【摘 要】
：
以西藏高山嵩草草甸为研究对象,研究不同放牧强度对高山嵩草草甸群落盖度、生物量和优势种盖度和高度以及草地土壤的理化性状的影响。研究结果表明:随着放牧牦牛强度的增加,高山嵩草草甸群落的盖度和生物量以及优势种高山嵩草和紫花针茅盖度和高度均显著降低,重度放牧(HG)与对照间差异达到显著水平(P＜0.05),适度放牧群落盖度和高山嵩草的盖度与对照间的差异没有达到显著水平(P＞0.05);0～10cm土层中草
【机 构】
：
北农林科技大学 动物科技学院,陕西 杨凌 712100 西藏农牧学院 植物科学学院,西藏 林芝 8
论文部分内容阅读
以西藏高山嵩草草甸为研究对象,研究不同放牧强度对高山嵩草草甸群落盖度、生物量和优势种盖度和高度以及草地土壤的理化性状的影响。研究结果表明:随着放牧牦牛强度的增加,高山嵩草草甸群落的盖度和生物量以及优势种高山嵩草和紫花针茅盖度和高度均显著降低,重度放牧(HG)与对照间差异达到显著水平(P＜0.05),适度放牧群落盖度和高山嵩草的盖度与对照间的差异没有达到显著水平(P＞0.05);0～10cm土层中草地土壤硬度、容重、pH值随着放牧强度的增加而增加,而土壤含水量随着放牧强度增加而减少,不同放牧处理间的差异达到显著水平(P＜0.05);放牧对土壤化学性状的影响主要表现为,随着放牧强度增加,0～30cm土层中有机碳、速效氮、速效磷和速效钾含量减少,而适度放牧全氮含量与对照间的差异不显著(P＞0.05).适度放牧下10～20cm土层中速效磷含量显著增加,与对照和重度放牧相比较,差异达到显著水平(P＜0.05).不同处理在20～30cm土层中有机碳和速效钾含量差异没有达到显著水平(P＞0.05).因此,青藏高原高山嵩草草甸合理载畜量为0.375头/hm2牦牛,超过这一阈值,草地可能发生退化。
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