Soil characteristics in an exhumed cemetery land in Central Singapore

Soils in urban landscape act as a component for various ecological functions. For sustainable urban greenery and effective management of urban ecosystems, evaluation of soil quality is of paramount importance. A study was undertaken to assess the existing soil quality and determine spatial soil variability of an exhumed cemetery land in central Singapore, so that systematic and sustainable soil management practices could be implemented for its conversion into an urban park. A stratified sampling method was followed to collect the soil samples from three depths: 0-30, 30-50, and 50-100cm. An integrated soil quality index (SQI) approach was undertaken to monitor the changes in soil properties. The visual assessment showed the uniformity of horizon distribution of the soil profiles across the park and the soils had acidic pH (x 5.2) and moderately high bulk density (x 1.6gcm(-3)). Considering the soil depths, top layer had higher organic carbon content (x 1.03%) and it was significantly lower in deeper layers (x 0.71%). Detailed soil analysis results indicated that the soils of the proposed park area were in low fertility status, devoid of macro nutrients (available nitrogen: x 486.1, phosphorus: x 8.5 and potassium: x 9.2mgkg(-1)) and high in iron content (x 114.8mgkg(-1)), and can be classified as Ferric Acrisol (FAO WRB) or Ultisol (USDA). The SQI map of total soil (0-100cm) was different from surface soil, indicating impact of human activities on overall changes in soil quality distribution.