基于宽窄行种植模式下稻秸非均匀性覆盖对土壤特性及小麦产量的影响

为探究宽窄行种植模式下稻秸非均匀性覆盖还田对土壤理化特性和小麦产量的影响,在大田条件下,本研究通过前期不同行间距配置试验筛选出30 cm+15 cm的优势宽窄行组合,并在此基础上设置5个不同梯度的宽窄行稻秸分布比例处理(T₁:0、T₂:25%、T₃:50%、T₄:75%、T₅:100%),分析窄行(苗带)土壤理化性质和小麦产量变化情况。结果表明,0~10 cm为土壤温度和含水率变化敏感层。随着窄行稻秸覆盖量的升高,小麦生育前期土壤增温幅度增大,中后期降温效果更明显,土壤保墒性能增强,拔节期各处理间土壤含水率差异增大(增加1.2%~3.4%)。窄行稻秸覆盖量增加可在一定程度上降低土壤容重,提高土壤孔隙度,这种增减效应与覆盖量呈一定正比关系,但与生育时期无关;开花期和成熟期,土壤有机质、全氮、速效磷和速效钾含量均随窄行稻秸覆盖量增加呈先升后降趋势,总体上表现出适量稻秸覆盖(T₃:窄行秸秆覆盖量为均匀覆盖时窄行秸秆量的1/2)更有利于增加土壤养分含量。小麦产量及其构成因素均随窄行稻秸覆盖比例的不断增加呈降低趋势,其中有效穗数和产量(降幅为4.0%~31.7%)均显著降低(P<0.05)。可见,在稻秸全(大)量非均匀还田和晚播情形下,只有合理配比宽窄行秸秆覆盖量,并适当增加小麦播种量,保证足够基本苗,才能达到稳产肥地的协同效应。

Effects of Rice Straw Non-Uniform Mulch on Soil Characteristics and Wheat Yield Based on Wide-Narrow Row Planting Pattern

In order to explore the effects of rice straw non-uniform mulch on soil physical and chemical properties and wheat yield under the wide-narrow row planting pattern, under field conditions, this study screened out the 30 cm+15 cm dominant combination of wide-narrow row through the early configuration experiment of different row spacing, and on this basis, five different gradients of rice straw distribution ratio (T₁:0, T₂:25%, T₃:50%, T₄:75%,T₅:100%)were set for wide-narrow row to analyze the changes of physical and chemical properties of the soil in narrow row (seedling belt) and wheat yield. The results showed that 0~10 cm was a sensitive layer of soil temperature and water content changes. With the increase in the narrow row of the rice straw coverage, the increase of temperature got larger in the early stage of wheat growth, while the cooling effect was more obvious in the middle and late stage, and the performance of soil moisture retention became enhanced with the largest difference in the moisture content between the treatments at the jointing stage (increased 1.2% ~ 3.4%). The increase in the coverage of narrow row rice straw could reduce the soil bulk density and increase the soil porosity to a certain extent, which was proportional to the coverage while had nothing to do with the growth stage. Regardless of the flowering or mature stage, the contents of soil organic matter, total nitrogen, available phosphorus and available potassium showed an upwards trend followed by a decline with the increase in the coverage of narrow row rice straw. In general, the appropriate amount of rice straw coverage (T₃: narrow row straw mulch amount was 1/2 of narrow row straw amount under uniform mulch pattern) was more conducive to increasing soil nutrient content. Yield and its components showed a decreasing trend with the increasing proportion of narrow row rice straw coverage, among which the effective panicle number and yield (4.0% ~ 31.7% decreased) decreased significantly (P<0.05). It can be seen that under the conditions of full(large) non-uniform return of rice straw and late-sowing, the synergistic effect of stable yield and fertile soil can be achieved, only if a reasonable allocation of straw coverage between wide row and narrow row, an appropriate increase in the amount of wheat sowing and guarantee of sufficient basic seedlings were performed.