Characterization of Spatial Distribution of Soil Organic Carbon Stocks in Selected Land Use Types and Landscapes in Chama District

Chikuta, Fred (2014) Characterization of Spatial Distribution of Soil Organic Carbon Stocks in Selected Land Use Types and Landscapes in Chama District. Masters thesis, University of Zambia.

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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.The results also showed that topography had a major influence in the SOC content of the top 20cm layer of the soils in the study area; this was very evident in that the SOC content showed a general tendency to increase from the summit to the depression. The SOC content at the depression was 2.38% as compared to the summit with a SOC content of 1.57%. The high SOC values at the depression could have been attributed to the chemical stabilization, decreased decomposition because of low redox conditions, and higher litter inputs from vegetation and upslope contributions. The Least Significant Difference (LSD) and the t-test was used to ascertain the influence of topography on SOC content. Results showed that soil texture influences SOC content through the role of clay in the protection of soil organic matter from decomposition and role of clay and silt in water availability and therefore plant productivity. This was clearly evident at the depression catena positions where the clay content was 40.8% and the SOC content was at its highest (2.38%). Generally, grasses, such as maize, rice and pastures had high levels of SOC (1.35%) and the forest Land Use Type (LUT) had 0.55% SOC.

Item Type:	Thesis (Masters)
Subjects:	G Geography. Anthropology. Recreation > G Geography (General) H Social Sciences > HD Industries. Land use. Labor
Divisions:	Africana
Depositing User:	Geoffrey Obatsa
Date Deposited:	14 Dec 2018 11:23
Last Modified:	14 Dec 2018 11:23
URI:	http://thesisbank.jhia.ac.ke/id/eprint/8626

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