高寒草甸冷季放牧对凋落物分解及C、N、P化学计量特征的影响

发布时间：2018-08-11 09:19

【摘要】：为深入理解放牧对青藏高原高寒草地冷季牧场凋落物分解及C、N、P化学计量特征的影响,本研究分析了不同放牧强度下冷季牧场凋落物现存量及C、N和P化学计量特征动态。结果表明,凋落物现存量随着放牧强度的增加而减少,轻度(22.50个羊单位·hm~(-2))、中度(26.25个羊单位·hm~(-2))、重度(32.04个羊单位·hm~(-2))放牧草地凋落物现存量依次为45.72~125.52、17.32~56.6、8.64~30.96g·m~(-2)。放牧季随时间推移各放牧强度下现存凋落物的C含量逐渐降低,同一时期现存凋落物C含量依次为轻度放牧中度放牧重度放牧。在休牧期,随时间推移,中度和重度放牧的凋落物C含量呈显著增加趋势。放牧期,凋落物N含量随时间推移呈下降趋势。放牧期,同一时期现存凋落物P含量均表现为重度放牧中度放牧轻度放牧;而休牧期,同一时期现存凋落物P含量均表现为轻度放牧重度放牧中度放牧。重度放牧下,草地现存凋落物C/N均在90以上,休牧初期(7月)草地现存凋落物C/P较高,均在1 000以上。综合得出,随着放牧强度的增加,凋落物损失率显著增大,N含量降低,C含量变化不显著,P出现富集。
[Abstract]:In order to understand the effects of grazing on litter decomposition and CnP stoichiometric characteristics in cold season pasture of alpine grassland in Qinghai-Xizang Plateau, the present study analyzed the dynamics of litter standing and Con N and P stoichiometric characteristics in cold season pasture under different grazing intensities. The results showed that the litter standing stock decreased with the increase of grazing intensity, and that of light (22.50 sheep unit hm ~ (-2),) (26.25 sheep unit hm ~ (-2) heavy (32.04 sheep unit hm ~ (-2) was 45.72N 125.5217.326.328.648.64g / m ~ (-2). The C content of the existing litter decreased gradually with time, and the C content of the existing litter in the same period was in the order of light grazing, moderate grazing and heavy grazing. During the grazing off period, the litter C content of moderate and heavy grazing increased significantly with the passage of time. During grazing period, N content of litter decreased with time. In the grazing period, the P content of the existing litter in the same period was moderate to moderate grazing, while in the rest period, the P content of the existing litter in the same period was mildly grazed and moderately grazed. Under heavy grazing, the existing litter C / N was more than 90, and in the early stage (July), the litter C / P was higher than 1 000. It was concluded that with the increase of grazing intensity, the loss rate of litter increased significantly, the content of N decreased and the change of C content was not significant.
【作者单位】：甘肃农业大学草业学院/草业生态系统教育部重点实验室/中-美草地畜牧业可持续发展研究中心/甘肃省草业工程实验室;
【基金】：国家自然科学基金(31360570)
【分类号】：S812

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