湖南主要植烟土壤磷的吸附与解吸特征研究

Study on the adsorption and desorption of phosphorus from main tobacco-planting soil in Hunan Province

采用Langmuir等温吸附方程,对湖南主产烟区的8个代表性植烟土壤进行磷的吸附与解吸特性研究。结果表明,8个植烟土壤磷的最大吸附量(X max)变化为(657.8±17.82)~(848.9±8.31)mg·kg-1,吸附平衡常数(K)的变化为0.026~0.145,最大缓冲容量(MBC)的变化为(21.5±0.97)~(123.1±18.56)mg·kg-1,易解吸磷(RDP)变化为(0.9±0.81)~(5.7±1.67)mg·kg-1,土壤磷饱和度(DPS)变化为(3.25±0.61)%~(12.81±0.49)%。永定谢家垭(Ⅰ)X max,K和MBC值最大,说明该土壤具有最大磷库、最大磷吸附结合能和最强的磷缓冲性能;龙山大安(Ⅱ)土样DPS值最大,土壤对磷的吸附能力较弱,游离态磷含量较高;龙山茨岩(Ⅰ)土样RDP值最大,表明土壤磷素容易流失;不同土壤间磷酸吸收系数(PAC)相差不大;永定谢家垭土壤(Ⅱ)对外源磷的缓冲能力和对磷的固定作用最强烈。

Langmuir isothermal adsorption equation was used to study the phosphorus adsorption and desorption characteristics of 8 representative tobacco-planting soils in the main tobacco producing area of Hunan Province.The results showed that in 8 tobacco-planting soils the maximum adsorption(X max)of phosphorus ranged from(657.8±17.82)to(848.9±8.31)mg·kg-1,the adsorption equilibrium constant(K)ranged from 0.026 to 0.145,the maximum buffer capacity(MBC)ranged from(21.5±0.97)to(123.1±18.56)mg·kg-1,and the maximum desorption phosphorus(RDP)ranged from(0.9±0.81)to(5.7±1.67)mg·kg-1.The variation range of soil phosphorus saturation(DPS)was(3.25±0.61)%~(12.81±0.49)%.Xiejiaya town of Yongding County(Ⅰ)has the maximum X max,K and MBC values,showing the library has the largest P in soil,the maximum phosphorus adsorption binding energy and the strongest phosphate buffer performance;The DPS value in soil sample of Da’an Town of Longshan(Ⅱ)County was the highest,revealing the weaker adsorption capacity of the soil to phosphorus,and the higher content of free phosphorus.The RDP value of Ciyan Town of Longshan(Ⅰ)was the largest,indicating that soil phosphorus was easy to be lost.Phosphoric acid absorption coefficient(PAC)of different soils did not differ significantly.The soil in Xiejiaya Town of Yongding County(soil(Ⅱ)had the strongest effect on buffering capacity of exogenous phosphorus and phosphorus fixation.