|Karlen, Douglas - Doug|
Submitted to: Trade Journal Publication
Publication Type: Trade Journal
Publication Acceptance Date: 5/15/2011
Publication Date: 6/1/2011
Citation: Karlen, D.L., Birrell, S.J. 2011. Stover harvest – Safe and sustainable with good resource management practices. Available: http://www.poet.com/discovery/releases/showRelease.asp?id=274&year=2011&categoryid=0. Interpretive Summary:
Technical Abstract: Quantitative data are needed to guide corn (Zea mays L.) stover harvest for bioenergy production. A 120 acre field study on the Clarion-Nicollet-Webster soil Association near Emmetsburg, IA was established in 2008 to evaluate seven stover management treatments. Each treatment is imposed on three replicated plots that are approximately five acres in size. Our objectives were to determine if the practices will reduce subsequent crop yield or if they will degrade soil quality by increasing erosion, decreasing soil organic matter, or depleting soil fertility. Grain yields showed significant (P = 0.1) seasonal effects (182, 162, and 155 bu/acre for 2008, 2009 and 2010, respectively), but this was not associated with the stover harvest treatments. The three-year relative grain yield also showed no statistically significant differences. There were no statistically significant (P = 0.1) effects on soil pH, organic matter (SOM), or potassium (K). Soil-test phosphorus (P) showed a statistically significant numerical difference (LSD(0.1) = 6 mg/kg) among management treatments, but the soil-test rating used to determine the annual fertilizer rate was not different. Ear leaf analysis at anthesis (pollination) showed that nitrogen (N) was definitely limiting the crop in 2010 (2.97% versus 1.82% for 2009 and 2010, respectively), presumably due to the excessive amount of rainfall received that year. Overall, the three-year results of this collaborative project showed that with good management, corn stover can safely and sustainably be harvested from fields similar to the one used for this research. Obviously, stover must not be harvested from areas subject to erosion and appropriate soil conservation practices should be applied to protect and improve those areas. However, based on this study, we conclude that 1½ to 2 tons/acre of corn stover can safely be harvested from fields such as those represented by the field used for this research.