Differences in Yields,Residue Composition and N Mineralization Dynamics of Bt and Non-Bt Maize |
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Authors: | Email author" target="_blank">Nancy W?MungaiEmail author Peter P?Motavalli Kelly A?Nelson Robert J?Kremer |
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Affiliation: | (1) Department of Soil Science, Egerton University, P.O. Box 536, Njoro, Kenya;(2) Department of Soil, Environmental and Atmospheric Sciences, University of Missouri, 65211 Columbia, MO;(3) Department of Agronomy, Greenley Memorial Research Center, University of Missouri, 63460 Novelty, MO;(4) USDA-ARS, 65211 Columbia, MO |
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Abstract: | Cultivation of genetically modified crops may have several direct and indirect effects on soil ecosystem processes, such as
soil nitrogen (N) transformations. Field studies were initiated in Northeast Missouri in 2002 and 2003 to determine grain
and biomass yields and the effects of application of crop residues from five Bt maize hybrids and their respective non-Bt
isolines on soil inorganic N under tilled and no-till conditions in a maize-soybean rotation. A separate aerobic incubation
study examined soil N mineralization from residue components (leaves, stems, roots) of one Bt maize hybrid and its non-Bt
isoline in soils of varying soil textural class. Three Bt maize hybrids produced 13–23% greater grain yields than the non-Bt
isolines. Generally no differences in leaf and stem tissues composition and biomass was observed between Bt and non-Bt maize
varieties. Additionally, no differences were observed in cumulative N mineralization from Bt and non-Bt maize residues, except
for non-Bt maize roots that mineralized 2.7 times more N than Bt maize roots in silt loam soil. Incorporation of Bt residues
in the field did not significantly affect soil inorganic N under tilled or no-till conditions. Overall Bt and non-Bt maize
residues did not differ in their effect on N dynamics in laboratory and field studies. |
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Keywords: | Above ground biomass Bt maize Grain yields N mineralization Soil inorganic N |
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