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The study was conducted in two agro-ecological zones of La Trinidad, Buguias and Atok, Benguet. The objectives of the study were to determine the physical and chemical properties of soils of agricultural farms; to determine the pesticide residues in soils and plants; and to determine toxic heavy metals in soils of agricultural farms. The two agro-ecological zones comprised of mid-mountain zone with elevation ranging from 1,100 to 1,500 meters above sea level represented by La Trinidad and Buguias, Benguet and high mountain zone with 1,600 to 2,000 meters above sea level elevation represented by Atok, Benguet.
For mid-mountain zone represented by La Trinidad, Benguet for wet season sampling and Buguias, Benguet for dry season sampling, most of the soil samples collected showed favorable values of bulk density, porosity, pH, organic matter, available phosphorus and exchangeable potassium for crop production. On the other hand, pesticide residue analysis on soil samples showed that only Cypermethrin and Chlorpyrifos have values higher than the maximum allowable concentrations. Toxic heavy metals like Mercury and Lead have values lower than maximum residual limit. Likewise, only Chlorpyrifos was detected in plants but its value is below the maximum allowable concentration.
For the high-mountain zone represented by Atok for wet and dry season sampling, the results of the analysis showed that values of bulk density, porosity, pH, organic matter, available phosphorus and exchangeable potassium are also found favorable for crop production. For pesticide residue analysis in soil, the samples were found to have residues of Dieldrin, Endosulfansulfate, Cypermethrin, Chlorotalonil, Cypermethrin and Deltamethrin. However, only Chlorothalonil and Cypermethrin were found to have values higher than the maximum allowable concentration. Mercury and Lead were found to have values below the maximum residual limit. No pesticide residues were detected in crops.