Stover Removal Impact on Corn Plant Biomass, Nitrogen, and Use Efficiency

Abstract

Core Ideas Corn stover has many uses, including recent interest for cellulosic bioenergy production. For corn stover use in ethanol production, an increased understanding is needed of plant component biomass and N content within a stover harvest system, and the impact on N cycling and corn N use. Improving N use efficiency in corn is important for optimizing yield and reducing environmental impacts. Corn (Zea mays L.) stover has become an important commodity for many uses, including cellulosic ethanol production. However, there are concerns about the impacts of aggressive stover removal at the industrial scale. The objective of this study was to evaluate the effect of continuous stover removal (SR) on plant component productivity, N uptake, and nitrogen use efficiency (NUE). Treatments were none, partial, and complete SR, no‐till (NT) and chisel plow (CP), and 0, 168, and 280 kg N ha−1 rates. Total plant, vegetative, grain, and cob dry matter (DM) increased with SR (5.2–7.5%), but no difference was detected between partial and complete removal and there were no interactions with tillage system or N rate. Chisel plow and N application increased total and plant component DM, with the same overall effect on plant components from tillage as occurred with SR. Grain harvest index (GHI) was not influenced by SR (mean of 51% with N application). Stover removal had little effect on NUE measures, with only partial factor productivity (PFP), total production efficiency (TPE), and system efficiency (SYE) increasing with SR. Increasing N rate decreased NUE, with no differential effect from SR or tillage system. Stover removal in this continuous corn system provided a soil environment conducive to increased overall productivity, plant N uptake, and NUE; with a similar effect with CP compared to NT. Nitrogen management will need to account for specific biomass removal because corn production level and N removal can be differentially affected by plant component harvest.