【作者】 薄涛；

【导师】 韩国栋；

【作者基本信息】 内蒙古农业大学 ， 生态学， 2009， 硕士

【摘要】 本研究于2005年~2008年在锡林浩特市西乌旗进行。以羊草草甸草原为研究对象,在自由放牧方式下家庭牧场的草地特征和土壤理化性质变化进行了研究。主要的研究结果如下:1.应用草地植被采食率确定了不同放牧强度的含义。2.放牧强度和气候对草地净初级生产力都有较大的影响。枯落物在各放牧强度间变化显著:CK>LG>MG>HG。放牧使草地植物发生了小型化现象。适当的放牧(LG,MG)可显著增加草地的植物种数;植物生殖枝的产生受降水和放牧强度双重作用的影响,并未表现出较强的的规律。3.植物功能群中禾草植物功能群的生态作用较大,各功能群在CK、和MG的草地表现出较好的气候稳定性。各主要植物的重要值在不同放牧强度下值不同,并在年度间保持较强的一致性,使得不同放牧强度下的草地处于不同演替阶段。4.随着放牧强度的增加表层土壤容重和紧实度也随之增大,年度间没有累积效果。土壤含水量随着放牧强度的增加有降低的趋势,其含量变化并不主要受大气降水的影响。随放牧强度的增加砂粒含量增加,粉粒含量降低,尤其HG变化明显,粘粒变化不显著:随土壤深度的增加砂粒含量增加,粉粒含量降低,粘粒含量变化不明显。5.土壤有机质随着土壤深度的增加显著减少。在LG下最高,MG、HG依次降低。放牧使表层土壤中全氮含量显著增加,放牧放牧降低了土壤全磷的含量。放牧有助于土壤全钾的积累,但放牧强度的变化对土壤全钾的积累作用不明显。放牧显著增加了土壤表层速效氮的含量。HG显著增加了土壤表面速效磷的含量,而且在放牧条件下土壤下层的速效磷的输出显著增加。随放牧强度的增加,土壤速K的含量增加。更多还原

【Abstract】 The trial was conducted in meadow steppe in Inner Mongolian from. 2005a to 2008a. Four grazing degraded stages of control, light, moderate, and heavy grazing were set up in order to understand grassland characteristics and soil physical properties. The results are as follows:1. The different grazing intensities were classified by utilization factor of vegetation.2. The grazing intensity and the climate have significant influence on the net primary productivity. The changes of litter under different grazing intensities were obvious, namely CK>LG>MG>HG. Plants became smaller with grazing. LG and MG obviously increased the species number. Plant reproduction was affected by precipitation and grazing intensity and no obvious change regulation with them.3. Grass functional group plays a significant ecological role in the plant functional groups. The functional groups show better climatic stability under control and moderate grazing. The importance values of the main plants are different and consistency among years, which made grassland in different succession stages under different grazing intensities.4. Soil bulk density and soil compaction increased with the increase of grazing intensity. Soil moisture content had the tendency of decrease, which had few relevance with rainfall. Sand content decreased with the increase of grazing intensity while silt content increased. No significant change was accrued in clay. Sand content increased with the increase of soil depth, clay content did not change significantly by reducing silt content.5. Soil organic matter decreased with the increase of grazing intensity. Grazing made the soil total nitrogen increase in soil surface layer. Grazing was benefit to soil total phosphor accumulation, but in different intensities the differences were not obvious. Grazing increased soil available nitrogen accumulation. Soil available phosphor in surface layer increased in HG, and output of phosphor increased obviously in subsoil. Soil available potassium increased with the increase of grazing intensity.更多还原