Water Retention And Warming Effect Of Integrated Rice Management For The Hilly Areas Of Southwest China (Vol 112, Pg 3140, 2020)

Seasonal drought and low temperatures strongly limit rice (Oryza sativa L.) grain yield in the hilly areas of Southwest China. An integrated rice management (IRM) system was developed, which integrates ridge cultivation with plastic mulching, furrow irrigation, and triangular transplanting. A field experiment was conducted from 2011 to 2015. The effects of IRM on grain yield, yield components, soil moisture content (theta), and soil temperature (T-soil) were evaluated. Compared with traditional rice management (TRM), IRM significantly improved grain yield by 29.9%. Furthermore, the yield of IRM (8181-9267 kg ha(-1), CV: 7.6%) remained relatively stable. The rice tiller of TRM was highly related to the accumulated rainfall during the rice tillering stage in drought years (2011 and 2014). The water retention capability of IRM decreased the influence of interannual rainfall on rice growth and grain yield. In 2015, the theta in the 0-20-cm layer was higher than the threshold for rice root growth over the rice-growing season. Compared with TRM, T-soil of the 0-20-cm layer in IRM was 4.7 degrees C higher during the early tillering stage. The >10 degrees C soil effective accumulated temperature in IRM was also higher, and the difference was highest at the maximum tillering stage. The warming effect of IRM, particularly during the tillering stage, stimulated early growth and stronger tillering. In summary, the water retention capacity and warming effect of IRM were key factors for the improvement of rice yield; most importantly, the yields were stabilized in both drought and rainy years.