|BIRRELL, STUART - Iowa State University|
Submitted to: Scientific and Technical Review
Publication Type: Other
Publication Acceptance Date: 6/12/2014
Publication Date: 7/2/2015
Citation: Karlen, D.L., Kovar, J.L., Birrell, S.J. 2015. Corn stover nutrient removal estimates for central Iowa. Scientific and Technical Review. 7:8621-8634. DOI:10.3390/su7078621.
Technical Abstract: One of the most frequently asked questions Project Liberty coordinators receive is “what quantity of nutrients will be removed if I harvest my corn (Zea mays L.) stover?” This report summarizes plant nutrient composition data collected in Boone and Palo Alto Counties of Iowa from 2008 through 2012 to help answer that question. More than 500 site-years of samples were collected by hand from approximately six linear feet of row and divided into four plant fractions: vegetative material from the ear shank upward, vegetative material from approximately four inches above the soil surface to just below the ear, cobs, and grain. Another 388 stover samples, representing the vegetative material collected directly from a single-pass combine harvesting system or from bales that had been prepared using two-pass stover harvest technologies, were also collected. All samples were analyzed for C, N, P, K, Ca, Mg, S, Al, B, Cu, Fe, Mn, and Zn concentrations. Mean concentration and dry matter estimates for each sample were used to calculate nutrient removal per dry ton of stover. Compared to harvesting only the grain, stover harvest increased N, P, and K removal by 14, 1.4, and 16 lbs per ton, respectively. For stover harvest rates of one ton/acre, we recommend making no changes in current N and P fertilization practices, but routine soil testing and plant analysis should be used to monitor plant available K levels.