祁连山高寒牧区不同类型草地植被特征与土壤养分及其相关性研究

为探究祁连山高寒牧区不同类型草地植被特征、土壤养分及其相关性,以山地草原、高山草原、高寒草甸草原草原3个类型草地为研究对象,采用野外调查、室内测定和数据统计分析相结合的方法,研究了3个类型草地的植被特征、土壤养分特征及其之间的相关性。结果表明：不同类型草地群落盖度、地上生物量差异明显,均为高山草原>山地草原>高寒草甸草原（P<0.05）;群落多样性、草本植物高度差异明显,均为山地草原 > 高山草原 > 高寒草甸草原（P<0.05）;小灌木平均高度差异明显,为高寒草甸草原 > 高山草原 > 山地草原（P<0.05）;不同类型草地土壤有机质含量变幅较大,其中以高寒草甸草原最为丰富;pH值变幅较大,变化趋势与有机质相反,即有机质含量越高,则土壤pH值低,反之亦然;全氮含量较高,都为1~2级（> 0.2%）;全钾含量居中,山地草原为2级（2.5%~3.0%）,高山草原和高寒草甸草原为3级（2.0%~2.5%）;全磷含量最低,均为3~4级（0.05%~0.10%）,全量养分表现出以低磷高氮富钾为特征;速效养分以贫磷为特征;土壤保肥能力较强;各类型草地土壤肥力因子间的相关性各有特点;总体看来,高山草原土壤养分含量最高,其群落的生产力也最高,但群落物种多样性最低。磷在祁连山高寒牧区很缺乏,建议在进行草原管理和人工饲草种植时补充磷素。

Study of Grassland Vegetation Characteristics and Soil Nutrient and Their Correlation between Different Grassland Types in Alpine Pastoral Area of Qilian Mountains

In order to study of grassland vegetation characteristics and soil nutrient and their correlation between different grassland types, we selected three different researching objects, such as upland meadow, alpine meadow and apine meadow-steppe type rangeland, and we used the combined analytical method to study vegetation characteristics, soil nutrient characteristics and their interrelations between three different grassland types. Our results show that:community coverage and aboveground biomass between different grassland types were significant differences, such as alpine steppe > upland meadow > apine meadow-steppe type rangeland (P<0.05); community diversity, herb height were significant differences between different grassland types, such as upland meadow > alpine steppe > apine meadow-steppe type rangeland (P<0.05); small shrubs height were significant differences between different grassland types, such as apine meadow-steppe type rangeland > alpine steppe > upland meadow (P<0.05). The content of soil organic matter in different grassland types is significant differences, the apine meadow-steppe type rangeland is the most abundant; pH value variation is large, and showed the opposite trend with organic matter, namely, higher organic matter content, low soil pH value and vice; the total content of nitrogen was up to 1th~2nd level (>0.2%); potassium, upland meadow to level 2 (2.5~3.0%), alpine meadow and apine meadow-steppe type rangeland for level 3 (2.0~2.5%); the content of total potassium, upland meadow to reach the 2nd level (2.5~3%), alpine steppe and apine meadow-steppe type rangeland up to the 3rd level (2~2.5%); the total content of phosphorus was lowest, were up to 3rd~4th grades (0.05~0.10%); total nutrients showed a characteristic that is low phosphorus, high nitrogen and potassium rich; the characteristic of total nutrients was low phosphorus, high nitrogen and relative rich potassium; the available nutrients were characterized with low available phosphorus; characteristics of soil has a strong ability to save fertilizer; correlation of soil fertility factors between different grassland types has different characteristics. In general, highest soil nutrient contents in Alpine grassland, which have the highest productivity in the community, but community diversity is the lowest. Phosphorus is scarce in alpine pastoral area of the Qilian Mountains, suggesting that fertilizing phosphorus, when cultivated artificially forage and grassland management.