Status of Soil Nutrient in Shanghai Farmland and Fertilization Recommendations

In 2005,30 soil samples(0~20cm),collected after rice was harvested in the Shanghai farmland,were analyzed.The results demonstrated that all the soil were fertile with high nutrient contents.The contents of soil organic matter,total nitrogen,available nitrogen,total phosphorus,available phosphorus,slow-acting potassium,and available potassium were 20.40 g/kg,1.06 g/kg,77.01 mg/kg,0.92 g/kg,36.93 mg/kg,863.63 mg/kg,and 216.18 mg/kg,respectively.However,nutrient distribution was of great difference among different plots,demonstrating significant spatial heterogeneity.The soil pH(9) and salts content were high,which demonstrated that the degree of salinization and basification was high.According to the practical situation of this farm,some scientific fertilizing measures should be applied to improve the farmland soil fertility.