三瓶演習林内の落葉広葉樹林における物質循環に関する研究(VIII) : リターフォールによる養分環元量について

The amounts of litter fall were measured for four years from 1975 to 1978 in a deciduous broad-leaved forest at Sanbe Forest of Shimane University. The amounts of nutrient elements of litter fall were also measured.
1. Concerning to the seasonal variation of litter fall, it showed sharp peak in the fall as being characteristic of the deciduous broad-leaved forest. Branch litter fell much in April-May, August and winter of snow fall. Flower and seed litter was more in the flowering and fruiting time.
2. The annual amount of total litter fall increased from 1975 to 1977, and decreased to 1978. This tendency was same as for the leaf litter. The snow damage at January in 1978 was influence upon the amount of litter fall. However, the degree of snow damage was no relation to the decrease rate of litter fall.
3. The concentration of nutrient elements ofleaflitter showedthe clearest seasonal yariation The introgen, phosphorus andpotassium concentration becamelower from spring to autumn but the calcium and magnesium concentration became higher. The nitrogen and phosphorus concentration of flower and seed litter became higher in May-June of flowering time and October-November of fruiting time.
4. The amounts of nutrients returned by litter fall did not change for four years as the amounts of litter fall. The amounts of nutrients were different among plots and were more at the lower part of slope than the upper part.