杉木成熟林乔木层营养元素生物循环的研究

广西龙胜县里骆林区25—28年生杉木林乔木层平均每年吸收10种营养元素的总量为139.278kg/ha，其中19.5%存留在立木上，48.1%通过凋落物、32.4%通过降水淋溶归还土壤。N、Mg、S、Mn、Zn、B的归还比都超过0.8；P、K、Ca的归还比为0.72一0.74；Cu的则低于0.7。影响杉木林乔木层营养元素循环的主要因素是土层厚度、土壤养分的浓度和林分测树因子。

STUDIES ON THE BIOCYCLING OF NUTRIENT ELEMENTS OF TREE LAYER OF CUNNINGHAMIA LANCEOLATA MATURE PLANTATIONS

The total uptake of the ten nutrient elements of 25—28 years old Cunninghamia lanceolata in Guangxi Longsheng county Lilao forest region were 139.278 kg/ha·a, 19.5% of which(was retained by the tree layer, and 48.1% and 32.4% of which were returned to the soil through litter and rain leaching respectively. The ratio of annual return to annual uptake of N, Mg, S, Mn, Zn, B was more than 0.8 for N, Mg, S, Mn, Zn and B, was 0.72—0.74 for P, K, Ca, and was under 0.7 for Cu.The main factors which affect the biocycling of nutrient elements on the tree layer of Cunninghamia lanceolata plantations were the soil depth and the nutrient concentration in soil, and the diameter and height of the tree, etc.