Soil carbon sequestration, socioeconomic impact and farmers’ perception of the role exclosure: the case of gimbichu woreda, central Ethiopia

Abstract

Land degradation is the most challenge in sustainable development. To overcome the problem of land degradation that cause climate change and poverty in Ethiopia, exclosure is used as strategy to minimize this environmental and livelihood threats. The overall objective of the study was to identify soil carbon sequestration, socioeconomic impact of exclosure and farmers’ perception on its role: the case of Gimbichu Woreda, Central Ethiopia. To achieve this objective Gara Girmi exclosure area was selected from Gimbichu woreda. Soil samples were collected from open land and 4 years exclosed land. Soil samples were collected by auger and core sampler from the same landscape positions; replicated four times in both land management(exclosure and open land) and two soil depts. (0-20 and 20-40cm) to determine BD and soil SOC and finally to calculate soil carbon stock. Besides, socio economic survey was conducted using structured questioner, focus group discussion and key informant and analyzed by SPSS (version 20). The result showed that exclosed lands had significantly (P<0.05) different from adjacent degraded open land for mean value of soil bulk density (BD), soil organic carbon (SOC), and soil carbon stock (SC). The study showed that the mean value at exclosure and open lands of soil BD, SOC, and SC were 1.03 and 1.23 g/cm3 , 2.40 and 0.96% and 49.38 and 26.2 ton/ha respectively. With regard to soil depth SOC and SC show significantly (P<0.05) different in the first depth where as soil BD didn`t show any difference as their mean value in 0-20cm and 20-40cm indicate 2.09 and 1.28% SOC, 1.11and 1.16 g/cm3 BD and 45.75 and 29.63 ton/ha SC respectively. The soil carbon also highly stored in surface depth of excloed land (59.16 ton/ ha) whereas the lowest is stored under the subsurface depth of degraded open land (20.07ton/ha) which indicate that the area exclosure play a vital role in climate change mitigation by sequestering atmospheric carbon in the form of CO2 in to the soil . Concerning exclosure impacts on socioeconomics’ of local farmers; all respondents under exclosure land (74.4%) perceived that they were getting economic, social and environmental benefits but all respondents (25.6%) from the degraded open land replied that they didn`t get any direct economic benefit from their non-exclosed land. The exclosure is on improving the livelihoods of the local community where they have probably harvested about 2550 kg/ha/yr or 1275ETB/ha/yr forage grass and 1400kg/ha/yr or 840ETB/ha/yr thatching grass which used for fattening purpose and house shade respectively or additional income by selling these products. Local community perceived exclosures positively and are optimistic to the performance of exclosure. The entire respondents agreed that the exclosure is an option for land rehabilitation and they obtain economic, social and environmental benefits. Besides, most of the respondents from open land decided to expand exclosure to the adjacent degraded lands. Generally, exclosure has a great role in climate change mitigation by sequestering carbon in the form of CO2 from atmosphere and also improve economic and social benefits of local community. Therefore, the local community living in degraded land could be adopting the area exclosure practice from the present studied area