Submitted to: Sugar Cane International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/11/2010
Publication Date: 1/20/2010
Citation: Lyn, M.E., Boopathy, R., Boykin, D.L., Weaver, M.A., Viator, R.P., Johnson, R.M. 2010. Sugarcane residue decomposition by white and brown rot microorganisms. Sugar Cane International. 28(1):37-42. Interpretive Summary: The majority of sugarcane in Louisiana is harvested with chopper harvesters that leave a blanket of crop residue on the field, which affects the sugar yield of the emerging crop if left untreated. In laboratory studies, we have found that the rate of removal of sugarcane residues could be accelerated by applying a nutritive formulation with a mixture of microorganisms isolated from sugarcane regions in Louisiana. By applying a nutritive formulation with indigenous microorganisms, the negative effect of sugarcane residue could be lessened and sugarcane growers could benefit from a reduction in sugar yield losses in the emerging crop.
Technical Abstract: Harvesting sugarcane with chopper harvesters results in up to 10 tons of field crop residue per acre. Residue management by soil microorganism decomposition offers numerous ecological and economical benefits to growers; however, this natural process is dependent on the biotic density, diversity and activity in the soil. In general, the process is unfavourably slow such that sugar yields are adversely affected in emerging ratoons. Therefore, the objective of this study is to identify a microbial based formulation that enhances the natural loss rate of sugarcane residues. The effect of amending residues with soil microbes and the influence of formulation composition on degradation rates of sugarcane residues have been investigated in laboratory bioassays. Containers of sugarcane residues were inoculated with different formulations consisting of indigenous fungi and bacteria. Mass loss over different time periods was monitored gravimetrically. The natural decomposition rate was enhanced by 15% when sugarcane residues were amended with indigenous microbes. When a nutritive formulation was applied with the indigenous microbes, the decomposition rate was improved by 25%. Decomposition rates were slower when either the nitrogen or mineral content was increased in the formulations. These findings indicate that sugarcane residues can decompose at an accelerated rate relative to the natural process. The level of increase in decomposition rate is formulation dependent. As part of a microbial residue management program, sugarcane growers could benefit by reducing sugar yield losses in emerging ratoons by application of an optimal formulation containing indigenous microbes.