Effect of straw returning to field on productivity of rice has been studied in three cropping systems, rice-rice-green manure, rice-rice-rapeseed and rice-rice-fallow. The main results show that under the condition of winter crop straw returning to field, yield of early rice in rice-rice-green manure system is the highest, and that in rice-rice-rapeseed is next to it, both of them are higher than that in rice-rice-fallow system by 3.1% and 1.8% respectively. The winter crop and early rice straw returning to field have increased the yield of lat...
