Effect of water salinity on rice production in Bang Nara river basin, Narathiwat province, Thailand

Date

1989

Abstract

The study was conducted to evaluate the effect of water salinity on rice production in Bang Nara River Basin, Narathiwat Province, Thailand. The results of the comparative analysis revealed that low saline farms (1,297 kg/ha) had significantly higher rice yield than those in high saline farms (1,010 kg/ha). Fertilizer use in high saline farms are significantly greater than those in low saline farms indicating the potential damages on the soil from salinity intrusion. However, the empirical results of the yield response function analysis showed that productivity did not differ significantly between low and high saline farms as the effects of salinity did not occur during the plantation period which is most sensitive to soil changes. The proxy measures of salinity indicate, on the other hand, that location or proximity to the source of saline intrusion has a large effect on yield. In terms of rice profitability, the results of the cost and returns analysis indicated that both low and high saline farms and negative net returns to land, own land and management. Policies can be recommended as follows: a) without salinity control projects, since traditional seed variety has low responsiveness to fertilizer. Over-fertilizer application in unfavorable condition, poor soil permeability, results rice depression. Therefore, if the farmers keep using traditional variety, extension service involving knowledge of fertilizer use should be improved. In addition, the farmers paid large share of landlord though there were some of them. Landlord sharing system should ne adjusted. b) With salinity control projects all farmers will have water supply to increase their income assuming that they all have access to the resource. Low saline farms will obtain higher marginal benefit while high saline farms will get more change in benefit. To obtain greater productivity, high yielding variety (HYV) is normally recommended. Since HYV is responsive to fertilizer application, government should somehow support fertilizer supply and also improve extension service in the area. Moreover, landlord sharing should also be improved through some form of tenure reform on the land.

Document Type

Master Thesis

Degree

Master of Science in Environmental Science

College

School of Environmental Science and Management (SESAM)

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