Cultivation techniques combined with deficit irrigation improves winter wheat photosynthetic characteristics, dry matter translocation and water use efficiency under simulated rainfall conditions

Abstract

Determining the effect of different cultivation techniques on photosynthetic characteristics, dry matter translocation and water use efficiency (WUE) will provide insight for the development of water-saving farming systems and exploiting the photosynthetic characteristics of winter wheat under deficit irrigation. In the current study, a mobile rainproof shelter was used to explore the potential role of two cultivation techniques: (1) the ridge and furrow precipitation harvesting technique (R); and (2) the flat cultivation technique (F), under two levels of deficit irrigation (150, 75 mm) levels and three levels of rainfall (1: 275, 2: 200, 3: 125 mm). We found that cultivation technique had a significant effect on rainfall water harvesting and enhanced soil water content under all levels of deficit irrigation and simulated precipitation. Under the R cultivation technique with 150 mm deficit irrigation and 200 mm simulated rainfall level can efficiently improve moisture content, thus significantly increased the average net photosynthetic rate (Pn) (10.4%), stomatal conductance (Gs) (27.2%), transpiration rate (Tr) (9.3%), intercellular CO2 concentration (Ci) (4.0%), dry matter translocation (31.6%), translocation efficiency (15.2%), pre-flowering assimilate translocation to grain (10.6%), grain yield (18.9%), WUE (75.8%) and economic return (12197 Yuan ha−1) of winter wheat, while significantly reduce (32.7%) ET rate compared with F cultivation technique. The R cultivation technique significantly improved photosynthetic characteristics such as Pn, Gs, Tr, Ci and dry matter translocation in the later growth stage (grain filling stage) compared with the F cultivation technique at each irrigation and rainfall level. Furthermore, these photosynthetic parameters were positively correlated with dry matter translocation, soil water content and grain yield. The greatest improvement in the photosynthetic characteristics, translocation efficiency, WUE, grain production and economic return was achieved when using the R cultivation technique with 150 mm deficit irrigation and 200 mm simulated rainfall (R2150). Therefore, we conclude that the R2150 treatment is the best water-saving management strategy for growing wheat crops in rain-fed farming systems.