Study on Correlation between Rocky Desertification Degree and Forest Water Conservation in Karst Area

In order to investigate the water conservation capacity of different types of forest in karst rocky desertification areas, the water-holding capacity of litter layer and soil layer of different forests was measured in nine types of forest in Bijie-Salaxi potential-mild rocky desertification research area, Guanling-Zhenfeng Huajiang medium-intensity rocky desertification research area and Shibingwu potential rocky desertification research areas in southern China. The results showed that: (1) The order of effective retention capacity of litter layer in the medium-intensity rocky desertification study area was: Tectona grandis > Cladrastis platycarpa > Zanthoxylum bungeanum, in the potential-mild rocky desertification study area was: Pinus armandii > Betula luminifera > Juglans regia, in the non-potential rocky desertification study area was: Pyrus > Tilia nanchuanensis > Pinus massoniana. (2) Soil bulk density of different forest types varied from 0.85 g·cm⁻³ to 1.34 g·cm⁻³, and total porosity varied from 47.71% to 65.69%. Soil bulk density was negatively correlated with soil porosity, water holding capacity and water storage (p < 0.05), while soil water content was positively correlated with soil porosity (p < 0.05). (3) The comprehensive water-holding capacity of different forest types was calculated by Topsis method. The results showed that in medium-intensity rocky desertification study area: Tectona grandis > Cladrastis platycarpa > Zanthoxylum bungeanum, in potential-mild rocky desertification study area: Pinus armandii > Betula luminifera >Juglans regia, and in non-potential rocky desertification study area: Pinus massoniana > Pyrus > Tilia nanchuanensis. The results could provide a basis for subsequent rocky desertification management and vegetation restoration.