Interactive effects of planting models with limited irrigation on soil water, temperature, respiration and winter wheat production under simulated rainfall conditions

The development of effective water-saving farming practices have been vitally important for increasing wheat productivity in semi-arid regions of China. Ridge-furrow (RF) rainfall harvesting is a technique for efficient consumption of precipitation that increases water accessibility to crops at critical growth stages. However, this system has not yet been characterized under simulated rainfall conditions with limited irrigation. A two-year field study was carried out from Oct 2015 to May 2017 to investigate the potential role of two planting models: (1) the RF system and (2) traditional flat planting (TF) under three levels of simulated precipitation (1:275 mm, 2: 200 mm, 3:125 mm), with two limited irrigation levels (150 mm or 75 mm). The topsoil (from 5 to 25 cm) temperature and ET were significantly higher under TF planting than in the RF system, which increased both soil moisture between (0-200 cm) and soil respiration rate during different growth stages. The RF system also regulated soil temperature and respiration rate, reduced ET (46%), and prolonged the period of water accessibility which led to exhibited fast and stable seedling establishment. The average grain yield increased by 10.6% and 12.6% for RF1(150) and RF1(75), compared to TF1(150) and TF1(75), and increased by 18.9% and 22.5% for RF2150 and RF275 as compared to TF2150 and TF275, while RF3(150) and RF375 treatments significantly increased by 14.3% and 8.9% as compared to TF3(150) and TF3(75), respectively. Average WUE significantly improved by (P < 0.05) in RF1(150), RF175, RF215o, RF275, RF3150, and RF375 were 53.3%, 56.4%, 75.8%, 85.1%, 68.2% and 75.3% compared to TF planting, respectively. As precipitation increased from 200 to 275 mm there were no significant increases in moisture contents, soil respiration rate, ET, WUE, and grain yield under both planting models. Therefore, we concluded that the RF2(150) treatment is suitable as a water-saving technology to achieve higher wheat production and WUE in semi-arid agro-ecosystems of China.