Effects of different planting modes on grain yield formation and economic benefits of rice( Oryza sativa L. )

In order to investigate the effects of different planting modes on grain yield formation and economic benefits,a Japonica rice cultivar Wuyunjing 24 was studied with direct seeding( two times seeding at June 1 and June 17),manual transplanting and mechanical transplanting in Taihu Lake area. Compared to manual transplanting and mechanical transplanting,direct seeding obviously speeded tillering and peak seedings,leading to higher effective panicles. However,the effective tillering rate of direct seeding was lower. Direct seeding generated lower spikelet number per panicle,seed setting rate and 1 000-grain weight than manual transplanting and mechanical transplanting did. The grain yield was shown as mechanical transplanting manual transplanting direct seeding. Earlier direct seeding were conducive to higher yield.Although the biomass of direct seeding was higher,the grain yield was lower due to lower economic coefficient. Mechanical transplanting achieved the highest economic benefits. Earlier seeding could improve grain yield so as to boost economic benefits.