High-yield characteristics and root support of rain-fed maize under film mulching

Full ridge-furrow plastic film-mulching (FM) is an important drought-resistant and high-yield agricultural method employed in the Loess Plateau. The characteristics of FM, which are closely related to high-efficiency resource utilization and root-shoot coordination of crops, may serve as references for yield increases in a broad range of farmland types. However, few studies have investigated this topic. A 2-yr field study was conducted in the rain-fed arid farmland of the Loess Plateau experimental station to investigate the canopy development and root support of FM maize (Zea mays L.). Our results showed that FM not only accelerated canopy growth in the vegetative phase and prolonged the reproductive phase but also promoted N and biomass accumulation in leaves after flowering. The leaf N concentration and biomass in FM maize increased by 6.2-24.7% and 16.9-29.3%, respectively, during R1 (silking)-R3 (milk) stage compared with the control. However, although the total root biomass decreased, and less RL (root length) and root surface area were distributed in deep soil, FM reduced the decline rate of RL and surface area during the R1-R3 period by 20.5 and 15.2% in topsoil, respectively, compared to the control. Moreover, FM significantly increased the root efficiency of leaf nitrogen (REN) absorption by 66.7-84.6% at the R1 stage and increased the water use efficiency (WUE) of grain yield by 20.3-69.4%. In conclusion, maize plants under FM had strengthened photosynthetic organs with high efficiency and long-lasting root support in a prolonged reproductive phase.