The response of organic matter mineralisation to nutrient and substrate additions in sub-arctic soils
The response of organic matter mineralisation to nutrient and substrate additions in sub-arctic soils
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DOI：
10.1016/j.soilbio.2009.10.004
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发表时间：
2010-01-01
影响因子：
9.7
通讯作者：
Wookey, Philip A.
中科院分区：
文献类型：
--
作者：
Hartley, Iain P.;Hopkins, David W.;Wookey, Philip A.
北极的全球变暖可能会改变北极土壤的分解速度，从而改变养分的可获得性。此外，改变生长季的长度可能会增加植物的生产力和地下不稳定的碳输入的速率。我们进行了一项实验，在瑞典北部山地白桦林-苔原荒漠交错带的土壤(森林中的有机土壤和矿物土壤)中添加无机养分(NH4NO3和NaPO4)和有机基质(葡萄糖和甘氨酸)。和仅来自石南的有机土壤)。在接下来的19天里，对二氧化碳的产生进行了连续监测。单独添加无机氮和无机磷对土壤呼吸速率均无显著影响。然而，N和P的联合添加促进了微生物的活动，其中以桦树林矿物土壤的反应最大(增加了57%的二氧化碳产量，相比之下，健康土壤增加了26%，桦树林有机土壤增加了8%)。因此，如果微生物的总体养分可利用性随着全球变化而增加，这些土壤中的矿化速率可能会被刺激，但单靠氮沉积不太可能促进分解。添加葡萄糖和甘氨酸中的一种或两种都可以增加微生物的呼吸。同位素分离结果表明，在健康土和森林矿质土中添加葡萄糖可以促进土壤有机质(SOM)的矿化，而在森林有机土中则不能。这些正的“启动”效应在森林矿质土壤中添加N后消失，在健康土壤中同时添加N和P后消失。为了满足日益增长的微生物营养需求，增加植物对活性碳的输入可以刺激土壤有机质的矿化，冻土带土壤的碳储量可能是最脆弱的。(C)2009爱思唯尔有限公司。保留所有权利。
Global warming in the Arctic may alter decomposition rates in Arctic soils and therefore nutrient availability. In addition, changes in the length of the growing season may increase plant productivity and the rate of labile C input below ground. We carried out an experiment in which inorganic nutrients (NH4NO3 and NaPO4) and organic substrates (glucose and glycine) were added to soils sampled from across the mountain birch forest-tundra heath ecotone in northern Sweden (organic and mineral soils from the forest. and organic soil only from the heath). Carbon dioxide production was then monitored continuously over the following 19 days. Neither inorganic N nor P additions substantially affected soil respiration rates when added separately. However, combined N and P additions stimulated microbial activity, with the response being greatest in the birch forest mineral soil (57% increase in CO2 production compared with 26% in the heath soil and 8% in the birch forest organic soil). Therefore, mineralisation rates in these soils may be stimulated if the overall nutrient availability to microbes increases in response to global change, but N deposition alone is unlikely to enhance decomposition. Adding either, or both, glucose and glycine increased microbial respiration. Isotopic separation indicated that the mineralisation of native soil organic matter (SOM) was stimulated by glucose addition in the heath soil and the forest mineral soil, but not in the forest organic soil. These positive 'priming' effects were lost following N addition in forest mineral soil, and following both N and P additions in the heath soil. In order to meet enhanced microbial nutrient demand, increased inputs of labile C from plants could stimulate the mineralisation of SOM, with the soil C stocks in the tundra-heath potentially most vulnerable. (C) 2009 Elsevier Ltd. All rights reserved.