Litter N and P dynamics in two secondary tropical dry forests after relaxation of nutrient availability constraints
Litter N and P dynamics in two secondary tropical dry forests after relaxation of nutrient availability constraints
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DOI：
10.1016/j.foreco.2007.06.022
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发表时间：
2007-11
影响因子：
3.7
通讯作者：
J. Campo;E. Solis;M. G. Valencia
中科院分区：
文献类型：
--
作者：
J. Campo;E. Solis;M. G. Valencia
研究了生长在墨西哥尤卡坦半岛石灰岩上的两种不同演替阶段和养分状况的再生热带干林在添加N和/或P后凋落物中的氮(N)和磷(P)循环。我们的研究地点包括演替早期(10年生)和演替后期(∼60年生)的森林，前者的初级生产力受到N和P的限制，后者的初级生产力受到P的限制。每个森林有4个重复样地(12m×12m)，要么保持原状(对照)，要么连续3年施N、P或N+P。养分限制的放松导致了演替早期和演替后期森林土壤N、P通量的增加。这一效应在N通量(N质量在3年期间增加)中较快，而P通量在重复施肥2年后增加。然而，凋落物养分通量的变化与两个森林的森林地面养分积累(浓度或池)并不平行。凋落物和森林土壤养分库不变的N、P通量的增加表明，施肥通过增加养分的释放，加速了演替早期和演替后期森林养分的系统内循环。
Nitrogen (N) and phosphorus (P) cycling in litterfall were studied following N and/or P additions in two regenerating tropical dry forests (TDFs) growing on limestone in the Yucatán Peninsula (Mexico) differing in successional stage and nutrient status. Our sites included forests in early-successional stage (10-year-old), where primary production is limited by N and by P, and in late-successional stage (∼60-year-old), where primary production is limited by P. Four replicate plots (12m×12m) at each forest were either left intact (controls) or fertilized with N, with P, or with N plus P for 3 consecutive years. Relaxation of nutrient limitation resulted in an increase of N and P fluxes to the soil at both the early-successional and late-successional forests. This effect was faster in the N flux (N masses increase in the 3-year period); while P flux increased after 2 years of repeated fertilization. However, changes in litterfall nutrient fluxes were not paralleled by nutrient accumulation (concentrations or pools) on the forest floor of both forests. The increase in the magnitude of N and P fluxes from litterfall combined with unchanged nutrient pools in the forest soil, suggests that fertilization accelerated the intrasystem cycling of both nutrients in early- and late-successional forests, by a rise the nutrient release.