不同秸秆还田技术模式对冬小麦强弱势粒灌浆特性的影响

为揭示砂姜黑土区不同秸秆还田技术模式对冬小麦籽粒灌浆进程的影响，该研究基于农业农村部华东地区作物栽培科学观测站15a的长期定位试验，设置单季小麦秸秆全量粉碎覆盖还田（T1）、小麦秸秆全量粉碎覆盖还田+玉米秸秆全量粉碎翻埋还田（T2）、单季玉米秸秆全量粉碎翻埋还田（T3）和小麦玉米秸秆全年不还田（CK）4种不同秸秆还田技术模式，采用Richards方程模拟冬小麦籽粒灌浆过程，研究不同秸秆还田技术模式对冬小麦强弱势粒灌浆特征参数的调控效应。结果表明：1）相较于秸秆不还田，秸秆还田处理能提升冬小麦强、弱势粒的籽粒体积、千粒质量和产量，T1、T2、T3处理下强势粒千粒质量和籽粒产量较CK分别显著提升11.02%、10.63%、13.75%和16.28%、14.29%、13.94%，弱势粒千粒质量和籽粒产量较CK分别显著提升9.73%、6.64%、7.57%和19.24%、23.25%、11.50%。Richards方程能极显著模拟不同秸秆还田技术模式下冬小麦籽粒灌浆过程，拟合方程决定系数（R²）均在0.997以上。2）对冬小麦强势粒，秸秆还田可延长小麦强势粒灌浆时间，主要通过缩短灌浆渐增期持续时间和提高其灌浆速率，延长灌浆缓增期的持续时间来提升强势粒千粒质量。其中T1、T3处理下冬小麦强势粒灌浆持续时间较CK分别延长2.137 d和4.443 d，T1、T2处理下强势粒单粒最大灌浆速率较CK分别显著提高了7.81%和12.26%。3）对冬小麦弱势粒，T1处理下弱势粒灌浆持续时间较CK延长1.477 d，T1、T2、T3弱势粒单粒最大灌浆速率较CK分别显著提升16.46%、22.69%和17.13%。该研究表明秸秆全量还田可提升砂姜黑土区冬小麦籽粒库容和籽粒灌浆速率，最终增加粒质量。研究可为砂姜黑土区秸秆资源的高效利用提供理论指导和技术支撑。

Effects of straw returning modes on the superior/inferior grain filling of winter wheat

A large amount of straw has been an agricultural resource in recent years. Straw returning mode can also determine the soil fertility and wheat yield. Among them, grain filling is one of the important influencing factors on wheat yield. This study aims to reveal the effects of straw returning mode on the grain filling of winter wheat in sand ginger black soil. The 15a long-term positioning experiment was carried out at the Crop Cultivation Scientific Observation Station in East China of the Ministry of Agriculture and Rural Affairs. Yannong19 was taken as the research object. Four modes of straw returning were set, namely, single-season wheat straw total crushing mulching and returning to field (T1), wheat straw total crushing and mulching and returning to field + corn straw total crushing and burying to field (T2), single-season corn straw total crushing and burying to field (T3) and wheat-corn straw no returning to field all year round (CK). Richards equation was used to simulate the grain filling of winter wheat. Different modes of straw returning were regulated on the filling characteristic parameters for the superior and inferior grains of winter wheat. The results showed as follows: 1) Compared with non-returning straw, straw-returning treatment increased the grain volume, 1000-grain weight, and yield of superior and inferior winter wheat. The 1000-grain weight and grain yield of superior grain under T1, T2, and T3 treatment significantly increased by 11.02%, 10.63%, 13.75%, and 16.28%, 14.29% and 13.94%, respectively, compared with the CK. The 1000-grain weight and grain yield of inferior grain significantly increased by 9.73%, 6.64%, 7.57% 19.24%, 23.25%, and 11.50%, respectively. Richards equation was performed better to simulate the grain filling of winter wheat under straw returning. The coefficient of determination (R²) of the fitted equation was above 0.997. 2) In the superior grain of winter wheat, straw returning to the field also prolonged the filling time of the superior grain of wheat, thus shortening the duration of the gradual filling period. The filling rate increased to extend the duration of the slow filling period for the increase in the 1000-grain weight of superior grain. The filling duration of superior grain under T1 and T3 treatments was 2.137d and 4.443d longer than that of CK, respectively. The maximum filling rate of superior grain under T1 and T2 treatments significantly increased by 7.81% and 12.26%, respectively, compared with the CK. 3) For an inferior grain of winter wheat, the filling time of inferior grain under T1 treatment was 1.477 d longer than that of CK, and the maximum filling rates of inferior grain in T1, T2, and T3 significantly increased by 16.46%, 22.69%, and 17.13%, respectively, compared with the CK. Therefore, the total straw returning increased the grain storage and grain filling rate of winter wheat in the area of sandy ginger black soil. Finally, there was an increase in the grain weight. The finding can provide theoretical guidance and technical support for the efficient utilization of straw resources in sand-ginger black soil areas.