The Ecological Effects Of Litter-fall Of Phyllostachys In Northern Subtropical Area

The thesis conducted a research on the hydrological characteristics of litter-fall of Phyllostachys, nutrients decomposition and release, soil properties and soil absorption of moso bamboo in Kongqing Forest Station of Nanjing Forestry University. The results are as follows:(1) Under the condition of indoor simulated rainfall, the slope gradient is an important factor in slope erosion. With the increase in slope, the sediment concentration increase in different extents. The trend is gentle in the slope of 5°,10°,15°; and is obvious in the slope of 20°and 25°. The rainfall intensity is also an important factor in slope erosion. With the rainfall intensity increasing, the sediment concentration also increases, and the amplitude of trend increases.(2) Compared with the average sediment concentration of bare soil and soil covered with litter in different slopes, the sediment concentration of bare soil substantial increases with increasing slopes, while the amplitude of soil covered with litter increase is significantly reduced. The extent ion is 52.9%-87.1%.(3) Compared with the total erosion of bare soil and soil covered with litter in different rainfall intensities, it decreases soil erosion of slope land 35.58g/m2,66.82 g/m2,130.32 g/m2, 190.62g/m2 and 256.16 g/m2 respectively. With the increase of rainfall intensity, the total runoff increases both in slope covered with bamboo litter and bare soil in different rainfall intensity, however, slope covered with bamboo litter increase amplitude of runoff reduced to 25%.(4) There is a visible seasonal variation of the phyllostachy litter dynamics in the year, the monthly maximum of litter amount is 343.5 kg/hm2 in June; while the minimum is 195.62 kg/hm2 in December.(5) Bamboo litter with different soaking time has an extremely significant effect of water-holding rate, and it is not significant to correlation of litter water-holding characteristics in different seasons.(6) In bamboo experimental field, the soil bulk density increases from top layer to bottom, while total porosity of soil decreases. The water content of forest land increases from top layer to bottom.(7) Through the comparison of different nutrients decomposition and release of bamboo forest litter in different stages, we find that decomposition of litter is faster in summer, and is slower in winter, and the different elements have different decomposition rates.The largest element is K (0.00368), followed by P (0.00264) and Mg (0.00258); the least is N (0.00177) and Ca (0.00102). (8) The feedback effect of litter nutrients to soil is to make better maintenance of soil fertility and improve the productivity of bamboo.