Effects of Lime and Starch Application on The Soil Nitrogen Mineralization in Sandy Loam and Loam

사양토(砂壤土) 및 양토(壤土)에서 토양질소(土壤窒素) 무기화(無機化)에 미치는 석회(石灰)와 전분(澱粉)의 영향(影響)

Effects of liming and starch application on the soil pH and mineralization of organic nitrogen were compared to control at $30+/10^{\circ}C$ incubation for six weeks in two soil types(loam, sandy loam) adjusted with 80% of field moisture capacity. 1. While soil pH was increased abruptyl one week after incubation in loam applied with lime and lime+starch, it tended to decrease at control during incubation period. Liming on sandy loam increased soil pH, and application of lime+starch together showed high pH at first week of incubation which was lowered slowly after wards. Significant changes in soil pH was not detected at control or starch application only. 2. The content of $NH_3-N$ in loam started to increse three weeks after incubation, and was maximized at fifth week. Positive correlation was shown at control during incubation period between soil pH and $NO_3-N$ content. Level of $NO_3-N$ content applied with starch or lime+starch was low compared to control. 3. The $NH_4-N$ content was high when sandy loam was applied with lime+starch together. At the first week of incubation, the $NO_3-N$ content was high at control or lime application.

토성(土性)을 달리하는 두 토양(土壤)(사양토(砂壤土), 양토(壤土))을 공시(供試)하여 무처리, 석회(3%, w/w), 전분(3% w/w), 및 석회+전분처리를 하고 토양수분을 포장용수량(圃場溶水量)의 80%로 조절(調節)한 뒤 항온(恒溫)($30+/-0.1^{\circ}C$, 6주간(周間)) 처리하여 pH와 무기태(無機態)질소함량 변화를 조사(調査)하였다. 양토(壤土)에서 항온에 따른 pH는 석회와 석회+전분처리에서 항온 1주 후에 급격히 pH가 증가(增加)되었고, 무처리에서는 항온 전보다 pH가 낮아졌다. 사양토에서는 석회처리시 양토에서와 유사(類似)한 pH증가를 보였으나 석회+전분처리에서는 항온 2주째부터 낮아졌다. 그리고 무처리와 전분처리에서는 항온(恒溫) 전(前)과 큰 차이가 없었다. 양토(壤土)에서 $NH_4-N$은 항온 후 3주부터 증가(增加)되기 시작하여 5주째 최대치(最大値)를 보였고 6주째는 다소 감소(減少)되었다. $NO_3-N$은 석회, 무처리에서 항온기간경과에 따라 pH상승(上昇)과 $NO_3-N$축적간에 정(正)의 상관관계(相關關係)를 보였으며, 전분, 석회+전분처리에서는 오히려 항온 전(前)보다 낮아졌다. 사양토(砂壤土)에서 $NH_4-N$은 양토에서와 유사(類似)하여 항온 3주째부터 증가되었으며, 처리별로는 양토에서와는 달리 석회+전분처리에서 매우 높았다.