Grain‐filling rate and duration largely affect the grain‐filling capacity, which determines the grain yield of maize (Zea mays L.). Nevertheless, there is little about the mechanism of how various soil mulching practices affect the leaf photosynthetic potential and subsequent grain‐filling capacity of maize. Field experiments were undertaken on rainfed summer maize in northwest China under flat cultivation without mulch (FNM), flat cultivation with straw mulch (FSM), flat cultivation with transparent film mulch (FTF), flat cultivation with black film mulch (FBF), ridge‐furrow cultivation with transparent film mulch (RTF) and ridge‐furrow cultivation with black film mulch (RBF) in 2021 and 2022. This study explored the impact of various soil mulching patterns on soil hydrothermal condition, leaf growth, photosynthetic potential, aboveground dry matter growth and grain‐filling process of rainfed maize. The dynamics of leaf area index (LAI) and grain‐filling were fitted with growth equations, and the relationships of grain‐filling rate, leaf area duration and LAI withering rate were quantified. The results showed that, compared with FNM, other five soil mulching practices improved soil hydrothermal condition, the maximum LAI and leaf expansion rate but reduced leaf withering rate, thereby increasing radiation interception rate (RI) at the grain‐filling stage. The soil mulching practices also increased leaf SPAD value, net photosynthetic rate, photosynthetic nitrogen use efficiency and the aboveground dry matter. Compared with FNM, other five practices extended the effective grain‐filling period and the active period of grain‐filling, increased the maximum and mean grain‐filling rates, improved the 100‐kernel weight and the average kernel per ear (KPE), thereby increasing grain yields by 9.2%, 33.7%, 38.0%, 46.3% and 58.6%, respectively. The functional relationships of grain‐filling rate and accumulated leaf area duration (y = a/(1 + b*exp(−kx))), and the functional relationships of grain‐filling rate and LAI withering rate (y = (a + cx + ex2)/(1 + bx + dx2)) were first proposed. In conclusion, various soil mulching practices improved the soil hydrothermal condition, green leaves growth process and RI, which improved the leaf photosynthetic potential and the grain‐filling capacity, thereby increasing the 100‐kernel weight, KPE and grain yield. This study can help us quantitatively describe and better understand the maize grain‐filling process under various mulching practices.

中文翻译：

---

土壤覆盖措施通过改善土壤热液条件和叶片光合潜力来提高雨花玉米 （Zea mays L.） 的籽粒灌浆能力


籽粒灌浆速率和持续时间在很大程度上影响籽粒灌浆能力，而籽粒灌浆能力决定了玉米的产量 （Zea mays L.）。然而，关于各种土壤覆盖做法如何影响玉米叶片光合潜力和随后的籽粒填充能力的机制，几乎没有什么。以西北地区雨养夏玉米为研究对象，采用无地膜平耕、秸秆覆盖平耕、透明膜覆盖平耕、黑膜覆盖平耕、透明膜覆盖垄沟耕作和黑膜覆盖垄沟耕作，分别于 2021 年和 2022 年开展田间试验。本研究探讨了各种土壤覆盖模式对雨养玉米土壤热液条件、叶片生长、光合潜力、地上干物质生长和籽粒灌浆过程的影响。用生长方程拟合叶面积指数 （LAI） 和籽粒灌浆的动力学，量化籽粒灌浆速率、叶面积持续时间和 LAI 萎凋率的关系。结果表明，与FNM相比，其他5种土壤覆盖措施改善了土壤水热状况，提高了土壤叶面积和叶片扩张速率，但降低了叶片萎凋速率，从而提高了灌浆期的辐射拦截率（radiation interception rate，RI）。土壤覆盖措施还提高了叶片 SPAD 值、净光合速率、光合氮利用效率和地上干物质。 与FNM相比，其他5种做法延长了籽粒有效灌浆期和灌浆活跃期，提高了最大灌浆率和平均灌浆率，提高了百粒重和平均每穗籽粒率（KPE），从而分别提高了9.2%、33.7%、38.0%、46.3%和58.6%。首先提出了籽粒灌浆率与累积叶面积持续时间的函数关系（y = a/（1 + b*exp（−kx）））和籽粒灌浆率与LAI萎凋率的函数关系（y = （a + cx + ex2）/（1 + bx + dx2））。综上所述，各种土壤覆盖措施改善了土壤热液条件、绿叶生长过程和 RI，提高了叶片光合潜力和籽粒灌浆能力，从而提高了百粒重、KPE 和籽粒产量。这项研究可以帮助我们定量描述和更好地了解各种覆盖做法下的玉米籽粒填充过程。