Submitted to: Applied Soil Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2004
Publication Date: 10/1/2004
Citation: Lachnicht Weyers, S.L., Hendrix, P.F., Potter, R.L., Coleman, D.C., Crossley, D.A. 2004. Winter decomposition of transgenic cotton residue in conventional-till and no-till systems on the Georgia Piedmont, USA. Applied Soil Ecology. 27:135-142. Interpretive Summary: Growing genetically modified cotton crops that express insect and herbicide resistance is becoming common. We investigated decomposition of genetically modified and unmodified crop residues to determine if the alteration would have an impact on nutrient cycling. Crop residue decomposition rates and nutrient content were not influenced by genetic modification, but tillage did have an effect. Conventional tillage caused faster decomposition and greater change in nutrient content of remaining cotton residue than no-tillage.
Technical Abstract: We investigated residue decomposition of cotton that was genetically modified to express the Cry-toxin pesticide isolated from Bacillus thuringiensis (Bt) and round-up resistance, in agricultural systems under conventional tillage (CT) and no-tillage (NT) regimes. Factors investigated were resource quality and differences in environmental conditions and decomposer community structure inherent in conventional and no-tillage systems. Mass remaining and nutrient content (C and N) of cotton litter material were determined over a twenty-week period from December to May. Percent mass remaining, total N, and total C decreased over time and were significantly different between tillage regimes. Mass loss with decomposition reached 55% in the CT but only 45% in the NT over twenty weeks. Type of cotton had no significant influence on decomposition rates or nutrient contents in decomposing litter.