Abundance and deficiency indices of phosphorus in South China vegetable field based on different soil testing methods

Based on the results of field experiments on vegetable conducted during the year 2002-2009, the abundance and deficiency indices of soil available phosphorus was investigated. The different soakage methods of soil available phosphorus were also discussed. Soil available phosphorus were classified into four classes (low, medium, high, and extremely high) corresponding to the percentage of maximum vegetable yield (＜75%, 75%-90%, 90%-95% and ＞90% relative yield). The abundance and deficiency indices were simulated by the logarithm models. The results indicates that available phosphorus indices for different soakage methods are Olsen-P ＜23, 23-59, 59-81 and ＞81 mg/kg; Mehlich1-P ＜19, 19-102, 102-179 and＞179 mg/kg; Mehlich3-P ＜19, 19-96, 96-165 and ＞165 mg/kg; ASI-P ＜22, 22-68, 68-98 and ＞98 mg/L, corresponding to different class of soil available phosphorus. There were significant correlation between the results obtained from Olsen, Mehlich 3, Mechlich 1 and ASI methods.