Assessing soil organic carbon stock under different land-uses in Koto XI Tarusan District, West Sumatra

Abstract

Organic carbon in soil can be utilized to assess soil quality and aid to climate change mitigation. Soil organic carbon stock assessment in West Sumatra is still limited. This research focused on soil organic carbon stock distribution in various land-uses in Duku, Koto XI Tarusan, Pesisir Selatan Regency. Research area included secondary forest, scrubland, paddy field, and dryland agriculture. Soil samples were obtained by stratified sampling. Samples were taken at depths of 0-30 and 30-60 cm from each land-use type with the same slope and soil type. A soil unit polygon was randomly selected for sampling. 21 samples were collected and analyzed for bulk density, texture, soil respiration, total nitrogen content, and organic carbon. Secondary forest had the highest soil organic carbon storage (128.82 - 294.09 tons per hectare), followed by paddy fields (16.99 - 227.14 tons per hectare), dryland agriculture (10.40 - 65.43 tons per hectare), and scrubland (13.39 - 53.19 tons per hectare). Nitrogen content was higher in secondary forest>paddy soil>scrubland>dry land. Bulk density was found to be higher in scrubland than in dry land, paddy soils, and secondary forest. Soil pH was greater in paddy soil>scrubland>dryland>forest.