Consequences of land use change on land quality, water resource and food availability in Phatthalung, Watershed, Thailand | |
| Author | Anisara Pensuk |
| Call Number | AIT Diss. no.NR-09-01 |
| Subject(s) | Land use--Thailand--Phatthalung Watershed |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Natural Resources Management, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. NR-09-01 |
| Abstract | Land use change affects land and water resources as well as the quality of environment. The degradation of land and water resources affects the agricultural production and eventually affects food security. Recognition of the current situation of land use change and its consequences can be useful for planning the future land use to protect the environment and enhance the food security. In Phatthalung watershed of Thailand, rice cultivation is the major crop. Recently, the area has been experiencing an extensive rice area conversion to rubber plantation. This conversion process has affected rural livelihoods through decline in rice production and increased environmental problems. This study aimed to monitor land use change and study their effects on land and water quality, and peoples’ livelihood as well as assess food availability under different scenariosin order to provide valuable information to serve as guideline for sustainable land use planning for ensuring the food security in the area. The methodology included the land use classification by using remote sensing satellite images, Landsat Thematic Mapper, of three time periods (1976, 1990 and 2006) and analyzing land use changes. Field analyzed data on water quality and soil characteristics were used to characterize the water and land quality. Assessment of land degradation, soil erosion in particular, and water resource status was largely based on the gathered secondary data. The effect of land use change on land quality was assessed using selected land quality indicators. Similarly, water quality and quantity were assessed by computing Water Quality Indices (WQI) consisting water quality parameters, such as pH, suspended solid and plant nutrients. Water quantity was assessed through the available soil moisture storage. The effect of land use change on rural livelihoods, assessed using DFID framework, was studied with respect to the type of land use change the farm households have adopted using primary data collected through household. The food availability, particularly rice, was assessed under different scenarios in order to project the of rice availability per capita in the area in the future to serve as the guideline for needed strategies to be self-reliant in food production. Land use change analysis revealed that the study area has relatively less proportion of forest cover as it has been depleting over time though not speedily. The two major changes observed were reduction in overall paddy areas particularly during 1990-2006 and increase in overall area under rubber plantation, basically due to better commodity price of and market access for the rubber. Although not serious, the estimated soil erosion amount at the watershed level was found increasing corresponding to the increasing of rubber plantation as it generated the highest in soil erosion severity rate (3-14 tons/ha/yr), forest and paddy field area gave the similar results (0.06-0.15 tons/ha/yr) which was found much lower than rubber plantation. Land quality, of two different areas where change occurred and no change occurred during the study period, was assessed through land quality indices, i.e., soil resource index, land degradation status index and water resource index. According to soil resource and land degradation status index, no-change area were found relatively better than area where land use change has occurred, whereas it was vice versa in case of water resource index. WQI indicated that the water quality in recent years (2005 and 2006) has relatively decreased compared to the past, e.g. in 1997 and 2003, particularly due to higher concentration of suspended solid. Water availability was found to be increasing in recent years than in past as indicated by the increasing number of months within a year with water ivsurplus. Paddy areas generated higher runoff compared to other land uses and since the area under paddy was declining, the computed higher moisture storage can be attributed to this fact. More than 90% of surveyed households owned their land. The rice growers group (R-R), who did not change land use during the study period, has smaller land holding size than average land holding size (2.0 ha) of the study area and other groups who either grow rubber or changed paddy to rubber during study period. Regarding the credit and loan, majority of farm households (52.63%) borrowed loan for crop production followed by loan for household consumption (31.58%). The overall livelihood of the surveyed household in the wholestudy area is average indicated by an index value of 0.571. All groups have medium level of livelihood and there was no significant difference between the groups, however computed livelihood index showed that those farm households who have been growing rubber are relatively better off than who have converted their paddy land to rubber plantation or those who have been growing paddy for during the study period.. The projection of food availability under different scenarios, using the criteria, such as population and its growth rate, the agricultural commodity prices, rice area and yield, indicated that just adequate rice availability in the baseline and moderate case, while it is deficit in worst case and surplus in best case. The projected scenarios of per capita rice availability are able to explain the required strategies for attaining desired level of rice production in the study area. The study also makes some recommendations of policy implementation and future research. |
| Year | 2009 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. NR-09-01 |
| 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 P. ; |
| Examination Committee(s) | Schmidt-Vogt, Dietrich ;Clemente, Roberto S.; |
| Scholarship Donor(s) | Thaksin University, Phatthalung Campus ;Cooperative Research Network (CRN) ;Commission on Higher Education Ministry of Education, Thailand; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2009 |