Junliang Fan

College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China

Soil mulching, e.g. straw mulching (SM) and ridge-furrow plastic film mulching (RP), has been reported to promote rainfed crop production in semi-arid regions, but its applicability in improving maize yield and especially yield stability in semi-humid drought-prone regions has been rarely explored. The capture and utilization of thermal, light, water and nutrients resources by maize plants under various soil mulching conditions are also poorly understood. A consecutive five-season field experiment was conducted on rainfed maize in a semi-humid drought-prone region of China during 2015–2019 to assess the effects of SM and RP on soil hydrothermal conditions, radiation interception, photosynthesis, evapotranspiration and grain yield stability, profitability and resources use efficiency compared with non-mulching (NM). The results showed that RP enhanced soil hydrothermal conditions, promoted the conversion of water from soil evaporation to plant transpiration and improved water productivity by 10.9%−203.2% compared with NM (P < 0.05). Although the growth duration was shortened, the accumulative soil thermal time and intercepted photosynthetically active radiation under RP were still 4.4% and 3.9% higher, with average increases in thermal time use efficiency by 23% and radiation use efficiency by 24%, which resulted in significantly higher nutrients accumulation (by 6.7%−19.7% for nitrogen and 4.1%−42.0% for phosphorous), grain yield (by 9.5%−186.4%) and yield stability (by 38.1%). These improvements were particularly pronounced in normal and dry years (2015, 2016 and 2017). No significant difference existed in maize’s capacity of absorbing water and nutrients and maize productivity between SM and RP under sufficient precipitation supply (2018 and 2019). The average net profit was highest under RP, especially in dry and normal years, while SM could achieve comparable net profit to RP in wet years. Overall, RP was preferable for rainfed maize production in semi-humid drought-prone regions in any precipitation year, while SM can be an alternative mulching practice in wet years. These results can improve our understanding of how RP and SM enhance rainfed maize productivity by improving resources capture and use efficiency.