Abstract Decomposition is a key process for rain forest nutrient cycling, and this may be altered by the increasing rate of deposition of reactive nitrogen on rain forests. Tropical heath forests are characterised by slow litter decomposition rates due to low quality litter, along with acidic soil pH and low availability of soil nitrogen (N). To investigate whether soil N or pH is most important in regulating tropical heath forest organic matter decomposition, we used a factorial N and CaCO3 addition experiment, and measured wood and leaf litter decomposition rates and mesofaunal activity (using bait-lamina sticks and numbers of worm casts). Our heath forest site in the Kabili-Sepilok Forest Reserve (Sabah, Malaysia) had a decomposition rate (calculated using standard tea material) comparable to that of temperate forest soils. Overall, the experimental modification of both soil pH and available N had weak effects on decomposition rates, although different materials responded differently to the experimental treatments. There was a clear, but transient, increase in number of worm casts in the CaCO3 and N + CaCO3 treatment. Although we obtained some evidence that low soil acidity reduced decomposer activity, it may take longer than one year for the decomposer community, and associated processes, to be influenced by the experimentally altered edaphic conditions.

中文翻译：

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土壤氮素有效性和 pH 值对热带荒地森林有机质分解和分解者活性的影响

摘要 分解是雨林养分循环的关键过程，这可能会随着活性氮在雨林中沉积速率的增加而改变。热带荒地森林的特点是枯枝落叶质量低，枯枝落叶分解速度缓慢，同时土壤 pH 值呈酸性，土壤氮 (N) 的可用性低。为了研究土壤 N 或 pH 值在调节热带荒地森林有机质分解方面是否最重要，我们使用了因子 N 和 CaCO3 添加实验，并测量了木材和树叶凋落物的分解率和中动物活动（使用诱饵叶片棒和蠕虫数量演员）。我们位于 Kabili-Sepilok 森林保护区（马来西亚沙巴）的荒地森林的分解率（使用标准茶材料计算）与温带森林土壤的分解率相当。全面的，尽管不同的材料对实验处理的反应不同，但土壤 pH 值和有效氮的实验修改对分解速率的影响很小。在 CaCO3 和 N+CaCO3 处理中，蠕虫模型的数量有明显但短暂的增加。虽然我们获得了一些证据表明低土壤酸度会降低分解者的活动，但分解者群落和相关过程可能需要一年以上的时间才能受到实验改变的土壤条件的影响。