Author
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Karlen, Douglas |
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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 9/16/2014 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Corn (Zea mays L.) stover has been identified as an important feedstock for several uses including advanced biofuel production, enhanced animal feeds, mushroom production, and several green chemistry constituents. Harvesting stover for any of these uses will increase macronutrient (N, P, and K), secondary nutrient (Ca, Mg, Na, and S), and micronutrient (Al, B, Cu, Fe, Mn, and Zn) removal compared to harvesting only corn grain. This presentation will: (1) provide a brief introduction to N, P, and K cycles within the soil profile; (2) review the ARS-REAP/DOE/NIFA Sun Grant Regional Partnership study findings, and (3) share what we have learned regarding nutrient removal when corn stover is harvested. Nutrient removal by various plant fractions and cycling through spent mushroom substrate (SMS), as well as farmer and industry perspectives on stover harvest will be discussed. Important lessons are that nutrient cycling within the soil profile is (1) complex and dynamic and (2) influenced by inherent soil chemical, physical, and biological properties and processes. Furthermore, crop residues are an important source of nutrients for subsequent crops, and accurate estimates of stover removal are essential to prevent the development of nutrient deficiencies or impairments to ecological services. Lessons regarding recycling of SMS are that it has the potential to reduce soil erosion while increasing soil P and K concentrations, soil C levels, and producer profitability. Average C, N, P, K, Ca, Mg, S, Al, B, Cu, Fe, Mn, and Zn removal in 388 machine-harvested stover samples as well as 530 hand samples from the ear shank upward, ear shank downward, cobs, and grain will be reviewed. Farmers are individuals and therefore have very different perspectives regarding stover harvest. Typical concerns focus on balancing the need for stover to protect soil resources from wind and water erosion versus challenges that stover presents with N management. POET-DSM anticipates using 285,000 tons of biomass annually, while DuPont Cellulosic Ethanol anticipates harvesting up to 135,000 acres of corn stover to support cellulosic conversion facilities that will be operational by the end of 2014. The final lessons are that: (1) with regard to stover harvest rates, field averages are meaningless, (2) sustainable harvest must be site specific, (3) a landscape approach utilizing multiple feedstock sources would be the most desirable management strategy, and finally (4) corn stover and other crop residues should never be referred to as “trash”. |
