數十年來,化學肥料之使用已帶來許多負面影響,主要來自農耕施肥之氮、磷等營養鹽對水體之污染,集約施肥使氮、磷累積於地下及地面水體。迴歸水遭受污染後不僅限制其再利用之用途,甚至產生諸多環境問題,包括藻類大量繁殖及水體之優養化,甚至對人類健康產生潛在性之威脅。為評估水稻田施肥對周邊水體之影響,本研究利用位於新竹縣新埔鎮之水稻實驗田區進行土壤、地面及地下水體之水質監測,包括田區灌溉水源、出水口逕流及淺層地下水觀測井水質。監測結果顯示水稻施肥對於地表水體之影響,僅於基肥初期造成銨氮及硝酸鹽氮較明顯上昇,其他時間則維持相對穩定之低濃度,且幾與灌溉原水質相當(分別為<0.1mg/L 及 <3mg/L),但對於磷顯著累積於土壤及淺層地下水之現象,仍需進一步研究評估其影響性。綜合現地監測結果顯示,水田施肥並非主要之非點源汙染來源,且可藉由良善之排水控制及合理化施肥進一步降低其可能產生之汙染負荷。
The use of chemical fertilizer has negatively impacted on environments in recent decades, mainly through water pollution by nitrogen and phosphate originating from agricultural activity. Intensive use of fertilizer for crops may be responsible for nitrogen and phosphate accumulation in both groundwater and surface waters. The return flow polluted by nutrients not only result in the limitation of water reuse goal but also create many environmental problems, including algal blooms and eutrophication in aquifers or in surface water bodies, and may pose potential hazards to human health. This study is to evaluate the fertilizer application of terraced paddy fields impacting on soil and return flow water quality. Water quality monitoring continued for two crop-periods around subject to different water bodies, including the irrigation water, drainage water at the outlet of experimental terraced paddy field, shallow groundwater were conducted in the Hsin-pu experimental paddy field located at Hsin-chu County, north Taiwan. The results indicate that obviously increasing of NH4+-N and NO3--N concentrations in the surface drainage water and ground water were just observed during the early stage of basal fertilizer application, but reduced to relatively low concentrations (<0.1mg/L and <3mg/L respectively) in the remaining period of cultivation. But the significance of phosphate accumulation in both shallow groundwater and surface soil need to be further studied. It can be confirmed that fertilizer application of paddy field not the main non-point pollution source and the potential pollution load could be reduced by well drainage water control and rational fertilizer management.