Department of Plant Sciences, University of Cambridge, Downing St., Cambridge, CB2 3EA, UK.
Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
Ecology. 2018 Mar;99(3):735-742. doi: 10.1002/ecy.2143.
Many old-growth lowland tropical rain forests are potentially nutrient limited, and it has long been thought that many such forests maintain growth by recycling nutrients from decomposing litter. We investigated this by continuously removing (for 10 yr) freshly fallen litter from five (45 m × 45 m) plots, adding it to five other plots, there were five controls. From monthly measures over 1 yr we show that litter removal caused lower: fine root (≤2 mm diameter) standing mass, fine root standing length, fine root length production and fine root length survivorship. Litter addition did not significantly change fine root mass or length or production. Nutrient concentrations in fine roots in litter removal plots were lower than those in controls for nitrogen (N), calcium (Ca) and magnesium (Mg), concentrations in fine roots in litter addition plots were higher for N and Ca. Chronic litter removal has resulted in reduced forest growth due to lack of nutrients, probably nitrogen. Conversely, long-term litter addition has had fewer effects.
许多古老的低地热带雨林可能受到养分限制，长期以来人们一直认为，许多这样的森林通过从分解的凋落物中回收养分来维持生长。我们通过连续 10 年从五个（45m×45m）样地中去除新鲜凋落物（去除组），并将其添加到五个其他样地中（添加组），同时设置了五个对照组来研究这个问题。从一年的每月测量中，我们发现凋落物去除导致：细根（≤2mm 直径）现存量、细根总长度、细根长度生产量和细根长度存活率降低。添加凋落物并没有显著改变细根的质量或长度，也没有改变细根的生产。去除组细根中的养分浓度低于对照组的氮（N）、钙（Ca）和镁（Mg），添加组细根中的氮和钙浓度高于对照组。由于缺乏养分（可能是氮），长期的凋落物去除导致森林生长减少。相反，长期添加凋落物的影响较小。
