Is Corn Stover Harvest Predictable Using Farm Operation, Technology, and Management Variables?

Abstract

C orn residue can be removed from fields following grain harvest for several non-mutually exclusive reasons. Residues may be grazed in field or harvested to provide feed for livestock (Larson et al., 2011; Rakkar et al., 2017; Schmer et al., 2017). In areas with cooler and wetter climates, such as the northern Corn Belt, stover can be removed to prepare for the next crop (Allmaras et al., 1964; Karlen et al., 2014), but in drier locations this may not occur (Jin et al., 2015). Residues can be harvested to help control pests and crop diseases (Cook et al., 1978; Sindelar et al., 2013) or can be incorporated into the soil through tillage (Bailey and Lazarovits, 2003; Shelton et al., 1995). Finally, residues can be removed as a bioenergy feedstock (USDOE, 2016, 2017). When corn residues are harvested from the field they are commonly referred to as stover, and this term is used throughout this paper. Available data suggest harvesting corn stover is not as common as other field residue management operations including grazing and tilling. Estimates using 2010 Agricultural Resource Management Survey (ARMS) data indicate 4.06 million ha of corn residues were grazed. Stover was removed and baled at an average rate of 3.6 Mg ha-1 from 0.81 million ha that comprised 2% of the corn area in the 19 surveyed states (Schmer et al., 2017). Managing surface residues through tillage is more common than harvesting them. National data suggest some form of tillage, excluding no-till, occurred on approximately 74% of corn acres. Pest management practices including tilling, chopping, mowing, and burning were used on approximately 44% of planted corn areas (USDA ERS, 2017). An emerging use for corn stover that could significantly increase the harvested area is as feedstock for bioenergy or bioproduct markets. Corn stover was identified as a key resource for achieving U.S. renewable fuel standard goals (Keeler et al., 2013). Depending on price, corn stover could supply up to 136 million Mg yr-1 (USDOE, 2016), but currently only 2.9 million Mg yr-1 are being harvested (Schmer et al., 2017). Regardless of the end use, excessive crop residue removal can increase soil erosion and degrade soil functions. Substantial research efforts, including the Regional Feedstock Partnership within the Sun Grant Initiative (Owens et al., 2016), have evaluated how soils may be impacted by harvesting corn stover and other crop residues. When left in the field, plant residues protect

Near‐term practical strategies to improve the life cycle techno‐economics, energy use and greenhouse gas emissions of corn stover supply system for biobased industries

“…Through these, the harvest rate can be increased from current level of 3.6 to 4.5 t ha −1 . This is also consistent with the values in the literature, 10,42,43 which indicates a harvest rate as high as 6.9 t ha −1 . This can minimize additional $7.3/t, 0.9% and 5.1 kg‐CO 2 e/t of the average overall cost, EUR, and GHGE, respectively, primarily by reducing the overall supply area for corn stover feedstock, resulting in reduced travel distance for trucks and improving the productivity of windrowers and balers.…”

A global meta‐analysis of soil organic carbon response to corn stover removal

“…While field experiments often included both low and high removal treatments, intensive removal is unlikely to be widely adopted because farmers recognize the need for corn residues to protect the soil and replenish soil organic matter (Obrycki & Karlen, 2018;Schmer, Brown, Jin, Mitchell, & Redfearn, 2017). In the Corn Belt, stover removal can also be limited by conservation guidelines.…”

Physiochemical Properties of Biochar and Activated Carbon from Biomass Residue: Influence of Process Conditions to Adsorbent Properties

“… 2 Corn stover, consisting of stalks, leaves, and cobs, was removed from approximately 6.3% of corn operations in the United States, suggesting an ample supply with a minimal demand. 3 In addition to bioethanol, corn stover can be used for other purposes, including fibers, hydrocarbons, and animal feed. The full utilization of lignocellulosic biomass by turning corn stover into value-added products will help progress the circular bioeconomy, increase the agricultural sector’s profitability, and decrease the dependence on non-renewable resources.…”