Research on Litter and Soil Hydrology Functions of Natural Secondary Forests in North of Da Xing'an Mountains

Litter and soil hydrological functions of four types of natural secondary forests was studied in the north of Da Xing'an Mountains.The results showed that,the differences in thickness and storage capacity of litter under different forest types were significant.The litter thickness and storage capacity of Populus davidiana were the largest.The litter storage capacity of four forest types ranged from 8.13t/hm2 to 18.42t/hm2,the order was Populus davidiana mixed Populus davidiana and Betula platyphylla mixed Betula platyphylla and Larix gmelinii Betula platyphylla.The litter thickness ranged from 49.33mm to61.67mm.The maximum water-holding capacity of litter ranged from 55.65t/hm2 to 89.01t/hm2,mixed Populus davidiana and Betula platyphylla was the largest.The water-holding capacity in semi-decomposed layer was significantly larger than that in undecomposed layer.The order of effective holding-capacity was Populus davidiana mixed Betula platyphylla and Larix gmeliniimixed Populus davidiana and Betula platyphylla Betula platyphylla,the average was 37.86t/hm2.The order of non-capillary porosity was the same as effective holding-capacity of litter,Populus davidiana was the largest,the value was 16.96%.The water-holding capacity of soil layer ranged from 228.69t/hm2 to 339.14t/hm2,Betula platyphylla was the lowest,while Populus davidiana was the highest,the difference was highly significant(P0.01).With the rapid decline in soil depth,the differences in rate of soil initial infiltration and steady infiltration were not obvious,steady infiltration rate ranged from 0.15mm/min to 0.33mm/min.The effective waterholding capacity of forest land ranged from 261.88t/hm2 to 381.59t/hm2,and the order was Populus davidiana mixed Betula platyphyllaand Larix gmeliniimixed Populus davidianaand Betula platyphylla Betula platyphylla.