Tradeoffs between forage quality and soil fertility: Lessons from Himalayan rangelands
Tradeoffs between forage quality and soil fertility: Lessons from Himalayan rangelands
复制标题
牧草质量和土壤肥力之间的权衡：喜马拉雅牧场的经验教训
DOI：
10.1016/j.agee.2016.04.023
复制
发表时间：
2016-10-16
影响因子：
6.6
通讯作者：
Lechowicz, Martin J.
中科院分区：
文献类型：
--
作者：
Niu, Kechang;He, Jin-sheng;Lechowicz, Martin J.
欧亚牧场的牧民往往认为，适度轮牧的传统管理做法可确保可持续产量，提高植物的消化率，促进生物多样性。为了评估这些假设的一般性，我们比较了生物量生产，群落叶C，N和P的化学计量，叶性状多样性和碳和养分库在根和土壤中的中度放牧与未放牧的地块在西藏高山草甸。我们使用了五个叶性状（叶C，叶N和叶P浓度; SLA：比叶面积，和LDMC：叶干物质含量）作为植物消化率和牧场质量的指标。我们测量了这些叶片性状和分株数量的组成物种在适度放牧的地块，以及在围栏（3-11年）在青藏高原的5个地点。群体加权平均（CWM）性状值和功能离散度（FDis）分别用于量化性状值分布的平均值和方差。放牧条件下，叶片P-CWM和叶片P-FDis普遍增加，LDMCCWM减少，从而改善植物消化率和牧场质量（例如，高，社区范围内的叶片营养素）。放牧条件下，叶片C-CWM、N-CWM和SLA（CWM）均呈上升趋势，而FDIS呈下降趋势。放牧总体上增加了物种多样性，但降低了地上生物量、有机碳、土壤和根系养分浓度，尤其是降低了根系氮和土壤有效磷。在湿润的放牧样地，根系生物量和叶片C：N（CWM）均下降，而在干燥的放牧样地，根系生物量和叶片C：N均上升。整个社区的增加和更大的种间多样性，再加上减少LDMCCWM的叶营养浓度表明，放牧引起的植物消化率，营养浓度和营养多样性在这些高山草甸的增加。然而，这种饲料质量的提高是以碳储量和养分可用性的损失为代价的，这些损失抑制了生物量的生产。我们的研究结果和对相关文献的回顾表明，传统的放牧方式涉及短期产量和可持续性之间的权衡，这是一个必须在土壤肥力低的牧场上解决的管理挑战。(C)© 2016 Elsevier B. V.版权所有。
Pastoralists on Eurasian rangeland often believe that traditional management practices involving moderate rotational grazing ensure sustainable yield, increase plant digestibility and promote biodiversity. To assess the generality of these suppositions we compared biomass production, community leaf C, N and P stoichiometry, leaf trait diversity and carbon and nutrient pools in root and soil for moderately grazed vs. ungrazed plots in Tibetan alpine meadows. We used five leaf traits (leaf C, leaf N and leaf P concentrations; SLA: specific leaf area, and LDMC: leaf dry matter content) as indicators of plant digestibility and rangeland quality. We measured these foliar traits and the ramet numbers for component species in moderately grazed plots as well as in exclosures (3-11 years) at five sites across the Qinghai-Tibetan plateau. Community weighted mean (CWM) trait values and functional dispersion (FDis) were used to quantify the mean and the variance in the distribution of trait values, respectively. Both the leaf P-CWM and leaf P-FDis generally increased under grazing and the LDMCCWM decreased, leading to improved plant digestibility and rangeland quality (e.g. high, community-wide leaf nutrients). The leaf C-CWM, leaf N-CWM and SLA(CWM) increased under grazing but the FDis of these traits tended to decrease. Grazing generally increased species diversity but decreased aboveground biomass, organic carbon, and nutrient concentrations in soil and root, especially decreasing root nitrogen and soil available phosphorus. Both root biomass and the leaf C:N (CWM) decreased in grazed plots at wet sites, but increased at dry sites. The community-wide increase and greater interspecific diversity in leaf nutrient concentrations coupled with decreasing LDMCCWM show that grazing induced an increase in plant digestibility, nutrient concentrations, and nutrient diversity in these alpine meadows. However, this increase in forage quality comes at the cost of losses in both carbon stock and nutrient availability that depress biomass production. Our findings and a review of related literature suggest that traditional grazing practices involve a trade-off between short-term yield and sustainability, a management challenge that must be addressed on rangelands with low soil fertility. (C) 2016 Elsevier B.V. All rights reserved.