미국 일리노이주 옥수수 재배 농경지 내 암거배수 시설 설계에 따른배수량 및 질산성질소 배출 평가

Subsurface drainage improves crop productivity in poorly drained soils but may also substantially contribute impairment of surface water quality dueto excess leaching losses of nutrients like Nitrate-Nitrogen (NO3-N). This research presents preliminary findings from a 3-years tile depth and spacingstudy in Illinois state that includes three drain spacings implemented in 2 plots. We found that the plot with the narrower subsurface drainage (Case1) exported more drainage water compared to the plot with the narrower subsurface drainage system (Case 2). The total drainage water from Case 1plot showed 57% more compared to Case 2 plot. Whereas we observed that the plot with narrower drain spacing (Case 1) exported only 9% moreNO3-N leaching losses compared to the wider plot (Case 2). The average corn yield was observed higher in plot Case 1 compared to Case 2. Especially,we observed about 7% higher corn yield in plot Case 1 compared to Case 2 plot in the relatively dried year (2022). The preliminary findings for thisstudy suggest that subsurface drainage systems can be optimized to reduce nutrient losses while improving the crop productivity.