Optimization of ridge–furrow mulching ratio enhances precipitation collection before silking to improve maize yield in a semi–arid region

Insufficient soil moisture and heat often limit crop productivity in semiarid regions. The effects of the ridge–furrow mulching system (RFMS) on improving the soil water and temperature conditions have been confirmed in many studies, but the effects of different ridge–furrow ratios on the changes in soil water, temperature, and the interception rate of canopy photosynthetically active radiation (PARIR), and thus crop productivity remain unclear. Therefore, we conducted a field experiment from 2015 to 2020 in the Loess Plateau region of northwest China by testing conventional tillage without mulch (CK) as a control treatment and three ridge–furrow ratios (60:60 cm, 80:40 cm, and 50:10 cm). We studied the changes in the soil hydrothermal characteristics and the response of maize canopy under continuous mulching with different ridge–furrow ratios. Compared with CK, RFMS increased the soil water storage in the 0–200 cm soil layer by 5.2–9.3% and the effective accumulated soil temperature by 10.4–29.1%. The hydrothermal properties affected the maize canopy under RFMS where compared with CK, PARIR increased by 6.3–11.7% at 61 to 90 days after planting (DAP) and the maize yield finally increased by 44.8–77.9%. Correlation analysis showed that the contribution of precipitation from 0 to 90 DAP to the maize yield was greater than that of the effective accumulated soil temperature, whereas the contribution of the effective accumulated soil temperature was greater at 91 to 150 DAP. The precipitation during 61 to 90 DAP was the most important factor that affected the yield during the whole growth period. Thus, increasing the ridge–furrow ratio can improve the soil hydrothermal properties and maize productivity to ensure food security and avoid resource shortages in the Loess Plateau region and similar areas.