Impacts of Fertilization on the Change of Nutrient Content in Soil and Leaf in Young Loblolly Pine Plantation in Acid Rain Region

From 1990 to 1992, experiments on the effect of fertilization on the change of nutrient content in soil and leaf in young loblolly pine plantation were conducted in Longchang County, Sichuan Province. The result showed that the nitrogen content in soil increased in the following year after corresponding amount of fertilizer was applied, within a range of 0.01～0.22 g/kg. Nitrogenous and potash fertilizer should be applied once every two years. In order to increase phosphorus content and control the content of Al3+ and H+ in soil, calcium magnesium phosphate should be applied. Nitrogen and phosphorus in leaves were positively related with the application of nitrogenous and phosphorus fertilizer in soil. The relationship between the potassium content of leaf and the application of potash fertilizer in soil was complicated. Whether the application of calcium fertilizer was conducted or not, calcium contents of terminal leaf and lateral leaf decreased gradually from 1900 to 1992, within a range of 1.67～3.86 mg/g and 2.45～5.18 mg/g respectvely.