Estimation of Chemical Forms of Phosphate Released from the Paddy Soils with Different Effect of Phosphate Application

인산비옥도(燐酸肥沃度)가 상이(相異)한 답토양(畓土壤)에서 환원용출(還元溶出)되는 인산형태(燐酸形態)의 추정(推定)

1. Solubility diagram was used to estimate Chemical form of the Soil phosphates which supply phosphorus into soil solutions under submerged condition with soils originated from granite and basalt rocks. The granite origin soils with different amounts of available phosphorus have no effect of phosphate application on rice yield, while the basalt origin soil has the big effect. 2. Almost same pattern of change in pH and concentrations of phosphorus and cations in the soil solutions during the submerging period was. shown. Almost no difference in the values was recognized between NPK and NK treatments of the granite origin soils, but the difference of the basalt origin soil was recognized. 3. it was estimated from solubility diagram that phosphorus concentration in the soil solutions was governed by phosphate applied and variscite in the soils for the early stage of submerging period, and then it became to be governed by vivianite in the soils.

1. 벼수량(收量)에 미치는 인산시용효과(燐酸施用効果)가 현저(顯著)하지 않은 화강암유래(花崗岩由來) 보통답(普通畓)과 시용효과(施用効果)가 현저(顯著)한 현무암유래중점질답(玄武岩由來重粘質畓)에 있어서 담수(湛水)에 따라 용출(溶出)되는 인산염(燐酸塩)을 추정(推定)하기 위해 solubility diagram법(法)을 사용(使用)했다. 2. 토양용액중(土壤溶液中) 인산농도(燐酸濃度), 양(陽)이온농도(濃度), pH치(値)의 담수(湛水)에 따른 변화(変化)를 측정(測定)했다. 그 변화양상(変化樣相)은 어느 토양(土壤)에서도 비슷했다. 보통답(普通畓)의 인산시용구(燐酸施用区), 무시용구(無施用区)의 값은 비슷했으나 중점질답(中粘質畓)에서는 차이(差異)가 보였다. 3. 보통답(普通畓), 중점질답(重粘質畓) 공(共)히 담수(湛水)에 따라 용출(溶出)되는 인산농도(燐酸濃度)는 담수후(湛水後) 얼마동안은 시용인산(施用燐酸)과 토양중(土壤中)알루미늄인산(燐酸)에 의해 지배(支配)되고, 그후 환원발달(還元発達)에 따라 토양중(土壤中) vivianite계(系) 인산(燐酸)에 의해 지배(支配)되는 것으로 추정(推定)되었다.