|Birrell, Stuart -|
|Wirt, Adam -|
Submitted to: Agrociencia
Publication Type: Proceedings
Publication Acceptance Date: June 1, 2012
Publication Date: September 24, 2012
Citation: Karlen, D.L., Birrell, S.J., Wirt, A.R. 2012. Corn stover harvest strategy effects on grain yield and soil quality indicators. In: Ernst, O., Perez, M.T., Barbazan M., editors. Proceedings of the 19th Triennial ISTRO Conference, September 24-28, 2012, Montevideo, Uruguay. p. 51-55. Technical Abstract: The development of technologies to use cellulosic biomass as a feedstock for biofuels was recognized as an important research challenge because cellulose is available from sources that do not directly compete with food and feed production. One result was that corn (Zea mays L.) stover, the aboveground material left in fields after grain harvest, was identified as an important feedstock because of the vast area upon which corn is grown in the Midwestern U.S.A. However, as International Soil and Tillage Research Organization (ISTRO) scientists know, corn stover has many other functions within the soil. Therefore, if (1) yields are not high enough, (2) an excessive amount is harvested for any use, or (3) tillage intensities are not reduced, harvesting stover may decrease the amount of carbon (C) returned to the soil to a level that will not be sufficient to sustain soil organic carbon (SOC), soil aggregation, or other soil quality indicators. To help resolve the emerging questions regarding the sustainability of stover harvest, a private-public research project involving POET, Iowa State University (ISU), and the USDA-Agricultural Research Service (ARS) was initiated in 2008. The field study was conducted on a 50 ha (125 acre) Clarion-Nicollet-Webster soil Association site near Emmetsburg, IA, using seven stover management treatments that included no removal, cobs only, and approximately 50 or 90% of the above-ground biomass. The quantity of stover harvested, subsequent grain yields and soil-test results for the first four years will be presented. Our initial assessment indicates that there were no statistically significant differences among the seven stover harvest strategies, but there are preliminary indications that the intensity of tillage should be reduced and/or the grain yields being achieved should be increased through more intensive management for long-term sustainability of the various harvest strategies.