수도(水稻)에 대(對)한 가리(加里)의 전량추비분시(全量追肥分施)에 관(關)한 연구(硏究)

Studies on split top dressing of total quantity of potassium to rice

벼에 대(對)한 가리(加里)의 전량추비분석(全量追肥分施) 효과(効果)를 검토(檢討)할 목적(目的)으로 1972년도(年度)에 1/2,000a 폿트시험(試驗)을 실시(實施)하였다. 가리추비분시(加里追肥分施)는 전량(全量)의40, 30, 20, 10%를 각각 이앙후(移秧後)15일(日), 유수형성기(幼穗形成期), 출수기(出穗前)13일(日) 및 출수후(出穗後)7일(日)에 시용(施用)한 것이다. 시험설계(試驗設計)는 무처리토양(無處理土壤)과 규회석(珪灰石) 및 고토석회(苦土石灰)를 시용(施用)한 처리토양(處理土壤)에 대(對)하여 가리(加理)의 전량기비(全量基肥)와 전량추비분시(全量追肥分施)의 효과(効果)를 비교하도록 되었던바 얻어진 결과(結果)는 아래와 같다. 1. 가리(加里)를 기비(基肥)없이 전량추비분시(全量追肥分施)하는 것이 가리(加里)의 비효(肥効)를 크게 높일수 있는 방법(方法)임을 인정할수 있었다. 2. 가리(加里)의 시용(施用)은 무처리토양(無處理土壤)에서는 등열율(登熱率) 또는 천립중(千粒重) 증대(增大)에 유효(有効)하였고 규회석(珪灰石)과 고토석회(苦土石灰)를 시용(施用)한 처리토양(處理土壤)에서는 입수증대(粒數增大)에 크게 유효(有効)하였으나 이러한 가리(加里)의 역할(役割)은 가리(加里)를 전량추비분시(全量追肥分施)했을때 더욱 현저하여 유의성(有意性) 있는 증수(增收)를 얻었다. 3. 벼짚중(中) 가리함량(加里含量)과 다른성분(成分)과는 부(負)의 상관(相關)이 있으며 유수형성기(幼穗形成期)에 가리함량(加里含量)과 부(負)의 상관(相關)이 인정(認定)되는 성분(成分)은 고토(苦土), 인산(燐酸) 및 질소(窒素)이었고 출수기(出穗期)에는 3성분외(成分外)에 고회(石灰)와 규산(珪酸)이었다. 4. 가리(加里)의 전량추비분시구(全量追肥分施區)와 전량기비구(全量基肥區)를 비교할 때에 가리(加里)의 전량추비분시(全量追肥分施)에 의하여 유수형성기(幼穗形成期)에 있어서는 인산(燐酸)과 고토(苦土)의 흡수억제(吸收抑制)가 감소(減少)되나 질소(窒素)의 흡수억제(吸收抑制)는 더욱 증대(增大)되며 출수기(出穗期)에 있어서는 석회(石灰)와 규산(珪酸)의 흡수억제(吸收抑制)가 감소(減少)되는 반면(反面) 고토(苦土)의 흡수(吸收)는 더욱 억제(抑制)되었다.

A pot experiment was conducted to study the effect of two methods of applying potassium fertilizer to rice. One basic application was compared with the split of same total quantity into four applications as follows: 15 days after transplanting (40%), Ear formation stage (30%), 13 days before heading (20%) and 7 days after heading (10%) Each of these two treatments was carried out on both untreated soil and soil to which wollastonite and lime material had been added. The number of ripened grains or the 1,000 grain weight was increased by application of potassium to untreated soil. However, on soil treated with lime and wollastonite only the number of total grains was increased by potassium application. In both cases, split application of the potassium was more affective than a single basic application. No significant increase in yield was obtained from a single basic application of potassium. However, split application of the same total quantity of potassium did give a significant increase in yield. A negative correlation was found between the content of $K_2O$ and that of other nutrients in the rice plant at two stages of growth. Significant negative correlation was obtained between the content of $K_2O$ and magnesium, phosphorus and nitrogen at ear formation stage, and between the content of $K_2O$ and calcium and silicate including magnesium, phosphorus and nitrogen at heading stage. This result also indicated that the depression of uptake of phosphorus and magnesium at ear formation stage and that of calcium and silicate at heading stage were decreased by potassium split application. However, the degression of uptake of nitrogen at ear formation stage and that of magnesium at heading stage were increased by potassium split application.