BackgroundThe changes in land use and land cover have a strong effect on the total soil organic carbon, its fractions and its overall soil health. This study carried out in Olesharo Catchment, Kenya, was to quantify the differences in total organic carbon (TOC), particulate organic carbon (POC), mineral organic carbon (MOC) and carbon management index (CMI) among four land use types: grasslands, shrublands, agricultural lands and barelands. It was also purported to evaluate the use of CMI as an indicator for soil degradation or improvement in response to land use and land cover changes.ResultsThe results of the study show that the mean values of TOC, POC and MOC are significantly different between land use types. Thus, shrublands have significantly higher TOC (22.26 g kg−1) than grasslands (10.29 g kg−1) and bare lands (7.56 g kg−1). They also have significantly higher POC (7.79 g kg−1) and MOC (10.04 g kg−1) than all the other land use types. The agricultural lands have higher CMI than grasslands (53% vs 41% relative to shrublands) suggesting that grasslands face serious degradation through overgrazing.ConclusionsThis study shows that different land use types have an influence on soil organic carbon pools, and consequently on the CMI, the CMI could be used as an indicator for soil degradation or improvement in response to land use and land cover changes.

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Combating land degradation in the semi-arid rangeland of sub-Saharan Africa is essential to ensure the long-term productivity of these environments. In the Lake Baringo basin in Kenya, communities and individual farmers restored indigenous vegetation inside enclosures in an effort to combat severe land degradation and address their livelihood problems. This study quantified the benefits of rangeland rehabilitation using yearly communal enclosures' utilisation data compiled by Rehabilitation of Arid Environments (RAE) Trust over a 6-year period (2005)(2006)(2007)(2008)(2009)(2010). Results showed that communal enclosures provide a source of income through the sale of fattened livestock, harvested grass seeds, hay, honey and charcoal, among other products. Regression analysis showed an increasing total enclosure income with time. The enclosures also provide grasses for thatching, livestock feed and dry season grazing. Indirect products like milk, blood and meat are essential for household nutrition and food security. These benefits reinforce the management through incentive to maintain existing enclosures and establish new ones and therefore the increasing trend in rangeland enclosure. Increased soil and biomass carbon storage could come with other indirect environmental benefits including improvement in soil quality, land productivity for pasture production and food security, and prevention of land degradation, thus leading to economic, environmental and social benefit for the local agropastoralist communities.

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