Livestock grazing modifies the effect of environmental factors on soil temperature and water content in a temperate grassland
Livestock grazing modifies the effect of environmental factors on soil temperature and water content in a temperate grassland
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DOI：
10.1016/j.geoderma.2014.08.002
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发表时间：
2014-12
期刊：
影响因子：
6.1
通讯作者：
I. Odriozola;G. García-Baquero;N. A. Laskurain;A. Aldezabal
中科院分区：
文献类型：
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作者：
I. Odriozola;G. García-Baquero;N. A. Laskurain;A. Aldezabal
大型食草动物的放牧调节了土壤温度和含水量以及返回土壤的资源质量。因此，为了预测放牧对复杂交互作用的土壤过程和植物生产的影响，需要一种综合的方法。我们假设放牧通过增加(i)土壤温度和波动、（ii）保水能力和（iii）饲料质量来加速养分循环。为了验证这一生物学假说，我们在半自然山地草地样地进行了模拟弃牧条件的野外试验。我们的研究结果表明，放牧通过所有三种假设机制加速了土壤过程。由于放牧维持了一层薄薄的有机层，对土壤的绝缘性较差，放牧地区的平均温度较高，日温度波动较大（绝缘性较差）；这些日波动与未放牧地块的季节变化一样大。土壤含水量对放牧的响应是复杂的。虽然总体上排斥减少了土壤含水量，特别是在粗质土壤中，但在长时间的高太阳辐射（即高蒸发）期间，这种趋势被逆转。排除放牧者后，所有样地的牧草质量均下降。试图真实地模拟放牧的实验可能会受益于这些发现，特别是在非常高产的草原上，在不放牧的情况下，有机层的厚度迅速增加。
Grazing by large herbivores modulates the soil temperature and the water content as well as the quality of resources returned to the soil. Therefore, in order to predict the effects of grazing on complex interacting soil processes and plant production, an integrated approach is needed. We hypothesized that grazing accelerates nutrient cycling by increasing (i) soil temperature and fluctuations, (ii) water-holding capacity, and (iii) forage quality. To test this biological hypothesis, we conducted a field experiment simulating grazing abandonment conditions in semi-natural mountain grassland plots. Our results show that grazing accelerates soil processes through all three hypothesized mechanisms. Since grazing maintains a thin organic layer that provides less insulation to the soil, higher mean temperatures and large daily temperature fluctuations were recorded in grazed areas (less insulated); these daily fluctuations were as large as seasonal variation in the ungrazed plots. The response of the soil water content to grazing was complex. Although overall exclusion reduced the soil water content, particularly in coarse-textured soils, this trend was reversed during long periods of high solar radiation (i.e. high evaporation). Forage quality was reduced in all plots when grazers were excluded. Experiments attempting to realistically simulate grazing may benefit from these findings, particularly in very productive grasslands where the thickness of the organic layer increases rapidly under grazing exclusion.