施灌對農田土壤及地下水之影響

雲林地區為畜牧業密集區，其廢水經過三段式處理後，申請施灌將沼渣沼液廢水施灌至農田，但因畜牧業者使用含過量銅、鋅之飼料餵養，造成其排放畜牧廢水可能含有過量的銅、鋅及氨氮，而過量之銅、鋅排放至土壤或溝渠，可能會導致土壤中重金屬累積甚至滲透到地下水而影響土壤及地下水品質。因此本研究以雲林縣虎尾鎮及水林鄉申請畜牧廢水施灌農田許可之農田採集其土壤、灌溉水、畜牧廢水以及地下水進行pH、ECs、銅、鋅等各項理化性分析，並將分析結果與無施灌之農田比較。依據土壤及水樣之數據顯示，施灌農田土壤銅、鋅高於對照土壤，因養豬戶為了增加豬隻免疫力而添加過量銅、鋅至飼料中，導致畜牧廢水中銅、鋅含量過高間接影響施灌之農田土壤，但其增加幅度不高，因申請施灌有限定其施灌量，均無超出食用作物農地監測標準，以2016及2017數據比較，虎尾及水林土壤銅濃度增加分別為2.22及3.45mg kg⁻¹；土壤鋅濃度0.21及1.30 mg kg⁻¹，若以此趨勢持續上升虎尾土壤銅濃度將於50年後超出食用作物農地監測標準，而水林將於28年超出標準，而土壤鋅濃度則需要100年以上時間才會超出食用作物監測標準。

關鍵字

施灌；畜牧廢水；鋅；銅；地下水

並列摘要

Yunlin is a livestock-intensive area, and the wastewater has undergone three-stage treatment. Applying for irrigation to apply biogas residue biogas wastewater to farmland. However, animal husbandry operators use feed containing excessive amounts of copper and zinc, cause it to discharge waste water may contain excess copper, zinc and ammonia nitrogen. Excess copper and zinc are discharged into the soil or the ditch; it may cause heavy metals in the soil to accumulate or even penetrate into groundwater and affect the fabric of soil and groundwater. Therefore, this study used Huwei Township and Shuilin Township of Yunlin County to apply for the permit of farmland irrigated farmland for land, irrigation water, animal husbandry wastewater and groundwater. Physicochemical analysis of pH, ECs, copper, and zinc was performed, and the results were compared with farmland without irrigation. Because pig farmers add excessive amounts of copper and zinc to feed in order to increase the immunity of pigs, the copper and zinc content in animal husbandry wastewater will indirectly affect the farmland soil to be used for irrigation. Based on soil and water sample data display, irrigated farmland soil copper and zinc higher than control soil. Because pig farmers add excessive amounts of copper and zinc to feed in order to increase the immunity of pigs, the copper and zinc content in animal husbandry wastewater will indirectly affect the farmland soil to be used for irrigation. However, the rate of increase was not high, and there was no excess of monitoring standards for food crops for food crops because of the limited application of irrigation. Comparing the 2016 and 2017 data, the soil copper concentrations in Huwei Town and Shuilin Township increased by 2.22 and 3.45 mg kg⁻¹, respectively, and the soil zinc concentrations were 0.21 and 1.30 mg kg⁻¹. If this trend continues to increase, the soil copper concentration in Huwei Town will exceed the monitoring standards for food crops after 50 years, while Shuilin Township will exceed the standard in 28 years, and the soil zinc concentration will take more than 100 years to exceed the monitoring of food crops standard.