Impacts of Sugarcane Post-Harvest Rsidue Management on Runoff, Soil Erosion, and Nitrate Loss

Authors: Grigg, Brandon; Fouss, James; Southwick Jr, Lloyd

Submitted to: American Society of Agricultural Engineers Meetings Papers
Publication Type: Proceedings
Publication Acceptance Date: 6/1/2005
Publication Date: 5/27/2005
Citation: Grigg, B.C., Fouss, J.L., Southwick Jr, L.M. 2005. Impacts of sugarcane post-harvest residue management on runoff, soil erosion, and nitrate loss. American Society of Agricultural Engineers Meetings Papers. ASAE Paper No. 052136.

Interpretive Summary: Public concern over the burning of sugarcane residue has resulted in increased in-field residue management in Louisiana. However, this practice has been linked to increased soil water content and delayed spring growth. We established a soil-bed experiment under simulated rainfall to evaluate residue management effects on runoff quantity, soil erosion and nitrate loss. Liquid fertilizer was applied in an 8 cm deep knife cut prior to the first simulated rainfall, with soil immediately repacked over the cut. Three soil-beds were established for each treatment: Bare soil to mimic burning; residue applied evenly over the soil surface (Blanket); and residue applied as a center strip to mimic sweeping residue from row tops to the furrows. Rainfall (30 mm in one half hour) was applied twice weekly for four weeks. Bare soil resulted in 199 mm runoff, erosion of 1.9 metric tons per hectare, and nitrate loss of 9.0 kilogram per hectare. Blanket residue reduced runoff by 85 %, erosion by 95 %, and nitrate loss by 90 % compared to bare soil. Swept residue reduced runoff by only 6 %, but did decrease erosion by 60 % and nitrate loss by 32 % compared to bare soil. Leaving a residue blanket would provide the greatest benefit. However, at this slope, sweeping residue to the furrows would decrease erosion to an acceptable rate, without increasing soil water content and reducing yield.

Technical Abstract: Public concern over the burning of sugarcane residue has resulted in increased in-field residue management in Louisiana. However, this practice has been linked to increased soil water content and delayed spring growth. We established a soil-bed (< 0.2 % slope) experiment under simulated rainfall to evaluate residue management effects on runoff quantity, total solids (erosion) and nitrate loss, and on antecedent soil water content. Fertilizer (220 kg/ha applied as 32% N solution) was applied in an 8 cm deep knife cut prior to the first simulated rainfall, with soil immediately repacked over the cut. Three soil-beds were established for each treatment: Bare soil to mimic burning; a blanket of residue applied at 5 Mg/ha; and 5 Mg/ha of residue applied as a center strip to mimic brushing to the furrows (Swept). Rainfall (30 mm in 0.5 h) was applied twice weekly for four weeks. Bare soil resulted in 199 mm runoff, erosion of 1.9 Mg/ha, and nitrate loss of 9.0 kg/ha. Blanket residue reduced runoff by 85 %, erosion by 95 %, and nitrate loss by 90 % compared to bare soil. Swept residue reduced runoff by only 6 %, but did decrease erosion by 60 % and nitrate loss by 32 % compared to bare soil. Residue management did not affect soil water content; however these containers were well-drained. Leaving a residue blanket would provide the greatest benefit. However, at this slope, sweeping residue to the furrows would decrease erosion to an acceptable rate, without increasing soil water content.