Influence Of Different Plants In Limestone Mountainous Areas On Soil Water Conservation

The natural environment consisting of specific geological background,unique hydrological conditions and moist climate with abundant rainfull in Guizhou Karst District;along with the social environmental such as overloaded population density,socio-economic poverty,ethnic culture and unreasonable human activities,have led to increasingly serious water and soil erosion,which promoted the formation of karst rocky desertification.The intensification of karst rocky desertification includes degradation of soil as well as vegetation and the decline of productivity with a series of ecological and environmental problems.The catastrophic chain reaction caused by karst rocky desertification has severely restricted regional economic development.For this reason,the restoration and construction of forest vegetation has become the foundation of ecological environment construction in karst area.Meanwhile,limestone mountainous area is the common geological condition in karst area of Guizhou.Therefore,this paper selects surface litters and soils of 73 species of plants grown in the limestone mountainous areas of Guizhou as research objects,so as to measure and analyze the litter volume,water holding capacity,soil physical properties and permeability of different plants.It aims to explore the differences water conservation of tree species grown in Guizhou limestone mountainous areas.The research results indicated that,1?In terms of litter volume,the storage volume in undecomposed layer of deciduous broad-leaf species ranged 5.12⁰.80 t?hm-² and semi-decomposing layer ranged 3.45⁰.36 t?hm^-2 with a total volume of 6.78¹.16 t?hm^-2;the storage volume in undecomposed layer of evergreen broad-leaf species ranged 3.35⁰.69 t?hm^-2 and semi-decomposing layer ranged 3.57⁰.40 t?hm^-2 with total volume of 6.58¹.09 t?hm^-2;the storage volume in undecomposed layer of coniferous species ranged 3.24¹.43 t?hm^-2and semi-decomposing layer ranged 6.55⁰.94 t?hm^-2 with total volume of 9.80².37t?hm^-2;the storage volume in undecomposed layer of bush species ranged 1.92⁰.45 t?hm^-2 and semi-decomposing layer ranged 1.46⁰.22 t?hm^-2 with total volume of 3.12⁰.67t?hm^-2.The the storage volume in undecomposed layer of bamboo species ranged 4.73⁰.77 t?hm^-2 and semi-decomposing layer ranged 6.96⁰.86 t?hm^-2 with total volume of 11.70¹.63t?hm^-2.2?In terms of litter retention,the total water holding capacities of deciduous broad-leaf species ranged 1.39¹3.73 t?hm^-2,evergreen broad-leaf species ranged 2.32⁹.31 t?hm^-2,coniferous species ranged 3.37¹2.78 t?hm^-2,bush species ranged 1.08⁴.78 t?hm^-2,bamboo species ranged 3.21¹0.90 t?hm^-2.During the process of retention,it was found that litter retention and soaking time met the relation of Y=aLn?x?+b,and the water absorption rate and the soaking time met the relation of Y=axt.3?In terms of soil physical properties,the volumetric weight of deciduous broad-leaf species ranged 0.87¹.46 g?cm^-3,the maximum soil water-holding capacity ranged 669.75³14.48 t?hm^-2,the effective soil water retention 9.22⁴7.79 t?hm^-2.The volumetric weight of evergreen broad-leaf species ranged 0.95¹.53 g?cm^-3,the maximum soil water-holding capacity ranged663.10³74.69 t?hm^-2,the effective soil water retention 10.88⁶0.98 t?hm^-2.The volumetric weight of coniferous species ranged 0.89¹.46 g?cm^-3,the maximum soil water-holding capacity ranged 602.95³84.96 t?hm^-2,the effective soil water retention 7.22³.92 t?hm^-2.The volumetric weight of bamboo species ranged 0.84¹.24 g?cm^-3,the maximum soil water-holding capacity ranged 687.88³93.36 t?hm^-2,the effective soil water retention 7.27⁴6.41 t?hm^-2.The volumetric weight of bush species ranged 0.95¹.53 g?cm^-3,the maximum soil water-holding capacity ranged 582.32³37.24 t?hm^-2,the effective soil water retention8.00³2.81 t?hm^-2.4?In terms of soil penetrating quality,soil steady infiltration rates of deciduous broad-leaf species ranged 0.10²6.99mm/min,evergreen broad-leaf species ranged 0.78²9.63mm/min,coniferous species ranged 1.14⁹.10mm/min,bush species ranged 0.12³3.53mm/min,and bamboo species ranged 0.21²6.51mm/min.The three plant species with largest soil steady infiltration rate respectively were Rhus chinensis?33.53mm/min??glossy privet?31.71mm/min??oriental white oak?29.63mm/min?.5?Based on the principal component analysis and cluster analysis of litter layer and soil layer data of studied plants,the plants were divided into three groups of excellent,good and average according to water conservation capacity.Among them,13 plants were excellent,accounting for17.8%;27 were good,accounting for 37.0%;and 33 were general,accounting for 45.2%.Among the 13 plants with excellent rating,coniferous species accounted for 0%,bamboo species accounted for 15.38%,deciduous broad-leaf species accounted for 38.46%,evergreen broad-leaf species accounted for 15.38%,bush species accounted for 30.78%;among the 27 good plants,coniferous species accounted for 11.11%,bamboo species accounted for 0%,deciduous broad-leaf species accounted for 59.26%,evergreen broad-leaf species accounted for 11.11%,bush species accounted for 18.52%;among the 33 average plants,coniferous species accounted for 9.09%,bamboo species accounted for 6.06%,deciduous broad-leaf species accounted for 45.46%,evergreen broad-leaf species accounted for 9.09%,and bush species accounted for 30.30%.