EFFECTS OF RAINFALL ON THE NUTRIENT CYCLING IN MAN-MADE FORESTS OF CUNNINGHAMIA LANCEOLATA AND Pinus massoniana

The preliminary study indicates that the nutrient concentration of throughfall has increased obviously in man-made forests of Cunninghamia lanceolata and Pinus massoniana as compared with rainfall in adjacent openning. The relative abundance of nutrient content for precipitation was NCaKMgP. The relative abundance of nutrient content for throughfall was KNCaMgP. The total amount of nutrient input with rainfall in two stands account for 48-53% of total nutrient returns. More amounts of N, K, Mg were transferred to the soil through throughfall than litterfall while more Ca and P were added to the soil through litterfall. Nutrient return approximates precipitation closely in a semi-log curve, indicating a limited and gradual supply of nutrients from their respective sources between the intervals of rain.