赤红壤有效磷分级指标的研究

Study on the Grading Index of Soil Available P in Latosolic Red Soil

用盆栽试验方法得到玉米幼苗干物质相对积累量与赤红壤土壤有效磷含量的关系曲线可以用一元二次响应方程来拟合,土壤Olsen P含量的响应方程为：y=-0.4831x2＋13.88x＋2.664,决定系数为0.9555＊＊;土壤Mehlich 3 P含量的响应方程为：y=-0.2621x2＋9.4821x＋18.891,决定系数为0.9400＊＊。赤红壤区的土壤有效磷分级指标为：Olsen P,小于4.0 mg kg-1为＂极低＂,4.0~6.8 mg kg-1为＂低＂,6.8~10.5 mg kg-1为＂中＂,大于10.5 mg kg-1为＂高＂;Mehlich 3 P,小于3.6mg kg-1为＂极低＂,3.6~7.5 mg kg-1为＂低＂,7.5~12.0 mg kg-1为＂中＂,大于12.0 mg kg-1为＂高＂。

Under pot culture conditions,the relationship of the relative dry matter weight of corn and soil available P content of latosolic red soil could be fitted by quadratic equation.The response equation of Olsen P was y =-0.4831x2 ＋ 13.88x ＋2.664,and R2=0.9555＊＊.The response equation of Mehlich 3 P was y =-0.2621x2 ＋ 9.4821x ＋18.891,and R2=0.9400＊＊.The grading index of soil Olson P were as follows： lower than 4.0 mg kg-1,very low;4.0-6.8 mg kg-1,low;6.8-10.5 mg kg-1,medium;greater than 10.5 mg kg-1,high.The grading index of soil Mehlich 3 P were as follows： lower than 3.6 mg kg-1,very low;3.6-7.5 mg kg-1,low;7.5-12.0 mg kg-1,middle;greater than 12.0 mg kg-1,high.