Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/24/2003
Publication Date: 11/2/2003
Citation: MOTAVALLI, P.P., KREMER, R.J., NELSON, K.A. CHANGES IN SOIL C AND N MINERALIZATION RATES WITH ADDITION OF BT CORN RESIDUES IN SOILS OF VARYING TEXTURE AND CLAY MINERALOGY. AGRONOMY ABSTRACTS. 2003. CD-ROM (UNPAGINATED). AMERICAN SOCIETY OF AGRONOMY. MADISON, WI.
Technical Abstract: Chemical and physical properties of crop residues from Bt corn may differ from non-transgenic corn residues, thereby potentially affecting soil C and N mineralization rates and the growth of subsequent crops. The objectives of this research were to determine if any differences in Bt corn residue properties could be observed under field conditions and to evaluate whether soil C and N mineralization rates are affected by addition of these residues to soils of differing texture and clay mineralogy. A field experiment planted to five Bt corn varieties and their respective non-transgenic isolines was initiated in 2002 in northeastern Missouri. Grain yield, leaf, stem and root biomass, crop residue cover, and the proportion of European corn borer infestation in stems were evaluated. Analysis of stem tissue showed significant differences in acid detergent fiber (ADF), lignin, total organic C, and total N content among the Bt and non-Bt corn hybrids. However, only one Bt corn hybrid had a significantly higher lignin and lignin:N ratio compared to its non-transgenic isoline. Two subsequent incubation experiments were conducted to determine the effects of adding Bt and non-Bt leaf, stem, and root tissue on C and N mineralization in soils with silt loam, silty clay and sandy loam textural classes as well as in soils with kaolinitic, smectitic, allophonic, and calcitic clay mineralogies.