Impact of soil conservation measures on soil organic carbon stocks in the South Western Highlands

Abstract

Land degradation caused by erosion is one of the greatest environmental threats that hamper agricultural production in the south western highlands of Uganda, the causes include: over cultivation, overgrazing, slash and burn and deforestation which in turn leads to a gradual co accumulation in the atmosphere causing global warming hence climate change causing excessive droughts and floods leading to Loss of productive land, and undermining rural livelihoods and national food security. The study assessed the impact of soil conservation measures on soil organic carbon stocks in agro ecosystems in Kabale District. Assessment of the effects of SWC on SOC in 2 key areas; Center for Rural Development(CRD) located in Mukoni village where SWC measures had been practiced for 2 years and Trans-boundary Agro-ecosystem Management Project(TAMP) in Kaliko and Kagarama were SWC had been practiced for 5years was made. From each site, 3 paired sites were assessed. Soil samples were collected and analyzed for OC using the Walkley-Black(1934) procedure at a depth of 0-15 and 15-30cm. The study was guided by three research questions as derived from the objectives under study. These research objectives were; (1)To identify land use practices being used by the farmers in Kabale District, (2) to evaluate the effectiveness of calliandra hedgerows and organic manure as a soil and water conservation measure on soil organic carbon. From the study, findings revealed that SOC does not statistically increase with the use of calliandra hedgerows and organic manure within 2 years. However with SWC interventions for five years OC increases mainly at the top layer of 0-15 cm. The results therefore showed that it is possible to recover abandoned and or degraded areas, resulting from a number of causes such as deforestation, shifting cultivation, over grazing,swamp reclamation and or over cultivation of ecologically sensitive areas in Kabale District through the promotion of Calliandra (Calliandra calothyrsus) and organic manure. Calliandra and organic manure therefore have the potential for restoring degraded land, maintaining soil fertility and, more recently, sequestering C, mitigating C emissions to the atmosphere once maintained through proper management.