Nutrient addition affects net and gross mineralization of phosphorus in the organic layer of a tropical montane forest
Nutrient addition affects net and gross mineralization of phosphorus in the organic layer of a tropical montane forest
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DOI：
10.1007/s10533-017-0392-z
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发表时间：
2017-11-01
期刊：
影响因子：
4
通讯作者：
Oelmann, Yvonne
中科院分区：
文献类型：
--
作者：
Dietrich, Karla;Spohn, Marie;Oelmann, Yvonne
在热带强风化土壤生态系统中，有机磷向生物有效无机磷的转化对生物体的营养起着至关重要的作用。在这些生态系统中，P被怀疑是生长限制，因此可能会受到大气养分沉积的影响，即使在偏远地区，如山地雨林。我们评估了磷和氮（N）的净和毛磷矿化率的影响，以及微生物磷固定在有机层沿着海拔梯度的热带山地雨林在厄瓜多尔。净磷矿化率为1.8 +/- 0.9（海拔1000米），3.7+/- 0.6（2000米）和2.0 +/- 0.4（3000米）mg P kg（-1）天（-1）。海拔差异导致增加微生物磷固定在1000米补偿较高的总磷矿化。磷添加增加净磷矿化率在2000和3000米，这表明在1000米更高的磷需求。在高海拔地区，磷可能是有机质分解过程中的副产物。总P矿化，通过同位素稀释法测定，不能计算控制和N处理由于快速微生物P固定。对于P（+N）处理，总P矿化率最低的1000米的网站对长期潜伏期结束。热带地区大气磷沉降可能通过直接输入以及加速有机质中磷的释放而产生磷肥效应，从而增加有机体对磷的利用率。
In tropical ecosystems with highly weathered soils, transformation of organic phosphorus (P) to bioavailable inorganic P plays a crucial role for the nutrition of organisms. In these ecosystems, P is suspected to be growth-limiting and might therefore be affected by atmospheric nutrient deposition occurring even in remote areas such as montane rainforests. We assessed effects of P and nitrogen (N) addition on net and gross P mineralization rates, and microbial P immobilization in the organic layer along an altitudinal gradient of a tropical montane rainforest in Ecuador. Net P mineralization rates amounted to 1.8 +/- 0.9 (at 1000 m a.s.l.), 3.7 +/- 0.6 (at 2000 m) and 2.0 +/- 0.4 (at 3000 m) mg P kg(-1) day(-1). Altitudinal differences led to an increased microbial P immobilization at 1000 m compensating for a higher gross P mineralization. P addition increased net P mineralization rates at 2000 and 3000 m, suggesting a higher P demand at 1000 m. At higher altitudes, P likely was released as a by-product during organic matter decomposition. Gross P mineralization, determined by means of the isotopic dilution approach, could not be calculated for control and N treatments due to rapid microbial P immobilization. For P (+N) treatments, gross P mineralization rates were lowest at the 1000 m site towards the end of the long-term incubation period. Atmospheric P deposition in the tropics might lead to P fertilization effects through direct input as well as through acceleration of P release from organic matter, thereby increasing P availability for organisms.