Exogenous phosphorus inputs alter complexity of soil-dissolved organic carbon in agricultural riparian wetlands
Exogenous phosphorus inputs alter complexity of soil-dissolved organic carbon in agricultural riparian wetlands
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外源磷输入改变农业河岸湿地土壤溶解有机碳的复杂性
DOI：
10.1016/j.chemosphere.2013.09.117
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发表时间：
2014
期刊：
影响因子：
8.8
通讯作者：
Schoer Jonathan
中科院分区：
文献类型：
--
作者：
Liu Meng;Zhang Zhijian;He Qiang;Wang Hang;Li Xia;Schoer Jonathan
高强度的农田施肥导致大量养分和元素输入到农业河岸湿地。湿地沉积物中的溶解有机碳（DOC）是全球碳循环的重要中间体，是连接土壤碳库和大气CO2的重要纽带。但是，磷（P）对沉积物DOC的影响在很大程度上仍然是未知的，尽管越来越多的研究强调磷拦截河岸湿地。在这里，我们模拟了外源P对沉积物DOC的时间影响，通过整合梯度P负荷率为0%，5%，10%，20%，30%，和60%，相对于沉积物的初始总磷含量，说明外源P的作用，土壤DOC的复杂性，其数量和组成。培养9个月后，观察到Olsen-P与被认为是DOC骨架的荧光和紫外光谱指数之间的显着线性相关。加上更多的微生物来源的DOC和DOC的芳香性或腐殖度的减少，激发-发射矩阵已显示出蓝移，反映了一个简单的沉积物DOC的分子结构的趋势后，磷添加。与此同时，土壤DOC含量及其占总有机碳（TOC）的比例也随着磷负荷的增加而增加，同时高活性有机碳和两种与碳相关的酶的含量也随之增加。TOC和难溶性有机碳显著降低。这种影响DOC的数量和组成的外部磷负荷刺激可能会提高其生物利用度，从而诱导对土壤碳循环和响应全球气候变化的潜在C损失的加速效应。
High-strengthened farmland fertilization leads to mass inputs of nutrients and elements to agricultural riparian wetlands. The dissolved organic carbon (DOC) of such wetland sediments is an important intermediate in global carbon (C) cycling due to its role in connecting soil C pools with atmospheric CO2. But the impact of phosphorus (P) on sediment DOC is still largely unknown, despite increasing investigations to emphasize P interception by riparian wetlands. Here, we simulated the temporal influences of exogenous P on sediment DOC of riparian wetlands by integrating gradient P loading at rates of 0%, 5%, 10%, 20%, 30%, and 60% relative to the initial total phosphorus content of the sediment with the purpose of illustrating the role of external P on the complexity of soil DOC in terms of its amount and composition. After incubating for nine months, a dramatic linear correlation between Olsen-P and fluorescent and ultraviolet spectral indices considered DOC skeleton was observed. Together with a more microbial-derived origin of DOC and a reduction of DOC aromaticity or humicity, the excitation-emission matrix had shown a blue shift reflecting a trend towards a simpler molecular structure of sediment DOC after P addition. Meanwhile, the content of soil DOC and its ratio with total organic carbon (TOC) were also increased by P loading, coupled with enhanced values of highly labile organic carbon and two C-related enzymes. While TOC and recalcitrant organic carbon decreased significantly. Such implications of DOC amounts and composition stimulated by external P loading may enhance its bioavailability, thereby inducing an accelerated effect on soil C cycling and a potential C loss in response to global climate change.