Effects of cultivars intercropping on maize water balance under different planting densities

Water transport is a fundamental aspect of crop physiology and an active area of research. Also water budget research under different maize cultivation patterns has been largely inadequate, especially on the area of maize cultivars intercropping and water balance. To determine the impacts of maize cultivars intercropping on plant-level water balance, "Zhengdan958" and "Shendan16" maize cultivars were planted in inter-lacing rows at two different inter-planting densities (45 000 plants·hm^-2 and 60 000 plants·hm^-2) in a total of four treatments. Grain yield, soil water content, stem sap flow (SSF) and root water conductivity (RHC) at different growth stages were investigated. The combined effects were analyzed for different characteristics of plant water consumption and transpiration. This enabled the efficient analysis of all the relevant factors of plant water transport. The results showed that intercropping improved root water conductivity, enhanced root water absorption vigor and functional continuity. Just as RHC, SSF obviously increased with increasing intercrop density. Daily variations in SSF followed an M-shaped curve under high density, but inverted a V-shaped curve under low density. Because of interplant density, maximum SSF appeared earlier in high than in low density treatments. Based on the changes in RHC and SSF, daily plant transpiration was extremely higher in high than low density plants. The maximum transpiration value for high-density plants occurred at grain filling and waxing stages. It occurred at tasseling and milking stages in low-density plants. Consequently, water use efficiency (WUE) was in the order of: low-density monoculture < intercropping < high-density monoculture. The above sequence was directly driven by yield differences. Cultivar intercropping improved root water absorption, extended root vigor and enhanced WUE. However, WUE distinctly varied with cultivar type and intercropping density. Further research was needed to build more understanding into these plant processes.