Effects of Polyethylene Film Mulching on Growth and Yield of Green Soybean in Early-Direct Sowing Cultivation in Upland Field Converted from Rice Paddy in the Hokuriku District

Abstract

For establishing the stable production technology in early-direct sowing green soybean, the contribution of polyethylene (PE) film mulching to the growth and yield of green soybean was evaluated in an upland field converted from rice paddy in the Hokuriku district. Dry matter at harvest and yield of green soybean were higher in the plots of direct sowing with transparent or black PE film mulching compared with the plots of transplanting with black PE film mulching and direct sowing without mulching. This is probably due to higher seedling emergence, higher leaf area index from an early growth stage and larger number of pods. On the other hand, weed dry weight at harvest in the plot of direct sowing with transparent PE film mulching increased markedly compared with the plots of direct sowing or transplanting with black PE film mulching. These results suggest that direct sowing with black PE film mulching is effective to stabilize the yield and weed control in early-direct sowing of green soybean cultivation.