Study on index system for soil testing and formulated fertilization—A case study of rice of Jiangdu City in Jiangsu Province

In this study, we constructed recommendation fertilization index system using rice as experimental materials at Jiangdu City in Jiangsu Province based on field experiments from 2005 to 2011, and determined N doses using soil fertility balance method, and determined P, K doses using nutrients abundance and deficiency index method. The results showed that when the target yield for rice was 6825-9270 kg/ha, averaging 8145 kg/ha, fertilizer N for rice was 146.4-257.4 kg/ha with an average of 207.5 kg/ha. Data indicated that when the the soil available P content exceeded 21 mg/kg, application of fertilizer P was unnecessary, and when the the soil available P content was ranged from 17 to 21 mg/kg, application amount of P2O5 should be 40.5 kg/ha, and when the soil available P content was ranged from 10 to 17 mg/kg, P2O5 application was 48 kg/ha, and when the soil available P content was below 10 kg/ha, application of P2O5 was 64.5 kg/ha. Fertilizer K should not be applied when the soil available K content exceeded 140 mg/kg, and application K2O was 225 kg/ha when the soil available K content was from 115 to 140 mg/kg, and application of K2O was 40.5 kg/ha when the soil available K content was ranged from 60 to 115 mg/kg, and application of K2O was 82.5 kg/ha when the soil available K content was below 60 mg/kg. Fertilization index system was based on the field experiments and its availabality was testified in the serve for soil testing and formulated fertilization.