Search Results (387)

Straw return is essential for improving soil fertility, recycling organic matter, and sustaining productivity in rice–wheat systems. This study focuses on the conceptual design and systematic analysis of the spatial and temporal variability of straw return methods and their classification. We proposed and analyzed 36 technical models for straw return by integrating spatial distribution (depth and horizontal placement) with temporal variability (decomposition period managed through mulching or decomposers). The models of straw return were categorized into five classes: mixed burial, even spreading, strip mulching, deep burial, and ditch burial. Field experiments were conducted in Babaiqiao Town, Nanjing, China, using clay loam soils typical of intensive rice–wheat rotation. Soil properties (bulk density, porosity, and moisture content) and straw characteristics (length and density) were evaluated to determine their influence on decomposition efficiency and nutrient release. Results showed that shallow incorporation (0–5 cm) accelerated straw breakdown and microbial activity, while deeper incorporation (15–20 cm) enhanced long-term organic matter accumulation. Temporal control using mulching films and decomposer agents further improved moisture retention, aeration, and nutrient availability. For the rice–wheat system study area, four typical straw return modes were selected based on spatial distribution and soil physical parameters: straw even spreading, rotary plowing, conventional tillage with mulching, and straw plowing with burying. This study added to the growing body of literature on straw return by providing a systematic analysis of the parameters influencing straw decomposition and the incorporation. The results have significant implications for sustainable agricultural practices, offering practical recommendations for optimizing straw return strategies to improve soil health. Full article

As a major agricultural country, China is also one of the world’s most abundant sources of crop straw, with production expected to reach 900 million tons by 2025. As an agricultural by-product, straw has been widely regarded as a potential renewable resource. It is rich in organic matter and essential nutrients such as nitrogen (N), phosphorus (P), and potassium (K), playing a critical role in global carbon and nitrogen cycles, agricultural productivity, and green environmental development. The efficient and rational utilization of straw can not only meet the resource demands supporting economic growth but also contribute to environmental protection and sustainable social development in China. By closely integrating comprehensive straw utilization with the annual key tasks of agriculture, rural areas, and farmers, the focus remains on prioritizing agricultural applications while adopting diversified measures. The efforts aim to improve straw utilization methods, strengthen technological support, explore replicable and sustainable industrial development models, and establish efficient utilization mechanisms to enhance the quality of agricultural straw use. To fully leverage the agricultural potential of straw, numerous technologies and equipment for straw utilization in agriculture have been developed in recent years, including straw harvesting and collecting equipment, straw crushing and returning-to-field equipment, full-straw seeding anti-clogging technology, combined straw and green manure returning-to-field equipment, and specialized straw seedling-raising equipment. Nevertheless, many challenges remain to be addressed, including bridging the equipment gap in mechanized processing, overcoming technical bottlenecks in resource conversion, and filling the lack of agronomy-adapted technologies. Therefore, this paper aims to provide a comprehensive and critical analysis of present straw utilization technology and equipment in agriculture, discussing their potential benefits, limitations, and challenges, as well as future prospects and directions. This study provides insights from the perspective of key technologies and equipment to strengthen technological research, enhance straw’s agricultural potential, and explore green circular economy models in agriculture. By leveraging innovation in science and technology, it aims to ensure food security and improve grain production capacity. Full article

This study developed an innovative model integrating straw subsoil deep burial (SD) and mixing plow to mitigate albic soil’s physical and chemical constraints and enhance crop yield. A field experiment with four treatments, including conventional tillage (CT), straw mulching (SM), straw subsoil deep burial (SD), and straw burning (SR), was conducted to assess impacts on soil enzyme activity, nutrient dynamics, crop yield, and soil physical properties. Results showed that SD treatment significantly improved albic soil properties compared to conventional tillage: catalase activity in the albic horizon decreased by 13.51%, reducing peroxide toxicity. In the albic horizon, alkaline hydrolysis nitrogen, total nitrogen, available phosphorus, total phosphorus, available potassium, total potassium, and organic matter increased by 29.98%, 58.70%, 36.86%, 20.46%, 5.00%, 21.70%, and 40.46%, respectively. Correspondingly, maize and soybean yield under SD reached 8686.6 kg/ha and 2245.3 kg/ha, increasing by 15.39% and 19.94% compared to CT, respectively. Additionally, SD treatment improved physical properties of the albic horizon: soil hardness reduced by 43.56%, with enhanced water-holding capacity, permeability coefficient, porosity, and hydraulic conductivity. Its findings not only boost agronomic productivity by improving crop yields but also support environmental sustainability by enhancing soil fertility, which is of great significance for ensuring food security. Full article

Low productivity in albic soils often results in excessive nitrogen input, while straw return further increases nitrogen accumulation through decomposition. To address this issue, a three-year field experiment was conducted in albic soils of high, medium, and low fertility. Two nitrogen management strategies were assessed: nitrogen addition and reduction. Addition treatments included conventional nitrogen application rate alone (N), straw return (8250 kg ha⁻¹) with conventional nitrogen application rate (SN), and straw return with increased nitrogen (SN₊). Reduction treatments comprised SN and straw return with 10%, 20%, and 30% reduced nitrogen (SN_0.9, SN_0.8, and SN_0.7). Soil physical properties, nutrient content, and rice yield were evaluated. Results showed that SN_0.9 exhibited advantages in high-fertility albic soils, as it increased rice yield and improved some soil quality while reducing the nitrogen input by 10%. However, yield under SN_0.9 declined progressively over the three years, indicating limitations of long-term application. SN performed better than both N and SN₊ in medium- and low-fertility albic soils, offering better yield and soil quality improvements. However, nitrogen overaccumulation risk under continuous application should not be overlooked. These findings highlight that fertility-based nitrogen adjustment combined with straw return can simultaneously improve rice productivity and soil quality while reducing nitrogen input in albic soils. Full article

Returning crop residues to soil is fundamental to sustainable agriculture, yet its adoption in cold-climate regions is hampered by an agronomic paradox: surface mulching conserves water but suppresses the spring soil temperatures required for crop establishment. In the present study, through a nine-year field experiment in a Mollisol under continuous maize cultivation, it was demonstrated that the method of maize straw incorporation, not merely its rate, is the decisive factor in resolving this conflict. While surface mulching maximized water conservation, it induced severe soil cooling and showed minimal gains in soil fertility. In contrast, incorporation via rotary tillage or deep plowing mitigated this cooling effect and proved superior for nutrient cycling. Among all strategies, rotary tillage of 50% residue (ROT-50) delivered the most balanced performance: it achieved the highest total nitrogen, substantially increased soil microbial biomass, and maintained one of the highest levels of Shannon diversity among incorporation treatments. These biogeochemical enhancements were driven by a fundamental, method-induced shift in the bacterial community from an oligotrophic to a copiotrophic structure. These findings shift the paradigm from a focus on residue quantity to one on incorporation method, providing a robust framework for reconciling crop productivity with long-term soil health in temperate agroecosystems. Full article

To analyze the impact of intercropping, maize straw returning, plastic mulching, and different configurations on potato quality in southwest China, a three-factor split-plot field experiment was designed to investigate the effects of crop management practices on the starch physicochemical properties and textural properties for two potato cultivars (Mira and Huayu-5). Results indicated that intercropping, maize straw returning, and plastic mulching reduced tuber dry matter, total starch, and amylose content, thereby decreasing the hardness of steamed tubers. Plastic mulching and maize straw returning increased starch granule size, promoted thermal properties, improved pasting properties, and increased adhesiveness and cohesiveness. The potato/maize relay intercropping increased the thermal properties, pasting viscosities, adhesiveness, and cohesiveness, with stronger effects observed in Mira compared to Huayu-5. The combination of intercropping with plastic film mulching and straw returning reduces tuber hardness while enhancing tuber adhesiveness and cohesiveness. Full article

Organic amendments, such as straw, biochar, and animal manure, have been demonstrated to enhance soil phosphorus (P) availability effectively; however, the long-term impacts and underlying mechanisms require further study. Based on a long-term field experiment, this research systematically analyzed the effects of biochar (BIO), biochar-based fertilizer (BF), straw-returning (CS), and pig manure compost (PMC) on soil phosphorus transformation and crop phosphorus uptake. Results showed that biochar significantly boosted soil available phosphorus (AP) by releasing soluble phosphorus, raising soil pH, reducing phosphorus fixation by iron and aluminum oxides, and enhancing soil cation exchange capacity (CEC) to promote phosphorus dissolution and transformation. Notably, biochar increased the proportion of NaOH-P, facilitating phosphorus accumulation in peanut grains and improving the phosphorus harvest index and utilization efficiency. Straw-returning primarily elevated soil AP by promoting organic phosphorus mineralization and inorganic phosphorus release; however, its acidification of the soil impaired phosphorus translocation to grains, resulting in lower phosphorus-use efficiency compared to biochar. Pig manure compost reduced soil phosphorus fixation and increased soil total organic carbon (TOC), thereby boosting phosphorus transformation. Despite enhancing phosphorus dry-matter production in plants, most phosphorus remained in stems and leaves, with limited translocation to grains, leading to lower phosphorus-use efficiency than biochar. In conclusion, biochar was most effective in enhancing soil phosphorus availability and crop phosphorus-use efficiency, highlighting its potential in sustainable soil fertility management and optimized crop production. Full article

Straw return is widely adopted to promote agricultural sustainability, but it can also increase cadmium (Cd) bioavailability in contaminated paddy soils, potentially leading to higher Cd accumulation in rice grains. Although numerous studies have investigated straw incorporation, the specific differences between early- and late-season straw return regarding Cd dynamics within double-cropping rice systems remain inadequately characterized. To address this knowledge gap, we conducted a two-year field experiment comparing early-rice (ER) and late-rice (LR) straw return, complemented by controlled pot experiments simulating ER (ER-S, ER-CK; July–September 2023) and LR (LR-S, LR-CK; December 2022–March 2023) straw incorporation. The results revealed that the Total-Cd exhibited an upward trend following both ER and LR straw incorporation. The ER treatment caused a rapid yet short-lived increase in CaCl₂-extractable Cd (CaCl₂-Cd) concentration, peaking around 60 days following straw return and exhibiting a 28.83% increase compared to the LR treatment. In contrast, the LR treatment induced a slower but more prolonged Cd release, with CaCl₂-Cd concentration peaking around 210 days and exhibiting a 34.89% increase relative to the ER treatment. Additionally, at the late-rice stage, grain Cd concentration in the ER treatment increased by 23.64% relative to the LR treatment. In the subsequent year, grain Cd concentrations in the LR treatment increased significantly by 32.12% to 45.08% compared to the ER treatment for both early- and late-rice crops. These differences were attributed to variations in straw decomposition rates, soil pH, and redox potential between warm, aerobic summer–autumn conditions and cooler, anaerobic winter–spring conditions. This suggests that returning late-rice straw constitutes an elevated hazard to soil health and rice safety compared to early-rice straw return. Full article

An appropriate drip irrigation amount and the straw return method are important ways to save water and achieve efficient maize production in semi-arid areas. A 2-year controlled field plot experiment was performed with two factors: straw return (straw removal, straw mulching) and differing drip irrigation amounts (200, 350, and 500 mm). Changes in growth, development, photosynthesis, yield, the components, and the water-use characteristics of maize under the intercropping conditions of drip irrigation amount and straw return were studied. The results showed that an increase in drip irrigation favored an increase in the net photosynthetic rate (P_n), stomatal conductance (G_s), and intercellular carbon dioxide concentration (C_i) of maize, and promoted an increase in maize plant height and leaf area index, which resulted in the accumulation of more dry matter and increased the maize yield. Compared with straw removal, straw mulching maintained a higher photosynthetic capacity at the later stages of maize growth and development under irrigations of 200 and 350 mm; the average increase in P_n over two years ranged from 4.06 to 19.19%; and good plant growth was maintained, thereby leading to the accumulation of more dry matter, with the average increase over two years ranging from 0.51 to 27.22%. Straw mulching also significantly improved water-use efficiency (WUE) at 350 mm of irrigation, with the average increase in yield over two years ranging from 4.58 to 4.83%. Overall, straw mulching had a positive impact on maize when irrigation was low, and when it was high, straw mulching did not adversely affect maize. Therefore, irrigation combined with straw mulching technology may be used to improve maize yield and WUE in semi-arid areas of Jilin Province. Full article

Soil organic carbon (SOC) represents a crucial factor in agricultural production, and its accumulation is influenced by soil microbial community and microbial metabolism. Straw returning combined with decomposing agents is recognized practice to enhance SOC. On the other hand, the impacts of controlled-release nitrogen fertilizer (CR) on the function of the decomposing agent in degrading straw are underexplored. In this study, an incubation experiment with ¹³C labeled straw in three nitrogen fertilizer treatments (CK, no nitrogen applied; UR, urea applied; CR, controlled-release fertilizer applied) was carried out to elucidate how CR regulates the straw decomposition agent and bacterial community to influence the SOC sequestration, based on field experiments. And we examined the changes in soil organic carbon and the stability of the bacterial networks by combining co-occurrence networks and a structural equation model. In the incubation experiment, the results demonstrated that CR increased the relative abundance of straw decomposition agent and straw-derived SOC (SO¹³C). Additionally, CR enhanced the stability of soil bacterial networks, compared with UR, by strengthening the interactions within the soil bacterial community. Pearson correlations confirmed that straw decomposition agent was positively associated with SO¹³C. Moreover, the straw decomposition agent was positively correlated with the activities of the nitrogen-cycling enzyme (urease, N-acetyl-β-glucosaminidase) and carbon-degrading enzyme (β-1,4-glucosidase, cellulase). Furthermore, structural equation modeling indicated that soil inorganic nitrogen played the most direct role in changes in the straw decomposition agent and then indirectly stimulated the activity of cellulase, ultimately increasing straw-derived carbon in the soil. This study elaborates the mechanism of straw returning combined with straw decomposition agent and controlled-release fertilizers to enhance the SOC of coastal saline–alkali soil from the perspective of underground biology. Collectively, the results of this research might improve the management of straw returning and sustainable utilization of fertility in saline–alkali soil. It provides a new perspective on fertilization for increasing soil carbon sequestration in future farmland ecosystems. Full article

Combining straw return with nitrogen fertilizer application is an effective strategy to enhance farmland productivity, improve soil structure, and mitigate climate change. Although straw return practices are widely recommended in agricultural ecosystems targeting sustainable agriculture, few studies have investigated the combined effects of consecutive years of straw return and nitrogen-fertilizer interactions on rice yield, nitrogen use, and lodging resistance, as well as the potential interactions among these variables. To investigate the effects of consecutive years of rice straw return and nitrogen fertilizer inputs on rice growth, a straw return experiment was conducted in 2021–2022 in Northeast China. The test crop was rice (cv. Jinongda No. 667), with four nitrogen fertilizer levels: 0 kg/ha (N0), 125 kg/ha (N1), 150 kg/ha (N2), and 175 kg/ha (N3). Five straw-return treatments were applied: no straw (S0), straw return to the field for one year (S1), continuous straw return to the field for two years (S2), continuous straw return to the field for three years (S3), and continuous straw return to the field for four years (S4). Results indicated that under the same straw return year, the N3 yield, nitrogen accumulation, nitrogen use efficiency, and apparent utilization were the highest. Under the same nitrogen treatment condition, S1 significantly reduced yield, nitrogen accumulation, nitrogen use efficiency, apparent nitrogen utilization, and lodging index compared to S0. However, under N3 conditions, S3 did not significantly differ from S0. Both S3 and N3 enhanced nitrogen uptake, translocation, and accumulation in rice. Their significant interactive effect increased yield while simultaneously enhancing the lodging resistance and stem strength. The study findings highlighted the effects of years of straw return and nitrogen fertilizer application on crop yield and resistance traits. They further demonstrated that the combination of straw return and optimized nitrogen fertilizer inputs could improve resource utilization and result in a high-yielding and efficient crop population. Full article

Aiming at the problems of intensified soil compaction under the conditions of no-tillage operations and machine blockage caused by large-scale straw returning to the field, an operation mode of “straw strip collecting-strip subsoiling” was proposed, and a Monomer Profiling Strip Tillage Machine (MPSTM) with Straw-Strip-Collecting and Subsoiling Functions was designed to achieve anti-blocking operation and three-dimensional soil compaction reduction. The principle and mechanism parameters of monomer profiling in strip tillage are analyzed, and the effective profiling conditions are clarified. It is determined that the deflection angle, inclination angle, and installation spacing have a key influence on the straw clearance effect. The theory of soil failure and soil compaction reduction under the operation of the subsoiling and strip tillage mechanism is studied, and a combination of a medium-sized Subsoiler shovel handle and a 150 mm double-wing shovel is adopted. Using the EDEM discrete element method, taking the spatial parameters of the stubble clean disc (SCD) as the test factors and the straw removal rate (SRR) as the test indicator, a quadratic orthogonal rotation test is conducted to clarify the influence of each parameter on the straw clearance. The optimal SCD spatial parameters were determined as a deflection angle of 16.5°, an inclination angle of 25°, and an installation spacing of 100 mm, achieving a maximum SRR of 95.34%. Field test results demonstrated stable machine operation. Post-operation measurements yielded the following results: the width of the straw-cleaning band (WSCB) in the sowing strip is 193.7 mm; the overall straw removal rate (OSRR) is 84.82%, which is basically consistent with the simulation results; the subsoiling depth (SD) is 271.7 mm; the subsoiling depth stability (SDS) is 91.85%; the soil fragmentation rate (SFR) is 81.19%; and the reduction of soil compaction in the 0–10, 10–20, and 20–30 cm soil layer is 50.08%, 21.78%, and 40.83%, respectively. These results confirm that the machine effectively cleaned straw within the seeding band and reduced soil compaction, meeting the agronomic and technical requirements for strip tillage. Full article

This study aimed to develop an effective method to overcome the challenge of straw return in cold-region soil. We systematically investigated the synergistic mechanism of montmorillonite (MMT) and composite amino acid (CAA) on straw humification and carbon sequestration through a low-temperature litterbag field experiment. The results indicate that the combined treatment (MMT-CAA) significantly increased the decomposition rate of straw by 42.1% compared to the control (CK), with MMT showing particular efficacy in lignin degradation (28.3% reduction), while the CAA preferentially decomposed cellulose (19.7% reduction). An FTIR analysis of the decomposition products confirmed these findings. Water-soluble organic carbon (WEOC) and its three-dimensional fluorescence spectra exhibited a 25.0% increase in MMT-CAA and enhanced aromaticity of humic acid-like substances. Humic substances and their ¹³C-NMR revealed that MMT-CAA enhanced humic acid formation and molecular stability by 31.4% (with a 47.8% increase in aromaticity). A further redundancy analysis and symbiotic network of microorganisms demonstrated that MMT-CAA increased the abundance of lignocellulose-degrading phyla (Actinomycetes and Stramenomycetes) and the formation of a complex co-degradation network. Field corn planting trials indicated that MMT-CAA increased plant height by 55.1%, stem thickness by 58.7%, leaf area by 70.2%, and the SPAD value by 41.1%. Additionally, MMT significantly reduced CO₂ and N₂O emission fluxes by 35.6% and 15.8%, respectively, while MMT-CAA increased CH₄ uptake fluxes by 13.4%. This study presents an innovative strategy, providing mechanistic insights and practical solutions to synergistically address the challenges of slow straw decomposition and carbon loss in cold regions. Full article

The yield of corn straw is huge, and returning straw to the field is an efficient utilization measure. The challenge in this approach is how to efficiently degrade the straw returned to the field. The study of efficient straw-degrading bacteria and their application conditions is an important approach. Therefore, after enrichment, separation, screening, and strain identification, three strains (X−2, X−4, and X−6) of highly efficient cellulose-degrading bacteria were obtained, namely Pseudomonas aeruginosa PA14, Brevibacillus parabrevis M3, and Bacillus cereus PgBE247. Based on antagonistic experiment results in which the strains were observed to not be antagonistic to each other, they were combined to prepare a bacterial consortium (M−1) for straw degradation. The CMCase, FPA, and β-Gase of the M−1 consortium were 28.46 U/mL, 30.93 U/mL, and 27.94 U/mL, respectively, higher than the values for single bacteria. On the 35th day, the degradation rate of corn straw by M−1 reached 79.81% in liquid medium, significantly increased by 72.06% (p < 0.01) compared to the sterile control (CK), and was significantly higher than single bacteria (p < 0.05). The straw degradation rate of M−1 was the highest at 69.69% in the simulated straw return, significantly increased by 59.84% compared to CK (p < 0.05), and increased by 18.32%, 11.59%, and 14.92% compared to the straw degradation rates of X−2, X−4, and X−6, respectively. The response surface condition optimization verification results showed that the straw degradation rate was 72.15 ± 1.21% when the amount of bacterial suspension was 25%, corn straw dosage was 9 g, initial pH was 7, and reaction temperature was 30 °C. Overall, this study revealed a new bacterial consortium for corn straw decomposition and optimized the conditions for its return to the field, providing a theoretical basis for subsequent studies. Full article

Straw return directly increases carbon inputs, enhancing soil organic carbon (SOC) stocks. However, long-term straw return leads to carbon saturation in the topsoil (0–20 cm). While most studies focus on the topsoil, the effects of long-term straw return on deep soil (100–200 cm) carbon sequestration remain poorly understood. This study investigated carbon dynamics in an arid region by analyzing 0–200 cm soil profiles under different straw return treatments: control (uncultivated) and cotton straw return for 5 (SR5), 10 (SR10), and 20 years (SR20). Straw return significantly improved soil properties by reducing electrical conductivity (EC), increasing nutrient availability, and enhancing bacterial activity. SR20 resulted in the most pronounced SOC increase (18.6–252.7%) across the entire profile and significantly enhanced soil inorganic carbon (SIC) (27.7–52.7%) in deep layers. In contrast, SOC in the topsoil (0–20 cm) increased initially but plateaued after 5–10 years. Principal component and random forest analyses showed that SOC sequestration was primarily driven by sucrase, urease, available phosphorus, dissolved organic carbon (DOC), microbial diversity indices, and available calcium (p < 0.05), while SIC dynamics were significantly influenced by sucrase, urease, DOC, CO₂ emissions, available calcium, and EC (p < 0.05). These findings underscore the importance of exploring subsoil carbon sequestration mechanisms in arid ecosystems. Full article