Evaluating the impacts of area development plans and soil conservation practices on soil productivity: a simulation approach
1997
De Guzman, M.T.
Results showed that the EPIC [Erosion Productivity Impact Calculator] model can predict soil erosion and yield data that are consistent with or not statistically significantly different from measured data based on plot level experiments. The evaluation of the area-based development plans also generated soil erosion figures and level of Biochemical Oxygen Demand that can be used by policy makers in evaluating which development paths to take. The study also estimated cost of erosion control and compared this figure to the economic contribution of the agriculture sector to the Gross Provincial Products. Of the soil conservation practices evaluated, alley cropping resulted in a significant reduction of soil erosion compared to that of farmers' practice of up-and-down cultivation. On a per hectare basis, erosion was reduced from an average figure of 59.2 tons to almost nothing under the high input alley cropping system using banana + sapodilla as hedgerows. A linear function relating yield of corn at the current period to soil loss last year generated a yield loss coefficient of -0.0125. This means that for every ton of soil loss, yield will decline by 12.5 kg. Future study should expand the analysis to test other forms of functional relationships. The development planning which pushes for the implementation of the Key Production Areas (KPA) approach of the Department of Agriculture will substantially reduce soil erosion in SOCSARGEN [South Cotabato-Sarangani-General Santos City]. For the three provinces covered, the total soil erosion will go down from 3.4 m tons to 0.4 m tons in Year 2002. The study demonstrated that erosion can be reduced with soil conservation practices and with development planning. Further, it also illustrated that the EPIC model can be used in development planning which looks into environmental considerations
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