施肥和围栏封育对青海湖地区高寒草原影响的比较研究 Ⅱ地上生物量季节动态

Comparative studies on the influence of chemical fertilizer application and enclosure on alpine steppes in Qinghai Lake area ⅡSeasonal and Annual Biomass Dynamics

选择青海湖北岸青海省三角城种羊场地区的天然高寒草原为研究对象,对多年围栏样地,围栏内外施N、P肥作为调控措施,并与围栏内外的天然草原做对照,旨在寻求退化草地恢复的最佳途径。结果表明:施肥和围栏封育都可明显提高优良牧草的地上生物量,且施肥的效果尤为明显;生物量的季节动态呈单峰曲线,不同处理措施下生长曲线的基本形状也相似,而且地上生物量的变化趋势与气象因子降水量和气温的变化同步。不同调控措施下干物质含量的季节变化也很明显,生长初期和生长后期干物质含量均高于中间阶段,有一个高—低—高的变化过程。

The study was conducted in the sheep breeding farm of Sanjiao city in Qinghai Province, which located in the northern bank of Qinghai Lake. Nitrogen and phosphor fertilizer were applied to the alpine steppe to find out an approach to restoring degraded grassland, the natural alpine steppe at the outside of the fence was used as control. The result showed that the aboveground biomass increased significantly after applying chemical fertilizes and enclosure, the effect of fertilizer was better than that of enclosure. The seasonal dynamics of aboveground biomass is a growth curve with single apex, and the forms of the curve were similar under different treatments. The trend of aboveground biomass took the same pace with the change of precipitation and temperature. The rate of dry weight had obviously changed with season under different management. The dry matter was higher at the initial and later stages than that of middle stage, showing a high-low-high change process.