Degradation and Water Quality Dynamics of Sugar Cane Residue in South Louisiana
PURPOSE: This research was conducted to assess methods to manage the residue blanket to avoid open field burning in sugarcane. Experiments were conducted in the state of Louisiana to evaluate methods to asses and potentially reduce water quality issues. METHODS: Concentrations and frequencies of biological compost tea were sprayed on sugarcane combine-harvester residue blanket to increase degradation rate and reduce potential for runoff water to transport nutrients and sediments that may impair water bodies, while sustaining suitable sugarcane yield. Carbon dioxide evolution rate (mg CO2-C) and CO2 fluxes were measured in laboratory and in open field conditions; as an index to measure organic matter degradation. A runoff water novel collector was proposed to collect runoff water samples from sugarcane fields. RESULTS: Results demonstrate that carbon dioxide evolution rates (mg CO2-C gr-1DW h-1) were increased when applying compost tea to a shredded and non-shredded material under laboratory conditions. However, no significant differences were found among treatments. The highest degradation rate was found when applying compost tea to a dosage of 5.6 m 3 hectare-1 for a non-shredded material and 2.8 m 3 hectare-1 for shredded material. Open field evaluations demonstrated that soil carbon dioxide fluxes (µmol m2 s-1) as an indication of organic matter degradation; were significantly increased when applying compost tea to sugarcane residue left in field. The most practical degradation rate may be achieved when applying a dosage of 2.8 m 3 hectare-1 two times during the spring-time. The findings indicate that applications of biological compost tea and slow release nitrogen fertilizer could enhance nitrogen transport to water bodies. It may also indicate the opportunity to reduce supplemental inorganic nitrogen to sugarcane fields. CONCLUSION: Results partially support previous research indicating that combine-harvester leaves a residue blanket on soil, which may reduce sugar yields in subsequent crops; since sugarcane residue management treatments were not significantly different (alpha = 0.05) with respect to yield during 2006 and 2007 harvest periods. Burning the residue also led to higher runoff water (175.2 m3 ha-1), high concentrations of suspended solids (93.4 mg L -1) and up to 6.93 mg L -1 of PO4 in runoff water.
Advisor:Michael Salassi; Gary Barbee; Axin Hou; John Pardue; Daniel Thomas; Steven Hall
School:Louisiana State University in Shreveport
School Location:USA - Louisiana
Source Type:Master's Thesis
Keywords:engineering science interdepartmental program
Date of Publication:01/22/2008