Effects of different soil tillage practices on biological characteristics and grain yield of rice in double cropping rice field

Soil tillage practices are the key factor affecting soil physical properties in paddy field and grain yield of rice. Therefore，the variation of plant biological characteristics and grain yield of early rice and late rice under different soil tillage practices were studied by using field experiments，which providing theoretical for choose reasonable soil tillage measures to obtain higher grain yield in double-cropping rice area. The biological characteristics of plant，grain yield of early rice and late rice were analyzed under no–tillage（ NT），moldboard plowing（ MP），rotary tillage（ RT），RT–NT and RT–MP during early rice and late rice growing season in this paper. The results showed that the leaf area index of rice were in a trend of MP>RT>RT-NT>RT-MP>NT and MP>RT-MP>RT>RT-NT>NT at different growth stages of early rice and late rice，respectively. The dry weight of root，stem，leaves and panicle with MP was significantly higher than that of other treatments at different growth stages of early rice. And the dry weight of root，stem，leaves and panicle were in a trend of MP ＞ RT ＞ RT-NT ＞ RTMP> NT at different growth stages of early rice. Meanwhile，the dry weight of root，stem and panicle with MP and RT MP was significantly higher than that of NT at different growth stages of late rice. And the dry weight of root，stem and panicle were MP ＞ RT-MP ＞ RT-NT>RT ＞ NT at different growth stages of late rice. Compared with NT， the grain yield of early rice and late rice with MP，RT，RT-NT and RT-MP increased by 681.3，395.9，248.1， 210.0 kg/hm2 and 880.3，495.5，99.1，710.1 kg/hm2，respectively，indicating the dry matter accumulation and grain yield of early rice and late rice with different soil tillage practices have their own characteristics. Compared with NT， MP and RT had significantly higher total dry matter accumulation and its reasonable distribution，and improved grain yield and yield components of rice.