Abstract
We analyzed the effects of planting pattern on the growth, yield and nitrogen fixiation activity (NFA) of the soybean cultivar’Sachiyutaka’in 2002-2005 to establish labor-saving cultivation techniques that improve yield of soybean cultivated by late planting and non-intertillage cultivation methods in paddy-upland rotational fields. The yields in late planting was lower than that in optimum planting time, but in 2005 the yield in late planting was higher than that in optimum planting time. The top dry matter and yield of ’Sachiyutaka’was increased by planting in narrow-spaced ridges as compared with normal ridges when late planting and non-intertillage cultivation techniques were used. Moreover, lodging was observed in non-intertillage cultivation. NFA showed a significant positive correlation with the top dry matter and yield, but a significant negative correlation with lodging. Therefore, heavy top dry matter and high lodging resistance are two important factors for enhancing the NFA. We conclude that for establishing effective labor-saving cultivation techniques that improve the yield of soybean cultivated by late planting methods it is important to plant in rows with narrow spacing to increase the top dry matter and NFA, and also to introduce a cultivar with lodging resistance greater than’Sachiyutaka’.
