Abstract:Based on the data of soil nutrients of soil testing and formulated fertilization and the results of “3414” field fertility test in Qinglin-Bashan area, this paper analyzed the changes of soil available phosphorus (P) in the past 30 years and the linear relationship between soil available P and the relative yields of P fertilizer tests for five crops, in order to provide theoretical basis for improving P fertilization method under current level of soil available P. The results showed that the average of soil available P was 18.1 mg/kg in 2008—2012, belonging to the moderate level. The relative yields of “3414” P field fertilizer test were 85.7% for wheat, 85.5% for maize, 88.7% for rice, 84.3% for rape and 86.0% for potato, respectively, indicating the current level of soil available P could basically meet the requirement of crop growth. Based on the middle and high levels of soil available P, the relative yields of five crops of P field fertilizer test, the fixation mechanism of P fertilizer in soil and characteristics of P uptake by crops, it is recommended that all phosphate fertilizers should be divided into base fertilizer and top dressing for the low fertility farmlands with soil available P less than 15 mg/kg, especial less than 10 mg/kg, while only part or a small amount of phosphate fertilizer of topdressing for the medium and high fertility farmlands with soil available P higher than 20 mg/kg, especial higher than 30 mg/kg, to ensure P balance supply in whole growth periods and maximal fertilizer requiring periods of crops, to improve P utilization rate, to save agricultural resources and improve the agricultural ecological environment.