Claire Patricia McSwiney
Michigan State University
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Featured researches published by Claire Patricia McSwiney.
Ecological Applications | 2010
Claire Patricia McSwiney; Sieglinde S. Snapp; Lowell E. Gentry
Soils in conventional agroecosystems are purposely held in a nitrogen (N)-saturated state to maximize crop yields. Planting winter annual cover crops when fields are usually fallow has been proposed to ameliorate N losses from soils. In this study we introduced winter annual cover crops into an N rate study with plots fertilized at 0, 34, 67, 101, 134, 168, and 202 kg N/ha in maize (Zea mays L.) to determine how winter annual cover crops affect yields, N2O and NO3- fluxes, and N pools. At the six-leaf stage and during flowering, incorporation of cover crop into soil resulted in a 30% reduction in maize biomass. Three weeks after fertilization, KCl-extractable soil mineral N was 75-87% lower in covercropped soils than in no-cover soils, indicating that N had been immobilized in the covercropped soils. At physiological maturity, there was no difference between cover and no-cover treatments in crop yield, which was maximized at 9 Mg/ha in 2006 and 7 Mg/ha in 2007. Where N rates exceed crop requirements, cover crop incorporation may reduce N exports as NO3- and N2O. Tighter N cycling in conventional agroecosystems could be fostered by matching N rates to the amount of N removed with grain and using N immobilization to retain N and support yields. If N immobilization is viewed as a means for efficient fertilizer N use rather than a process that decreases crop productivity, growers might be more willing to adopt cover-cropping practices.
Environmental Science & Technology | 2011
Morgan E. Gallagher; William C. Hockaday; Caroline A. Masiello; Sieglinde S. Snapp; Claire Patricia McSwiney; Jeffrey A. Baldock
Concerns about energy security and climate change have increased biofuel demand, particularly ethanol produced from cellulosic feedstocks (e.g., food crop residues). A central challenge to cropping for cellulosic ethanol is the potential environmental damage from increased fertilizer use. Previous analyses have assumed that cropping for carbohydrate in residue will require the same amount of fertilizer as cropping for grain. Using (13)C nuclear magnetic resonance, we show that increases in biomass in response to fertilization are not uniform across biochemical classes (carbohydrate, protein, lipid, lignin) or tissues (leaf and stem, grain, reproductive support). Although corn grain responds vigorously and nonlinearly, corn residue shows only modest increases in carbohydrate yields in response to high levels of fertilization (25% increase with 202 kg N ha(-1)). Lignin yields in the residue increased almost twice as much as carbohydrate yields in response to nitrogen, implying that residue feedstock quality declines as more fertilizer is applied. Fertilization also increases the decomposability of corn residue, implying that soil carbon sequestration becomes less efficient with increased fertilizer. Our results suggest that even when corn is grown for grain, benefits of fertilization decline rapidly after the ecosystems N demands are met. Heavy application of fertilizer yields minimal grain benefits and almost no benefits in residue carbohydrates, while degrading the cellulosic ethanol feedstock quality and soil carbon sequestration capacity.
Global Change Biology | 2005
Claire Patricia McSwiney; G. Philip Robertson
Soil & Tillage Research | 2008
Richard G. Smith; Claire Patricia McSwiney; A. Stuart Grandy; Pongthep Suwanwaree; Renate M. Snider; G. Philip Robertson
Biogeochemistry | 2014
M. E. Gallagher; Caroline A. Masiello; William C. Hockaday; Jeffrey A. Baldock; Sieglinde S. Snapp; Claire Patricia McSwiney
Journal of Natural Resources and Life Sciences Education | 2010
Claire Patricia McSwiney; Sven Bohm; Peter Grace; G. Philip Robertson
Archive | 2010
Marie E. Gallagher; William C. Hockaday; Sieg S. Snapp; Claire Patricia McSwiney; Jeffrey A. Baldock
Archive | 2009
Marie E. Gallagher; William C. Hockaday; Caroline A. Masiello; Sieg S. Snapp; W. H. Polley; Claire Patricia McSwiney; Jeffrey A. Baldock
Archive | 2008
Marie E. Gallagher; William C. Hockaday; Caroline A. Masiello; Claire Patricia McSwiney; G. Phillip Robertson; Jeffrey A. Baldock
Archive | 2008
Marie E. Gallagher; Caroline A. Masiello; William C. Hockaday; Claire Patricia McSwiney; G. Phillip Robertson
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Commonwealth Scientific and Industrial Research Organisation
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