Abstract: The citrus orchard in the Three Gorges Reservoir Area was choose as a research object to detect the effects of different fertilization management approaches such as integrated fertilization with water and fertilizer, traditional fertilization, mixed fertilizer fertilization on soil nutrient dynamics. The results showed that it was acidic soil in citrus orchard that suitable for citrus growth. In 0~10 cm soil layer, the organic matter, total nitrogen, total phosphorus, available nitrogen, available phosphorus and available potassium content under integrated fertilization with water and fertilizer management were significantly higher than those under traditional fertilization and mixed fertilization management. In 10~30 cm layer, the soil nutrients were no significant different among the three fertilization measures in citrus orchard. Compared to soil nutrients in April, the soil organic matter, total nitrogen, total phosphorus, total potassium content under different fertilization managements were lower in July, while the available nitrogen, available phosphorus and available potassium content were higher. The results indicated that the integrated fertilization with water and fertilizer can maintain the soil nutrient in a high level, while the soil under traditional fertilization was still lack of nutrient content which meand the excessive fertilization can not improve the soil nutrient consistently. In the future, applying organic fertilizer with low intensity and high frequency will be an effective way to keep enough available nutrients in citrus orchard. At the same time, soil and water conservation measures, such as grass cover and hedgerows, should be strengthened to reduce the loss of nutrients on the surface and underground leaching, so as to reduce the risk of non-point source pollution.

Key words: Three Gorges Reservoir Area, citrus orchard, fertilization management, soil nutrient dynamic