Effects of Narrow-Row Culture by Inter-Row Strip Tillage with Chisel Plough on the Growth and Yield of Soybean (Glycine max L.) on the Weed Control in Upland Field Converted from Paddy Field

We adapted the narrow-row culture by inter-row strip tillage with a chisel plough (NCISTCP), which can alleviate dry and wet injuries, to the upland field converted from paddy field, and investigated the growth and yield of soybean cv.'Ryuho' planted at two densities, namely normal and sparse planting, and also the amount of weed emergence in the middle of June in 2012 and 2013 in Daisen, Akita prefecture. Regardless of planting density, the rate of stand establishment was significantly high and weed emergence was low, but the extent of lodging was high in NCISTCP compared with those in wide-row culture by conventional tillage (WCCT). Seed yield in NCISTCP irrespective of planting density was similar to that in WCCT with normal planting (conventional culture). In NCISTCP with sparse planting the pod number m-2 was increased up to almost the same number as that in conventional culture due to narrow-row, and the yield was increased. These results inferred that inter-row strip tillage with a chisel plough was well adapted to narrow-row culture, that the labor for intertillage and ridging can be saved, and 24% reduction of seeds may be possible by NCISTCP with sparse planting compared with the conventional culture.