Resource manipulation effects on net primary production, biomass allocation and rain-use efficiency of two semiarid grassland sites in Inner Mongolia, China
Resource manipulation effects on net primary production, biomass allocation and rain-use efficiency of two semiarid grassland sites in Inner Mongolia, China
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资源操纵对中国内蒙古两个半干旱草地净初级生产力、生物量分配和雨水利用效率的影响
DOI：
10.1007/s00442-010-1890-z
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发表时间：
2011-04-01
期刊：
影响因子：
2.7
通讯作者：
Brueck, Holger
中科院分区：
文献类型：
--
作者：
Gao, Ying Zhi;Chen, Qing;Brueck, Holger
半干旱草地的生产力受土壤水分和养分供应的影响，在干旱条件下，水分控制净初级生产力，在湿润条件下，土壤养分限制生物量生产。为了研究根-冠生物量分配对水和氮（N）有效性的响应对植物的限制，在两个具有不同放牧历史的地点（中度（MG）和重度（HG）放牧）进行了一项田间试验，在恢复区与未施肥的对照区、接受N（25 kg尿素-N ha−1）和水（灌溉模拟雨季）的施肥区进行了对比。灌水和施氮对地下生物量没有影响。灌溉增加地上（ANPP）和地下净初级生产力（BNPP）和雨水利用效率的基础上，ANPP（RUEANPP），而氮添加在drought地块上没有任何影响的测量参数。施氮增加了灌溉地块的ANPP和RUEANPP，降低了根的部分（RF：根干物质/总干物质），导致较小的N对总净初级生产力（NPP）和基于NPP的雨水利用效率的影响。这表明，BNPP应包括在评估生态系统的响应，从整个植物的角度来看，资源的可用性。N对所有测量参数的影响在两个网站上是相似的。然而，网站HG灌溉响应较高的ANPP和较低的RF相比，网站MG，表明物种组成有显着的影响，由于地下和地上生态位互补的碳分配格局。
Productivity of semiarid grasslands is affected by soil water and nutrient availability, with water controlling net primary production under dry conditions and soil nutrients constraining biomass production under wet conditions. In order to investigate limitations on plants by the response of root–shoot biomass allocation to water and nitrogen (N) availability, a field experiment, on restoration plots with rainfed, unfertilized control plots, fertilized plots receiving N (25 kg urea-N ha−1) and water (irrigation simulating a wet season), was conducted at two sites with different grazing histories: moderate (MG) and heavy (HG) grazing. Irrigation and N addition had no effect on belowground biomass. Irrigation increased aboveground (ANPP) and belowground net primary production (BNPP) and rain-use efficiency based on ANPP (RUEANPP), whereas N addition on rainfed plots had no effect on any of the measured parameters. N fertilizer application on irrigated plots increased ANPP and RUEANPPand reduced the root fraction (RF: root dry matter/total dry matter), resulting in smaller N effects on total net primary production (NPP) and rain-use efficiency based on NPP. This suggests that BNPP should be included in evaluating ecosystem responses to resource availability from the whole-plant perspective. N effects on all measured parameters were similar on both sites. However, site HG responded to irrigation with higher ANPP and a lower RF when compared to site MG, indicating that species composition had a pronounced effect on carbon allocation pattern due to below- and aboveground niche complementarity.