Pot experiment is applied to study the effect of fertilization through drip irrigation systems on the dynamic change of soil
available nitrogen. The results show that, at bud stage,
soil available nitrogen content is lower in soil layer of 0～10 cm in depth than that in soil layer of 10～21 cm in depth in the contrast field without fertilization and the field with fertilization through drip irrigation systems; there is no obvious difference between the soil layers in the field with fertilization of
American diammonium; soil available nitrogen content in soil layer of 10～21 cm in depth in field with fertilization of special fertilizer is higher than that of American diammonium. At harvesting stage, the soil available nitrogen content is reduced from topsoil to the lower soil layers, and it is significantly higher in topsoil of 0～5 cm than that in other soil layers. The soil available nitrogen content is universally higher at harvesting stage than that at bud stage, it is higher in the fields with fertilization than that in the contrast field without fertilization, and it is higher in the fields with fertilization of special fertilizer than that of American diammonium. These reveal that the soil available nitrogen accumulation is different if the different fertilizers are fertilized under the same conditions of nitrogen, phosphorus and potassium. The study results also reveal that the special fertilizer is more suitable in fertilization through drip irrigation comparing with American diammonium.