Effects of soil moisture under plastic film mulching on the biological and yield characteristics of rice (Oryza sativa L.).

Pot culture was adopted in this experiment to study the effects of different levels of soil moisture on the growth and yield of rice under plastic film mulching condition.The results showed that the tiller produced later,and more slowly with less number,the plant height and leaf area of main functional leaves decreased,chlorophyll con-tent of main functional leaves increased,effective panicle ratio and harvest index were first enhanced and then de-pressed,the biological mass and yield of rice reduced gradually along with the decrease of soil moisture under plas-tic film mulching condition.Comparing with the treatment of traditional flooding(TF),the treatments of higher soil moisture(above field water capacity(FWC)±5%) under film mulching condition enhanced tillering,plant height,main functional leaves area,effective panicles,ripening grains rate,biological mass and yield of rice.At the begin-ning stage of tillering,it was necessary to keep enough soil moisture(above saturated water content SWC) for the rice filled under plastic film mulching dryland cultivation to enhance tillering;however,it was important to control the proper level of soil moisture [(FWC-80% FWC)±5%] to restrain invalid tillering at the later stage of tillering.At the booting stage,the soil moisture should be kept above SWC to increase the grains of panicle,while at blooming and filling stage,the soil moisture should be kept up to SWC to promote 1000-grain weight and to facilitate high yield of rice.