• Applied Biological Chemistry
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• v.41 no.3
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• pp.247-252
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• 1998

To obtain the basic information for suitable use of soybean-Bradyrhizobium japonicum symbiosis, on soybean cv. Danweonkong and Namhaekong the symbiotic potential of B. japonicum indigenous to plain upland (PU), plain paddy(PP), and mountainous upland(MU) soils in southern part of Korea were surveyed and discussed. Populations of B. japonicum in soils were the highest in MU soils with $5.7{\times}10^4\;cells/g.soil$ followed by PU with $5.0{\times}10^4$ and PP soils with $4.0{\times}10^3\;cells/g.soil$. Shoot dry weight at flowering stage and grain yields at harvesting stage, which mutually showed an high correlation $(P{\leqq}0.001)$, were high in the order of PU > MU > PP soil inocula. Amongst PU soils, Namhae acid Seonsan soils were prominent inocula for shoot dry weight and Kimhae for grain yields at P 0.05, respectively. In cases of nodule number and nodule mass surveyed at the flowering stage, shoot dry weight gave an higher correlation with the latter $(r=0.439^*)$ than the former $(r=0.383^*);$ grain yields with the former $(r=0.505^{**})$ that flue latter $(r=0.449^{**})$. In comparison with Namhaekong showed 1.7 and 1.4 fold higher values in shoot dry weight and grain yields per nodule mass, respectively.

• Applied Biological Chemistry
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• v.40 no.5
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• pp.438-441
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• 1997

The relatedness of naturalized Bradyhizobium japonitum populations with soil physico-chemical characteristics as affected by paddy rice-upland soybean rotation cropping with conventional and none fertilization in Chilgog clay loam soils were determined as follows. The populations of B. japonicum in soils were increased from about $10^1$ in continuous paddy upto $10^1cells/g.soil$ only in one-year rotation of upland use with soybean cropping. Compared to the densities in plots of conventional fertilization, those in none fertilization were high ranging from 1.9 to 10 fold in 2-year upland use rotation and both in 3-year upland use rotation and 4-year upland use, respectively. The populations were positively correlated with soil organic matter $contents(r=0.83^*),\;Ca/K(r=0.74^*),\;and(Ca+Mg)/K(r=0.72^*)$ and were negatively correlated with soil $hardness(r=-0.73^*)$. And the soil populations increased by paddy-upland rotation resulted in superior symbiotic potentials to those in continuous paddy use in terms of nodule mass, nitrogenase activity, and soy-bean shoot dry weight.