The Litter Storage and Its Water Capacity Characteristics in Different Artificial Soil and Water Conservation Forest Stands of Hilly and Gully Regions on the Loess Plateau

The hydrological character parameters of the litter storage,the maximum water holding capacity and water absorption speed of the litter on the forest land under four kinds of soil and water conservation forest(pure Pinus tabulaeformis forest,pure Robinia hisqida forest,pure Platycladus orientalis forest,mixed forest of Pinus tabulaeformis and Robinia hisqida)in Tuqiaogou basin were studied in this paper.The results showed:① The litter storage of the four kinds of forest ranges from 2.35 t/hm2 to 3.32 t/hm2.The sequence of the litter storage is pure Pinus tabulaeformis forestmixed forest of Pinus tabulaeformis and Robinia hisqidapure Platycladus orientalis forestpure Robinia hisqida forest;②There are some differences in maximum water holding capacity of the four kinds of forest.The maximum water holding capacity of the mixed forest of Pinus tabulaeformis and Robinia hisqida is equivalent to the rainfall of 0.739 mm,pure Pinus tabulaeformis forest 0.73 mm,pure Robinia hisqida forest 0.663 mm,pure Platycladus orientalis forest 0.524 mm.The four kinds of forest litter can absorb the rainfall from 2.11 to 2.9 of their dry weight;③The relationship of four undecomposed litter and half-decomposed litter of water holding capacity and immersion time is that the water will be absorbed very quickly by the litter in the first 2 hours.But it will be slowed down and reach the peak after 8 hours.④ The relational expression of the absorption rate and immersion time is that,between 0～2 h,litter absorb water speed very fast,drop the speed to slow down gradually after 4～6 h.