Effects Of Straw Incorporation Research Articles

Effects of Straw Incorporation and Decomposition on Soil Preferential Flow Patterns Using the Dye-Tracer Method

Effects of Straw Incorporation and Decomposition on Soil Preferential Flow Patterns Using the Dye-Tracer Method

Effect of straw incorporation on controlling runoff and soil erosion in cropland with different land degradation degrees

AbstractStraw incorporation plays a vital role in regulating runoff and soil erosion of cropland. However, the benefits of straw incorporation to control runoff and soil erosion on croplands under different degradation degrees have not been fully clarified. This study was performed to investigate the benefits of straw incorporation to reduce runoff and soil erosion under different degradation degrees and determine its dominant influencing factors. The event runoff and soil erosion were measured from late May to late September 2022 using 16 runoff plots (9 m in length and 3.3 m in width) in the black soil region of Northeast China. The results showed that straw incorporation significantly reduced runoff and soil erosion on croplands with different degradation intensities. Compared to croplands without straw incorporation, runoff and soil erosion of straw incorporation decreased by 48. 8%, 40.0%, 30.9%, 25.5%, and 55.2%, 48.8%, 40.8%, and 36.5% for croplands of no, light, moderate, and strong degradation intensities, respectively. The roles of straw incorporation in controlling runoff and erosion decreased with rainfall intensity. Compared to light rainfall, runoff reduction ratio and erosion reduction ratio of moderate and heavy rainfalls reduced by 19.5%–61.3% and 27.5%–64.4%. The benefit of straw incorporation to control runoff and erosion was limited on strong degraded cropland or under heavy storm. Moreover, soil hydrological properties and crop growth characteristics decreased by land degradation and improved by straw incorporation, which inevitably affected runoff and soil erosion. Soil bulk density, maximum rainfall intensity of 30‐min, saturated water content, precipitation, rainfall intensity, saturated hydraulic conductivity, and total porosity were the dominant factors affecting the roles of straw incorporation in controlling runoff and erosion on degraded croplands. The results of this study are helpful to prevent land degradation or recover the functions of degraded lands in semi‐humid region.

Disentangling the impact of straw incorporation on soil microbial communities: Enhanced network complexity and ecological stochasticity

Straw incorporation is typically employed to enhance the nutrient content of soil and promote crop growth in intensive agricultural systems. Despite studies regarding the effects of straw incorporation on soil microbial communities, the underlying mechanisms of its effect on community co-occurrence interactions and assembly processes remain poorly understood. Herein, soil samples with or without straw incorporation were collected across a latitudinal gradient from north to central China. We found that straw incorporation considerably altered the structure of soil microbial community. The relative abundance of bacterial Latescibacterota and fungal Mortierellomycota were higher in straw-amended soils owing to their ability to decompose straw residues. The co-occurrence network in straw-amended soil exhibited greater complexity, including more network connectivity and keystone species, and higher average degrees and clustering coefficients compared with the control sample network. The network robustness and vulnerability indices suggested that straw incorporation increased the microbial network stability. Normalized stochastic ratios demonstrated that the stochastic process was the dominant mechanisms shaping the assembly of microbial communities in straw-amended soils. Concurrently, null model analysis revealed that straw increased the contribution of dispersal limitation to the assembly of bacterial and fungal communities. The migration rate of the microbial community, obtained from Sloan neutral community model, was relatively low in straw-amended soil at all the sample sites, potentially indicating the great importance of dispersal limitation. These findings would enhance our understanding of the ecological patterns and interactions of soil microbial communities in response to straw incorporation.

Straw incorporation and nitrogen reduction effect on the uptake and use efficiency of nitrogen as well as soil CO2 emission of relay strip intercropped soybean.

Intercropping can increase crop N uptake and reduce carbon emissions. However, the effects of straw incorporation and N reduction on N use and carbon emissions in intercropping are still unclear. We explored the mechanism of N uptake, N use efficiency, and CO2 emissions in the wheat-maize-soybean relay strip intercropping system. A two-year field experiment was conducted with two straw managements, i.e., wheat straw incorporation (SI) and straw removal (SR), and four N application levels of soybean, i.e., 60 (N60), 30 (N30), 15 (N15), and 0 kg N ha-1 (N0). We assessed soil properties, CO2 emissions, and characteristics of roots, nodules, and aboveground N uptake of intercropped soybean. Results showed that geometry mean diameter of aggregate, soil porosity, soil total N, and soil urease activity were notably greater in SI than in SR. N input reduced from N60 to N30 did not significantly affect the soil total N content and urease activity in SI. The root length, root surface area, root volume, root biomass, root bleeding intensity, and inorganic N content of bleeding sap were greater in SI than in SR. In the SI, although the root length and surface area peaked at N60, the root biomass and inorganic N content of bleeding sap were insignificant between N60 and N30. The nodule number, nodule dry weight, nodule nitrogenase activity, and nodule nitrogen fixation potential in SI were notably increased compared with SR. The nodule nitrogen fixation potential in SI notably increased with the decrease of N input at the R3 stage, but it peaked in N30 at the R5 stage. On average, the aboveground N uptake and nitrogen recovery efficiency (RE) was notably higher by 43.7% and 76.8% in SI than in SR. SI+N30 achieved the greatest aboveground N uptake and RE. The CO2 emission and accumulated CO2 emission were notably greater in SI than in SR, and the accumulated CO2 emission of SI was the lowest with N30 input. In conclusion, SI+N30 promoted N uptake and utilization efficiency with reduced CO2 emissions during the soybean cropping season. It provides a potential strategy for sustainable agricultural development in intercropping systems.

Effect of straw incorporation and nitrification inhibitor on nitrous oxide emission in three cropland soils

AbstractIntroductionNitrification inhibitors and straw incorporation are used to reduce microbial mediated nitrogen (N) losses, thereby increasing N use efficiency (NUE) in cropland soil, but their effects on nitrous oxide (N2O) emission across different soil types and the underlying molecular mechanisms remain less understood.Materials and MethodsIn this study, we investigated how nitrification inhibitor nitrapyrin and straw incorporation affected soil N balance, N2O emission, nitrifiers and denitrifiers in three cropland soils (black, fluvo‐aquic and red soils).ResultsCompared with fertilization‐only treatment (N), nitrapyrin addition increased ammonium, while it decreased nitrate concentration in all soils; however, the performance of straw incorporation was less significant. Nitrapyrin decreased N2O emission only in the fluvo‐aquic soil, while straw incorporation strongly increased N2O emission in the red soil. Terminal restriction fragment length polymorphism analysis revealed that the denitrifier community was distinct across the three soils, but not strongly structured by nitrapyrin or straw incorporation. Compared with the N treatment, straw incorporation and nitrapyrin increased nosZ gene abundance only in the black soil. Structural equational modelling further confirmed that, after accounting for different soil properties, straw incorporation significantly increased N2O emission from black and red soils, and a decrease in nosZ gene abundance was the main biological factor for increased N2O emission in red soil.ConclusionTaken together, our work provides new knowledge that the performance of nitrification inhibitor and straw incorporation on N2O emission is soil type‐dependent, and management practices should be used as per soil type to balance NUE and N2O emission.

Cereal straw incorporation and ryegrass cover crops: The path to equilibrium in soil carbon storage is short

AbstractReduced use of fossil energy by removing cereal straw for bioenergy potentially threatens soil organic carbon (SOC) storage. Straw incorporation plays a key role for SOC storage in cereal‐based cropping systems, but the use of cover crops (CCs) may compensate for straw removal. However, assessing the SOC sequestration potential of management changes requires field experiments with long continued treatments and frequent soil sampling. Based on a field experiment initiated in 1981 on a sandy loam soil at Askov Experimental Station (Denmark), we examined the effect of annual additions of spring barley straw (0, 4, 8 and 12 Mg ha−1) and undersown ryegrass CC on SOC storage in the 0‐ to 20‐cm layer. The effect of straw incorporation and CC on SOC was additive. At steady‐state conditions, the SOC stock based on equivalent soil mass (SOC stockFM) increased 3.9, 6.7 and 9.3 Mg C ha−1 after annual incorporation of 4, 8 and 12 Mg straw ha−1, respectively. The ryegrass CC increased SOC stockFM by 3.3 Mg C ha−1 and thus almost compensated for removal of 4 Mg straw ha−1. An asymptotic regression model best described the temporal changes in SOC and showed that the effect of straw incorporation and ryegrass CC on SOC sequestration peaks after 10–15 years when a new equilibrium between input and output of C is reached. Clearly, reliable assessments of SOC sequestration potentials following changes in management require field experiments with frequent soil sampling until reaching steady‐state conditions.Highlights SOC sequestration potentials of straw incorporation and CCs were assessed. The crucial issue of sequestration duration of experimental treatments is often neglected. The effect of straw and CC peaked after 10–15 years when a new equilibrium in SOC was reached. Reliable assessments require frequent soil sampling until reaching steady‐state conditions.

Responses of nitrite-oxidizing bacteria community to excessive nitrogen application and straw incorporation under intensive cultivation

ABSTRACT N fertilization and straw incorporation often disturb the soil and may affect nitrite oxidation (NO); however, the underlying mechanism remains unclear. Here, we collected soil samples through a 4-year field experiment including no N fertilization, normal N application, excess N application (EN), and EN plus straw incorporation (ES) treatments. We measured the community composition, abundance, and activity of Nitrobacter-like and Nitrospira-like nitrite-oxidizing bacteria (NOB). N application and straw incorporation significantly enhanced potential NO activity (PNO). PNO was affected by the abundance of Nitrobacter but not Nitrospira and the community compositions of both NOB. With increasing N application rate, Nitrobacter abundance increased from 1.0 to 11.8 × 104 copies g−1 dry weight soil, whereas Nitrospira abundance increased initially then subsequently decreased, ranged from 2.1 to 5.2 × 106 copies g−1 dry weight soil. Moreover, N application and straw incorporation markedly affected the NOB community composition. Soil pH and organic C were the key factors shaping the NOB community composition. Overall, N fertilization combined with straw incorporation can affect NO by altering the Nitrobacter abundance and NOB community composition. These findings expand our understanding of mechanisms underlying the effects of straw incorporation on nitrification, particularly under N enrichment.

Effects of straw incorporation and potassium fertilizer on crop yields, soil organic carbon, and active carbon in the rice–wheat system

Active soil organic carbon (SOC) fractions play a key role in agricultural soil fertility. However, the effects of potassium application and straw incorporation on SOC and active SOC fractions as well as the relationships among these factors in a rice–wheat system are less well-studied. Hence, the objective of this study was to analyse the effects of potassium fertilization and straw incorporation on SOC sequestration, active carbon fractions, and crop yields in a long-term (6 years) field experiment. Four treatments were examined: no addition of potassium fertilizer and straw (CK), straw incorporation only (SI), potassium-fertilizer application only (K), and straw incorporation plus a recommended amount of potassium fertilizer (SI + K). SOC, dissolved organic carbon (DOC), light fraction organic carbon (LFOC), microbial biomass carbon (MBC), easily oxidizable carbon (EOC), crop yields, and the carbon pool management index (CMI) were determined. After 6 years, SOC content and labile C fractions in the SI treatment increased significantly, by 7.95–25.0 % and 23.6–185 %, respectively, compared to the CK treatment. Significant and positive correlations were observed between SOC, DOC, LFOC, MBC, EOC, and the CMI (r = 0.449–0.899, P < 0.01). Among the five C fractions, LFOC, DOC, and EOC were the most sensitive indicators of changes in SOC induced by incorporating straw with or without potassium fertilizer. The highest SOC contents and labile C fractions were observed in the SI + K treatment. Rice yields increased from 8.55 and 7.59 t ha−1 in the CK plots to 9.56 and 8.54 t ha−1 with SI + K at Guangde (GD) and Jiangyan (JY) sites, respectively. Wheat yields increased from 0.53 and 5.33 t ha−1 in the CK plots to 5.86 and 6.43 t ha−1 with SI + K at GD and JY sites, respectively. Overall, based on crop yields and C storage, straw incorporation in combination with a moderate amount of potassium fertilizer appears to be the best practice for improving soil fertility and productivity in the rice-wheat cropping system.

Drip fertigation with straw incorporation significantly reduces N2O emission and N leaching while maintaining high vegetable yields in solar greenhouse production.

Approximately 1/3 of vegetables in China are produced in solar greenhouses. Most farmers use conventional irrigation with over fertilisation (CIF), thereby applying approximately 2000kgN ha-1 fertiliser over two cropping seasons per year. Here, we tested the effect of drip irrigation with reduced fertilisation (DIF) combined with straw incorporation on reducing N2O emissions and nitrogen leaching from solar greenhouse vegetable production systems. Over three consecutive tomato cropping seasons, N2O emissions and nitrogen leaching were monitored in high temporal resolution, thereby producing a unique dataset. Compared to CIF, the realised drip fertigation scheme reduces N2O emission and nitrogen leaching of nitrate and dissolved organic nitrogen by approximately a factor of 5-10 (N2O-DIF: 10.3, CIF: 47.5kgN ha-1 yr-1; N leaching-DIF: 83.6, CIF: 863kgN ha-1 yr-1). Straw incorporation in CIF, though advantageous for soil health, resulted in pollution swapping as soil N2O emissions increased while NO3- leaching losses decreased. On the contrary, no significant negative environmental N effects of straw incorporation were found for DIF. As crop productivity was not affected by straw incorporation, neither for CIF nor for DIF, our study provides a sound basis for policy advice to recommend farmers to adopt drip fertigation combined with straw application. Wide scale adoption of this technique will result in reductions of environment N losses, alleviate major soil degradation signs, including soil acidity, nutrient imbalance and deterioration of soil microbial community structure, while allowing to maintaining high yields of vegetables in solar greenhouse production systems.

Long-term straw incorporation increases rice yield stability under high fertilization level conditions in the rice–wheat system

Straw incorporation is a global common practice to improve soil fertility and rice yield. However, the effect of straw incorporation on rice yield stability is still unknown, especially under high fertilization level conditions. Here, we reported the effect of straw returning on rice yield and yield stability under high fertilization levels in the rice–wheat system over nine years. The results showed that straw incorporation did not significantly affect the average rice yield of nine years. Straw incorporation reduced the coefficient of variation of rice yield by 25.8% and increased the sustainable yield index by 8.2%. The rice yield positively correlated with mean photosynthetically active radiation (PAR) of rice growth season and the effects of straw incorporation on rice yield depended on the PAR. Straw incorporation increased the rice yield by 5.4% in the low PAR years, whereas it did not affect the rice yield in the high PAR years. Long-term straw incorporation lowered soil bulk density but improved the soil organic matter, total N, available N, available P, and available K more strongly than straw removal. Our findings suggest that straw incorporation can increase rice yield stability through improving the resistance of rice plant growth to low PAR.

Effect of straw-incorporation into farming soil layer on surface runoff under simulated rainfall

Returning crop straw into farmland is an important application and effective soil amendment method as it can increase soil organic matter to improve soil fertility and crop yield. In addition, this practice can help retain soil moisture and slow down the rainfall runoff rate, particularly on sloping farmland. This study uses laboratory experiments with a silt loam soil to examine the effects of wheat straw incorporation into cultivated farmland soil on rainfall-runoff. The experiments involved four straw incorporation rates (0 (control), 2, 4, and 8 t/ha), three rainfall intensities (80, 120 and 160 mm/h) and three slope gradients (10, 15 and 20°), carried out by a completely randomized combination design, with three repetitions. In all the experimental runs, the total rainfall amount was 100 mm per event. Our experimental results showed that the duration of runoff initiation time at straw incorporation rates of 2, 4 and 8 t/ha were increased by 1.63% to 104.93%, 6.16% to 111.67% and 15% to 141.25%, while the total runoff amounts decreased by 11.74% to 28.81%, 24.21% to 49.67% and 38.90% to 65.93%, compared with those of our control group (0 t/ha). The effects of straw incorporation on the runoff initiation delay time and runoff reduction were significant, particularly when the rainfall intensity was 120 mm/h and the slope was 10°. With increases in rainfall intensity and slope gradient, the runoff initiation time durations were decreased and the runoff rate increased. In conclusion, incorporating wheat straw into the farmland soil can delay the runoff initiation time and reduce runoff volume, to significantly increase rainwater storage into soil, thereby increasing the rainwater utilization rate and to benefit soil erosion control. This study can provide a data basis for farmland soil and water conservation research and practice.

Effect of Straw Return on Hydroxyl Radical Formation in Paddy Soil.

Straw return, as an important agricultural management measure, is receiving growing attention. Hydroxyl radical (•OH) can be produced when subsurface soil interacts with oxygen, but the effects of straw incorporation on •OH formation have rarely been evaluated. In this study, we found that straw return had a significant effect on soil properties. Soil pH and redox potential (Eh) decreased while electronic conductivity (EC) showed an increment. Dissolved organic carbon content of soil initially increased and then decreased to the same level as the control by the end of the experiment of 120days. Moreover, Fe(II) formation was promoted by straw return under anaerobic conditions. •OH was produced in the flooded paddy soil when exposed to oxygen, which correlated well with Fe(II) content. The effect of rape (Brassica campestris L.) straw on •OH formation rate was more evident as compared to wheat (Triticum aestivum L.) straw, suggesting a potentially more profound influence of rape straw return on pollutant transformation in paddy soils.

Straw Incorporation Management Affects Maize Grain Yield through Regulating Nitrogen Uptake, Water Use Efficiency, and Root Distribution

Returning crop straw to soil can potentially improve soil health and crop production, facilitating sustainable agriculture. However, the effects of straw incorporation with various tillage management techniques combined with nitrogen (N) regimes on crop root growth, and water and N utility are not well understood. In this study, rotary tillage (RTS) and plow tillage (PTS) for straw incorporation combined with N regimes (CK, no N applied; LN, 112 kg N ha−1; MN, 187 kg N ha−1; and HN, 262 kg N ha−1) were used to determine their effects on soil water and mineral N availability, root distribution, crop N uptake, grain yield, and water use efficiency (WUE) of maize in northeast China. The results demonstrate that higher levels of pre-sowing soil-water storage and field evapotranspiration (ET), and lower levels of WUE and pre-sowing soil mineral N storage (Nmin-PS) at a depth of 0–60 cm were obtained with the RTS treatments as compared to the PTS treatments. N addition improved Nmin-PS and post-harvest soil mineral N storage (Nmin-PH) at a depth of 60–100 cm in 2016, and increased WUE compared to CK. RTS treatments enhanced root weight density (RWD) at a depth of 0–60 cm in 2016–2017, root length density (RLD), ratio of root length density (RLDR), and ratio of root weight density (RWDR) at a depth of 30–60 cm in 2016, and RLD at a depth of 0–30 cm in 2017. N addition promoted RLD and RWD at a depth of 0–10 cm in 2016–2017. RTS treatments reduced pre-silking shoot N uptake (NPS) and grain yield. Shoot N uptake and grain yield were enhanced in response to increasing levels of N; however, the grain yield did not show further significant improvements when the amount of N applied was over 187 kg N ha−1 (except for RTS in 2016). Overall, tillage with straw incorporation management and N levels markedly affected the soil physicochemical properties (such as ET, Nmin-PS, and Nmin-PH). This influenced grain yield indirectly by further mediating root traits (RLD, RWD, RLDR, and RWDR) with consequences for the NPS and post-silking shoot N uptake (NPOS) of maize, which were found to have greatest direct and positive impact on maize grain yield.

The effects of straw incorporation with plastic film mulch on soil properties and bacterial community structure on the loess plateau

AbstractThe application of plastic film mulch and the return and incorporation of crop straw into topsoil as independent treatments affect soil physicochemical properties, including nutrient balance/cycling. It remains unclear whether combining straw incorporation and plastic film mulch significantly affects soil physicochemical properties and bacterial communities. We conducted a two‐factor (plastic film mulch application and maize straw incorporation) randomized block design experiment with four treatments: no plastic film mulch or straw incorporation (C), plastic film mulch (M), straw incorporation without mulch (CS) and straw incorporation with mulch (MS). Soil was sampled at the end of the growing cycle after 3 years of treatment. Soil organic carbon (SOC), total nitrogen (TN) and nitrate‐nitrogen (NO3−‐N) concentrations significantly improved after straw incorporation. Plastic film mulch had a significant negative effect on soil bacterial richness, whereas straw incorporation had no effect. Straw incorporation had a significant positive effect on bacterial diversity, whereas plastic film mulch had no effect. The MS and M treatments had significantly more Proteobacteria than the C and CS treatments. Formation of the soil bacterial community structure was driven by soil TN, NO3−‐N and SOC in the treatments with straw incorporation, and soil ammonium‐nitrogen (NH4+‐N) in the treatments without straw incorporation. In conclusion, plastic film mulch coupled with straw incorporation can significantly change the taxonomical and functional composition of soil bacterial communities and enhance soil bacterial diversity by affecting carbon and nitrogen cycling in cropland soils of farmland, especially in arid and semiarid regions.Highlights SOC, TN and NO3−–N concentrations significantly improved after straw incorporation Straw incorporation had a greater effect on bacterial communities than plastic film mulch Soil bacterial community structure was driven by soil TN, NO3−–N and SOC after straw incorporation Soil bacterial community structure was driven by soil NH4+‐N without straw incorporation.

Coastal saline soil aggregate formation and salt distribution are affected by straw and nitrogen application: A 4-year field study

Little is known about the effects of straw incorporation on saline soil aggregate formation or salt distribution in coastal zones. In this study, a 4-year coastal wheat/maize rotation field experiment was employed. In each growing season, maize/wheat straw was applied at the rates of 5.0 × 103 kg ha−1 (S) and 1.0 × 104 kg ha−1 (2S), and inorganic N was applied at the rates of 75 kg ha−1 (N1/2), 150 kg ha−1 (N), and 300 kg ha−1 (N2). Treatment without straw addition and applied with 150 kg ha−1 inorganic N was used as the control (CK). Dry- and wet-sieving techniques were used to fractionate the soils into large macroaggregates (> 2 mm, LM), small macroaggregates (0.25–2.0 mm, SM), microaggregates (0.053–0.25 mm, MI), and silt-plus-clay particles (< 0.053 mm, CS). Results revealed that the proportion of dry and water-stable macroaggregate fractions (> 0.25 mm, LA + SA) ranged from 74.2 %–88.3 % and 28.4 %–37.6 % in straw applied treatments, which significantly increased by 14.7 %–19.0 % and 21.1 %–32.4 % compared to CK, respectively (p < 0.05). The mean weight diameter (MWD) and aggregate stability rate (AR) enhanced as straw and N application rate increased. After straw application, soil organic carbon (SOC) preferentially accumulated in MI fractions, which was significantly higher than other aggregate fractions, except SN1/2 and CK (p < 0.05). MWD and AR were significantly negatively correlated with soil salinity (p < 0.05), and soil salinity decreased by 20.5 %–26.9 % in straw treatments compared to the initial soil salinity. In the CK and SN1/2 treatments, soil salinity of LA + SA fractions was significantly higher than < 0.25 mm fractions (MI + CS) (p < 0.05). The same difference in soluble Ca2+ was also observed in CK, SN1/2, or SN. In conclusion, saline soil aggregate formation and stability improved after straw and N application, which caused the salinity to decrease and affected salt distribution in aggregates. The findings of this study suggest that adequate N should be applied in order to maximize saline soil reclamation efficiency with straw.

Effect of Straw Incorporation on Corn Yield in North China: A Meta-Analysis

Crop straw incorporation (SI) is as an effective method of soil improvement, which is playing an increasingly important role in improving corn productivity, soil fertility and reducing nitrogen leaching and ammonia volatilization in North China. We conducted a meta-analysis to examine the effect of crop SI on corn yield in North China, and to investigate how the effect varies with region, climate, soil, duration of crop SI, cropping system, and application of inorganic fertilizer (nitrogen, phosphorus, potassium). Results indicated that crop SI significantly increased corn yield by 12.3% in North China. Crop SI had the most significant effect on improving corn yield under the annual precipitation ≤ 400 mm (18.6%) and mean temperature &gt; 12 °C (15.4%) environment. The change rate of corn yield was higher with the experimental duration of 2–3 years (13.3%) than that of ≥4 years (8.52%). Corn yield responses to crop SI in the corn–corn cropping system (10.42%) were not as obvious as that in the corn–wheat cropping system (14.73%). Therefore, we conclude that crop SI could significantly increase corn yield, which can reduce environmental pollution and add farmer income.

Effects of straw incorporation on nitrogen absorption of split fertilizer applications and on rice growth

A greenhouse experiment investigated the effect and mechanism of straw incorporation (0 and 6 t ha−1) on the absorption of fertilizer nitrogen (N) of split applications and on the growth of rice shoots and roots. N fertilizer was split into: (1) base fertilizer (BF), incorporated before transplanting; (2) tillering fertilizer (TF), broadcasted at tillering stage; and (3) panicle-formation fertilizer (PF), broadcasted at panicle-formation stage. 15N-urea was used as one of three splits. To evaluate the hypothesis that straw incorporation influences the 15N absorption of one split by enhancing 15N immobilization or changing root growth, we measured the 15N residual rate in soil at maturity and root growth throughout the rice-growing season. Straw incorporation significantly decreased 15N absorption of BF, accompanied by significantly higher 15N immobilization in soil than in the no-straw treatment. However, straw incorporation significantly increased 15N absorption of top-dressing (both TF and PF), accompanied by significantly greater dry matter and length of surface roots (0–5 cm depth) throughout the rice-growing season (top-dressing 15N was seldom found in soils &gt; 5 cm). Shoot dry matter with straw incorporation decreased significantly in the early stage but increased in the late stage, compared with the no-straw treatment, and shoot total N with straw incorporation decreased significantly throughout the rice-growing season (this negative effect had decreased by the late stage). To better synchronize N supply with rice demand and reduce the risk of water eutrophication, N levels of BF and top-dressing should be reviewed when straw is incorporated.

Effects of straw-incorporation combined with autumn plastic mulching on soil water consumption characteristics and winter wheat yield in arid farming areas

Effects of straw-incorporation combined with autumn plastic mulching on soil water consumption characteristics and winter wheat yield in arid farming areas

Effect of straw incorporation on aldehyde emissions from a maize cropping system: A field experiment

Aldehyde may occupy an important role in the volatile organic compound (VOC) emissions from soil and plant residue. However, aldehyde emission from agricultural soil as well as the effect of straw incorporation is poorly understood. Therefore, a field straw incorporation experiment comprising two treatments, (1) S0 (no straw incorporation) and (2) S1 (incorporation of maize straw at a rate of 9000 kg ha−1), was performed in a maize cropping system to characterize the emissions of aldehyde as well as to estimate the effect of straw incorporation on aldehyde emissions. Nine kinds of aldehydes were investigated and three emission dynamic modes were observed during the experiment. Total aldehydes emissions were significantly different (426.8 and 540.2 g ha−1 for S0 and S1, respectively). Generally speaking, decanal and nonanal had an obvious predominance in both treatments, taking up 33.1% and 29.2% of the total aldehydes emission for S0, and 30.4% and 28.4% for S1, respectively. In addition, the practice of straw incorporation significantly increased the emissions of the 9 kinds of aldehydes by 11.2%–103.3%, and the total aldehydes emission from incorporated straw alone was calculated as 2918.8 ng kg straw−1 h−1. These results showed that straw incorporation substantially influenced the emissions of aldehydes from the agricultural soil. Additionally, a rough comparison indicated that straw incorporation might not have much advantage over straw open burning in terms of reducing VOC (i.e., aldehyde) emissions. The results also suggested that environmental conditions (i.e., soil temperature, moisture and pH), especially soil pH, played an important role in aldehyde fluxes from the agricultural soil.

Discrepant responses of methane emissions to additions with different organic compound classes of rice straw in paddy soil

Crop straw incorporation has become a prevailing agricultural practice that guarantees the food production and security. There is a significant body of work on the effects of straw incorporation on the methane (CH4) emissions in paddy fields. However, it is unclear whether there are diverse links between CH4 emission dynamics and incorporations of different organic compound classes of straw to paddy fields. In this study, soil incubations were conducted to assess the respective effect of incorporations of hydrolysable amino acid (HAA), dilute-acid extractable carbohydrate (DAC), lipid and acid-insoluble organic matter (AIOM) fractions of rice straw on the CH4 emission in paddy soil. It is revealed that incorporations of HAA and DAC fractions exert the greatest intensities to stimulate the CH4 emissions, which mainly takes place in the early period of incubation; on contrary, the incorporation of lipid fraction exerts the lowest intensity and mainly takes place in the late period. The pattern of CH4 emission after incorporation of AIOM fraction occurs peaks both in the early and late periods of incubation. Our findings highlight that the time of occurrence and intensity of effects of rice straw incorporation on CH4 emissions vary significantly depending on the different organic compound classes of rice straw, which may be key to proposing a promising management strategy for mitigating CH4 emissions in paddy fields in the context of straw incorporation.