Abstract
The amounts of litter fall and nutrients contained therein were measured throughout a year in six forests (two Pinus densiflora, a Chamaecyparis obtusa, a Fagus crenata, a Quercus mongolica and an evergreen broad leaved forests) and one nursery (Camptotheca acummata).
1) The amount of total litter fall was 2.51_??_7.76 ton/ha•yr. Leaf-litter accounted for 54_??_78% thereof in conferous forests and 83% in deciduous forests.
2) The total litter fall per annum contained 15.2_??_72.5kg/ha in nitrogen, 0.7_??_5.0kg/ha in phosphorus, 3.6_??_16.4kg/ha in potassium, 22.3_??_72.6kg/ha in calcium and 2.7_??_13.8kg/ha in magnesium. Nitrogen, phosphorus and potassium were contained more in broad leaved forests than in coniferous forests.
3) Ratios of nutrient return with the total litter fall to nutrient uptake of the forest growth were 33_??_52% for nitrogen, 36_??_69% for phosphorus, 23_??_43% for potassium, 62_??_85% for calcium and 52_??_98% for magnesium.
4) Ratios of nutrient return with the total annual litter fall to the respective existing nutrients in the forest ecosystems were 0.2_??_0.9% for nitrogen, 1.8_??_4.5% for phosphorus, 0.6_??_2.9% for potassium, 1.6_??_5.4% for calcium and 3.3_??_9.4% for magnesium.
