关键词: 耕作方式, 夏玉米, 土壤贮水量, 干物质转运, 籽粒灌浆, 产量, 小麦

Abstract:

【Objective】 The Huang-Huai-Hai Plain is a typical annual rotation area of winter wheat and summer maize in China, and the effect of pre-season tillage on the yield of summer maize in this area was studied, so as to provide a theoretical basis for optimizing the tillage mode under the wheat-maize double cropping system to improve the high and stable yield of summer maize. 【Method】 Based on the 6-year long-term positioning experiment, three pre-sowing tillage modes of winter wheat were set up, including Deep tillage (DT), No-tillage (NT), and Rotation tillage (RT) with deep tillage for one year and two years, to explore the tillage mode with the greatest potential for increasing summer maize yield. 【Result】 RT and DT treatments significantly increased the soil water storage of 0-40 cm soil in tillage disturbance during the tillage period of summer maize at the grain filling stage, which was 4.89% to 11.02% (2022) and 4.43% to 6.06% (2023) higher than that under DT treatment, and 8.16% to 16.69% (2022) and 6.78% to 17.23% (2023) higher than that under NT treatments, respectively. RT treatment could maintain a high leaf area index at the maize grain filling stage, and the leaf area index under RT treatment increased by 1.41% to 14.28% (2022) and 9.03% to 14.46% (2023) compared with DT treatment before and during the grain filling stage, respectively and increased by 14.80% to 27.56% (2022) and 21.25% to 29.39% (2023) compared with NT treatment, respectively. Compared with DT and NT treatments, the contribution rate of dry matter transfer after anthesis to grain under RT treatment increased by 3.77%, 40.36% (2022) and 7.26%, 19.91% (2023), respectively. The results of logistic equation simulation showed that the parameters of the 3 grain filling stages were roughly in the order of rapid growth stage>gradual growth stage>slow growth stage, and the three grain positions showed the lower grain>the middle grain>the upper grain, and the changes of the parameters in the 3 treatments showed RT>DT>NT, in which the RT treatment reached the maximum grouting rate in advance, and the average grouting rate was the highest, thereby increasing the theoretical maximum 100-grain weight. In 2022 and 2023, the yield under RT was significantly increased by 8.92%, 14.15%, 6.25% and 19.45% compared with DT and NT treatments, respectively, and in 2022 and 2023, the 100-grain weight RT and DT treatments were significantly increased by 2.71%, 6.03%, 9.02% and 12.56% compared with NT treatments, respectively. According to the structural equation model of yield formation, the direct effect and indirect effect of 0-40 cm soil water storage on yield were 0.420 and 0.551, respectively. 0-40 cm soil water storage not only directly promoted yield formation, but also affected yield through aboveground biomass and average grain filling rate. 【Conclusion】 In conclusion, soil water storage was an important driving factor for increasing yield, and RT could increase soil water storage at summer maize filling stage, thereby increasing leaf area index with higher activity, delaying leaf senescence time, increasing dry matter accumulation, optimizing grain filling characteristics, promoting the increase of dry matter to grain filling rate, and ultimately increasing summer maize yield.

Key words: tillage regime, summer maize, soil water storage, dry matter transfer, grain filling, yield, wheat