琼西北 ３ 种林分类型枯落物与土壤的持水能力.

The water-holding capacity of litter and soil was measured in three different forest types（Eucalyptus robusta, Hevea brasiliensis, and Acacia mangium plantations) in the Mahuangling watershed in the north-west of Hainan, China, to provide a reference for the construction of local soil and water conservation forests. The hydrological functions of litter and soil were determined quantitatively using immersion and cutting-ring methods, and the water conservation capacity of each forest type was analyzed using the entropy weight method（EWM). The results showed that: the litter total storage in the three forest types was about 3.01～14.66 t·hm-2, in the order, A. mangium plantation＞H. brasiliensis plantation＞E. robusta plantation, the storage of semi-decomposed litter was higher than that of undecomposed litter, which was 75.09%～81.86% of the total storage; the maximum water holding capacity and the effective water interception capacity of litter were 8.60～33.95 t·hm-2 and 6.92～26.73 t·hm-2, respectively, in the order, A. mangium plantation＞E. robusta plantation＞H. brasiliensis plantation. The water-holding capacity had a logarithmic relationship with soaking time（R²＞0.940); whereas the water-absorption rate had a power function relationship with soaking time（R²＞0.880). The average soil bulk density ranged from 1.45 g·cm-3 to 1.52 g·cm-3, with total porosity ranging from 32.82%～37.56%, the effective water holding capacity of soil was 61.80～77.16 t·hm-2, in the order, A. mangium plantation＞E. robusta plantation＞H. brasiliensis plantation. The initial soil water infiltration rate was 24.74～29.67 mm·min-1, with the highest observed in A. mangium plantation, the stable soil water infiltration rate was 1.01～1.38 mm·min-1, a power function relationship was observed between the infiltration rate and infiltration time（R²＞0.920). The evaluation of the water conservation capacity indicated that soil water infiltration capacity and total litter storage were the main factors, in the order, A. mangium plantation（81.098 7) ＞E. robusta plantation（69.741 6) ＞H. brasiliensis plantation（67.151 4). Considering the hydrological effects of the litter and soil in the three forest types, the water conservation abilities of the A. mangium plantation were higher than those of other vegetation types. This suggests that the E. robusta and H. brasiliensis plantations should be transformed into mixed forests by planting A. mangium to increase their soil and water conservation capacities. [ABSTRACT FROM AUTHOR]