Forage nutritional characteristics and yield dynamics in a grazed semiarid steppe ecosystem of Inner Mongolia, China
Forage nutritional characteristics and yield dynamics in a grazed semiarid steppe ecosystem of Inner Mongolia, China
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DOI：
10.1016/j.ecolind.2015.07.027
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发表时间：
2016-01-01
影响因子：
6.9
通讯作者：
Taube, Friedhelm
中科院分区：
文献类型：
--
作者：
Ren, Haiyan;Han, Guodong;Taube, Friedhelm
在内蒙古大草原，牧草是绵羊唯一的饲料来源。绵羊的采食量可以从数量和质量两个方面来描述，这是由环境和人为因素决定的，放牧对草原生产力和草原生态系统有很大的影响。因此，评价牧草的质量和数量至关重要。通过6年（2005-2010年）的控制放牧试验，在内蒙古典型草原上沿着7种放牧强度（从非放牧到重度放牧）梯度，研究了放牧强度、年际变异效应和物种组成对地上净初级生产力（ANPP）和牧草营养特性的影响。粗蛋白质（CP）、纤维素酶可消化有机物（CDOM）、代谢能（ME）和中性洗涤纤维（NDF）的营养价值和营养产量是牧草营养特性的主要指标。牧草营养产量是牧草营养价值和牧草净初级生产力的函数。随着放牧强度的增加，牧草营养价值增加，但ANPP和营养产量下降。年平均净初级生产力、牧草营养价值和产量的年际变化与降水量的年际变化关系较弱。但在生长季节，牧草的ANPP和营养价值也存在差异，这取决于降水和温度的季节分布，影响牧草的消化率（CDOM）和代谢能（ME），在高降水和低温度条件下，CDOM和ME较高。牧草营养价值和产量，以及ANPP，主要是由优势种，而不是由物种多样性。结果表明，内蒙古草原牧草营养产量主要由草地净初级生产力决定，其次由牧草营养价值决定;主要由优势种决定，其次由物种多样性决定。因此，牧草生产力似乎是管理这个草原生态系统作为牲畜的饲料资源的最限制因素，是最好的生态和环境指标的草地管理措施。(C)2015作者由Elsevier Ltd.发布。这是CC BY-NC-ND许可证下的开放获取文章（http：//creativecommons.orgilicenses/by-nc-nd/4.0/）。
In the steppe of Inner Mongolia, forage is the only source of feed for sheep. The forage intake of sheep can be characterized in both quantity and quality terms, which are determined by environmental and anthropogenic factors and grazing has a strong effect on steppe productivity And the grassland ecosystem. Evaluation of forage quality and quantity is therefore of critical importance. The effects of grazing intensity, interannual variability effects, and species composition on aboveground net primary productivity (ANPP) and forage nutritional characteristics were investigated in a controlled grazing experiment along a gradient of 7 grazing intensities (from non-grazed to very heavily grazed) over six years (2005-2010) on typical steppe in Inner Mongolia. Forage nutritional characteristics were defined by the nutritional value (concentrations of crude protein (CP), cellulase digestible organic matter (CDOM), metabolizable energy (ME) and neutral detergent fibre (NDF)) and the nutritional yield. The forage nutritional yield is a function of ANPP and the forage nutritional value. Forage nutritional value increased but ANPP and nutritional yields decreased with increasing grazing intensity. The inter-annual variation of ANPP, forage nutritional value and yield were weakly linked to the inter-annual variability of precipitation. However, ANPP and nutritional value also varied during the growing season, depending on the seasonal distribution of precipitation and temperature, which influence forage digestibility (CDOM) and metabolizable energy (ME), with higher CDOM and ME under high seasonal precipitation and low seasonal mean temperature. Forage nutritional value and yield, as well as ANPP, were predominantly determined by the dominant species rather than by species diversity. The results suggest that forage nutritional yield in the Inner Mongolian steppe is predominantly determined by the ANPP and only to a minor extent by forage nutritional value, and is predominantly determined by the dominant species and only to a minor extent by species diversity. Therefore, herbage productivity seems to be the most limiting factor in managing this steppe ecosystem as a feeding resource for livestock and to be the best ecological and environmental indicator for grassland management practices. (C) 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.orgilicenses/by-nc-nd/4.0/).