Corn Stover Yield Research Articles

Increasing Single-Pass Corn Stover Yield by Combine Header Modifications

HighlightsRotary knives were added to an ear-snapper header to increase corn stover yield in a single-pass biomass system.Stover yield increased with the number of knives but at the expense of combine productivity and fuel consumption.Bale moisture was often greater than would be considered appropriate for good aerobic conservation.Abstract.Modifications were made to a conventional ear-snapper corn header to increase corn stover yield when a single-pass round baling system was integrated with a combine harvester. To collect more leaves and top portions of stalks, knives oriented parallel to the deck plates were added to shear crop material above the ear-snapper rolls. Stover yield was primarily altered by the number of knives on the header; and to a lesser extent by the fore-and-aft position of the knives and the header height. The number of knives on a 12-row header was varied from two to six in increments of two. Stover yield increased linearly with the number of knives, and dry basis stover yield ranged from 1.1 Mg ha-1 (no knives) to 3.6 Mg ha-1 (six knives) over the five years of data collected (2012 to 2016). Combine productivity decreased linearly and specific fuel consumption increased linearly with greater stover yield. Combine productivity declined by as much as 50% when six knives were used. Dry basis bale density decreased linearly with the number of knives because the dense cobs became a smaller fraction of the total bale mass. In three of the five years, bale moisture increased linearly with the number of knives; in those three years, bale moisture was typically greater than 30% (wet basis). Adding knives to the header increased single-pass stover yield but at considerable cost to combine harvester productivity, and aerobic bale conservation would be challenged by high bale moisture. Keywords: Baling, Combine, Corn, Density, Moisture, Productivity, Stover, Yield.

Total environmental impacts of biofuels from corn stover using a hybrid life cycle assessment model combining process life cycle assessment and economic input-output life cycle assessment.

Studies on the environmental analysis of biofuels by fast pyrolysis and hydroprocessing (BFPH) have so far focused only on the environmental impacts from direct emissions and have included few indirect emissions. The influence of ignoring some indirect emissions on the environmental performance of BFPH has not been well investigated and hence is not really understood. In addition, in order to avoid shifting environmental problems from one medium to another, a comprehensive assessment of environmental impacts caused by the processes must quantify the environmental emissions to all media (air, water, and land) in relation to each life cycle stage. A well-to-wheels assessment of the total environmental impacts resulting from direct emissions and indirect emissions of a BFPH system with corn stover is conducted using a hybrid life cycle assessment (LCA) model combining the economic input-output LCA and the process LCA. The Tool for the Reduction and Assessment of Chemical and other environmental Impacts (TRACI) has been used to estimate the environmental impacts in terms of acidification, eutrophication, global climate change, ozone depletion, human health criteria, photochemical smog formation, ecotoxicity, human health cancer, and human health noncancer caused by 1 MJ biofuel production. Taking account of all the indirect greenhouse gas (GHG) emissions, the net GHG emissions (81.8 g CO2 eq/MJ) of the biofuels are still less than those of petroleum-based fuels (94 g CO2 eq/MJ). Maize production and pyrolysis and hydroprocessing make major contributions to all impact categories except the human health criteria. All impact categories resulting from indirect emissions except eutrophication and smog air make more than 24% contribution to the total environmental impacts. Therefore, the indirect emissions are important and cannot be ignored. Sensitivity analysis has shown that corn stover yield and bio-oil yield affect the total environmental impacts of the biofuels more significantly than the biomass transportation distance and biofuel transportation distance. Integr Environ Assess Manag 2018;14:139-149. © 2017 SETAC.

Elimination of gibberellin from Kappaphycus alvarezii seaweed sap foliar spray enhances corn stover production without compromising the grain yield advantage

Sustainable intensification of agricultural productivity is a global challenge. The sap of the commercially important red seaweed, Kappaphycus alvarezii, has been of interest in this regard, and its application as foliar spray has had a profound impact on the yields of many crops. It has been shown to contain indole acetic acid, kinetin, zeatin and gibberellic acid (GA3) but no study is yet reported on the interactions among these constituents, if any. In the present study, selective solvent extraction was undertaken to obtain GA3-free and indole acetic acid-free sap compositions. Another composition was prepared by autoclaving the sap which resulted in degradation of all the above growth hormones. The sap variants, along with water spray (control) and pristine sap, were applied on Zea mays as foliar spray over three consecutive seasons in dilute form. The four sap treatments were at par with one another—and significantly superior to control treatment—in so far as grain yield and quality were concerned. Pristine sap was subsequently shown to also contain choline and glycine betaine, and these were detected in similar amounts in all the sap variants, apparently indicating their profound influence on grain yield. Another important observation was that GA3-free sap led to heightened photosynthetic activity which translated into 26 % increase in corn stover yield compared to pristine sap. This is hypothesized to be on account of prevention of negative interactions between GA3 and other hormones. The study constitutes the first report of enhancement of performance of a natural seaweed plant stimulant towards increasing plant growth through simplification of its composition.

The Effect of Landscape Position on Biomass Crop Yield

Integrating annual and perennial crops at the field scale creates new opportunities for increasing financial return while addressing important environmental and ecological issues. An understanding of biomass productivity on specific landscape positions is essential to realizing this goal. The objective of this research was to determine the effect of landscape position on the productivity of herbaceous and woody biomass crops. Alfalfa (Medicago sativa L.), corn (Zea mays L.), willow (Salix spp.), cottonwood (Populus deltoides W. Bartram ex Marshall), poplar (Populus maximowiczii × P. nigra), and switchgrass (Panicum virgatum) were planted on seven landscape positions. Soil attributes were measured and included soil nitrogen, P, K, and profile darkness index (PDI). Terrain attributes included specific catchment area (SpecCat) and compound terrain index (CTI). A hierarchical Bayesian approach was used to analyze spatial data. Corn grain and stover yield was lowest in depositional and flat areas that retain water for longer periods of time and highest on well drained summit positions. Corn stover yield was positively correlated to nitrogen, PDI, SpecCat, and CTI, whereas corn grain yield was not correlated to any of the soil or terrain attributes tested. Conversely, willow productivity was among the highest at the depositional position and lowest at the summit position. For SX67 willow, growth was positively correlated to SpecCat, whereas 9882 willow growth was negatively correlated to PDI and CTI. Alfalfa and poplar productivity was highest at a site characterized by a relatively steep slope with potentially erosive soils.

Corn Stover Availability and Collection Efficiency Using Typical Hay Equipment

Corn stover has been identified as a potential feedstock for the production of fermentable sugars and thermochemical processes. The availability and efficiency of typical hay equipment for collecting corn stover has not been well quantified. Corn stover was collected for two years on a central Kentucky farm near Louisville. Six different harvesting treatments, using traditional hay equipment, were used to harvest corn stover. A rotary mower, rotary scythe (flail-type mower with windrow-forming shields), parallel bar rake, and a round baler were utilized. The average stover moisture content prior to grain harvest was above 40%, and field drying was required before baling. All treatments were analyzed for collection efficiency and corn stover yield. The stover collection yields varied from 1.93 to 5.34 dry t/ha, with collection efficiencies (ratio of stover collected to the total above-ground stover excluding grain) between 32.1% and 94.5%. The most promising collection strategy was disengaging the straw chopper and spreader to produce a windrow behind the combine. This windrow could then be baled in a separate operation that resulted in a collection efficiency of 74.1%.