Characterization of spatial distribution of soil organic carbon stocks in selected land use types and landscapes in Chama District

Abstract

Soil Organic carbon (SOC) because of its influence on all aspects of soil fertility, is a useful indicator of soil health and the performance of mixed farms, and increasing SOC can improve productivity, stability and resilience of the soil. Thus the overall objective of the study was to characterize the spatial distribution of SOC in selected land use types and landscapes of Chama District of Zambia. The grid survey of 10m by 10m was used to sample the soils in the top 20cm of the soil for all the land uses and landscapes, composite samples were made for each land use type that was replicated 5 times. The other parameters determined were soil texture and bulky density. The percentage SOC was determined for all the selected land use types and landscapes by using the Walkley-Black experiment. The Analysis of Variance (ANOVA) preceded by Duncan’s Multiple Range Test (DMRT) was used. Results of this study have shown that there are statistically significant differences in the levels of SOC in the top 20 cm layers of soils under different land use types in the study area. The levels of SOC ranged from 0.02 % to 2.62 % with soils under maize cultivation having the highest levels and soils in game management areas having the lowest levels. The high levels in soils under maize production could be attributed to the use of chemical fertilizers and high dry matter production associated with the application of chemical inorganic fertilization which leads to higher inputs of carbon to the soil through increased root bio mass, root turn over, stubble and crop debris. The low carbon content was estimated in the Game Management Area soils (0.02%), which could be attributed to low dry matter production and sandy soils in most of this area. vi The results also showed that topography had a major influence in the SOC content of