Dynamics of the physico-chemical erodibility factors of soil under different management scenarios in the watersheds of Chiang Mai, Thailand | |
| Author | Meka, Assefa Gizaw |
| Call Number | AIT Thesis no.NR-04-02 |
| Subject(s) | Soil erosion--Thailand--Chiang Mai Soils--Thailand--Chiang Mai--Quality |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. NR-04-02 |
| Abstract | Productivity and sustainability are governed not only by the efficiency but also by the total flux of nutrients, energy and water through a system. The replacement of swidden agriculture by alternative land use systems considering it as unsustainable from separate evaluation results of interacting issues in the traditional system may result in fu rther degradation of watersheds. In order to evaluate the impact the swidden system in sustaining soil quality relative to the alternative land use systems provided to hilltribe farmers, representative augur samples were collected at 0-25 and 25-50 centimeters soil depth from permanent agriculture, swidden cultivation under five, ten and twenty years fallow and native forest fields in three replications. Soil organic matter, total and available nitrogen, exchangeable potassium, total and available phosphorous, cation exchange capacity, texture, bulk density, permeability, aggregate stability, available water capacity and soil erodibility were analyzed. Statistical analysis of the results showed significant impact of land use systems in aggregate stability, total phosphorous (P), cation exchange capacity (CEC) and bulk density (BD) at the surface while the sub-surface soil showed significant variation in pH, CEC and P only. Swidden fields under five year fallow and twenty year fallow showed better performance relative to the other treatments indicating the emphasis that need to be given to fallow management. The pH, available N, total and available P, exchangeable K, CEC, BD, permeability and erodibility showed higher values in five years fallow while the total nitrogen, clay content, organic matter and aggregate stability only were higher in twenty years fallow. The other soil parameters were nearly the same in both fallow periods. The ten years fa llow showed relatively poor soil quality. However, the nutrient status and water holding capacity of the soils under all the land use systems were generally poor for crop production. The result also indicated as soil erodibility did not have significant contribution to soil erosion though the nutrient depletion showed the existence of erosion in the watershed. The comparative analysis of the land use systems showed as swidden agriculture did not affect the physical properties of soil, K, CEC and erodibil ity though the total and available N, P, and WC are highly affected. From the study, recommendations for further research and integration of swiddening with other soil management systems facilitating organic matter decomposition are set to clearly conclude the sustainability of swidden systems. |
| Year | 2004 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. NR-04-02 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Natural Resources Management (NRM) |
| Chairperson(s) | Webb, Edward L.; |
| Examination Committee(s) | Clemente, Roberto S.; Schmidt-Vogt, Dietrich; |
| Scholarship Donor(s) | Ethiopian Agricultural Research Organization;World Bank;Asian Institute of Technology Fellowship; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2004 |