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A large amount of agricultural waste is produced annually in China, and these agricultural wastes include crop residues and the manure generated from poultry and livestock farming. But there is still a considerable portion of agricultural waste that is not recycled and disposed of or directly burned. Therefore, if these agricultural wastes can be reasonably utilized, it will generate significant socio-economic and environmental benefits. Soil salinization has become one of the main threats to soil health, and agricultural waste is considered an effective tool for improving saline alkali land due to its unique properties. Utilizing agricultural waste to improve saline alkali land has advantages such as wide material sources, low cost, and low environmental risks. This article reviews the effectiveness and potential physical, chemical, and biological mechanisms of agricultural waste in improving soil health in saline alkali soils. Agricultural waste is mainly used to improve saline alkali land through a direct return to the field, burial of salt barriers, pyrolysis and carbonization into biochar, and composting, which can play a positive role in physical, chemical, and biological aspects. Finally, the problems existing in the improvement of saline alkali land with agricultural waste were discussed, and future research directions and hotspots in this field were proposed. It is believed that the improvement of ecological service functions is the key to its sustainability. This article can provide a theoretical basis for the study of agricultural waste in the improvement of saline alkali land, and help to further explore the resource utilization pathways of agricultural waste in sustainable agriculture. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Xinjiang University (Natural Science Edition) is the property of Xinjiang University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

【Objective】The present paper aimed to improve the effect of straw returning in sandy soil in the old Yellow River course region, thereby improving soil quality and crop yield.【Method】The effect of nitrogen (N), organic fertilizer (M), microbial agent (B), organic fertilizer + microbial agent (MB), soil enzyme agent (S), organic fertilizer + microbial agent + soil plant enzyme agent (MBS) on soil nutrients and crop yields was studied and compared based on the technique of straw-activated returning.【Result】The technique of straw-activated returning by adding exogenous materials could improve soil fertility and crop yield. The effect of N treatment on soil nutrient content and crop yield was no significant when N application was increased by 187.5 kg/hm². Compared with non-exogenous material (CK) treatment, MB treatment could increase soil organic matter and nutrient content, and the crop yield was also increased significantly. MBS treatment could further increase the straw returning effect. Compared with CK treatment, the soil organic matter content of MBS was increased by 4.5%-10.3%, total nitrogen was increased by 18.3%-33.8%, available phosphorus was increased by 11.3% -25.5%, and available potassium was increased by 52.6%-99.6%; Compared with the other five treatments of exogenous application, the corn yield of MBS was increased by 3.0%-32.0%, soybean yield was increased by 0.5%-30.2%, and wheat yield was increased by 5.4%-14.3%. 【Conclusion】In all treatments, straw returning combined with organic fertilizer + biological agents + soil enzyme (MBS) additives have the best effect on improving soil nutrient content and crop yield. [ABSTRACT FROM AUTHOR]

Copyright of Acta Agronomica Sinica is the property of Crop Science Society of China and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Straw returning may stimulate soil microbial activity, thereby influencing microbial-mediated soil nitrification, which can lead to nitrate leaching and nitrogen (N) loss. However, its effects under long-term nitrogen fertilization remain unclear. At an experimental station with 34 years of fertilizer application (0, 135, and 270 kg ha−1 N), we investigated how nitrogen fertilization and straw returning affected the soil potential nitrification rate (PNR) and ammonia-oxidizing microorganisms (AOM). Our results suggest that N fertilization concurrently inhibits soil PNR, but this inhibition can be alleviated by straw returning, particularly with low nitrogen fertilization (p < 0.05). Long-term N fertilization significantly decreased the abundance of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), and complete ammonia-oxidizing bacteria cladeB (CAOB-cladeB). Straw returning increased AOA abundance and diversity, especially with low or no fertilization (p < 0.05). Furthermore, the partial least squares path model demonstrated that AOA abundance affected soil PNR by altering the AOA community. According to random forest analysis, soil pH and AOA beta diversity were the primary factors affecting soil PNR (explaining 10.76% and 10.03% of the variation, respectively). Overall, our findings highlight the importance of straw returning and AOA in soil nitrification under long-term nitrogen fertilization, emphasizing the need to consider these interactions for sustainable agriculture. [ABSTRACT FROM AUTHOR]

Under a full straw returning system, the relationship between soil bacterial community diversity and straw decomposition, yield, and the combined application of slow-release nitrogen and urea remains unclear. To evaluate these effects and provide an effective strategy for sustainable agricultural production, a 2-year field positioning trial was conducted using maize as the research object. Six experimental treatments were set up: straw returning + no nitrogen fertilizer (S1N0), straw returning + slow-release nitrogen fertilizer:urea = 0:100% (S1N1), straw returning + slow-release nitrogen fertilizer:urea = 30%:70% (S1N2), straw returning + slow-release nitrogen fertilizer:urea = 60%:40% (S1N3), straw returning + slow-release nitrogen fertilizer:urea = 90%:10% (S1N4), and straw removal + slow-release nitrogen fertilizer:urea = 30%:70% (S0N2). Significant differences (p < 0.05) were observed between treatments for Proteobacteria, Acidobacteriota, Myxococcota, and Actinobacteriota at the jointing stage; Proteobacteria, Acidobacteriota, Myxococcota, Bacteroidota, and Gemmatimonadota at the tasseling stage; and Bacteroidota, Firmicutes, Myxococcota, Methylomirabilota, and Proteobacteria at the maturity stage. The alpha diversity analysis of the soil bacterial community showed that the number of operational taxonomic units (OTUs) and the Chao1 index were higher in S1N2, S1N3, and S1N4 compared with S0N2 at each growth stage. Additionally, the alpha diversity measures were higher in S1N3 and S1N4 compared with S1N2. The beta diversity analysis of the soil bacterial community showed that the bacterial communities in S1N3 and S1N4 were more similar or closely clustered together, while S0N2 was further from all treatments across the three growth stages. The cumulative straw decomposition rate was tested for each treatment, and data showed that S1N3 (90.58%) had the highest decomposition rate. At the phylum level, straw decomposition was positively correlated with Proteobacteria, Actinobacteriota, Myxococcota, and Bacteroidota but significantly negatively correlated with Acidobacteriota. PICRUSt2 function prediction results show that the relative abundance of bacteria in soil samples from each treatment differed significantly. The maize yield of S1N3 was 15597.85 ± 1477.17 kg/hm2, which was 12.80 and 4.18% higher than that of S1N1 and S0N2, respectively. In conclusion, a combination of slow-release nitrogen fertilizer and urea can enhance the straw decomposition rate and maize yield by improving the soil bacterial community and structure within a full straw returning system. [ABSTRACT FROM AUTHOR]

Straw return is a crucial method for utilizing agricultural waste as a resource. Against the backdrop of increasing straw production in China, most scholars focus only on the behavioral decision of whether farmers choose to transfer land. However, few studies have touched on the specific content of the land transfer contract and its impact on farmers' behavior. This paper innovatively starts from the perspective of land transfer contracts to explore the impact of land transfer contracts on straw return in terms of standardization, stability, and profitability and to make theoretical contributions to the rational use of straw and the protection of arable land resources. Using data from the 2020 China Rural Revitalization Survey (CRRS) database, this study empirically analyzed the effects of different elements of land transfer contracts on straw returns to the field. The results show that: (1) Written transfer contracts are more effective than verbal contracts in encouraging farmers to adopt the straw return behavior. (2) Fixed-term contracts are more stable and can effectively promote farmers' adoption of straw return technology. (3) The remunerative transfer method is more profitable and can effectively encourage farmers to adopt straw return technology compared to the non-remunerative transfer method. (4) Farmers in mountainous areas or with smaller areas of farmland have a lower probability of adopting straw return technology. Therefore, the important role of remunerative, fixed-term, written land transfer contracts in the process of straw return should be emphasized, and the adoption rate of straw return should be increased through differentiated policy guidance and comprehensively promoting the sustainable development of agriculture. [ABSTRACT FROM AUTHOR]

Straw returning has gradually been adopted as an effective approach to address the serious degradation of farmland. However, the carbon/nitrogen (C/N) ratio of rice straw is generally too high for microorganisms to decompose the organic materials and release nutrients, which may minimize the benefits of straw returning to the agricultural production system. This study aimed to investigate the effects of straw returning on rice production and propose optimum nitrogen (N) management for early rice production under a straw returning system. The total N fertilizer that was evaluated was 165 kg N ha-1, urea (46% N), applied in different proportions in three stages of rice cultivation: basal, tillering, and panicle. Using no straw returning with the N fertilizer ratio of basal:tillering:panicle = 5:2:3 treatment (T1) as the control, four different N fertilizer ratios of basal:tillering:panicle, including 5:2:3 (T2), 5:2:2 (T3), 5:4:1 (T4), and 5:5:0 (T5) were set under straw returning. The return of straw decreased the available N in the soil at the tillering stage, and impeded root growth and the crop canopy from establishing, which decreased the effective panicles by 10.1% compared with that of T1, limiting the increases in rice grain yield. Increasing the N fertilizer ratio 10–20% (T3 and T4) at the tillering stage effectively increased the content of soil ammonium and nitrate nitrogen, improved the root growth, and increased the root activities by 16.0–40.5% at the tillering stage. As a result, the effective panicle number increased by 5.1–16.2%. Among these, T4 treatment maximized the benefits of straw returning the most. Additionally, increasing the N fertilizer ratio at the tillering stage increased the shoot uptake across the early rice growing season and synchronized crop N uptake with the accumulation of carbon assimilates, which enhanced the crop growth rate and increased the rice yield by 13.5–25.1%. It is concluded that increasing the N fertilizer ratio by 20% at the tillering stage is a promising strategy to increase the availability of N in the phases of high demand for this nutrient. [ABSTRACT FROM AUTHOR]

Straw returning has been shown to improve farmland soil, increase crop yield, and reduce global warming. This study investigated the models of six rice straw-returning techniques based on the life cycle assessment method. Compared to the direct modes, the indirect ones showed a greater environmental impact; up to 20.56 times in acidification and emission potentials. There was no significant difference in climate change among the six types. Except for the burning effect, all other modes showed improvement in soil fertility; phosphorus and organic matter content increased by 66.66% and 30.85%, respectively, microbial biomass carbon content doubled (105%), the four organic carbon components increased by >50%, crop morbidity was reduced, and diversity of soil fungus was improved. Feeding, as an indirect method for enhancing soil fertility and economic benefits, is set to emerge as a leading practice in China's straw management. However, straw-returning technology is limited by cost, greenhouse gases, and increased risk of diseases and pests. There is an urgent need for further improvement and development of carbon sequestration and emission reduction in China's agriculture. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the impact of straw returning (SR) combined with appropriate N application rates on soil properties and maize yield for a double cropping maize system in South China. From 2021 to 2022, a two-year field experiment was conducted (the perennial orientation study began in 2018) with two nitrogen application rates, 0 kg ha−1 (N0) and 250 kg ha−1 (N250), under various straw treatments (SR and traditional planting). The findings revealed that SR, along with the nitrogen application of 250 kg ha−1 (N250), increased soil total nitrogen (TN), soil total phosphorous (STP), and the soil total potassium (STK) content besides soil organic carbon (SOC) and labile organic carbon (LOC); similarly, their interaction improved SOC and LOC in the 0–20 cm soil layer. In addition, within the 20–40 cm soil layer, SR and N250 also increased the soil TN, SOC, LOC, STP, and STK content. Notably, these soil properties exhibited a decrease with increasing soil depth. Furthermore, SR and N250 led to improvements in the grain yield and yield component of maize. Combining SR with N250 led to a significant 101.53% increase in SOC content from 2018 to 2022. Our research indicates that implementing N rates of 250 kg ha−1 under SR is an effective method to boost maize grain yield, enhance soil chemical characteristics, and ensure safe and productive maize cultivation. [ABSTRACT FROM AUTHOR]

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

Copyright of Acta Agriculturae Zhejiangensis is the property of Acta Agriculturae Zhejiangensis Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Prataculturae Sinica is the property of Acta Prataculturae Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the context of the carbon peak and carbon-neutral era, it is crucial to effectively utilize maize straw as a resource for achieving carbon (C) sequestration and emission reduction in rural agriculture. Maize straw carbon undergoes two processes after being added to the soil: mineralization (decomposition) and humification (synthesis) by soil animals and microorganisms. These processes contribute to the reintegration of carbon into the agroecosystem's carbon cycle. However, understanding of the transformation and stabilization of straw carbon, as well as the differences in C fixation capacity in soils with various fertilization treatments in black soils, remains limited. This study aims to quantify the relationship between straw carbon input and organic carbon sequestration in various fertilization treatments of black soil. Based on a long-term positional fertilization trial (45 years) in black soil, 13C-labeled maize straw (1.5 g in 120 g of dry soil) was applied and combined with an in situ incubation method using carborundum tubes. Throughout the 360-day trial, we observed the influence of fertilization on soil total organic C levels, organic carbon δ13C values, maize straw addition rate, and straw C fixation capacity. The decomposition of straw was most prominent during the initial 60 days of the incubation period, followed by a gradual decrease in the rate of decomposition. Compared with day 0, the SOC δ13C value and straw C residue rate were highest in the no-fertilization treatment (CK) after 360 days of incubation. The amount of organic carbon transformed and fixed in the soil was significantly higher in the organic fertilizer treatment (M) compared to other treatments, highlighting the stronger decomposition, transformation, and carbon fixation capacity of straw carbon in the M treatment. Moreover, the highest carbon storage of 43.23 Mg·ha−1 was observed in the M fertilization treatment after 360 days, which was significantly different from other treatments (p < 0.05). The study demonstrates that soil with low fertility exhibits increased sequestration potential for straw carbon. Additionally, organic fertilizer input would increase soil organic carbon storage and facilitate straw carbon conversion. [ABSTRACT FROM AUTHOR]

Tillage modes and straw returning influence soil aggregate stability and the distribution of organic carbon (C) and nitrogen (N) in aggregates of different particle sizes. In the typical hilly regions of southwest China, the predominant soil type is purple soil, characterized by heavy texture and high stickiness, with relatively lower soil fertility compared to other soil types. The improper use of fertilizers and field management practices further exacerbates soil compaction. However, abundant straw resources in the region provide an opportunity for comprehensive straw utilization. The effective utilization of straw resources is of significant importance for stabilizing agricultural ecological balance, improving resource utilization efficiency, and alleviating ecological pressure. Previously, most studies have focused on the impact of different mechanized tillage systems on the physical and chemical properties of soil in hilly areas, while research on the preservation of water-stable aggregates' organic C and N content remains limited. In this study, the soil properties of fields under a winter pea–summer corn rotation for two years were studied with regards to the effects of straw returning on its water-stable aggregate distribution, macroaggregate content (R0.25), mean weight diameter (MWD), geometric mean diameter (GMD), and the organic C and N content in soil aggregates of different particle sizes and at different depths. The effects of five different tillage modes were assessed, namely rotary tillage with straw mixed retention (RTM), conventional tillage with straw burial retention (CTB), no-tillage with straw covered retention (NTC), subsoiling with straw covered retention (STC), and no-tillage without straw retention (NT). Based on the study results, under different tillage modes, straw returning effectively enhanced the soil organic carbon (SOC) and total nitrogen (TN) reserves at the plow layer (0–30 cm), SOC increased by 17.2% to 88%, and TN increased by 8.6% to 85.9%. At the same time, the content of 0.25–2 mm aggregates increased under the straw-return treatments under different tillage patterns. The NT treatment had the lowest R0.25 and MWD and GMD values for soil aggregates at different depths, which were significantly different (p < 0.05) from the other treatment modes. The correlation coefficients between SOC and soil aggregate stability indices ranged from 0.68 to 0.90, with most of them showing highly significant positive correlations (p < 0.01). In conclusion, straw returning under different tillage systems has improved soil aggregate stability and promoted soil structure stability. Specifically, the STC treatment has shown more pronounced effects on soil improvement in the upper soil layer of the hilly regions in southwest China, while the RTM treatment is beneficial for improving the lower soil layer. Therefore, the comprehensive experimental results indicate that the combination of STC and RTM treatments represents the most promising mechanized tillage and straw returning practices for the hilly regions in southwest China. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

China’s agricultural production suffers significant constraints due to low water productivity (WP) and partial factor productivity for nitrogen (PFPN). The pivotal solution to enhance maize yield, WP, and PFPN is through optimizing field management practices. However, previous studies primarily focused on the effects of individual or coupled field management practices on maize yield, WP, or PFPN in an area or land mass, so it is necessary to conduct a comprehensive quantitative analysis of various field management practices on maize yield, WP, and PFPN at the national scale. In this study, we compiled 286 studies encompassing 6959 pairs of experimental data spanning from 1990 to 2023. Meta-analysis was conducted to observe the variations in maize yield, WP, and PFPN across diverse field management practices (straw returning, nitrogen fertilizer application, irrigation practice, and tillage practice) on a national scale. The results showed that nitrogen fertilizer application (215 kg N ha−1) was the most effective in enhancing maize yield and WP by 68.1 % and 54.8 %, respectively. Additionally, irrigation had the most substantial impact on PFPN, enhancing 16.8 %. Straw mulching, application of slow and controlled release fertilizers, drip irrigation, and subsoiling were identified as the most effective practices in increasing maize yield, WP, and PFPN by Random forest model. Maize straw returning could reduce nitrogen fertilizer application by 20 kg ha−1, while increasing WP and PFPN by 4.2 % and 11.6 %, respectively. Moreover, straw returning could reduce water consumption by 23–60 mm, while increasing WP and PFPN by 2.9 % and 6.8 %, respectively. These findings can provide a reference for the formulation of comprehensive management strategies for sustainable maize production in China and globally.

Abstract Straw returning is an important strategy for effectively using straw resources to improve soil fertility and quality, but the effects of this process on reactive intermediates (RIs) formation in paddy water are not fully explored. In this study, we conducted a field experiment to explore the effects of straw returning on RIs formation including triplet chromophoric dissolved organic matter (3CDOM*), hydroxyl radicals (•OH), and singlet oxygen (1O2) in paddy water. It was found that straw returning considerably increased the steady-state concentration of RIs, and the application of rice straw with 25% and 75% organic replacement ratio increased RIs concentration by 2.52 and 2.25 times, respectively. The optical spectroscopy, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) analysis and structural equation model showed that straw returning produces abundant humified and aromatic DOM containing fulvic acid, lignin and protein-like substances, which could induce more RIs under irradiation. In addition, straw returning significantly accelerated imidacloprid (IMD) degradation, yielding degradation products that were highly toxic to aquatic animals (i.e., fish and daphnia) but less toxic to aquatic plants (i.e., green algae). This study would offer an innovative viewpoint on the effects of straw returning on the photochemistry of paddy water and the naturally occurring abiotic degradation pathway of organic contaminants.

Copyright of Acta Agronomica Sinica is the property of Crop Science Society of China and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Henan Agricultural Sciences is the property of Editorial Board of Journal of Henan Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Straw returning is an important strategy for effectively using straw resources to improve soil fertility and quality, but the effects of this process on reactive intermediates (RIs) formation in paddy water are not fully explored. In this study, we conducted a field experiment to explore the effects of straw returning on RIs formation including triplet chromophoric dissolved organic matter (3CDOM*), hydroxyl radicals (•OH), and singlet oxygen (1O2) in paddy water. It was found that straw returning considerably increased the steady-state concentration of RIs, and the application of rice straw with 25% and 75% organic replacement ratio increased RIs concentration by 2.52 and 2.25 times, respectively. The optical spectroscopy, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) analysis and structural equation model showed that straw returning produces abundant humified and aromatic DOM containing fulvic acid, lignin and protein-like substances, which could induce more RIs under irradiation. In addition, straw returning significantly accelerated imidacloprid (IMD) degradation, yielding degradation products that were highly toxic to aquatic animals (i.e., fish and daphnia) but less toxic to aquatic plants (i.e., green algae). This study would offer an innovative viewpoint on the effects of straw returning on the photochemistry of paddy water and the naturally occurring abiotic degradation pathway of organic contaminants. Highlights: • Straw returning produces abundant humified and aromatic DOM as a key photosensitizer. • Straw returning increased the steady-state concentration of RIs in paddy water. • Straw returning significantly accelerated IMD degradation and 3DOM* was the dominant RI for IMD degradation in paddy water. [ABSTRACT FROM AUTHOR]

BACKGROUND: The shortage of water resources and the increase of greenhouse gas emissions from soil seriously restrict the sustainable development of agriculture. Under the premise of ensuring a stable yield of winter wheat through a reasonable irrigation scenario, identifying a suitable straw returning method will have a positive effect on agricultural carbon sequestration and emission reduction in North China Plain. RESULTS: Straw burying (SR) and straw mulching (SM) were adopted based on traditional tillage under in the winter wheat growing season of 2020–2021 and 2021–2022. Three irrigation scenarios were used for each straw returning method: no irrigation (I0), irrigation 60 mm at jointing stage (I1), and irrigation of 60 mm each at the jointing and heading stages (I2). Soil moisture, soil respiration rate, cumulative soil CO2 emissions, yield, water use efficiency (WUE) and soil CO2 emission efficiency (CEE) were mainly studied. The results showed that, compared to SM, SR improved the utilization of soil water and enhanced soil carbon sequestration. SR reduced soil respiration rate and cumulative soil CO2 emissions in two winter wheat growing seasons, and increased yield by increasing spike numbers. In addition, with an increase in the amount of irrigation, soil CO2 emissions and yield increased. Under SR‐I1 treatment, WUE and CEE were the highest. SR‐I1 increases crop yields at the same time as reducing soil CO2 emissions. CONCLUSION: The combination of SR and irrigation 60 mm at jointing stage is a suitable straw returning irrigation scenario, which can improve water use and reduce soil CO2 emission in NCP. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Appropriate strawincorporation has ample agronomic and environmental benefits, butmost studies are limited to strawmulching or application on the soil surface. To determine the effect of depth of straw incorporation on the crop yield, soil organic carbon (SOC), total nitrogen (TN) and greenhouse gas emission, a total of 4 treatments were set up in this study, which comprised no straw returning (CK), straw returning at 15 cm (S15), straw returning at 25 cm (S25) and straw returning at 40 cm (S40). The results showed that straw incorporation significantly increased SOC, TN and C:N ratio. Compared with CK treatments, substantial increases in the grain yield (by 4.17~5.49% for S15 and 6.64~10.06% for S25) were observed under S15 and S25 treatments. S15 and S25 could significantly improve the carbon and nitrogen status of the 0-40 cmsoil layer, thereby increasedmaize yield. The results showed that the maize yield was closely related to the soil carbon and nitrogen index of the 0-40 cm soil layer. In order to further evaluate the environmental benefits of straw returning, this study measured the global warming potential (GWP) and greenhouse gas emission intensity (GHGI). Compared with CK treatments, the GWP of S15, S25 and S40 treatments was increased by 9.35~20.37%, 4.27~7.67% and 0.72~6.14%, respectively, among which the S15 treatment contributed the most to the GWP of farmland. GHGI is an evaluation index of low-carbon agriculture at this stage, which takes into account both crop yield and global warming potential. In this study, GHGI showed a different trend from GWP. Compared with CK treatments, the S25 treatments had no significant difference in 2020, and decreased significantly in 2021 and 2022. This is due to the combined effect of maize yield and cumulative greenhouse gas emissions, indicating that the appropriate straw returning method can not only reduce the intensity of greenhouse gas emissions but also improve soil productivity and enhance the carbon sequestration effect of farmland soil, which is an ideal soil improvement and fertilization measure. [ABSTRACT FROM AUTHOR]

Straw return and appropriate planting density are beneficial for improving soil physicochemical properties and optimizing microbial community structure. This study investigated the effect of different straw-returning modes (H1: straw crushing deep plowing back to the field, H0: straw was not returned to the field) and different planting densities (D1: 67500plants·ha-1, D2: 82500plants·ha-1, D3: 97500plants·ha-1) on the diversity and community structure of rhizosphere fungi at maize maturity using Illumina MiSeq high-throughput sequencing technology. The study was established as a split-plot experiment and conducted on maize farmland of the Yinhuang Irrigation area in Ningxia for five consecutive years. Results showed that: (1) the interaction effect of straw return mode and planting density was highly significant for the Chao1 index, ACE index, and Shannon index of soil fungal communities (P<0.01), with the indexes being highest under the H1D2 treatment. (2) Soil fungal community in the inter-root area of maize in the farmland was mainly composed of fungi from 509 genera in 14 phyla, such as Ascomycota (63.50%-81.82%), Basidiomycota (4.83%-18.03%), and Mortierellomycota (3.18%-9.61%), etc. The structure of the fungal community differed among different density and straw return mode combinations, and the relative abundance of the dominant phyla and genera varied greatly. (3) The interaction of straw return mode and planting density significantly influenced the soil pH, organic matter, alkaline dissolved nitrogen, and quick-acting phosphorus content (P<0.01), with H1D2 treatment being the optimal treatment combination. Pearson's correlation analysis showed that there were significant or highly significant correlations among soil pH, organic matter, total nitrogen, total phosphorus, alkaline dissolved nitrogen, quick-acting phosphorus, quick-acting potassium content, and the α-diversity of the fungi. Soil pH was significantly and negatively correlated with the relative abundance of Cladosporium (P<0.05). Organic matter, total phosphorus, alkaline-dissolved nitrogen. And quick-acting potassium content were significantly and positively correlated with the relative abundance of Cladosporium (P<0.05). Organic matter content was significantly and negatively correlated with the relative abundance of Chaetomium (P<0.05). RDA analyzes showed that total nitrogen, organic matter, fast-acting potassium, and pH were the main environmental factors that drive the variation of soil fungal communities in maize rhizosphere at different densities under different straw return patterns. In this study, straw return combined with a planting density of 82500 plants·ha-1 was optimum for increasing farmland soil fertility and improving inter-root soil fungal diversity. [ABSTRACT FROM AUTHOR]

Improving the soil structure and fertility of saline–alkali land is a major issue in establishing a sustainable agro-ecosystem. To explore the potential of different straw returning in improving saline–alkaline land, we utilized native saline–alkaline soil (SCK), wheat straw-returned saline–alkaline soil (SXM) and rapeseed straw-returned saline–alkaline soil (SYC) as our research objects. Soil physicochemical properties, fungal community structure and diversity of saline–alkaline soils were investigated in different treatments at 0–10 cm, 10–20 cm and 20–30 cm soil depths. The results showed that SXM and SYC reduced soil pH and total salinity but increased soil organic matter, alkali-hydrolyzable nitrogen, available phosphorus, total potassium, etc., and the enhancement effect of SYC was more significant. The total salinity of the 0–10 cm SCK soil layer was much higher than that of the 10–30 cm soil layers. Fungal diversity and abundance were similar in different soil layers in the same treatment. SXM and SYC soil had higher fungal diversity and abundance than SCK. At the genus level, Plectosphaerella, Mortierella and Ascomycota were the dominant groups of fungal communities in SXM and SYC. The fungal diversity and abundance in SXM and SYC soils were higher than in SCK soils. Correlation network analysis of fungal communities with environmental factors showed that organic matter, alkali-hydrolyzable nitrogen and available phosphorus were the main environmental factors for the structural composition of fungal communities of Mortierella, Typhula, Wickerhamomyces, Trichosporon and Candida. In summary, straw returning to the field played an effective role in improving saline–alkaline land, improving soil fertility, affecting the structure and diversity of the fungal community and changing the interactions between microorganisms. [ABSTRACT FROM AUTHOR]

Recently, replacing chemical fertilizers with straw returning and new fertilizers has received considerable attention in the agricultural sector, as it is believed to increase rice yield and improve soil properties. However, less is known about rice growth and soil properties in paddy fields with the addition of different fertilizers. Thus, in this paper, we investigated the effects of different fertilizer treatments, including no fertilization (CK), optimized fertilization based on the medium yield recommended fertilizer amount (OF), 4.50 Mg ha−1 straw returning with chemical fertilizers (SF), 0.59 Mg ha−1 slow-release fertilizer with chemical fertilizers (SRF), and 0.60 Mg ha−1 water-soluble fertilizer with chemical fertilizers (WSF), on rice growth, yield, and soil properties through a field experiment. The results show that compared with the OF treatment, the new SF, SRF, and WSF treatments increased plant height, main root length, tiller number, leaf area index, chlorophyll content, and aboveground dry weight. The SF, SRF, and WSF treatments improved rice grain yield by 30.65–32.51% and 0.24–1.66% compared to the CK and OF treatments, respectively. The SRF treatment increased nitrogen (N) and phosphorus (P) uptake by 18.78% and 28.68%, the harvest indexes of N and P by 1.75% and 0.59%, and the partial productivity of N and P by 2.64% and 2.63%, respectively, compared with the OF treatment. However, fertilization did not significantly affect the average yield, harvest indexes of N and P, and partial productivity of N and P. The contents of TN, AN, SOM, TP, AP, and AK across all the treatments decreased significantly with increasing soil depth, while soil pH increased with soil depth. The SF treatment could more effectively increase soil pH and NH4+-N content compared to the SRF and WSF treatments, while the SRF treatment could greatly enhance other soil nutrients and enzyme activities compared to the SF and WSF treatments. A correlation analysis showed that rice yield was significantly positively associated with tiller number, leaf area index, chlorophyll, soil NO3−-N, NH4+-N, SOM, TP, AK, and soil enzyme activity. The experimental results indicate that SRF was the best fertilization method to improve rice growth and yield and enhance soil properties, followed by the SF, WSF, and OF treatments. Hence, the results provide useful information for better fertilization management in the Chaohu Lake region of China. [ABSTRACT FROM AUTHOR]

Despite the well-documentation of the effects of straw returning on soil structural stability and fertility, its long-term in situ impacts on profile aggregate size composition and organic carbon (OC) fractions remain poorly investigated. To address this research gap, the present nine-year field trial explored the co-effects of straw returning and chemical fertilization on soil total OC (TOC), dissolved OC (DOC), resistant OC (ROC), easily oxidative OC (EOC), as well as soil aggregate size composition of different soil depths (0–15, 15–30, and 30–50 cm) in a paddy field, East China. To do so, four different treatments were set up, including no straw returning plus no fertilization (CK), conventional fertilization (F), straw returning plus conventional fertilization (SF), and straw returning plus 80 % conventional fertilization (SDF). Our findings revealed that the >2 mm aggregates were dominant in all treatments, particularly in SF and SDF 0–30 cm soil layers ranging from 62 to 70 % (P 2 mm aggregates, respectively, differing from 3.86 to 15.8 g/kg and 250–413 mg/kg, respectively (P

Abstract: 【Objective】Clarify the effects of continuous tillage and straw returning on soil nutrients and maize yield, to provide references for the improvement of maize yield.【Methods】Four treatments including subsoiling with straw returning（STS), subsoiling (ST0), no-tillage with straw returning (NTS) and no-tillage (NT0) were set up. Soil samples were collected from 0-100 cm soil layer at maize maturity stage, and tested for soil nitrogen content, nitrogen storage, polysaccharide content, fulvic acid content, humic acid content, aggregate relative content and mean weight diameter, as well as aggregate nitrogen content. Maize yield was tested as well to analyze the effects of continuous tillage and straw returning on soil nutrient content and maize yield.【Results】STS significantly increased the soil nitrogen content and nitrogen storage in 0-20 cm soil layer by 96.19% and 89.35% compared with NT0. In the 20-100 cm soil layer, STS soil nitrogen content were higher, with a 13.13% increase compared with NT0. STS significantly increased 20-100 cm soil layer nitrogen storage by 29.20% compared with NT0. STS increased 0-40 cm soil layer polysaccharide, fulvic acid and humic acid content by 17.45%, 62.66%, and 10.63% compared with NT0. In 0-40 cm soil layer, STS significantly increased 2-1 mm and <0.053 mm aggregate relative contents by 41.92% and 336.42% compared with NT0. Nitrogen content of aggregates at >1 mm and <0.053 mm in the soil were highest, increased by 14.46% and 6.86% compared with NT0. STS improved maize yield by 8.29% compared with NT0.【Conclusion】Subsoiling with straw returning was more conducive to increasing the continuous tillage and straw returning nitrogen content in 0-20 cm soil layer, the contents of polysaccharide, fulvic acid and humic acid in 0-40 cm soil layer, and promoting the formation of larger aggregates, thus increased maize yield. [ABSTRACT FROM AUTHOR]

In this study, effects of loss-control urea ratio on the nutrients of fluvo-aquic soil and crop yield in north China under straw returning and non-returning conditions were evaluated. The wheat-maize rotation system in fluvo-aquic soil in north China was used in this experiment. The design of splitting plots was adopted, with straw returning as the main area and loss-control urea ratio as the sub-area. Two methods of straw returning were adopted：straw returning and non-returning, expressed as S1 and S0, respectively. Additionally, five treatments were set up for no fertilization（CK）and different loss-control urea ratios which were 0, 40%, 70%, and 100% of the total nitrogen application（LCU0, LCU40, LCU70, and LCU100）, respectively. Crop yields were measured and 0–20 cm of topsoil was collected for routine soil chemical property measurements after harvest. The results showed that compared with the S0 treatment, the S1 treatment significantly increased soil organic matter and available potassium contents. Loss-control urea significantly increased soil nitrate nitrogen content. Other soil chemical properties also increased, but the difference was not significant. Under the condition of straw not returning to the field, the application of chemical fertilizer significantly reduced the soil pH. When the ratio of loss-control urea was 70%, the soil nutrients were greatly improved. No significant effect of straw returning to the field was observed on wheat yield and nitrogen uptake, but loss-control urea had a significant effect on wheat grain yield, straw yield, total nitrogen content, and total nitrogen uptake. The grain and straw yields of the S1-LCU40 treatment were the highest under different treatments, with a grain yield of 7 009.26 kg·hm-2, and a straw yield of 11 361.38 kg·hm-2. Straw returning had significant effects on soil nitrogen dependence rate, and different proportions of loss-control urea had significant effects on nitrogen harvest index, apparent nitrogen recovery efficiency, and nitrogen dependence rate. The best nitrogen absorption and utilization index was 40% or 70%. Overall, in the North China Plain, straw return to soil and 40% loss-control urea could significantly increase soil nitrogen supply, wheat yield, and index of nitrogen uptake and utilization, which constitutes a more appropriate management measure, but its mechanism and long-term effect need to be further studied. [ABSTRACT FROM AUTHOR]

The strip rotary tillage method effectively reduces the occurrence of straw clogging and creates a favorable seed bed environment. However, the mixture of crushed straw and soil in the seeding area results in inadequate seed-soil contact following compaction by the press wheels. A chisel-type opener furrow side pick-up blade was proposed to improve seed-soil contact by picking up wet soil from the furrow's side. The discrete element method was used to investigate the impact of earth blade surface parameters on soil dynamics. The key factors of the blade, including forward velocity, endpoint tangent angle, and angle of soil entry, were determined through theoretical analysis. Soil cover thickness and straw ratio in the seed furrow were evaluated using orthogonal rotation regression tests. The results show that the endpoint tangent angle and angle of soil entry have the greatest influence on soil cover thickness, while the angle of soil entry has the greatest influence on the straw ratio. The optimal values for the forward velocity, endpoint tangent angle, and angle of soil entry are 4.86 km/h, 107.17°, and 5.46°, respectively, resulting in a soil cover thickness of 40 mm and a straw ratio of 21.46%. Confirmatory soil bin tests showed similar results, with a soil cover thickness of 40.4 mm and a straw ratio of 18.03%. These results provide a viable solution for improving seed-soil contact after strip rotary tillage planter seeding. [ABSTRACT FROM AUTHOR]

Soil C and N input drives microbial biomass in paddy-upland rotations. We explored how crop straw return impacts microbial C and N (MBC and MBN) dynamics and their role in rice-oilseed rape rotations at three sites in Hubei Province, China. These sites, under a subtropical monsoon climate, were categorized (using the modified Nemoro equation) as high, moderate and low soil fertility respectively. We found that with straw return, total nitrogen (TN) and soil organic carbon (SOC) increased to the greatest degree in the high fertility soils. Notably, soil MBC and MBN levels varied with soil fertility and were seasonably dependent, being lower in the rice season compared to the oilseed rape season. Structural equation modelling (SEM) revealed diminishing effects of MBC and MBN on soil N accumulation during the oilseed rape season compared to the rice season. In summary, our results highlight the role that microbial biomass can play in C and N accumulation as a soil fertility indicator in paddy-upland rotations. [ABSTRACT FROM AUTHOR]

Straw returning not only improves carbon (C) and nitrogen (N) pools but also increases soil nitrous oxide (N2O) emissions, which poses a threat to the sustainable development of agriculture. To investigate the effect of straw return combined with nitrogen fertilizer on labile C and N pools in the soil and short-term response to soil N2O emissions in wheat-maize rotation system. The consecutive field experiment was conducted from 2019 to 2021. Single factor randomized block design was used in the experiment design, with no straw returning and no fertilizer (CK), no straw returning and nitrogen fertilizer (S0N) and straw returning combined with nitrogen fertilizer (SN). The results indicated that the SN and S0N treatments significantly (p < .05) increased N2O emissions by 170.45% (2.43 kg N ha-1 year-1) and 119.5% (1.70 kg N ha-1 year-1), soil organic carbon (SOC) by 17.23% and 14.50% and soil total nitrogen (STN) by 58.50% and 31.50% respectively. In the 2020-2021 growing season, The soil microbial biomass carbon (SMBC) content of the SN and S0N treatments were higher than those of CK in the winter wheat seedling, winter wheat jointing, winter wheat booting, summer maize seedling and summer maize bell-mouth stages. The structural equation model (SEM) indicated that C:N and NO3 --N were the major drivers that increased soil N2O emissions, but SMBN was the main driver that decreased soil N2O emissions. The SN and S0N treatments significantly increased soil N2O emissions by increasing the NO3 --N content. However, compared with the CK and S0N treatments, the SN treatment mitigated soil N2O emissions by increasing the SMBN content. More importantly, compared with CK treatment, SN treatment increased annual yield by 48.41% and 34.52%, the SN treatment could effectively improve the soil C and N pools. Therefore, straw return combined with nitrogen fertilizer (SN) may be the best choice of the treatments tested for reducing greenhouse gas emissions and achieving green and sustainable development. [ABSTRACT FROM AUTHOR]

To enhance rice yields, synthetic nitrogen (N) fertilizers are often applied in rice paddy fields. Under waterlogged conditions, denitrification, anaerobic ammonium oxidation (anammox) and dissimilatory nitrate reduction to ammonium (DNRA) are the main N transformation processes. However, the effects of longterm fertilization on the dissimilatory nitrate reduction processes remain largely unclear. Here, we investigated rates of denitrification, anammox and DNRA and the abundance of bacterial and nitrate reduction-related genes (16S rRNA, narG, nirK, nirS, nosZ and hzsB) in rice paddy fields under different fertilization regimes [i.e., non-fertilization (CK), NPK fertilization (NPK) and NPK fertilization plus straw returning (NPKS)]. The rates of denitrification, anammox and DNRA in the CK treatment were 46.18, 0.35 and 1.29 nmoL N g-1 h-1, respectively, which were significantly (p < .05) increased by 7.32%-27.78%, 2.45-4.12 folds and 1.01-13.23 folds by NPK and NPKS treatments. This was largely consistent with the increased bacterial and nitrate reduction-related gene abundances in the NPK and NPKS treatments. In addition, NPKS also significantly increased the relative contribution of DNRA to the total nitrate reduction relative to NPK and CK treatments, indicating that NPKS was more beneficial to N retention in the paddy field. Changes in rates of dissimilatory nitrate reduction processes in response to NPK and NPKS treatments were correlated to variations of soil total N, ammonium contents, pH, soil organic carbon (SOC) contents and nitrate reduction-related genes, among which SOC contents had the highest explanation. Specifically, fulvic-like compounds, alkyl C and methoxyl and nitrogen-alkyl C were the key components determining denitrification, anammox and DNRA rates, respectively. Overall, our study suggests that long-term NPK and NPKS fertilization stimulate rates of dissimilatory nitrate reduction processes mainly by altering soil C components and NPKS is more effective in maintaining soil fertility in the paddy field. [ABSTRACT FROM AUTHOR]

Currently, there is a noticeable scarcity of applications that harness composite microbial inoculants to stimulate straw decomposition, nitrogen fixation, and crop growth. This study addresses this gap by selecting and coculturing three bacterial strains to create a composite microbial inoculant named HY-1. This innovative inoculant exhibits multifunctional capabilities, including nitrogen fixation, straw decomposition, and crop growth promotion. Furthermore, we aimed to explore its impact on soil microbial communities. The results showed that the optimal preparation conditions for the compound microbial inoculant HY-1 were 28.5 ± 0.6 °C, pH = 7.34 ± 0.40, and bacteriophage ratio 1:2:1 (Microbacterium: Streptomyces fasciatus: Bacillus amyloliquefaciens). Compared to single strains, the combination exhibited higher levels of cellulose-degrading and nitrogen-fixing enzyme activity, increased the straw degradation rate by 37.91% within 180 days, and significantly promoted the growth of corn seedlings. Under the condition of straw return, the compound bio-fungicide HY-1 effectively improved the soil microbial diversity. At that time, the soil had the highest number of unique bacterial operational taxonomic units (166), and the abundance of Proteobacteria in the soil increased by 7.24%, while that of Acidobacteriota decreased by 2.27%. The biosynthetic function of the cell wall/membrane/periplasm and the metabolic function of transporting inorganic ions were significantly enhanced. In this study, we discovered that employing coculturing techniques to produce the composite microbial inoculant HY-1 and applying it in the field effectively compensates for the limitations of single-strain inoculants, which often exhibit fewer functions and less pronounced effects. This approach demonstrates significant potential for enhancing the quality of agricultural soils. [ABSTRACT FROM AUTHOR]

Returning crop straw to the soil is an effective measure to increase soil fertility and maintain crop yield in agroecosystems. In this study, we conducted a 34-year field experiment (1984–2017) to investigate the relationships among the impacts of straw return on soil nutrients, phosphorus (P) fractions, phosphorus transformation-related functional microbial communities, and key genes in black soil. The results of the soil chemical properties showed that straw return could slow the decline in soil pH and increase soil nutrients, i.e., soil organic carbon (SOC), available K (AK), and available P (AP) concentrations, with the straw addition (PKS) treatment resulting in the highest soil AP and AK contents. Compared with conventional fertilizer (NPK) and conventional fertilizer with straw (NPKS), straw return alone (S) significantly increased the soil AP and AK contents by 1.1–42.8 and 38.3–114.3 mg/kg (p < 0.05), respectively. The results of the phosphorus fraction experiment indicated that long-term straw return promoted labile and moderately stable phosphorus content by altering the composition and increasing the relative abundances of functional genes regulating soil P activation (ugpQ, ppk, phoD, and gcd). The compositional changes in the phosphorus-cycling-related functional genes of the soil were affected mostly by soil total P (TP), AK, and NO3−-N, whereas pH, SOC, and available N (AN) were the main environmental factors influencing the phosphorus-cycling-related microbial community composition. These direct measurements provide insight into the soil phosphorus fractions, phosphorus-cycling-related functional genes, and microbial communities associated with straw returning, which enhances our understanding of the chemical and biogeochemical behavior of soil phosphorus upon straw incorporation. [ABSTRACT FROM AUTHOR]

The liable organic carbon (LOC) plays an imperative role in soil fertility and rice production. The diverse crop rotations and straw returning appreciably improve the crop yield and soil health. Therefore, the present experiment was conducted from 2016 to 2017 comprising five treatments including winter fallow, winter Chinese milk vetch (CMV), winter rape, winter garlic, winter rotation-early rice-late rice to determine the impacts on liable carbon fractions and rice yield. The results showed that compared with the winter fallow treatment, except winter garlic treatment, all other winter cropping and double straw returning improved the soil organic carbon (SOC), total organic carbon (TOC) and microbial biomass carbon (MBC). However, water-soluble organic carbon (WSOC) content of winter CMV, rape, and garlic treatments decreased, but easily oxidizable carbon (EOC) and soil particulate organic carbon (POC) content of winter rotation treatment was increased. At the same time, organic carbon content in 0–15 cm soil was significantly higher than that in 15–30 cm soil layer (P < 0.05). The soil carbon pool management index (CPMI) of both earlier and late rice in the soil layer of winter treatment except 15–30 cm of winter garlic treatment was significantly improved and the CPMI was higher in 0–15 cm soil as compared to 15–30 cm. The two-year average yield of late rice was better than that of early rice and rice yield was positively correlated with TOC, WSOC and MBC, and negatively correlated with EOC and POC. In conclusion, different rotations and double straw returns improved LOC, which was conducive for improving yields of both early and late rice. [ABSTRACT FROM AUTHOR]

To improve wheat grain quality, propose comprehensive wheat tillage and straw returning measures. In this paper, the relevant literature on tillage and straw returning in 2 000~2 020 was selected, and the effects of tillage and straw returning measures on wheat grain quality were quantitatively studied by meta-analysis, and the source of difference were analyzed. The results showed that compared with ploughing tillage treatment, no-tillage treatment increased grain protein, wet gluten, flour yield, total starch, and sedimentation value, but the difference between treatments was not significant. Compared with straw non-returning treatment, the grain protein and wet gluten content of straw returning treatment were significantly increased by 2.73% and 2.09%, respectively. Seeding rate was significantly and positively correlated with protein content, while nitrogen application rate was significantly and negatively correlated with sedimentation value. The further analysis of the source of difference showed that compared with the straw non-return treatment, the grain protein and wet gluten content of straw return treatment in southeast China were significantly increased by 3.07% and 2.80%, respectively, and the total starch content of straw returning treatment in North China was significantly increased by 5.97%. The wet gluten and sedimentation values of 135 kg/ha of seeding rate straw treatment were significantly increased by 3.38% and 6.68%, respectively, and the protein content of straw returning at 150 and 180 of kg/ha sowing rates was significantly increased by 2.41% and 12.27%, respectively. The grain protein, wet gluten, and sedimentation values of straw returning with Yangmai 15 were significantly increased by 6.02%, 7.44% and 16.35%, respectively. Under rice straw returning treatment, grain protein and wet gluten were significantly increased by 2.73% and 2.65%, respectively. The flour wet gluten and sedimentation values of straw returning treatment along with 240 kg/ ha of nitrogen application rate were significantly increased by 7.70% and 9.90%, respectively, whereas the flour sedimentation value with 270 kg/ha of nitrogen application rate was significantly reduced by 20.12%. There was no significant effect of the different factors on wheat flour yield. In summary, straw returning measures could improve the content of grain protein or wet gluten. Among them, in the southeast region, rice straw return, planting variety Yangmai 15 treatment combined with straw returning measures could significantly increase the content of grain protein and wet gluten. [ABSTRACT FROM AUTHOR]

xUnder the current situation of comprehensive utilization of straw resources in Wuhu City, the nutrient inputs and their spatial distribution characteristics under straw returning can provide a decision-making basis for coordinating the effective utilization of straw nutrient resources and promoting the reduction and efficiency of agricultural chemical fertilizers. The main straws (maize, rice, wheat, cotton, and rape straw) in Wuhu City in 2019 were chosen as the research objects. According to the crop planting area and nutrient content of straw, the inputs of nitrogen, phosphorus, and potassium nutrients and their weighted coefficients of variation under straw returning per unit area, and the spatial difference characteristics and specific embodiment of nutrient inputs under straw returning in Wuhu City were determined. The results showed that the contents of N, P, and K were 12 223, 1 747 t, and 23 404 t, respectively, for the main straws in Wuhu City. Furthermore, the total amount of straw nutrient resources of counties were as follows：Wuwei>Nanling>Jiujiang>Wanzhi> Fanchang>Yijiang>Jinghu. The straw resources per unit planting area of crops in Wuhu City were 5.63 t·hm-2, of which maize reached the highest 13.71 t·hm-2. The inputs of N, P, and K of maize straw returning per unit planting area in Wuhu were 126.16, 20.57 kg·hm-2, and 161.81 kg·hm-2, respectively. The weighted coefficient of variation of the inputs of N, P, and K of straw returning per unit planting area of the main straws in Wuhu City were 0.137 5, which indicated moderate variation. The spatial difference was great in Jiujiang and Nanling. The spatial difference of maize straw was the largest, and its weighted coefficient of variation was significantly higher than that of other crop straws in Wuhu City. [ABSTRACT FROM AUTHOR]

Applying biochar to soil has been proposed as a strategy to enhance soil quality and crop productivity. Four treatments were undertaken, including no amendment of biochar and straw addition (CK), original straw return only (SR), biochar return only (BR), and straw return with biochar addition (SB). The results showed that compared with the CK treatment, SR, BR and SB significantly increased soil bacterial community diversity, and the contents of soil organic matter (SOM), soil total nitrogen (TN), soil total phosphorus (TP), soil available phosphorus (AP), soil available potassium (AK), soil total potassium (TK) and soil cation exchange capacity (CEC) could be significantly increased by applying straw returning and biochar. Based on NMDS analysis at the OTU level for the soil bacterial community compositions, SB clearly separated from CK, SR and BR. The results of RDA for bacteria showed that TP, TN, TK, SOM, CEC and AK were the main factors affecting the composition of bacterial communities, and simple plot of BR and CK had highly significant effects with TN. Compared with CK and SR co-occurrence networks, BR and SB form a more complex co-occurrence network structure. [ABSTRACT FROM AUTHOR]

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【Objective】The research was performed to investigate the effects of planting year (Y) and tillage mode (T) on soil improvement and maize yield in thin-layer black soil in the southern part of the Songliao Plain.【Method】Three tillage modes namely strip-tillage (ST), conventional ridge planting (CT) and no-tillage (NT) were conducted to analyze the changes in soil physical properties and yield traits through field location experiment.【Result】The results showed no significant differences were found in the thickness of soil layers (TSL) and soil water holding capacity (SWHC) of the tillage layer under treatments of ST, NT and CT in 2-year cultivation field, while the results were opposite in 4-year cultivation field, with TSL and SWHC increasing by 15.46% and 30.28% under ST compared with that of CT, whereas no difference was observed between ST and NT. For 0-20 cm depth soil, the soil penetration resistance (PR) under ST treatment increased by 57.57% and 42.86% in the 2-year and 4-year cultivation fields, compared with that under CT treatment, while decreased by 5.22% and 19.22% compared with that under NT treatment. And no significant differences were observed in soil bulk density (BD) and soil porosity (SP) between the 2-year and 4-year cultivation fields under the three treatments. For the 20-40 cm depth soil, only BD under ST treatment in 4-year cultivation field was 11.56% lower than that of CT, whereas no difference was found between ST and NT. The PR under ST in 2-year and 4-year cultivation fields were 5.22% and 19.22% lower than that of CT, respectively, while SP increased by 11.8% and 15.92%, correspondingly. Compared with treatments of CT and NT, maize yield under ST in 2-year cultivation field increased by 3.62% and 3.52%, respectively, and that in 4-year cultivation field increased by 16.08% and 9.29%, respectively. From the results of yield components, the increase in effective ear number per unit area was the main factor for the increase of maize yield under ST treatment. The analysis of the random forest model further demonstrated that the TSL and PR in plough layer were the most important factors affecting maize yield with 2-year and 4-year cultivation.【Conclusion】In conclusion, ST is beneficial for the formation of better plough layer and enhancement of maize yield in thin-layer black soil farmland.

Straw returning has gradually been adopted as an effective approach to address the serious degradation of farmland. However, the carbon/nitrogen (C/N) ratio of rice straw is generally too high for microorganisms to decompose the organic materials and release nutrients, which may minimize the benefits of straw returning to the agricultural production system. This study aimed to investigate the effects of straw returning on rice production and propose optimum nitrogen (N) management for early rice production under a straw returning system. The total N fertilizer that was evaluated was 165 kg N ha-1, urea (46% N), applied in different proportions in three stages of rice cultivation: basal, tillering, and panicle. Using no straw returning with the N fertilizer ratio of basal:tillering:panicle = 5:2:3 treatment (T1) as the control, four different N fertilizer ratios of basal:tillering:panicle, including 5:2:3 (T2), 5:2:2 (T3), 5:4:1 (T4), and 5:5:0 (T5) were set under straw returning. The return of straw decreased the available N in the soil at the tillering stage, and impeded root growth and the crop canopy from establishing, which decreased the effective panicles by 10.1% compared with that of T1, limiting the increases in rice grain yield. Increasing the N fertilizer ratio 10–20% (T3 and T4) at the tillering stage effectively increased the content of soil ammonium and nitrate nitrogen, improved the root growth, and increased the root activities by 16.0–40.5% at the tillering stage. As a result, the effective panicle number increased by 5.1–16.2%. Among these, T4 treatment maximized the benefits of straw returning the most. Additionally, increasing the N fertilizer ratio at the tillering stage increased the shoot uptake across the early rice growing season and synchronized crop N uptake with the accumulation of carbon assimilates, which enhanced the crop growth rate and increased the rice yield by 13.5–25.1%. It is concluded that increasing the N fertilizer ratio by 20% at the tillering stage is a promising strategy to increase the availability of N in the phases of high demand for this nutrient.

Straw returning may stimulate soil microbial activity, thereby influencing microbial-mediated soil nitrification, which can lead to nitrate leaching and nitrogen (N) loss. However, its effects under long-term nitrogen fertilization remain unclear. At an experimental station with 34 years of fertilizer application (0, 135, and 270 kg ha−1 N), we investigated how nitrogen fertilization and straw returning affected the soil potential nitrification rate (PNR) and ammonia-oxidizing microorganisms (AOM). Our results suggest that N fertilization concurrently inhibits soil PNR, but this inhibition can be alleviated by straw returning, particularly with low nitrogen fertilization (p < 0.05). Long-term N fertilization significantly decreased the abundance of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), and complete ammonia-oxidizing bacteria cladeB (CAOB-cladeB). Straw returning increased AOA abundance and diversity, especially with low or no fertilization (p < 0.05). Furthermore, the partial least squares path model demonstrated that AOA abundance affected soil PNR by altering the AOA community. According to random forest analysis, soil pH and AOA beta diversity were the primary factors affecting soil PNR (explaining 10.76% and 10.03% of the variation, respectively). Overall, our findings highlight the importance of straw returning and AOA in soil nitrification under long-term nitrogen fertilization, emphasizing the need to consider these interactions for sustainable agriculture.

Straw returning has been shown to improve farmland soil, increase crop yield, and reduce global warming. This study investigated the models of six rice straw-returning techniques based on the life cycle assessment method. Compared to the direct modes, the indirect ones showed a greater environmental impact; up to 20.56 times in acidification and emission potentials. There was no significant difference in climate change among the six types. Except for the burning effect, all other modes showed improvement in soil fertility; phosphorus and organic matter content increased by 66.66% and 30.85%, respectively, microbial biomass carbon content doubled (105%), the four organic carbon components increased by >50%, crop morbidity was reduced, and diversity of soil fungus was improved. Feeding, as an indirect method for enhancing soil fertility and economic benefits, is set to emerge as a leading practice in China’s straw management. However, straw-returning technology is limited by cost, greenhouse gases, and increased risk of diseases and pests. There is an urgent need for further improvement and development of carbon sequestration and emission reduction in China’s agriculture.

Straw return is a crucial method for utilizing agricultural waste as a resource. Against the backdrop of increasing straw production in China, most scholars focus only on the behavioral decision of whether farmers choose to transfer land. However, few studies have touched on the specific content of the land transfer contract and its impact on farmers’ behavior. This paper innovatively starts from the perspective of land transfer contracts to explore the impact of land transfer contracts on straw return in terms of standardization, stability, and profitability and to make theoretical contributions to the rational use of straw and the protection of arable land resources. Using data from the 2020 China Rural Revitalization Survey (CRRS) database, this study empirically analyzed the effects of different elements of land transfer contracts on straw returns to the field. The results show that: (1) Written transfer contracts are more effective than verbal contracts in encouraging farmers to adopt the straw return behavior. (2) Fixed-term contracts are more stable and can effectively promote farmers’ adoption of straw return technology. (3) The remunerative transfer method is more profitable and can effectively encourage farmers to adopt straw return technology compared to the non-remunerative transfer method. (4) Farmers in mountainous areas or with smaller areas of farmland have a lower probability of adopting straw return technology. Therefore, the important role of remunerative, fixed-term, written land transfer contracts in the process of straw return should be emphasized, and the adoption rate of straw return should be increased through differentiated policy guidance and comprehensively promoting the sustainable development of agriculture.