Search Results (283)

Conservation tillage methods, including straw return (SR) and no tillage (NT), are widely used to improve the soil organic carbon (SOC) content and crop yield. However, applying SR or NT separately has become a common practice for farmers producing different crops or those in different regions. Evaluating the effects of SR or NT on the SOC content, carbon emissions, and crop yield are important for guiding the correct application of conservation tillage and promoting sustainable agricultural development. Therefore, we conducted a meta-analysis based on 1014 sets of data obtained in China to assess the effects of SR and NT on the SOC content, carbon emissions, and crop yield. Compared with no straw return, SR increased the SOC content and crop yield by 10% and 8.6%, respectively, but with no significant impact on carbon emissions. Compared with conventional tillage, NT increased the SOC content by 2.9% and reduced the carbon emissions and crop yield by 18% and 3.9%, respectively. We also found that SR combined with NT had an additive effect, where the combination improved SOC more than applying SR or NT alone. If applying SR or NT alone, the specific climatic conditions, soil characteristics, and field management strategies need to be considered to maximize SOC. In particular, SR should be used in limited hydrothermal conditions (low temperature or low precipitation) and areas where rice–wheat rotation is implemented. NT can be used under any climate conditions, but it can effectively increase the SOC content in continuous wheat cropping areas. Full article

Straw returning enhances soil fertility and increases corn yield, but the impact on soil fertility varies with different incorporation methods. To explore the optimal straw-returning method, this study, based on a long-term field experiment, investigated the following different corn-straw-returning methods: deep plowing and straw returning (B), rotary tillage and straw returning (RT), crushing and mixing straw returning (TM), pulverized cover straw returning (C), high-stubble-retention straw returning (LHS), strip cover (S), and flat no-tillage without straw returning (CK). High-throughput sequencing technology was employed to analyze the soil bacterial community composition and structural changes under different straw-returning methods. The study further explored the relationships between the soil bacterial community and nutrient content. The results indicated that different straw-returning methods altered the composition and structure of the soil bacterial community. The TM treatment significantly increased the richness and diversity of the soil bacterial communities. Shredding and covering (C and TM) effectively improved the soil nutrient content and bacterial community structure. In the C treatment, the abundance of Blastococcus, Nocardioides, and Microvirga increased the most, by 241.02%, 77.79%, and 355.08%, respectively, compared with CK. In the TM treatment, Pseudarthrobacter showed the highest abundance, increasing by 343.30%. The genes involved in soil carbon hydrolysis (pulA), nitrification (hao), organic nitrogen degradation and synthesis (gudB), and the nitrogen limitation response (glnR) significantly decreased by 56.21%, 78.75%, 66.46%, and 67.40%, respectively, in the C treatment. The genes involved in soil carbon hydrolysis (IMA), carbon fixation (pccB-A), methane metabolism (moxF), nitrate reduction in soil (nirD), organic nitrogen degradation and synthesis (gdh, ureAB, ureE), and phosphate absorption (glpT) significantly increased by 93.37%, 92.68%, 95.00%, 23.42%, 35.40%, 114.21%, 59.14%, and 75.86%, respectively, in the C treatment. The nitrate reduction gene (nrfA) significantly increased by 80.27% in the TM treatment. Therefore, we concluded that straw primarily stimulates the activity of bacterial communities and regulates the bacterial community by changing the relative abundance of the soil microorganisms and functional genes, thereby improving the soil nutrient content. This study considered pulverized cover straw returning and crushing and mixing straw returning to be the most reasonable methods. Full article

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

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

Long-term intensive tillage has led to soil environment degradation, reduced fertility, and difficulty in increasing crop yield in the Mollisol region of northeast China. In order to improve the soil’shydrothermal environment and nutrient content, we conducted field experiments to investigate the effects of different tillage practices and the amount of straw mulching on soil hydrothermal environment and nutrient content in agricultural soils in seasonal permafrost areas. Four treatments were established: no-tillage without straw (NT0), no-tillage with half straw mulching (NT1), no-tillage with full straw mulching (NT2), and rotary tillage without straw (CK) as the control treatment. The results indicate that the no-tillage with straw mulching treatments increased the soil ammonium nitrogen (NH₄⁺-N) and nitrate nitrogen (NO₃⁻-N) content, accompanied by improvements in the soil’s water content and regulation of soil temperature changes, as compared to the CK treatment. Specifically, the soil’s NH₄⁺-N and NO₃⁻-N content in the NT2 treatment were significantly increased by 25.65% and 38.81%, respectively. Our study indicates that NT2 treatment is the most suitable tillage practice and straw-returning method in the Mollisol region of northeast China. This study can provide a theoretical basis and reference for the efficient utilization of farmland soil in seasonal permafrost areas. Full article

Planting salt-tolerant plants is an efficient method of biological improvement for saline–alkali land. However, few studies have examined the soil improvement effects of the rotation of the green manure plant sesbania and the grain crop sorghum. Thus, we planted sesbania in native soil on heavily saline–alkaline coastal land and subsequently planted sorghum after returning the sesbania straw to the soil. The effect of this sesbania–sorghum rotation on soil improvement was clarified by comparing indicators of soil quality before and after sesbania and sorghum were planted, such as the soil structure, water infiltration, soil salt content, and soil microbial changes. The results showed that the soil bulk density of the plow layer (0–40 cm) after crop harvest decreased by 9.63% compared with that of bare land, and the soil porosity increased by 5.67%. The cumulative infiltration, initial infiltration rate, and stable infiltration rate of saline soil were 3.6 times, 2.8 times, and 3.3 times higher than those of bare land, respectively. With the growth of sesbania and sorghum, the soil salt content in the plow layer of the cultivated land decreased by 37.73%, while that of bare land decreased by 9.1%. A further analysis of desalination showed that the total desalination amount in the plow layer was 15.58 t/ha, of which 5% was due to plant absorption, and the rest was from salt leaching. Moreover, sesbania–sorghum rotation increased the soil organic matter content in the plow layer from 69.1 t/ha to 73.8 t/ha. The quantities of some microorganisms that are mainly found in coastal saline soil decreased, while those of some common soil microorganisms increased, reflecting an improvement in the soil quality. The above results prove that sesbania–sorghum rotation had a significant effect on soil improvement and salt reduction, which is of great significance for the further utilization of saline–alkali land to enhance crop productivity. Full article

Mulching plays a pivotal role in modern sustainable agriculture, offering a versatile solution to enhance soil quality, improve soil health, conserve resources, and optimize crop performance. This study examined the effects of various mulching materials on soil properties, seasonal variations in soil and environmental variables, and yam production in a tropical environment, with a focus on sustainable agricultural practice. We applied a range of mulch treatments, including black polythene, weedmat, sugarcane straw, organic compost, cowpea-live, juncao grass, sawdust, and a control with no mulch. The results indicated that the organic compost mulch significantly increased soil pH and soil electrical conductivity (EC). The control treatment resulted in the highest soil moisture content, while the highest soil temperature were recorded for the black polythene and organic compost mulch treatments. The organic compost mulch enhanced the soil organic carbon (SOC) content, soil available phosphorus (SAP) content, and soil exchangeable calcium (SECa) content. The weedmat mulch showed the highest soil exchangeable potassium (SEK) content, and the control treatment exhibited the highest soil exchangeable magnesium (SEMg) and sodium (SENa) content. In terms of micronutrients, the sawdust mulch and black polythene mulch significantly increased soil exchangeable iron (SEFe) and copper (SECu) levels, respectively. Notable seasonal variations in soil pH, temperature, and environmental humidity were observed during the crop period. The soil pH fluctuated from slightly acidic levels in August 2023 to neutral levels in October, and then decreased to slightly acidic levels in early 2024 before stabilizing by March 2024. The soil temperature peaked in November and dropped in January, while the environmental humidity ranged from 48.25% in December to 76.33% in February. The study demonstrated that the organic compost mulch stood out as an advantageous choice because of its capacity to enhance the soil’s properties and offer a balanced nutrient mix, making it particularly beneficial for yam cultivation. It also proved to be a reliable and balanced option to enhance soil quality with stable soil quality indices (SQIs). The weedmat mulch proved to be highly effective in enhancing yam growth and productivity. The weedmat mulch is the most profitable and cost-effective option for yam cultivation, providing the highest net returns and strong financial viability. This study emphasizes the value of choosing the right mulching materials to support soil quality, crop productivity, and economic returns in tropical settings, making strides toward more sustainable farming practices. Full article

Returning straw to the field is a crucial practice for enhancing soil quality and increasing efficient use of secondary crop products. However, maize straw has a higher carbon-to-nitrogen ratio compared to other crops. This can result in crop nitrogen loss when the straw is returned to the field. Therefore, it is crucial to explore how different methods of straw return affect maize (Zea mays L.) farmland. In this study, a field experiment was performed with three treatments (I, no straw returned, CK; II, direct straw return, SR; and III, straw returned in deep furrows, ISR) to explore the effects of the different straw return modes on soil carbon and nitrogen content and greenhouse gas emissions. The results indicated that the SR and ISR treatments increased the dissolved organic carbon (DOC) content in the topsoil (0–15 cm). Additionally, the ISR treatment boosted the contents of total nitrogen (TN), nitrate nitrogen (NO₃⁻-N), ammonium nitrogen (NH₄⁺-N), dissolved organic nitrogen (DON), and DOC in the subsurface soil (15–30 cm) compared with CK. When it comes to greenhouse gas emissions, the ISR treatment led to an increase in CO₂ emissions. However, SR and ISR reduced N₂O emissions, with ISR showing a more pronounced reduction. The ISR treatment significantly increased leaf and grain biomass compared to CK and SR. The correlation analyses showed that the yield was positively correlated with soil DOC, and soil greenhouse gas emission was correlated with soil NO₃⁻-N. The ISR technology has great potential in sequestering soil organic matter, improving soil fertility, and realizing sustainable agricultural development. Full article

The dissolution of Ca and Mg in soil and their translocation in plants from different families when using different doses of liming materials of industrial waste origin have not yet been sufficiently studied. In this study, the influence of increasing doses of ameliorants of carbonate (dolomite flour—DF) and silicate (blast furnace slag—BFS) natures on the change in acid–base properties of soddy-podzolic light loamy soil, yield, and chemical composition of plants of the families Gramíneae (spring wheat), Brassicáceae (spring rapeseed), and Leguminósae (vetch and beans) was studied in five-year pot experiments. In the five-year experiments, the ameliorant of a carbonate nature showed greater effect on soil acid–base properties than that of a silicate nature. A return to the initial state of soil pH was not established in any of the treatments. Both ameliorants showed similar effects on wheat straw biomass, but DF had a greater positive effect on wheat grain yield than BFS. Regardless of the dose of DF applied, the accumulation of Ca and Mg by the plants throughout the study period was higher than when BFS was applied. Among the studied plants, those of the family Brassicáceae were the most responsive to liming and, at the same time, showed high ecological adaptability. Differences in the effects of the two ameliorants on the soil chemical properties were more significant than differences in their effects on plant productivity. Full article

Straw return is an effective measure to increase soil sustainability. However, few studies have examined the effects of different straw return methods on soil structure, soil organic carbon content and maize yield or the potential relationships between those variables. Therefore, we developed a field orientation experiment to study the effects of different straw return methods on soil porosity, soil aggregate stability, the soil organic carbon content and maize yield. Four treatments were established: flat no-tillage with full straw mulching (FM), ridge no-tillage with full straw mulching (LM), rotary tillage with full straw incorporation (LX), and conventional tillage without straw (CK) as the control treatment. Compared with those of the CK treatment, the soil porosities (f) in the FM, LM and LX treatments significantly increased by 6.7%, 8.8% and 7.9%, respectively; the soil aggregate destruction rates (PAD) decreased by 17.3%, 34.3% and 16.9%, respectively. In addition, the FM, LM and LX treatments effectively increased the mean mass diameters (MWDs) of the soil aggregates and the soil organic carbon content. Compared with those in the CK treatment, the three-year average yields in the FM, LM and LX treatments significantly increased by 5.2%, 7.2% and 4.1%, respectively. Moreover, the f, MWD, soil organic carbon content and corn yield were positively correlated. Our study indicates that the LM treatment was most effective in improving soil structure and increasing soil organic carbon content with corn yield. Full article

Straw return has important impacts on black soil protection, food security, and environmental protection. One year of straw return (S1) reduces rice yield and increases greenhouse gas (GHG) emissions. However, the effects of successive years of straw return on rice yield, soil nutrients, and GHG emissions in the northeast rice region are still unclear. Therefore, we conducted four successive years of straw return (S4) in a positional experiment to investigate the effects of different years of straw return on rice yield, soil nutrients, and GHG emissions in the northeast rice region. The experimental treatments included the following: no straw return (S0), a year of straw return (S1), two successive years of straw return (S2), three successive years of straw return (S3), and four successive years of straw return (S4). Compared with S1, the rice yields of S2, S3, and S4 increased by 10.89%, 15.46%, and 16.98%, respectively. But only S4 increased by 4.64% compared to S0, while other treatments were lower than S0. S4 increased panicles per m² and spikelets per panicle by 9.34% and 8.93%, respectively, compared to S1. Panicles per m² decreased by 8.06% at S4 compared to S0, while spikelets per panicle increased by 13.23%. Compared with S0, the soil organic carbon, total nitrogen, NH₄⁺-N, NO₃⁻-N, available phosphorus, and available potassium of S4 increased by 11.68%, 10.15%, 24.62%, 21.38%, 12.33%, and 13.35%, respectively. Successive years of rice straw return decreased GHG intensity (GHGI). Compared with S1, the GHGI of S4, S3, and S2 decreased by 16.2%, 11.84%, and 9.36%, respectively. Thus, S4 increased rice yield and soil nutrients, reducing GHGI. Full article

Microbes may play an important role in the sugarcane leaf degradation and nutrient conversion process. Soil bacterial communities are more or less involved in material transformation and nutrient turnover. In order to make better use of the vast sugarcane leaf straw resources and reduce the overuse of chemical fertilizers in the subtropical red soil region of Guangxi, a pot experiment, with three sugarcane leaf return (SLR) amounts [full SLR (FS), 120 g/pot; half SLR (HS), 60 g/pot; and no SLR (NS)] and three fertilizer reduction (FR) levels [full fertilizer (FF), 4.50 g N/pot, 3.00 g P₂O₅/pot, and 4.50 g K₂O/pot; half fertilizer (HF), 2.25 g N/pot, 1.50 g P₂O₅/pot, and 2.25 g K₂O/pot; and no fertilizer (NF)], was conducted to assess the interactions of different SLR amounts and chemical FR levels in the soil bacterial network and the relationship between the soil properties and bacterial network by using Illumina Miseq high-throughput sequencing technology. According to the results of the soil bacterial community compositions and diversity, the soil bacterial network was changed during maize growth. SLR exerted a stronger effect on soil bacterial function than FR. Returning the sugarcane leaf to the field increased the diversity of the soil bacteria network. The bacterial communities were consistently dominated by Acidobacteria, Actinobacteria, and Bacteroidetes across all treatments, among which Actinobacteria was the most abundant bacteria type by almost 50% at the phylum level. The analysis results of the experimental factor on maize growth showed that the effect of SLR was lower than that of FR; however, this was opposite in the soil bacterial community structure and diversity. The soil bacterial network was significantly correlated with the soil total K, available N and organic matter contents, and EC. The soil bacteria community showed different responses to SLR and FR, and the FF in combination with FS partly increased the complexity of the soil bacteria network, which can further benefit crop production and soil health in the red soil region. Full article

The intensive use of chemical fertilizers in China to maintain high crop yields has led to significant environmental degradation and destabilized crop production. Returning straw to soil presents a potential alternative to reduce chemical fertilizer requirements and enhance soil fertility. This study investigates the effects of different nitrogen (N) input levels and straw additions on crop phosphorus (P) uptake and soil P availability based on a long-term N-fertilizer trial. The treatments included no fertilizer input (CK), conventional (NPK), reduced NPK (0.75NPK), and straw-amended (SNPK) treatments. Results indicate that SNPK significantly enhances shoot P uptake and crop yields by 43.7–61.9% and 29.3–39.6%, respectively. The SNPK treatment improved rhizosphere P availability and increased the phosphorus activation coefficient (PAC) by 1.72-fold compared to NPK alone. The enhanced soil P availability under SNPK was primarily attributed to an abundance of functional microbes, leading to higher P storage in the microbial biomass P pool and its turnover. Additionally, SNPK promoted root exudate and phosphate-mobilizing microbes, enhancing P mobilization and uptake. Nitrogen fertilization primarily influenced root functional traits related to P acquisition. These findings provide valuable insights for developing effective fertilizer management strategies in maize–oilseed rape rotation systems, emphasizing the benefits of integrating straw with chemical fertilizers. Full article

With the development of commercialized planting of genetically modified crops, their ecological security risks remain a key topic of public concern. Insect-resistant genetically modified maize, Ruifeng125, which expresses a fusion Bt protein (Cry1Ab-Cry2Aj), has obtained the application safety certificate issued by the Chinese government. To determine the effects of Ruifeng125 on the diversity and dynamics of bacterial communities, the accumulation and degradation pattern of the fusion Bt protein in the rhizosphere soil of transgenic maize were detected. Results showed that the contents of Bt protein varied significantly at different developmental stages, but after straw was returned to the field, over 97% of Bt proteins were degraded quickly at the early stages (≤10 d) and then they were degraded at a relatively slow rate. In addition, the variations in bacterial community diversity in the rhizosphere soil were detected by 16S ribosomal RNA (Rrna) high-throughput sequencing technology. A total of 44 phyla, 435 families, and 842 genera were obtained by 16S rRNA sequencing, among which Proteobacteria, Actinobacia, Acidobacter Acidobacterium, and Chloroflexi were the dominant taxa. At the same developmental stage, no significant differences in soil bacterial diversity were detected between Ruifeng125 and its non-transgenic control variety. Further analysis revealed that developmental stage, rather than the transgenic event, made the greatest contribution to the changes in soil microbial diversity. This research provides important information for evaluating the impacts of Bt crops on the soil microbiome and establishes a theoretical foundation for their environmental safety assessment. Full article

Biochar application has received much attention because biochar can be used as an organic amendment. The nutrient release patterns and interactions in straw biochar produced at different temperatures are not well understood. In this study, we observed the release patterns of carbon (C), nitrogen (N), phosphorus (P), and potassium (K) and the interaction between released C, N, P, and K from straw biochar prepared from 225 to 600 °C through a 180-day degradation experiment. The results showed that the degradation rate of the two kinds of straw biochar was faster in the first 30 days at different temperatures, and that of the straw biochar prepared before 300 °C was more rapid, indicating that 300 °C is an important turning point. The rule of nutrient release in the straw biochar showed that the K release rate was the highest and most rapid and was more than 60% in the first 30 days. The nutrient release rates for the two kinds of straw biochar were in the order K > N > P > C. The release of nutrients accompanied the decomposition of the straw biochar, and there was an exponential relationship between the amount of nutrients released from straw biochar and its degradation mass. There were collaborative or similar release processes indicated by significant positive correlations between the released C and N (R² = 0.96) and P and K (R² = 0.94) in the tobacco straw biochar and an obvious correlation between the released C and N (R² = 0.76) in the rice straw biochar. These results indicated that the released C and N, P, and K in tobacco straw biochar, as well as C and N in rice straw biochar, have synergistic effects and the same degradation path. The application of straw biochar can provide a source of P and N in the short term and a source of P and C in the long term. This study suggests that returning straw biochar to the soil could appropriately reduce the input of K fertilizer in the early stage. Full article