Dependence of 0.01M CaCl₂ Soluble Phosphorus on Extractable P and P Sorptivity in Upland Soil

밭토양(土壤)에서 유효린산함량(有效燐酸含量)과 인산흡수능(燐酸吸收能)에 따른 0.01M CaCl₂ 가용(可溶) 인산농도(燐酸濃度) 변화(變化)

The identification of soil P level that exceed crop requirement is a prerequisite in implementing sustainable management of fertilizer and manure P to prevent soil and freshwater from contamination. To investigate the relationship between 0.01M $CaCl_2$ soluble P, and available P and P sorption capacity of 40 soils, P content and P sorptivity were analyzed. Single linear relationship revealed the dependence of 0.01M $CaCl_2-P$ on available P($r^2=0.479$), bioavailable P($r^2=0.281$), P sorption($r^2=-0.465$) and P absorption coefficient($r^2=-0.056^{NS}$). Thus available P as $P_2O_5$(AVP) and P sorption (PS) were most important factors in determining the concentration of 0.01M $CaC1_2-P$($CaC1_2-P$). In multinomial equation related $CaC1_2-P$ with AVP and PS, the determination coefficient was improved to 0.745. The logarithm of $CaC1_2-P$ was linearly related to AVP/PS. Consequently, the equation, $0.01M\;CaCl_2-P=0.1284e^{0.3288AVP/PS}$ could be suggested to estimate the concentration of P in 20mL of 0.01M $CaCl_2$ solution containing 2g of soil shaken for 17 hours.

밭토양의 수용성 인산농도의 예측방법을 개발 할 목적으로 토양특성이 다양한 40개 토양에 대하여 0.01 M $CaC1_2-P$와 유효인산 및 인산흡수능 등과의 관계를 검토한 결과, 직선회귀관계에서 0.01 M $CaC1_2-P$와의 결정계수는 유효인산이 $0.479^{**}$, 부영양화인산이 $0.281^{**}$이었으며 토양의 인산흡수능중에는 인산흡수량이 $-0.465^{**}$, 인산흡수계수가 -$-0.056^{NS}$이었다. 0.01 M $CaC1_2-P$와 독립 변수인 유효인산과 인산흡수능을 함께 고려한 2차 다항 회귀관계로 보면 결정계수가 $0.745^{**}$로 향상되었고 독립변수로 유효인산과 인산흡수계수를 함께 고려하면 결정계수가 $0.566^{**}$ 이었으며 유효인산/인산흡수량의비를 독립변수로 하여 만든 지수함수식(指數函數式)에서는 결정계수가 0.818로 크게 향상되었다.