Soil microbial and nutrient responses to 7years of seasonally altered precipitation in a Chihuahuan Desert grassland
Soil microbial and nutrient responses to 7years of seasonally altered precipitation in a Chihuahuan Desert grassland
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DOI：
10.1111/gcb.12418
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发表时间：
2014-05-01
影响因子：
11.6
通讯作者：
Zak, John C.
中科院分区：
文献类型：
--
作者：
Bell, Colin W.;Tissue, David T.;Zak, John C.
奇瓦瓦沙漠草原的土壤微生物群落通常经历高度可变的时空降雨模式。降水状况的变化可通过改变土壤微生物群落结构和功能影响地下生态系统过程，如分解和养分循环。本研究的目的是确定是否增加季节性降水的频率和幅度超过7年的时间内会产生微生物群落特征和土壤养分供应的持续变化。我们补充了自然降雨与大型事件（一个/冬季和三个/夏季），以模拟该地区的气候模型预测的基础上增加降水。我们观察到一个2年的延迟微生物的反应，以补充降水处理。在第3-5年，较高的微生物生物量，丛枝菌根丰度，和土壤酶C和P的收购活动观察补充水地块，即使在延长干旱期。在5-7年，土壤有效磷是一贯较低的浇水地块相比，对照地块。在土壤P的变化对应于较高的真菌丰度，微生物C利用活性，和土壤pH值。这项研究表明，25%的季节性降雨的变化可以显着影响土壤微生物和养分特性，这反过来又可能有长期的影响养分循环和植物P吸收在这片荒漠草原。
Soil microbial communities in Chihuahuan Desert grasslands generally experience highly variable spatiotemporal rainfall patterns. Changes in precipitation regimes can affect belowground ecosystem processes such as decomposition and nutrient cycling by altering soil microbial community structure and function. The objective of this study was to determine if increased seasonal precipitation frequency and magnitude over a 7-year period would generate a persistent shift in microbial community characteristics and soil nutrient availability. We supplemented natural rainfall with large events (one/winter and three/summer) to simulate increased precipitation based on climate model predictions for this region. We observed a 2-year delay in microbial responses to supplemental precipitation treatments. In years 3-5, higher microbial biomass, arbuscular mycorrhizae abundance, and soil enzyme C and P acquisition activities were observed in the supplemental water plots even during extended drought periods. In years 5-7, available soil P was consistently lower in the watered plots compared to control plots. Shifts in soil P corresponded to higher fungal abundances, microbial C utilization activity, and soil pH. This study demonstrated that 25% shifts in seasonal rainfall can significantly influence soil microbial and nutrient properties, which in turn may have long-term effects on nutrient cycling and plant P uptake in this desert grassland.