|Rau, Benjamin - Forest Service (FS)|
|Roth, Gregory - Pennsylvania State University|
Submitted to: BioEnergy Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/8/2015
Publication Date: 2/28/2015
Citation: Adler, P.R., Rau, B.M., Roth, G.W. 2015. Sustainability of corn stover harvest strategies in Pennsylvania. BioEnergy Research. DOI:10.1007/s12155-015-9593-2.
Interpretive Summary: Pennsylvania has a long history of harvesting corn grain and silage for animal feed, however, not the stover which can serve as a feedstock for bioenergy production. ARS scientists from University Park, PA evaluated the effect of harvesting corn stover as a feedstock for bioenergy production on corn grain and stover yields, and soil carbon and nutrients removed with the stover, along with the potential for cover crops to maintain soil cover to reduce erosion. They found that although the precipitation was quite variable, corn yields and soil carbon were not affected when 50% of the stover was removed and the soil was always covered with crop residue above the threshold needed to protect the soil from erosion. These results demonstrate that a 50% stover harvest could be sustainable under the climate and notill management practices in Pennsylvania without negative effects on yield, or soil carbon or cover; however a monitoring program including soil nutrients should continue to verify this strategy over the long term.
Technical Abstract: Pennsylvania has a long history of harvesting corn stover after grain harvest for animal bedding and feed or as a component of mushroom compost, or as silage for dairy cattle feed. With the shallow soils and rolling topography, soil erosion and carbon losses have been minimized through extensive use of cover crops, no-till, and organic matter additions from animal manure. Our objective was to determine the effect of harvesting corn stover as a feedstock for bioenergy production in continuous corn or corn-soybean rotations on corn grain and stover yields, and soil carbon, nitrogen, phosphorus, and potassium, along with the potential for cover crops to mitigate the negative impacts on soil cover. Although there was not a significant effect of stover harvest on corn grain yields in continuous corn, there was a trend for increased yields with removal in years with wet springs and decreased yields in dry years. Under the corn soybean rotation, 100% stover removal always had lower grain yields. The harvest index varied from 0.45 to > 0.6 over the 5 year period with the lowest harvest index during a late summer drought and highest during an early summer drought. This variation in timing of drought will affect the availability of corn stover relative to grain yields. A 60% soil cover was maintained in fall and spring with 50% harvest of corn stover in most cases. Without a rye cover crop, cover for 100% stover harvest was 20-30% whereas it was greater than 40% when rye was established promptly in the fall. Soil carbon was similar across stover removal levels, crop rotations, and cover crops, as were soil nitrogen, phosphorus, and potassium, as removal rates in grain and stover were replaced with additions. Based on the crop yield, cover, and soil nutrients, partial stover removal could be sustainable under the climate and management practices in Pennsylvania.