Thesis Abstract of AGS Students

The Assessment of Rice Replacement Policy at the Farm Level in Chao Phraya Basin : A Case Study in Suphan Buri Province

Tospol Cheawcherngngarn (1997)

This research of dry season rice replacement activity was implemented for agricultural land in Samchuk District, Suphan Buri Province, according to Agricultural Restructuring Project in Chao Phraya Basin. This study tries to search for appropriate areas for four dry season crops i.e. dry season rice, sweet corn, water melon and yard long bean.

Land suitability ratings were achieved by matching Land Use Requirement (LUR) of the specific crop required and Land Quality (LQ) of particular area defined by the characteristics of soil unit. IDRISI, a raster GIS system, was used to assess both physical and economic integrated suitability. The evaluation results were stored as spatial data that can be further required, displayed and analyzed through the IDRISI.

For physical suitability, two criteria were used i.e. soil suitability and irrigation water availability. Water supply can be obtain from RID irrigation projects as well as from shallow wells. For economic suitability, farmers survey was conducted with costs, returns and profit analyzed. These were integrated into physical suitability scores yielding economic suitability scores which were consequently classified spatially into economic zones.

Results of the physical suitability assessment indicated that the cultivated areas in Samchuck District were suitable in S₁ ( best zones) for dry season rice totaling 3.5 % of total area in the district and in S₂ ( second best zones) totaling 9.5 % of total area. S₁ zone for sweet corn constituted 0.2 %, and S₂ zone constituted 8.2 % of total area. For water melon and yard long bean, S₁ zone was 3.5 % of total area, the same percentage as in S₂ zone. On the other hand, economic suitability zone was such that 13.9 % of total area was in SE₁ zone, and 0.2 % was in SE₂ zone. For water melon,0.2 % of total land was classified in SE₁ zone and 13.7 % was classified in SE₂ zone. For sweet corn and yard long bean, 7 % of the total land were suitable to SE₁ and SE₂ each.

Comparing physical suitability class S₁ (best physical zone) with economic suitability class SE₁ ( best economic zone). It was found that, dry season rice could increase 4 times, sweet corn 34 times, yard long bean doubled the area but it could decrease 20 times in water melon. Comparing with DOAE planned land use for dry season rice can be further reduced giving way to other economic crops such as sweet corn, water melon and yard long bean.

According to dry season rice consumes large amount of water. The cropping pattern is dominated by double cropping system, the economic crops were dominant patterns. Farmers identified mostly technical and economic problems to the adoption of these crops. However, institutional support is critical to this policy as the survey identified. There seem to be no important social and institutional obstacles to the adoption of new replacement crops. The role of government organization and information as the key factor as well as water shortage in introduce to change dry season rice into field crops.

There are some limitation of this analysis, it is very time consuming and requiring skills to enable extension of this method. Most of the extension officials are unfamiliar in GIS method. Although, yard long bean and water melon could get higher income than sweet corn but the weakpoint of them is that they could not grow all year round or planted in a large area, requiring much more labor than sweet corn as well as they being capital intensive. Various survey results showed that yard long bean and water melon are susceptible to disease and have risk of total crop damage. Both these crops are highly labor intensive with is a major constraint in the study area. Note however that marketing factors can play an important role in determining which crops are better than the others although they are not yet taken into account in this study. Another important limitation lies in the fact that DOAE do not have actual land use map. Therefore, comparison of the physical and economic suitability with actual land use cannot be done. High priority should be given by DOAE to the development of actual land use map so that rigorous analysis can be facilitated.

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