Assessment of environmental and socio-economic benefits of soil conservation in semi-arid regions of Tanzania : the case of Kandoa Eroded Area | |
| Author | Ligonja, Paul Jonas |
| Call Number | AIT Diss. no.NR-13-02 |
| Subject(s) | Soil conservation--Tanzania Land degradation--Tanzania Soil erosion--Tanzania |
| Note | A dissertation submitted in partial fulfillment of the requirements for thedegree of Doctor of Philosophy in Natural Resources Management, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. NR-13-02 |
| Abstract | Land degradation has continued to be a major development problem in developing countriesdespiteconsiderableconservationinvestments.Thisstudy assessedthebenefits of soilconservation in Kondoa ErodedArea(KEA)inTanzania where Dodoma region soil conservation project(HADO) was establishedsince1973. Measuresimplementedincludedphysical, administrativeandbiologicalaspectssuchasconstructionofcutoffdrains;destocking; andtreeplantingrespectively.Methodology usedinthisstudy wereliteraturereview, questionnairesurvey of10%sampledhouseholds,directobservations,key informant interview, landuse/covermapping usingLandsatdataandGISandsoilerosionderived fromUniversal Soil Loss Equation (USLE). Soilmap,digitalelevationmodel(DEM),rainfall, field assessments of slope length and land management practicesas well asland use/cover data were used as inputsdata to predictsoilerosion.Results from questionnaire survey showedthat participation in soil conservation startedwithonly45%ofrespondentsin1973-85,andthenchangedinto53.8% and 82.5% in 1986-96 and 1997-2010, respectively. Non participation conservation measures under top downapproach causedinitiallow adoption of measures. On the other hand strategies such aszerograzing, limited decentralization oftree planting activities to villagesand schools, education and awareness, material supports including distribution of stall feeding cows and freetreeseedlingsprovidedto farmers increasedparticipation in soil conservation since mid 1980s. Linear regression model identified access to extension services, household sizes, and awareness on HADO soil conservation project, long term land ownership and crops income as determinants of participation in soil conservation in the area.Examination of social perception of local people revealed that 88.7% and 70% of respondents consider soil conservation activities have increased vegetation and soil fertility, respectively. Decreased soil erosion was perceived by 68% respondents, increased firewood by 98%, increased fodder by 50%, while high crop yield by 56% and food sufficiency by 68%.The predicted average soil erosions were 14.7; 23 and 15.7t ha-1yr-1during 1973, 1986 and 2008, respectively. The area under very high soil erosion severity was 30% of the study area in 1973, 26% in 1986 and 25% in 2008, whereas area with high erosion severity was 46% in 1973 changed into 49% in 1986 and 2008 indicating recent stabilization. Area with moderate erosion increased from 15%, 16% and 18% during the same period. Reduction of very high erosion, stabilization of high erosion and increased of moderate soil erosion indicate success in controlling soil erosion. Age of farmers, long-term adoption of conservation measures, and on-farm tree planting were found to be the major factors contributing toward reduction of soil erosion. Observed challenges for further progress in soil conservation by reducing soil erosion were dependent on external interventions by donors and central government, biastowardsphysicallandrehabilitation, forceddestocking andfailuretomainstreamHADOactivitiesintolocal productionsystemsand local institutional mechanisms for environmental management. HADO used hired labor to construct cut off drains, manage trees nurseries and demonstration woodlots and for surveillances. One option would have been to use village governments to enforce laws for providing standard sustainable farm management in order to ensure environmental protection and optimum production in the farm and protection of non-farmland resources. That could reduce the likelihood of recurrence of land degradation in former restored areas particularly after withdrawal of resources and support from donors and central government.Recent increase of bare lands ivand decline of grasslands and bushlands as determined by land use change analysis is an environmental threat, which requires government attention by supporting farmers to plant more trees on their farms and ensuring livestock carrying capacity in farm lands and outside not to aggravate the sheet and gully erosion like what occurred during 1970s. The farm land could be better sites for tree planting in order to address declining efforts in tree planting by integrating trees in croplands as provided in the recent Kondoa District environmental by-laws. Farmers may also be supported to establish woodlotsin degraded land outside their farms with agreements to allocate such lands to the farmers. The breakdown of centralized conservation activities can be addressed by more local community based participatory approaches particular in forest management. That requires among other efforts to enhance the social economic factors which determine increased participation in soil conservation, such as mobilization of group of farmers into local institutions, and development of participatory forest management (PFM) as provided in the Tanzanian forest policy of 1998 and forest Act of 2002. Research and extension services to introduce technologies which are less destructive to environment, for instance using cattle manure as fuel, introduction of high quality cattle breeds and sustainable agriculture production practices would further help achieve soil conservation and environmental management. Regular monitoring using advanced erosion models along with their field-based validation to improve the accuracy of soil erosion prediction for formulating better land management strategies in the future is suggested.Despite significant conversion of natural landscape into croplands and existing challenges, past government efforts on large scale soil conservation activities initiated since early seventies through decentralization, institutional collaboration, government supports to farmers and continuous local community participation in restoring degraded ecosystem of KEA have contributed to ensuring environmental and socio-economic sustainability in the area. |
| Year | 2013 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. NR-13-02 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Development and Sustainability (DDS) |
| Academic Program/FoS | Natural Resources Management (NRM) |
| Chairperson(s) | Shrestha, Rajendra Prasad; |
| Examination Committee(s) | Grunbuhel, Clemens ;Datta, Avishek; |
| Scholarship Donor(s) | Ministry of Livestock Development and Fisheries,Tanzania ;Asian Institute of Technology Fellowship; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2013 |