Abstract Poor grain filling of inferior kernel of summer maize is a major challenge restricting grain yield of summer maize, especially under higher plant densities. Much work so far has proved that tillage practices could regulate soil properties and grain yield of maize effectively. In order to explore the effect of tillage practice on grain filling of inferior kernel of summer maize, field experiments were conducted over two consecutive years (2016–2017), and three tillage practices (T1, no tillage; T2, no tillage with subsoiling; T3, deep horizontal rotary tillage) were assessed. The grain filling parameter showed that final grain weight (A), the time reaching the maximum grain filling rate (Tmax), the dry matter accumulation under the maximum grain filling rate (Wmax), the mean grain filling rate (Gmean), and the active grain filling period (D) of T2 were usually higher than that of T1 and T3, and significant difference was observed between T2 and T1. Compared with T1, T2 and T3 reduced the soil bulk density and increased the soil porosity, and significantly increased the root dry matter accumulation in the 0–40 cm soil profile by 13.4% and 28.7%, respectively. Soil water content decreased among tillage practices in the order T2 > T1 > T3. However, T2 and T3 increased the water consumption, compared to that of T1. Moreover, T2 and T3 increased post-anthesis photosynthetic capacity, including the photosynthetic rate, leaf area duration, and chlorophyll content, and further improved the post-antheisis and total dry matter accumulation. The enzyme activities of SuSase, StSase, and ADPG-PPase of inferior and superior kernel in T2 and T3 were also higher than that of T1. In conclusion, the present results indicate that subsoiling could promote the grain filling of inferior kernel of summer maize by regulating soil water content, soil water consumption, and photosynthetic capacity.

中文翻译：

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耕作方式通过调节土壤水分和光合能力影响夏玉米劣质籽粒灌浆

摘要 夏玉米劣质籽粒灌浆不良是制约夏玉米籽粒产量的主要挑战，尤其是在较高植株密度下。迄今为止的大量工作已经证明，耕作方式可以有效地调节玉米的土壤性质和粮食产量。为探讨耕作方式对夏玉米劣质籽粒灌浆的影响，连续两年（2016-2017年）进行田间试验，进行了3​​次耕作（T1，免耕；T2，免耕，深松； T3，深度水平旋耕）进行了评估。灌浆参数表明，最终粒重（A）、达到最大灌浆率的时间（Tmax）、最大灌浆率下的干物质积累量（Wmax）、平均灌浆率（Gmean）、且T2的活跃灌浆期(D)通常高于T1和T3，且T2和T1之间存在显着差异。与T1相比，T2和T3降低了土壤容重，增加了土壤孔隙度，0-40 cm土壤剖面根系干物质积累量分别显着增加了13.4%和28.7%。在耕作实践中，土壤含水量按 T2 > T1 > T3 的顺序下降。然而，与T1相比，T2和T3增加了耗水量。此外，T2和T3增加了花后光合能力，包括光合速率、叶面积持续时间和叶绿素含量，并进一步改善了花后和总干物质积累。SuSase、StSase、T2和T3中下、上核的ADPG-PPase也高于T1。综上所述，本研究结果表明，深松可通过调节土壤含水量、土壤耗水量和光合能力，促进夏玉米劣质籽粒灌浆。