Conservation tillage improves the yield of summer maize by regulating soil water, photosynthesis and inferior kernel grain filling on the semiarid Loess Plateau, China.

BACKGROUND Poor inferior kernel grain filling is a challenge restricting summer maize yield. The effect and mechanism of conservation tillage on improving grain filling of inferior kernel in semi-arid rained areas remains uncertain and little research on tillage management integrated with straw mulching to improve soil water content and photosynthesis in the region. A two year (2019-2020) field experiment was established to study the impact of tillage practices on soil water content and summer maize root system morphology, photosynthetic capacity, inferior kernel grain filling, and grain yield. Treatments included reduced tillage (RT), no tillage (NT), and conventional tillage (CT). RESULTS Under RT and NT, the final 100-kernel weight and maximum and mean grain filling rates were higher than CT. RT (NT) increased soil water content by 22 (7), 11 (8), and 14% (6%) at the jointing stage, silking stage and grain filling stage, respectively, compared to CT. RT and NT increased root system morphology and dry matter accumulation (22, 18%); net photosynthetic rate (29, 23%), transpiration efficiency (23, 12%), stomatal conductance (55, 34%); decreased intercellular CO2 concentration; increased chlorophyll content (34, 35%); and aboveground dry matter accumulation (46, 18%) compared to CT. RT and NT increased evaportranspiration of maize, and ultimately, increased grain yield by 17% and 14%, respectively, compared to CT. CONCLUSION Conservation tillage could promote summer maize photosynthetic capacity and grain filling of inferior kernel by regulating soil water content, and root system morphology. This article is protected by copyright. All rights reserved.