Comparison of Several Methods for the Determination of Available Phosphorus in the Soils for Corn and Rice

전(田)·답토양(畓土壤)의 유효인산(有效燐酸) 분석방법(分析方法) 비교(比較) 연구(硏究)

To compare different methods for the determination of available soil P in the relationship between the soil P and plant uptake of P, rice and corn were cultivated in the pot filled with soils of different available P contents. The soils were taken from 20 rice fields and 20 upland soils. The available soil P were determined before the experiment by Olsen, Lancaster, Bray 1, Bray 2, Mehlich II and Calcium lactate methods and the correlations between the available soil P measured by different methods and the amount of P taken up by corn at 10 leaf stage and by rice at maximum tillering stage were investigated. In upland soils, the available P measured by all the methods was linearly regressed with high significance to the amount of P taken up by corn. The coefficients of determination($R^2$) in the regression equations ranged from 0.596(Calcium lactate method) to 0.891(Olsen method). In rice soils, the soil available P did not regressed by first-order to the amount of P taken up by rice plant, while Michaelis-Menten equation better explained the relationship between the two parameters. In the Michaelis-Menten equation the coefficients of determination for each analytical method ranged from 0.607(Mehlich II method) to 0.923(Lancaster method). Based upon these observations it is concluded that for testing of available P for corn soils Olsen, Bray 2 and Lancaster methods are equally superior to other methods. For rice soils Lancaster, Bray 1, and Bray 2 methods are better than others.

토양(土壤)의 유효인산(有效燐酸) 분석방법(分析方法)에 있어서 우리나라 토양(土壤)에 적합(適合)한 인산(燐酸) 분석방법(分析方法)을 확립(確立)하고자 밭토양과 논토양에 각각 옥수수와 벼를 재배(栽培)하여 Lancaster법(法), Olsen법(法), Bray No.1, Bray No.2법(法), Mehlich II 법(法), Calcium lactate법(法) 등(等) 6개 분석방법(分析方法)을 사용한 토양중(土壤中) 유효인산함량(有效燐酸含量)과 식물체중(植物體中) 인산흡수량(燐酸吸收量)과의 관계를 비교 검토하였다. 1. 분석방법을 달리한 밭토양의 유효인산함량(有效燐酸含量)과 옥수수 식물체중(植物體中) 인산흡수량(燐酸吸收量)과의 관계(關係)는 모든 분석방법(分析方法)이 유의성(有意性) 있는 직선회귀(直線回歸) 관계(關係)를 나타내었고, 분석(分析) 방법별(方法別) 결정계수(決定係數)($R^2$) 크기는 Olsen-P $0.891^{**}$, Bray No. 2-P $0.880^{**}$, Lancaster-P $0.878^{**}$, Bray No.1-P $0.792^{**}$, Mehlich II-P $0.787^{**}$, Calcium lactate-P $0.596^{**}$이었다. 2. 논토양중 有效燐酸含量과 벼의 燐酸含量과의 關係에서 밭토양과 달리 Michaelis-Menten 式 ($Y=K_1X/(1+K_2X)$을 따랐으며 (Y, 벼의 燐酸吸收量, X ; 土壤 有效燐酸, K : 係數), 본 식에 따른 決定係數 ($R^2$)는 Lancaster-P $0.923^{**}$, Bray No.1-P $0.919^{**}$, Bray No.2-P $0.914^{**}$, Calcium lactate-P $0.769^{**}$, Olsen-P $0.712^{**}$, Mehlich II-P $0.607^{**}$이었다.