Studies On The Function Of Conservation Water Of Terraced Field In Yuanyang County

This paper combining by using field test investigation and laboratoryexperiment analysis method. Analysis of water-holding of the canopy layers, water-holdingof litter, soil retention and soil infiltration in six different typical plantations: Alnuscremastogyne （Ⅰ）, Alnus cremastogyne （Ⅱ）, Cunninghamia lanceolata, Symplocospaniculata （Ⅲ）, Dillenia indica （Ⅳ）, Cunninghamia lanceolata（Ⅴ）, Castanopsisorthacantha (Ⅵ）to research water conservation function, in order to sustainabledevelopment of the terrace.The results showed that:1）water-holding of the canopy layers the total capacity:Ⅴ（8.42t/hm2）＞Ⅵ（7.60t/hm2）＞Ⅳ（6.91t/hm2）＞Ⅲ（5.31t/hm2）＞Ⅰ（3.47t/hm2）＞Ⅱ（3.33t/hm2）.Ⅴ,Ⅵcrowndensity taller, lush foliage, biomass high, administrative levels is evident, and hold waterrate is high, so it moisture holding capacity is good.2）water-holding of litter:Ⅲ（17.21t/hm2）＞Ⅵ（15.48t/hm2）＞Ⅴ（14.42t/hm2）＞Ⅰ（13.26t/hm2）＞Ⅳ（5.43t/hm2）＞Ⅱ（4.01t/hm2）.Ⅵlitter cumulative capacityis much, administrative levels is taller, and its highest hold water rate, so it moistureholding capacity is good. AlthoughⅢhold water rate is relatively small, but litteradministrative levels is tall, cumulative capacity is largest, so it moisture holding capacityalso good. Conifer and broad leaved forest, Deciduous broad-leaved forest conducive torainfall interception, protection and improvement of soil structure, maintain and improvesoil permeability, played the role of water conservation.3）Soil retention showing forest bigger than wasteland:0-20cm soil levelⅢ（1169.80t/hm2）＞Ⅳ（1164.40t/hm2）＞Ⅴ（1024.00t/hm2）＞Ⅱ（1014.60t/hm2）＞Ⅰ（964.60t/hm2）＞Ⅵ（892.40t/hm2）＞wasteland（881.40t/hm2）;20-40cm soil levelⅠ（1235.40t/hm2）＞Ⅲ（1228.80t/hm2）＞Ⅵ（1190.40t/hm2）＞Ⅴ（1163.20t/hm2）＞Ⅱ（1016.20t/hm2）＞Ⅳ（920.80t/hm2）＞wasteland（874.60t/hm2）;40-60cm soil levelⅥ（1201.60t/hm2）＞Ⅲ（1104.80t/hm2）＞Ⅰ（991.60t/hm2）＞Ⅱ（931.20t/hm2）＞Ⅳ（835.40t/hm2）＞wasteland（819.80t/hm2）. Terraced surface of the soil water of forestlitter more, arbor, shrub and grass litter ash-rich element, easy to form humus, calcium andbasic cement, soil particles form a well-structured and easy cementation of soil, soil organic matter, nitrogen and phosphorus potassium content aggregation and increased soilporosity, thus enhancing the permeability of the soil water storage and the ability to play astrong soil layer of water conservation. Comparison of different stands, soil retention ofⅢ,Ⅰ,Ⅴare good.4）The forest soil initial water infiltration rate, steady infiltration rate, there is a bigdifference in the average infiltration rate. Soil initial water infiltration rateⅥ（23.00mm/min）＞Ⅴ（15.00mm/min）＞Ⅲ（20.00mm/min）＞Ⅱ（4.00mm/min）＞Ⅳ（4.00mm/min）＞Ⅰ（3.00mm/min）＞wasteland（3.00mm/min）; Steady infiltrationrate and the average infiltration rate:Ⅴ （0.18mm/min and8.80mm/min）＞Ⅲ（0.15mm/min，and5.95mm/min）＞Ⅵ（0.08mm/min and3.60mm/min）＞Ⅳ（0.04mm/min and1.48mm/min）＞Ⅱ（0.04mm/min and1.28mm/min）＞Ⅰ（0.03mm/minand0.98mm/min）＞wasteland（0.02mm/min and0.91mm/min）. Illustrates the terracedwater permeability is better forest soil, the forest soil permeability index were higher thanslopes; infiltration capacity of the forest, we can knowⅤandⅢsoil infiltration the bestperformance.5）Water conservation functions of forest mainly by forest and soil combine to play arole in common only the same time have a good forest cover and deep soil, will havegreater and higher the hydrological function of the hydrological benefits. Comprehensiveanalysis of the canopy layer, shrub and grass layer, the litter layer, soil layer four levels ofregulation and redistribution of precipitation capacity, we can see terraced slopes tallerthan wastland. The best water conservation capacity of Deciduous broad-leaved forest.Comparison of different stands, soil retention ofⅢ,Ⅰ,Ⅴare good.