The Influence of Subsurface Drainage Practiceson Nitrogen and Phosphorus Losses in a Warm, Humid Climate
ABSTRACT SEDIMENT and nutrient losses were measured from a subsurface drainage-runoff-erosion experimental area for the years 1981 to 1986. The experimental area, located near Baton Rouge, LA, consisted of four surface drained plots, two of which were also subsurface drained. The plots were uniformly graded to a 0.1% slope and contained a clay loam alluvial soil. Subsurface drainage reduced surface runoff by 34%, soil loss by 30%, nitrogen loss by 20%, and phosphorus loss by 36%. Subsurface drainage increased total drainage by 35%.