Study On Effects Of Litter On The Soil Environment Of 9 Vegetation Communities In Baihua Mountainous Areas West Beijing

Though mensurated water-holding capacity of litter, litter and soil physiochemical characters correlation analysis, effects of litter on the soil respiration, interception of litter to the soil seed bank and effects of litter on germination seedlings of 9 vegetation communities in Baihua mountainous areas west Beijing. As a result showed that:(1) Water-holding capacity of the litter in forest communities was higher than litter of the shrub and the herb, semi-decomposed litter layer was higher than un-decomposed litter layer of water-holding capacity. Effective holding-capacity to rainfall of litter and stock, max water-holding rate showed positive correlation, especially it with max water-holding rate had significant correlation (n=9,p<0.01).(2) The litter could effectively improve soil physical characters. The larger stock of litter were, the better soil physical characters were. Correlation analysis revealed that stock of litter had positive correlation with all soil physical characters except soil bulk density showed negatively. Soil water-holding capacity had significant relationship with non-capillary porosity, but in essence, it was affected by litter.(3)The litter could decomposed and released nutrients to soil, of which organic matter and total nitrogen increased particularly. Overpass established linear regression equations, soil organic matter and total nitrogen with stock of litter had significant positive correlation, especially with soil(0～10cm), Correlation coefficients were 0.8361 and 0.9223(n=9), at 0.01 level extremely significant.(4) Manifestations of effects of litter on the soil respiration of which could cause CO2 elevation from soil respiration, contribution rate of the litter respiration to the soil respiration was from 6.62% to 40.83% in 9 vegetation communities. Litter respiration rate with stock, thickness had positive correlation. The relationship between soil respiration rate and environment factors contained a significant correlation, the soil respiration rate showed significant positive correlation with the soil temperature (5cm) (n=48,p<0.001), but it showed negative correlation with the atmospheric pressure and CO2 concentration of ground surface(n=48,p<0.001).(5) Effects of litter on potential fecundity of vegetation soil seed bank showed two aspects:First, litter could intercept soil seed bank, the interception rate was between 30.8% to 77.3%, linear correlation analysis revealed the interception rate and litter thickness showed positive correlation at 0.01 level (r=0.7281,n=9,p<0.01). Second, Whether effects of litter on seedling growth had advantage, basically speaking, depended on thickness of litter. In which forest communities had thick litter layer, mortality of seedlings in the litter were higher than in the soil, but in the litter of shrub and herb communities, mortality of seedlings in the litter were lower than in the soil.