森林のリターフォール生産速度とその養分含有率に及ぼす土壌条件の影響

抄録

Changes in the amounts and nutrient concentrations of litterfall in a forest in relation to soil fertility were studied. The results obtained in four 26-year-old Chamaecyparis obtusa stands and in 19 plots of natural deciduous broadleaved forests, all of which grew in different soil conditions, indicated that the production of leaf and total litterfall was positively correlated with soil fertility when the annual increment of stem velume of the stand or the mean height of the trees were used as an index of soil fertility. The weighted annual mean concentrations of N and P of leaf and total litterfall decreased with the decrease in soil fertility. There was no relationship between soil fertility and the concentrations of Ca, Mg and K in the litterfall. The quantitative effects exerted by soil fertility on the rate and nutrient concentrations of litterfall could not be assessed using the present experimental data. However, data showed that the amount of nutrients contained in the litterfall decreased in the poor soil compared to the rich soil, particularly for N and P, due to the decrease in production and nutrient concentration of the litterfall.