Evaluation Of Anti Water Erosion Function Of Main Forests In The South Hilly And Mountain Region Of Jiangsu Province

This study chose main forests such as Quercus (Quercus acutissima), Bamboo (Phyllostachys pubescens), Chinese fir (Cunninghamia lanceolata) and Masson pine (Pinus massoniana Lamb) in the south hilly and mountain region of Jiangsu Province. The experiment studied the anti warer ersion fuction of the three main layers, such as canopy, litter and soil in the four typical forests by the method of the positioning observation in the field and indoor simulation. The main conclusions as follows:(1) There were some difference among the hydrological function of different forests, the canopy interception rate of Bamboo was the highest (26.64%), the second one was Quercus (22.64%), the third one was Chinese fir (21.29%), and the last one was Masson pine (15.28%). Canopy interception (mm) increased with the increase of rainfall (mm) by Power model (y=axb), canopy interception rate (%) reduced with the increase of rainfall (mm) by Logarithmic model (y=a+blnx). Four forests had slowed down the rainfall erosivity well, the annual rainfall erosivity under Quercus, Bamboo, Chinese fir and Masson pine were 63.397%,49.605%, 63.536% and 74.035% of the one outside respectively.(2) The largest water-holding capacity of litter was in order of Quercus (39.214t·hm-2)> Bamboo (38.182 t·hm-2)> Chinese fir(17.734t·hm-2)> Masson pine (6.765t·hm-2). When dry weigh was same, the roughness coefficient of litter of Quercus was the highest (26.64%), the second one was Bamboo, the third one was Chinese fir, and the last one was Masson pine. Water-holding velocity (mm/h) of litter reduced with the increase of impinging time (h) by Power model (y=axb). Roughness coefficient of litter increased with the increase of dry weigh by Logarithmic model (y=a+blnx).(3) Based on the principal component analysis, soil hydrological function was in order of Bamboo> Quercus> Chinese fir> Masson pine. Based on grey correlation analysis, evaluation results of soil anti-erodibility of forests showed that:Bamboo belonged to relatively strong, Quercus and Chinese fir belonged to middle, Masson pine belonged to relatively poor. Soil shear-resistantance of different forests was in order of Quercus> Masson pine> Chinese fir> Bamboo. Soil anti-scourability of different forests was in order of Bamboo> Chinese fir> Quercus> Masson pine. Soil permeability, soil shear-resistantance and soil anti-scourability could be described by plural linear regression equations of some soil physical and chemistry factors.(4) The comprehensive evaluation method of forest water conservation function, comprehensive evaluation method of soil anti water erosion function and comprehensive evaluation system of forest anti water erosion function, all of them had a certain extensive applicability and scientific. The evaluation results of forest water conservation function in the study region showed that:Bamboo belonged to relatively good, Quercus belonged to middle, Chinese fir belonged to relatively bad, Masson pine belonged to bad; the evaluation results of soil anti water erosion function showed that:Bamboo belonged to relatively strong, Quercus, Chinese fir and Masson pine belonged to middle; the evaluation results of forest anti water erosion function showed that:Bamboo belonged to relatively strong, Quercus and Chinese fir belonged to middle, Masson pine belonged to relatively poor.