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Characterizing Active Soil Organic Matter Pools Controlling Soil N Availability in Maize-based Cropping Systems
Department of Plant and Soil Sciences
Predicting the supply of soil nitrogen to maize (corn) remains difficult, if not impossible. This project examines a number of new methodologies for assessing the various forms of soil nitrogen. The context of the work is short-term corn-N response trials on corn grower fields and long-term corn-N response trials on research farms. The ultimate purpose of the project is to come up with a valid soil test for soil nitrogen supply to maize (corn).
2010 Project Description
The main objective of this work is to improve the nitrogen (N) use efficiency of corn (Zea mays L.). The most important goal of the research was to better understand the potential of split fertilizer N applications to improve corn's N use efficiency, across the corn production region of the United States. Field research was done over 3 years, from 2007 to 2009. The data were being summarized in 2010, and a regional grant proposal was written and submitted to the AFRI Climate Change program. The summarized research information continues to be used to promote split N applications, reduce total fertilizer N use rates, and lower the risk of N loss to the environment. Outputs include presentations to corn producers at field days and winter meetings, blog postings, and radio presentations.
The impacts of the research remain largely testimonial. We have actively promoted split N applications across the state for many years, especially on the wetter soils. Producers do expect to see continued research, in comparison with newer N management schemes/materials, to validate our current recommendations. No surveys documenting how KY producers provide N nutrition to corn have been completed.
Our results will have broad impact across the state, especially with producers farming less than well-drained soils. This will give a greater understanding of how N source, timing and placement combine to drive N use efficiency and the N rate decision that the corn producer must make. Considerable controversy remains regarding the need, or lack thereof, for split/delayed N applications for corn on tile-drained soils.
Grove, J.H., and E.M. Pena-Yewtukhiw. 2010. C and N coupling through time: Soil C, N and grain yield in a long-term continuous corn trial. Proceedings 10th Int. Conf. On Precision Agriculture (CD-ROM), 18-21 July, Denver, CO.
Murdock, L., J. Grove and G. Schwab. 2009. Fertilizer management. In C. Lee and J. Herbek (ed.). A Comprehensive Guide to Wheat Management in Kentucky. ID-125 (revised). Univ. Kentucky Coop. Ext. Svc., Lexington, KY. p.25-29.