Healthy soil ecosystems are important for urban sustainability, because they provide the basis for ecosystem services such as flood regulation, nutrient cycling and carbon sequestration. We investigated the soils beneath five types of urban land cover in the tropical city of Singapore—secondary forest, managed grass, shrubs, trees, and trees with shrubs. We quantified the capacity of these soils to support two key ecosystem functions: litter decomposition, which we measured using a standardised tea bag method, and infiltration, which we measured using a double ring infiltrometer. Soil samples (0–20 cm depth) were collected from 120 sites and were analysed for 15 soil and vegetation properties including pH, soil organic matter content, particle size, bulk density and soil nitrogen, phosphorus and potassium. The forest sites had significantly higher leaf litter cover and canopy leaf area index than the other land cover types. Rates of litter decomposition and infiltration were highest in secondary forest, followed by trees with shrubs, and lowest in grass. Litter decomposition rates were positively related to soils with presence of soil invertebrate activity, leaf litter cover and soil nitrogen content. Infiltration rates were negatively related to soil bulk density. To optimise the delivery of soil ecosystem services in tropical cities, city managers and planners should protect any remaining fragments of forest, allow natural succession to occur, plant multi-layered vegetation with trees and shrubs, and restore urban soil by improving soil nutrients, reducing bulk density, and leaving leaf litter in situ.

健康的土壤生态系统对于城市可持续发展至关重要，因为它们为诸如洪水调节，养分循环和碳固存等生态系统服务提供了基础。我们调查了新加坡热带城市五种城市土地覆盖下的土壤-次生林，经管理的草丛，灌木，乔木和带有灌木的乔木。我们量化了这些土壤支持两种主要生态系统功能的能力：凋落物分解（使用标准茶袋法测量）和渗透（使用双环渗透计）测量。从120个地点收集了土壤样品（深度为0–20 cm），并分析了15种土壤和植被特性，包括pH值，土壤有机质含量，粒径，堆积密度以及土壤氮，磷和钾。与其他土地覆盖类型相比，森林站点的叶子凋落物覆盖率和冠层叶面积指数显着更高。次生林凋落物分解和入渗率最高，其次是灌木林，草丛中最低。凋落物分解速率与土壤的无脊椎动物活性，枯枝落叶覆盖率和土壤氮含量呈正相关。入渗率与土壤容重负相关。为了优化在热带城市中提供土壤生态系统服务，城市管理者和规划者应保护任何剩余的森林碎片，允许自然演替发生，用树木和灌木种植多层植被，并通过改善土壤养分，减少土壤肥力来恢复城市土壤。堆积密度，并留在原地的叶子凋落物。