The Litter And Soil Hydrological Effects Of Five Different Forest Stands In Liuxi River

Taking the water conservation forest on the small watershed of the upper stream of the Liuxi River as the research background.5 different stand types(Chinese fir plantation,coniferous-broadleaved mixed forest,broadleaved mixed forest,Moso bamboo forest,and litchi forest)were selected as the research objects,and this paper analysed the understory plants diversity,canopy structure,water retention characteristics of litter,soil bulk density,soil porosity,soil water storage capacity,soil infiltration performance and soil nutrient.And further study of Liuxi river water source conservation forests litter layer and soil layer hydrology ecological function relationship.And provide scientific and effective guidance and reference basis for the ecological construction of water conservation forests in the reservoir area of Guangdong Province and the selection of tree species for forest regeneration.The main conclusions are as follows:(1)There were 153 plant species which belong to 68 families and 122 genera in shrub layer and herb layeroffive different forest types,including 110 shrub plants and 43herbs.The abundance index,Simpson index,shannon-wiener index and community evenness of the five stand forest were roughly represented by shrub layer>herb layer.The diversity of litchi forest plant in shrub layer was lower.In the herb layer,the plant diversity of broad-leaved mixed forest was lower;the plant diversity of Moso bamboo forest is the best overall,the plant species is the most abundant,and the plant distribution is more uniform.The similarity of the plant community was the highest among Chinese fir trees and broad-leaved mixed forest,and the lowest similarity was found between litchi forest and other forest plants.(2)The canopy openings of five different stand types were Chinese fir forest>broad-leaved mixed forest>Moso bamboo forest>coniferous-broadleaved mixed forest>litchi forest;the leaf area index size was opposite to the canopy opening degree,and the order was:litchi forest>coniferous-broadleaved mixed forest>broad-leaved mixed forest>Moso bamboo forest>Chinese fir plantation;direct light transmittance under forest,light transmittance under forest,and total light transmittance under forest showed a consistent pattern of changes,and the order was:Chinese fir plantation>Moso bamboo forest>broad-leaved mixed forest>coniferous-broadleaved mixed forest>litchi forest.(3)The total litter volume of five different stand types ranged from 2.07-6.64 t/hm~2,the size of which was in the order of litchi forest>coniferous-broadleaved mixed forest>Chinese fir forest>broad-leaved mixed forest>Moso bamboo forest;The total maximum water-holding capacity of litter fall of five forest stands was ranked as follows:broad-leaved mixed forest>bamboo forest>litchi forest>Chinese fir forest>coniferous-broadleaved mixed forest;due to the large difference in litter volume of each stand,the maximum water-holding capacity was also different,and it was represented as follows:litchi forest>coniferous-broadleaved mixed forest>Chinese fir forest>broad-leaved mixed forest>bamboo forest.(4)The soil bulk density of five different forest types gradually increased with the deepeness of soil depth.The soil weighted average weight of 60 cm soil layer thickness was litchi forest>Chinese fir forest>broad-leaved mixed forest>coniferous-broadleaved mixed forest>Moso bamboo forest;soil total porosity changes with the deepening of the soil layer gradually decreased;in the 0-60cm soil layer,the total porosity,capillary porosity,non-capillary porosity and ventilation porosity of the bamboo forest were the largest;and the pores of the broad-leaved mixed forest were relatively large,and the non-capillary porosity was relatively small.The retained water storage capacity of the 60 cm soil thickness in the five stands was Moso bamboo forest>coniferous-broadleaved mixed forest>litchi forest>Chinese fir forest>broad-leaved mixed forest.The initial infiltration rate of the 0-20cm soil layer in the five forest stands varies from 0.71 to 3.34 mm/min,and the initial infiltration rate of the Chinese fir forest was the largest,and the litchi forest was the smallest.The range of steady infiltration rate was 0.37-5.40mm/min,and the broad-leaved mixed forest was the largest,the litchi forest was the smallest.The infiltration rate of the soil in each stand gradually decreased with time,and eventually stabilized.The comprehensive order of soil physical properties of the five stands was Moso bamboo forest>broad-leaved mixed forest>Chinese fir forest>coniferous-broadleaved mixed forest>litchi forest.(5)The comprehensive evaluation based on the method of PCA showed that the litter layer and soil layer hydrological effects of five different stands were in the order of Mosobamboo forest>broad-leaved mixed forest>Chinese fir forest>coniferous-broadleaved mixed forest>litchi forest.