油松人工林养分循环的研究——Ⅲ.养分元素生物循环和林分养分的平衡

STUDIES ON THE NUTRIENT ELEMENTAL CYCLING IN THE PINUS TABULAEFORMIS PLANTAIONⅢ. Biological cycling and the balance of the nutrient elements

在1983年4月至1984年10月两个生长季中,我们对河北隆化的一片油松人工林养分元素生物循环进行了研究,同时,实测了林分养分元素的输入、输出量。实验林分养分总积累量(五种元素总量为575.46公斤/公顷,林木年吸收量为122.72公斤/公顷,归还量为69.9公斤/公顷·年,养分归还主要是以枯落物形式到达林地,这部分占总归还量的86％。以归还/吸收作为循环速率参数,各元素平均为0,57。林分养分的输入、输出主要受降雨和林地状况影响,由于实验地区年均降雨量较小(<500毫米),近几年又连续受旱,大气输入养分量及林分输出养分量均较小。林分的养分平衡,氮、磷略有盈余,钾、钙、镁有少量亏损。

The biological cycling of the nutrient elements was studied and inputs-outputs of the nutrient elements was measured meanwhile over a 2-years period (1983.4.-1984.10.)in a Pinus tabulaeformis plantation located in Long Hua county, He Bei province. Total accumulation of the elements in the experimental stand was 575.46kg/ha. The uptake was 122.7kg/ha.yr and the return was 69.9kg/ha.yr. The return of nutrient elements was mainly by litterfall of the trees which was 86% of total return. If we take return/uptake as the rate of the nutrient cycling, it averaged 0.57. Inputs-outputs of the nutrient elements were mainly affected by the atmospheric precipitation and the case of forest-floor. As the precipitetion in the experimental area was low (<500mm) and it was drought continually in recent years, the quantity of atmospheric inputs and outpust of the nutrient elements was small. The nutrient elemental balance shown, N, P had a small surplus, K, Ca, and Mg had a small deficit.