The Effect Of Litter On Vegetation And Soil Moisture In Typical Grassland

Grassland ecosystem is one of the important types in terrestrial ecosystem; typical grassland is the important part of Inner Mongolia grassland which plays a key role in the development of agriculture and husbandry production. Litter is the significant component of typical grassland, and also an important indicator of grassland health. This paper probes into the effect of the amount of litter on vegetation community composition, characteristics of above-ground biomass and soil moisture and infiltration rate. The paper could be seen as the theoretical basis of the importance of litter in maintaining the stability of grassland system, rangeland resources sustainability and grassland scientific management and utilization.The experiment was conducted in degraded site of Inner Mongolia Grassland Ecosystem Positioning Station, Chinese Academy of Sciences. In the fall of 2002 and 2005, the treatment of litter addition and removal were conducted respectively on degraded site. There are three treatments, including severe(H)and medium(M)litter addition and removal, and control(C).The above ground vegetation survey is implemented after addition and removal treatment in the growing season every year. The survey includes on above-ground biomass and biomass of each species. In the mean time, the determination of soil moisture content is conducted monthly in growing season. The experimental results show as follows:1. Litter addition and removal in different season has different impact on grassland productivity. Litter added in fall has greater impact on grassland biomass than that in spring. Proper addition in litter is useful for increasing grassland productivity. Litter removal has no obvious influence on grassland productivity no matter in spring or fall.2. The different functional groups in the typical grassland had the different response to litter addition or removal. Perennial forbs and annuals and biennials were sensitive to the litter change. Meanwhile, perennial forbs and bunch grass has ecological compensation effect which is good for the stability of the ecosystem.3. The litter addition and removal in different seasons has various impacts on soil infiltration rate. The litter added in spring and fall had little influence on the soil infiltration rate. Medium litter removed in fall affected the soil infiltration; the highest value was 1.38mm/min, significantly higher than the control plot(P<0.05).4. Soil moisture varied with the litter treatments but the significant difference of soil moisture appears in the following year after the treatments. The plot with litter covered had a large value of soil moisture (P<0.05). The removal of litter increased the loss of the water and decreased the soil moisture.