice and wheat, being major food crops worldwide, are susceptible to pollution risks associated with potentially toxic elements (PTEs). However, the accumulation and transfer patterns of different PTEs within rice and wheat systems remain a topic of debate. In this study, we conducted a holistic investigation of the risk flow of seven PTEs (As, Cd, Cr, Cu, Ni, Pb, and Zn) in the soil-root-straw-grain continuum of a typical rice-wheat rotation system. Laboratory analyses were performed on a total of 72 samples, comprising complete rice and wheat plants as well as paired soil samples. These samples were collected from nine cropland sites located in the Yangtze River Delta (YRD), a highly industrialized region in China. Our results revealed that Cd and Pb levels in the soils exceeded acceptable limits. Additionally, Cd, Cr, Ni, Pb, and Zn levels in wheat grains, as well as Cd in rice grains, exceeded food safety standards. Based on their behaviors within the soil-root-straw-grain continuum of rice and wheat, the seven PTEs can be classified into three categories: (1) The siderophile elements, Cr and Ni, exhibited higher concentrations in wheat roots, straws, and grains than in rice. (2) The chalcophile elements, Cd, Cu, Zn, and Pb, showed higher contents in rice roots and straws but lower contents in rice grains than in wheat. (3) The metalloid element, As, exhibited significantly higher concentrations and uptake capacity in rice than in wheat. Our findings suggest that wheat has a greater internal translocation capacity for PTEs than rice, leading to higher contamination levels and lower risk resistances for wheat crops. This study provides insights into agronomic regulations of different PTEs in rice and wheat cultivation areas.

基于实时光谱信息的小麦变量施肥效率分析与评价

Studying the effect of variable fertilization during the jointing stage on winter wheat production in the rice-wheat rotation area is critical for evaluating the application effect and economic benefits of variable fertilization technology. The variable fertilization experiment of wheat was carried out in Jiangsu province by using the self-developed fertilizer applicator. Three fertilization methods were used to conduct a comparative analysis of the fertilization amount, population structure, and yield of winter wheat during the jointing stage. On this basis, the economic feasibility of variable fertilization during the jointing stage was evaluated. The experimental results showed that the control accuracy of variable-rate fertilization with fertilization equipment was greater than 95%. After variable fertilization, the coefficient of variation of NDVI values in the winter wheat canopy spectral data remained between 0.076 and 0.125, and the Christensen uniformity coefficient remained between 0.901 and 0.940. Compared with the traditional empirical balance method for quantitative fertilization of plots, the real-time variable fertilization plot used 13.6 kg/hm2 less fertilizer during the jointing stage. The findings validate that implementing variable fertilization can help reduce nitrogen fertilizer input, improve nitrogen fertilizer utilization efficiency, reduce environmental pollution, and enhance the sustainability of agricultural production.

Increased anaerobic conditions promote the denitrifying nitrogen removal potential and limit anammox substrate acquisition within paddy irrigation and drainage units

Microbial nitrogen (N) removal is crucial for purifying surface water quality in paddy irrigation and drainage units (IDUs). However, the spatiotemporal microbial N removal potential characteristics within these IDUs and the effects of changing anaerobic conditions on this potential remain insufficiently studied. In this study, we investigated the microbial N removal potential of conventional rice-wheat rotation and anaerobically enhanced rice-crayfish rotation IDUs using field measurements, isotope tracing techniques, and quantitative PCR. Our findings reveal that paddy fields were identified as hotspots for anammox activity, contributing to 76.0 %–97.4 % of the total anammox N removal potential in the IDU, while denitrification processes in ditches accounted for 43.5 %–77.4 % of the IDU's denitrification potential. During the rice transplanting period, the anammox N removal potential peaked, representing 35.8 % and 71.8 % of the total anammox N removal potential of the paddy fields in rice-wheat and rice-crayfish IDUs, respectively. An increase in anaerobic conditions diminished the anammox N removal potential while amplifying denitrification capabilities. The N removal potential in paddy fields decreased with increasing depth, contrasting with the relative stability in ditches. Spatiotemporal fluctuations in N removal potentials within these units are influenced by Fe2+ concentration, carbon and N content, WFPS, and pH levels. This study provides a scientific basis for improving nitrogen removal and water quality treatment in IDUs.

Soil texture contributes to shaping comammox Nitrospira communities in rice-wheat rotation soils

Complete ammonia oxidizers (comammox Nitrospira) are intriguing discoveries that mark a significant milestone in the global nitrogen cycle. While numerous soil physiochemical variables have been identified as key influencers of comammox Nitrospira distribution, the role of soil texture in shaping these communities remains largely uncertain. Here, we explored the diversity, community structure of comammox Nitrospira, and their driving factors, including soil texture in 237 rice-wheat rotation soils. The results indicated that soil pH and texture were the primary factors influencing the Shannon diversity and richness of comammox Nitrospira. Comammox Nitrospira Shannon diversity and richness were positively associated with soil pH and silt content, but negatively correlated with clay content, suggesting that finer-textured soils harbored lower comammox Nitrospira diversity. Additionally, silt content emerged as the second most influential factor, after pH, shaping comammox Nitrospira community structure. Clade A.2 was found as the predominant comammox Nitrospira clade in rice-wheat rotation soils, representing 59.3 % of the total sequences. Clade A.2 exhibited a positive correlation with sand and clay contents but a negative association with silt content. Conversely, Clades A.3 and B demonstrated the opposite pattern. Overall, our study underscores the critical role of soil texture as a mediator of comammox Nitrospira diversity and community structure, emphasizing the need to consider soil texture in investigations of comammox Nitrospira.

12-year continuous biochar application: Mitigating reactive nitrogen loss in paddy fields but without rice yield enhancement

Numerous studies have documented the beneficial effects of short-term biochar application on soil carbon sequestration, greenhouse gas emissions reduction, and ecological functions enhancement. However, concerns persist regarding the impacts on soil reactive nitrogen (N) loss and crop yields under long-term biochar application (more than ten years), due to the irreversibility once biochar is incorporated into soils. This study presents the results of a 12-year field experiment in a rice-wheat rotation system with treatments including a control (CK, no corn straw or biochar), annual corn straw returning (CS, 6 Mg·ha−1·yr−1), and annual application of corn straw biochar pyrolyzed at 400°C at rates of 2.4, 6, and 12 Mg·ha−1·yr−1 (BC1, BC2, and BC3), investigating rice yields (2011–2022) and reactive N loss (2021–2022). The results showed that after 11 years of continuous biochar application until the 2021 rice season, alkaline hydrolysis N (AN, equivalent to an average of 347 kg N ha−1) within the 0–15 cm soil layer in biochar treatments was significantly higher than that of the CK (200 kg N ha−1), attributable to the biochar-induced enhancement of cation exchange capacity (CEC). The application of biochar reduced inorganic N leaching and NH3 volatilization losses by an average of 42.21 % and 30.85 %, respectively. However, N2O emission in the BC3 treatment was over 2 times as high as in the CK. Continuous biochar applications did not increase rice yield over the 12 rice seasons, as excessive soil AN level under biochar application reduced the rice harvest index. The results indicated that continuous biochar application was effective in reducing reactive N losses and increasing plant-available N supply, suggesting a potential to sustain rice production with lower fertilizer N inputs.

Crop Establishment, Residue Retention and Nutrient Management Influence the Phenology-mediated Greenhouse Gases Emission in an Intensive Rice-wheat System

The impact of management practices (i.e. crop establishment, tillage, residue addition etc.) on the global warming potential (GWP) and greenhouse gas intensity (GHGI) in rice-wheat cropping system accounting the economic viability is sparsely documented. A field experiment was established in 2020 to gain insight crop phonology mediated greenhouse gas emission into GWP, GHGI and economic viability on crop seasonal scale over three cycles (2020, 2021 and 2022) of rice-wheat rotations under subtropical climatic condition. Treatments were three planting techniques viz., System of rice intensification (SRI) followed by conventional wheat without residues (SRI-CW), Puddle Transplanted rice (TPR) followed by CW with 30% rice residue incorporation (TPR-CWRi) and zero-till direct sowing of rice (ZT-DSR) followed by ZT wheat with 30% rice residue retention (ZTDSR-ZTWRr) and four different nutrient management practices viz., 100% NPK (as per recommended dose) through mineral fertiliser (100% NPKi), 75% NPK through mineral fertiliser with 25% N trough organics (75% NPKi + 25%NOrg.), 50% NPK through mineral fertiliser with 50% N trough organics (50% NPKi + 50% NOrg.) was followed in both rice and wheat crop and 100% NPK through mineral fertiliser (100% NPKi) along with mung bean (Vigna radiata) green manure in rice and 100% NPK through mineral fertiliser in wheat (100% NPKi + GM). All treatments were established in a split-plot design and repeated three times; where three planting techniques were arranged in main plots and four different nutrient management practices were arranged in sub-plots. The highest system productivity was obtained under ZTDSR-ZTWRr treatment. Moreover, this system reduced the CH4 and N2O emission by 62.7 and 48% respectively over TPR-CWRi, hence, the Global Warming Potential (GWP), as well as gaseous intensity (GHGI), were reduced by 2.0-2.18 and 2.13-2.20 times, respectively than the traditional technique of cultivation. Green manure behaves differently by increasing the system productivity by 4.27% was and reducing the GHGI 4.56% over 100% NPKi. Thus, ZTDSR-ZTWRr along with 100% NPKi and green manuring in rice could be an economically viable opportunity for maintaining future yield standard of the system with lower emission scenario.

Partial Substitution of Nitrogen Fertilizer with Biogas Slurry Increases Rice Yield and Fertilizer Utilization Efficiency, Enhancing Soil Fertility in the Chaohu Lake Basin.

To investigate the effects of biogas slurry substitution for fertilizer on rice yield, fertilizer utilization efficiency, and soil fertility, a field experiment was conducted on rice-wheat rotation soil in the Chaohu Lake Basin for two consecutive years, with the following six treatments: no fertilization (CK), conventional fertilization (CF), optimized fertilization (OF), biogas slurry replacing 15% of fertilizer (15% OFB), biogas slurry replacing 30% of fertilizer (30% OFB), and biogas slurry replacing 50% of fertilizer (50% OFB). The field experiment results showed that, compared with CF treatment, OF treatment in 2022 and 2023 significantly increased (p < 0.05) rice yield, promoted the uptake of nitrogen (N), phosphorus (P), and potassium (K) by grains and straws, improved fertilizer utilization efficiency, and increased the contents of soil organic C (SOC), NH4+-N, NO3--N, hydrolysable N, and available P. The 15% OFB and 30% OFB treatments significantly increased (p < 0.05) rice grain and straw yields compared with CF treatment, and rice grain and straw yields were the highest in the 30% OFB treatment. Compared with CF and OF treatments, 30% OFB treatment significantly increased (p < 0.05) the N, P, and K uptake of grains and straws and increased the fertilizer utilization efficiency. Compared with CF treatment, the grain yield of 50% OFB treatment was significantly decreased (p < 0.05) in 2022, and there was no significant difference in 2023, which may be because the biogas slurry was applied before planting in 2023 to provide more nutrients for early rice growth. Compared with CF treatment, 30% OFB treatment significantly increased (p < 0.05) the contents of SOC, NH4+-N, available K, and hydrolysable N. In summary, optimizing N and K topdressing methods can increase rice yield and improve the fertilizer utilization efficiency and soil fertility. The 30% OFB treatment resulted in the highest rice yield, fertilizer utilization efficiency, and improved soil fertility, indicating that biogas slurry replacing 30% of fertilizer was the best application mode for rice in this region.

Effects of dose nitrogen on yield and global warming potential in a typical rice-wheat rotation system in China

Effects of dose nitrogen on yield and global warming potential in a typical rice-wheat rotation system in China

Diurnal and Seasonal Variations of Water Use Efficiency of Rice–Wheat Rotation Cropland in the Jianghuai River Basin of China

ABSTRACTRice–wheat rotation cropland is one of the most important agroecosystems in South China, the escalation of conflict between food demand augment and water supply shortage increased with climate change. Water use efficiency plays a more significant role in optimising water and carbon management. Thus, the diurnal and seasonal variations of water use efficiency were assessed by the 3‐year eddy covariance observations in the Shouxian National Observatory, a typical rice–wheat rotation station. The results revealed a ‘U’‐shaped diurnal pattern of water use efficiency for winter wheat (Triticum aestivum L.) and rice (Oryza sativa L.). Seasonal water use efficiency had two peaks with the highest in the winter wheat‐growing season. The average water use efficiency for the rice–wheat rotation cropland was 2.85 g C kg−1 H2O over the whole year with 2.62 and 3.11 g C kg−1 H2O for winter wheat and rice, respectively. However, gross primary productivity and evapotranspiration of rice were higher than those of winter wheat. Temperature, photosynthetically active radiation were the principal impact factors of water use efficiency in the rice‐growing season. Comparatively, soil water and vapour pressure deficit dominated the water use efficiency changes in the winter wheat‐growing season. Our analyses can help understand the water use requirements for carbon assimilation on rice–wheat rotation cropland on the field scale.

Women-led community institutions as a potential vehicle for the adoption of varieties and improved seed practices: an impact case from India

Rice–wheat rotation is the principal cropping system in South Asian countries. Increasing productivity under this cropping system in Northern India is not only a policy priority but also an important component towards ensuring food and nutritional security for the major portion of the Indian population. The objective of enhanced productivity is being pursued through innovative extension models focusing on the adoption of modern varieties and community-led seed production. The present experimental study (a randomized control trial) was conducted in Uttar Pradesh (India) to evaluate the efficacy of community institutions [e.g., women self-help group (WSHG)] based seed interventions in promoting the adoption of improved varieties amongst farmers. Besides, the impact on the implementation of quality seed production practices, adoption of seed quality measures, and participation in capacity-building trainings were also evaluated. The findings infer that implementing seed scaling programs through community institutions leads to a significantly higher rate of technological adoption than that executed through non-collectivized ways. Besides, farmers from WSHGs have more tendency towards learning new technologies and participating in training programs about improved crop management practices. The study also explains that WSHG-based programs are not a contributory factor in advancing farm technologies that are already in practice, such as seed cleaning and germination tests. This validated model can be suitably replicated for accelerated dissemination of seed-related innovations.

Land-use intensification exerts a greater influence on soil microbial communities than seasonal variations in the Taihu Lake region, China

The Taihu Lake region has undergone intensive land-use conversions from natural wetlands (NW) to conventional rice-wheat rotation fields (RW) and further to greenhouse vegetable fields (GH). Nevertheless, the effects of these conversions on soil microbes, particularly in wetland ecosystem, are not well explicit. To explore the impact of land-use intensification on soil microbial communities, monthly soil samples were obtained from replicate plots representing three land-use types (NW, RW, and GH) in subtropical wetlands and then subjected to amplicon sequencing. Land-use intensification had direct effects on bacterial and fungal community composition, with a more pronounced impact on bacteria than on fungi. These changes in bacterial communities were closely correlated with variations in soil environmental variables, such as NO3−-N, pH, and electrical conductivity. Land-use intensification led to a decrease in bacterial deterministic processes, with an opposing trend observed in the fungal community. In addition, arable lands (RW and GH), which are affected by anthropogenic activities, exhibited more complex networks. Potential metabolic functional groups in GH had higher absolute abundance. Seasonal variations significantly influenced microbial diversity, composition, and potential metabolic functional groups within each land-use type, particularly in summer, although the magnitude of this impact was much smaller than the impact of land-use intensification. Our findings emphasize the importance of comprehending the ecological consequences of land-use intensification in wetlands for sustainable resource management and biodiversity conservation.

High stochasticity in rare bacterial community assembly in rice-wheat rotation soils at a regional scale

A growing body of evidence highlights the important role of both abundant and rare microorganisms in agroecosystem for their respective ecological functioning. However, the ecological processes that govern the assembly of abundant and rare taxa microbial communities in rice-wheat rotation soils at a regional scale have not yet been elucidated. Here, we conducted a comprehensive investigation of bacterial diversity, community structure, and assembly in samples from 238 sites under rice-wheat rotation in eastern China. Soil pH was the most important edaphic factor shaping bacterial diversity and community structure. The Shannon diversity of both abundant and rare bacterial taxa had a parabolic relationship with soil pH, with diversity reaching its peak at pH values of 7.50 and 7.31, respectively. Abundant bacteria displayed greater sensitivity to soil pH than rare taxa. Stochastic processes, especially dispersal limitation, predominantly governed assembly for both abundant and rare bacteria, explaining 80% of observed variation. Remarkably, stochastic processes contributed >90% of variation in the assembly of rare taxa communities, surpassing its importance in abundant taxa community assembly. Moreover, the assembly of specific bacterial phyla was predominantly governed by stochastic processes in the rice-wheat rotation soils. Overall, our findings provide the first data that although soil pH can make an initial assessment of the variation of bacterial communities, the high level of stochasticity in rare taxa community assembly would make them highly unpredictable during agricultural managements in rice-wheat rotation soils. These findings contribute new perspectives to understanding the main processes underpinning the observed bacterial communities, with implications for soil sampling, biodiversity conservation and ecosystem functionality in rice-wheat rotation soils.