ON THE EFFECTS OF SOIL FERTILITY ON THE THROUGHFALL CHEMICALS IN A FOREST

Abstract

The effect of soil fertility on throughfall chemicals was studied in three Chamaecyparis obtusa stands differing in site conditions on Mt. Hiei, Shiga Pref. The three stands studied were located along a slope from the bottom to the ridge. There was no significant difference in the amount of throughfall among the plots. The throughfall was about 75% of the incident precipitation. The water chemicals differed among plots, however. The nutrient concentration of throughfall was higher than that of incident rain water. The difference was large for K, Ca and Mg and was small for N and P. Though there was no significant seasonal change in water chemicals of incident precipitation, the throughfall chemicals for three stands showed a similar seasonal change. The concentration of nutrients was high in the early winter for all elements, and there was another small peak in the summer for some elements, such as cation. The concentration of throughfall chemicals was higher in the fertile stand than in poor soil. The ratio of rain wash to standing amount of a nutrient in leaves (leachability index) was high in the stand developed on the fertile soil.