Sediment and nutrient loading from sugarcane fields in south Louisiana: Effect of residue management

Authors: SELIM, H - LSU Agcenter; ELBANA, TAMER - LSU Agcenter; White, Paul; ARCENEAUX, ALLEN - LSU Agcenter; TUBANA, BRENDA - LSU Agcenter

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/14/2019
Publication Date: 9/9/2019
Citation: Selim, H.M., Elbana, T., White Jr, P.M., Arceneaux, A., Tubana, B. 2019. Sediment and nutrient loading from sugarcane fields in south Louisiana: Effect of residue management. Journal of Soil and Water Conservation. 74(5):477-486. https://doi.org/10.2489/jswc.74.5.477.
DOI: https://doi.org/10.2489/jswc.74.5.477

Interpretive Summary: A substantial amount of sugarcane leaf material is left on the soil surface when sugarcane is harvested green. The leafy material creates mulch layer that prevents soil from drying or warming quickly in the spring; the delay results in cane and sugar yield reductions in the current and subsequent crops. The current best management practice is to burn the leaf material once it is dry to prevent yield losses the following year. But, burning is increasingly difficult due to urban encroachment. Many growers recognize the importance of the mulch layer to improving soil organic matter and retaining nutrients. Retaining the mulch layer, or sweeping the residue in the wheel furrows, also has advantages related to soil and water conservation. In this study, we evaluate the effect of managing this leaf residue (mulch, burn, and sweep) on sugarcane yield as well as the amounts of sediment and nutrients present in runoff water. Cane and sugar yields were similar regardless of residue treatment. Runoff was lowest in mulch fields, followed by burn, and swept fields. Soil and nutrient losses were higher for second year, across treatments, but similar among treatments either year. The results indicate that sugarcane growers can minimize soil and nutrient losses associated with runoff by retaining the mulch layer, and under the test conditions, expect similar yields with sweep or mulch residue management.

Technical Abstract: Sugarcane residue management such as sweeping or mulching poses several challenges for producers and affects soil and water conservation practices. In this study, we evaluate the effect of post-harvest residue (mulch, burn, and sweep) on the sugarcane yield as well as loads of sediment and nutrients exported in the runoff on field-scale experiments. Additionally, nonlinear regression analyses between the runoff from mulch, burn, and sweep fields and the associated sediment and nutrient loading were carried out. Average yield of five years across sugarcane varieties were statistically similar for the different treatments. The runoff coefficient (in a range of 0.1 to 0.4) is found to be in ascending order as mulch fields < burn fields < sweep fields and is proportionally enlarged by the increase of rainfall intensity that was observed in 2014. Moreover, total solids loading, as well as total losses of ammonia, nitrate, and dissolved phosphorus, were quantified. Results revealed that data varied significantly from the normal pattern distribution. There were no significant differences in total solids loading and ammonia losses among the various residue management treatments. However, nitrate and dissolved phosphorus losses from burn and sweep fields exhibited significant differences during 2014.