Status of soil fertility in citrus orchards of Chongqing Sanxia Reservoir Area

Knowing soil nutrient fertility status is a basis to formulate a suitable fertilization strategy. Top soil(0-30 cm)samples collected from 459 citrus orchards in Chongqing Sanxia Reservoir Area were tested and classified in present study. The results showed that the soil pH of 78.7% orchards was suitable for citrus growth, soil organic matter of 60.3% orchards were low, and the deficiency rate of available macro-nutrients N and P was 72.4% and 41.7%, respectively, while soil available K were high in some orchards. The deficiency rate of available B, Zn, Fe and Mn was 86.3%, 37.9%, 27.0% and 20.3%, respectively. The results also indicated that amounts of citrus soils which have excessive available Fe, Mn and Cu accounted for 52.5%, 36.4% and 26.4% of total citrus orchards. Therefore, it was suggested that more B, Zn, lime or other alkaline fertilizer and less Cu fungicide should be used in the tested citrus orchards.