CAJ | 학술논문

采用等温吸附法和离子交换树脂法研究水稻土对磷的吸附及吸附态磷的释放规律.磷的等温吸附研究表明:Langmuir方程能较好地拟合浙江金华市的20个代表性水稻土对磷的吸附特征,相关系数在0.970～0.999之间;Langmuir等温方程的参数与土壤的理化性质有关,发育于第四纪红色粘土的水稻土的参数Xm、K、MBC和X_(0.2)值都明显高于其他发育于冲积物的水稻土;在淹水条件下,溶液中P可能较易得到土壤固相P的补偿,和旱地作物相比,水稻生长所需要的平衡磷浓度(EPC)可能远低于0.2 mg·L～(-1).磷的解吸研究表明:离子交换树脂提取的磷量与土壤吸附态P总量成正比,不管是冲积型水稻土还是红壤性水稻土,这种直线关系都成立(r = 0.941～0.999);在淹水条件下土壤磷的释放与土壤对磷酸根的吸附饱和度,即土壤对磷酸根的吸附能大小紧密相关.在水稻土的P肥管理实践中,维持适当水平的土壤总P量与维持适当水平的土壤有效P含量同样值得重视.
채용등온흡부법화리자교환수지법연구수도토대린적흡부급흡부태린적석방규률.린적등온흡부연구표명:Langmuir방정능교호지의합절강금화시적20개대표성수도토대린적흡부특정,상관계수재0.970～0.999지간;Langmuir등온방정적삼수여토양적이화성질유관,발육우제사기홍색점토적수도토적삼수Xm、K、MBC화X_(0.2)치도명현고우기타발육우충적물적수도토;재엄수조건하,용액중P가능교역득도토양고상P적보상,화한지작물상비,수도생장소수요적평형린농도(EPC)가능원저우0.2 mg·L～(-1).린적해흡연구표명:리자교환수지제취적린량여토양흡부태P총량성정비,불관시충적형수도토환시홍양성수도토,저충직선관계도성립(r = 0.941～0.999);재엄수조건하토양린적석방여토양대린산근적흡부포화도,즉토양대린산근적흡부능대소긴밀상관.재수도토적P비관리실천중,유지괄당수평적토양총P량여유지괄당수평적토양유효P함량동양치득중시.
Characteristics of phosphate sorption and sorbed-P release in paddy soils were studied using adsorption isotherm and ion exchange resin method. The results show that phosphate adsorption isotherm of 20 rice soils of Jinhua City of Zhejiang Province fitted in with Langmuir equation very well. The correlation coefficients were from 0.970 to 0.999. Parameters of Xm, X_(0.2), K and MBC (maximum buffer capacity) of the Langmuir equation might correlate with soil properties. The highest values of Xm, K, MBC and X_(0.2) were found in red earth derived rice soils, which might relate to their high content of clay and Fe, Al oxides. Comparing with upland crops, which equilibrium P concentration of 0.2 mg·L～(-1) may satisfy P demand for most crops, irrigated rice might need a less equilibrium P concentration in solution for its growth because the solution P could be more easily compensated through P release from soil particles in rice soils. It was found that the resin extractable P was proportional to soil adsorbed P (sum of soil Resin-P and newly adsorbed P from solution). The linear relationship was valid for all the soils studied, that is RAQ P=A+BX, where A and B are constants (r=0.941 to 0.999). It seemed that under water submerged condition, phosphate adsorbing saturation controlled the rate and quantity of P released from soil to the resin sink. Thus, for P fertilizer management in paddy soils, it pay our attention to maintain an adequate level of total soil P content or to maintain an adequate level of soil available P.