Effects of Sustainable Soil Management Practices on Distribution of Soil Organic Carbon in Upland Agricultural Soils of Mid-hills of Nepal

Abstract

An abundance of soil organic carbon (SOC) generally enhances the quality of lands for agriculture or forestry. Concentration of SOC varies in accordance to the type of land use, the inputs to the soil, and natural factors including climate and vegetation. SOC is vital for sustaining agricultural productivity which chiefly depends on both the inherent soil type and crop management practices affecting depletion or replenishment of organic matter over the years. Assessment of SOC concentration is a characteristic measurement of evaluating soil quality and the carbon sequestration potential of agricultural land. This study aims to assess SOC distribution on selected farmlands of Nepal’s mid-hills, where farmers have adopted sustainable soil management practices in non-irrigable hill terraces (“Bari” land) in comparison with those of surrounding Bari and forests where no such interventions are made. Thus the present study estimated SOC content of three types of land use – farmland with sustainable soil management practices (SSMP), farmland without sustainable management practices (Non-SSMP) and the community managed forest in four mountain districts of Nepal, namely Baglung, Dhading, Kavre and Okhaldhunga. This study found the average SOC stocks in the SSMP land in the range of 20 - 44 Mgha-1,those in non-SSMP agricultural areas 15 to 48 Mgha-1, and in the forested land 16 to 23 Mgha-1. In general, the abundance of SOC stocks are in the order of SSM>Non-SSM>Forests. The analysis indicates the high potential for carbon sequestration in hill agriculture lands through sustainable soil management. Nepal Journal of Science and Technology Vol. 13, No. 1 (2012) 133-141 DOI: http://dx.doi.org/10.3126/njst.v13i1.7452