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칠곡통의 식양질 논에서 답전윤환시 밭작물로 콩을 재배했을 때 Bradyrhizobium japonicum의 밀도변화와 토양 이화학성과의 상관관계를 조사하였다. B. japonicum의 서식밀도는 계속 논이용구에서 $10^1cells/g.soil$ 수준이었고 답전윤환구에서는 $10^1cells/g.soil$ 이상 수준이었다. 그리고 시비수준별 균주 밀도는 무비구가 관행시비구보다 2년주기 윤환시 1.9배, 3년주기 윤환 및 4년연속 밭이용시는 10배가량 높은 수준이었다. 토착 B. japonicum 밀도변화는 토양의 유기물함량$(r=0.83^*),\;Ca/K(r=0.74^*)$ 및$(Ca+Mg)/K(r=0.72^*)$와 정상관 관계를 보였고 토양경도와는 부의 상관관계(r=-0.73*)를 보였다. 그리고, 계속 논이용구 대비 답전윤환구에서의 B. japonicum 밀도증가는 질소고정잠재능의 증가로 이어졌다.

Abstract ▼ AI-Helper

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 ...

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.

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