Study of classification of the soil nutrient status of citrus orchard in Hubei Province

Top soil(0～30cm)samples from 143 citrus groves in Hubei Province were tested and classified. The results showed that the soil pH in 89.5% orchards was suitable for citrus growth, and soil organic matter (OM) in 59.4% orchards was in low status, and the deficiency rate of available macronutrients N, P and K was 78.3%, 44.1% and 77.6%, available second nutrients Ca and Mg was 39.1% and 37.1%, and micronutrients Fe, Mn, Cu, Zn, B and Mo was 34.3%, 20.3%, 16.8%, 63.6%, 35.5% and 77.4%, respectively. The result also indicated that soil available Ca, Mg, Fe, Mn, Cu and Mo exceed percentage was in excess in 9.8%, 4.9%, 7.7%, 4.9%, 3.5% and 4.0%, respectively,of the citrus gardens in the province. The study revealed that the soil pH, OM and available nutrients changed with the citrus location distribution. For example, soil pH in the province southern production area was lower than that along Hanjiang river area (in north of Hubei), and Ca and Mg of orchard soil in the south was much lower than that in north, while the Fe, Mn and Zn was on the contrary. 