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Natural Resources and Genomics
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Corn Residue Removal Plots Study for Resilient Economic Agricultural Practices in Florence, South Carolina None
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SMT Study for Greenhouse gas Reduction through Agricultural Carbon Enhancement network in St. Paul, Minnesota Carbon and Nitrogen Storage are Greater under Biennial Tillage in a Minnesota Corn-Soybean Rotation. Venterea, Rodney T., Baker, John M., Dolan, Michael S., Spokas, Kurt A., Soil Science Society of America Journal; Madison. http://search.proquest.com/assets/r20171.4.0.302.1590/core/spacer.gif70.5http://search.proquest.com/assets/r20171.4.0.302.1590/core/spacer.gif (Sep/Oct 2006): 1752-1762. Few studies have examined the impacts of rotational tillage regimes on soil carbon (C) and nitrogen (N). We measured the C and N content of soils managed under corn (Zea mays L.)-soybean (Glycine max L.) rotation following 10 and 15 yr of treatments. A conventional tillage (CT) regime employing moldboard and chisel plowing in alternate years was compared with both continuous no-till (NT) and biennial tillage (BT), which employed chisel plowing before soybean only. While masses of C and N in the upper 0.3 m under both BT and NT were higher than CT, only the BT treatment differed from CT when the entire sampled depth (0.6 m) was considered. Decreased C inputs, as indicated by reduced grain yields, may have limited C storage in the NT system. Thus, while more C was apparently retained under NT per unit of C input, some tillage appears necessary in this climate and cropping system to maximize C storage. Soil carbon dioxide (CO2) fluxes under NT were greater than CT during a drier than normal year, suggesting that C storage may also be partly constrained under NT due to wetter conditions that promote increased soil respiration. Increased temperature sensitivity of soil respiration with increasing soil moisture was also observed. These findings indicate that long-term biennial chisel plowing for corn-soybean in the upper mid-west USA can enhance C storage, reduce tillage-related fuel costs, and maintain yields compared with more intensive annual tillage. Urea Decreases Nitrous Oxide Emissions Compared with Anhydrous Ammonia in a Minnesota Corn Cropping System. Venterea, Rodney T; Dolan, Michael S; Ochsner, Tyson E. http://search.proquest.com/assets/r20171.4.0.302.1590/core/spacer.gif. Soil Science Society of AmericanJournal; Madison http://search.proquest.com/assets/r20171.4.0.302.1590/core/spacer.gif74.2http://search.proquest.com/assets/r20171.4.0.302.1590/core/spacer.gif (Mar/Apr 2010): 407-418. Quantifying N2O emissions from corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] fields under different fertilizer regimes is essential to developing national inventories of greenhouse gas emissions. The objective of this study was to compare N2O emissions in plots managed for more than 15 yr under continuous corn (C/C) vs. a corn-soybean (C/S) rotation that were fertilized during the corn phase with either anhydrous NH 3 (AA) or urea (U). During three growing seasons, N2O emissions from corn following corn were nearly identical to corn following soybean. In both systems, however, N2O emissions with AA were twice the emissions with U. After accounting for N2O emissions during the soybean phase, it was estimated that a shift from C/S to C/C would result in an increase in annual emissions of 0.78 kg N ha-1 (equivalent to 0.11 Mg CO2-C ha-1) when AA was used, compared with only 0.21 kg N ha-1 (0.03 Mg CO2-C ha-1) with U. In light of trends toward increased use of U, these results suggest that fertilizer-induced soil N2O emissions may decline in the future, at least per unit of applied N, although further study is needed in different soils and cropping systems. While soil CO2 emissions were 20% higher under C/C, crop residue from the prior year did not affect soil inorganic N or dissolved organic C during the subsequent season. We also compared different flux-calculation schemes, including a new method for correcting chamber-induced errors, and found that selection of a calculation method altered N2O emissions estimates by as much as 35%.
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Alternative Rotation Study for Greenhouse gas Reduction through Agricultural Carbon Enhancement network in Brookings, South Dakota Greenhouse gas fluxes and ancillary data are being measured in a 2-yr corn-soybean rotation (business as usual) and a 4- yr corn-pea-winter wheat-soybean rotation (more sustainable)
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ORPEGN Study for Greenhouse gas Reduction through Agricultural Carbon Enhancement network in Pendleton, Oregon None
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PAUP Study for Resilient Economic Agricultural Practices in University Park, Pennsylvania None
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PHACE Study for Greenhouse gas Reduction through Agricultural Carbon Enhancement network in Cheyenne, Wyoming None
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Residue Removal Study for Greenhouse gas Reduction through Agricultural Carbon Enhancement network and Resilient Economic Agricultural Practices in Brookings, South Dakota None
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REAP Study for Resilient Economic Agricultural Practices in St. Paul, Minnesota Corn stover is an important livestock feed and will probably be a major source of renewable bioenergy, especially in the U.S. Corn Belt. Overly aggressive removal of stover, however, could lead to greater soil erosion and hurt producer yields in the long-run. Good residue management practices could help prevent erosion of valuable topsoil by wind and water while still providing a revenue source for producers, either as livestock feed or for use in renewable bioenergy. Plant residues also contribute to soil structure, nutrient cycling, and help sustain the soil microbiota. Good residue management could also help control the loss of greenhouse gases from agricultural soils that could add to already increasing levels of atmospheric greenhouse gases contributing to global climate change. Cumulative GHG emissions varied widely across locations, by management, and from year-to-year. Despite this high variability, maximum stover removal averaged across all sites, years, and management resulted in lower total emissions of CO2 (-12 ± 11%) and N2O (-13 ± 28%) compared to no stover removal. Decreases in total CO2 and N2O emissions in stover removal treatments were attributed to decreased availability of stover-derived C and N inputs into soils, as well as possible microclimatic differences. Soils at all sites were CH4 neutral or small CH4 sinks. Exceptions to these trends occurred for all GHGs, highlighting the importance of site-specific management and environmental conditions on GHG fluxes in agricultural soils..
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PAHAW Study for Greenhouse gas Reduction through Agricultural Carbon Enhancement network in University Park, Pennsylvania None
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2014 Swine CAFO Study SE for Agricultural Antibiotic Resistance in Mississippi State, Mississippi The environmental influence of farm management in concentrated animal feeding operations (CAFO) can yield vast changes to the microbial biota and ecological structure of both the pig and waste manure lagoon wastewater. While some of these changes may not be negative, it is possible that CAFOs can enrich antibiotic resistant bacteria or pathogens based on farm type, thereby influencing the impact imparted by the land application of its respective wastewater. The purpose of this study was to measure the microbial constituents of swine-sow, -nursery, and -finisher farm manure lagoon wastewater and determine the changes induced by farm management. A total of 37 farms were visited in the Mid-South USA and analyzed for the genes 16S rRNA, spaQ (Salmonella spp.), Camp-16S (Campylobacter spp.), tetA, tetB, ermF, ermA, mecA, and intI using quantitative PCR. Additionally, 16S rRNA sequence libraries were created. Overall, it appeared that finisher farms were significantly different from nursery and sow farms in nearly all genes measured and in 16S rRNA clone libraries. Nearly all antibiotic resistance genes were detected in all farms. Interestingly, the mecA resistance gene (e.g. methicillin resistant Staphylococcus aureus) was below detection limits on most farms, and decreased as the pigs aged. Finisher farms generally had fewer antibiotic resistance genes, which corroborated previous phenotypic data; additionally, finisher farms produced a less diverse 16S rRNA sequence library. Comparisons of Camp-16S and spaQ GU (genomic unit) values to previous culture data demonstrated ratios from 10 to 10,000:1 depending on farm type, indicating viable but not cultivatable bacteria were dominant. The current study indicated that swine farm management schemes positively and negatively affect microbial and antibiotic resistant populations in CAFO wastewater which has future “downstream” implications from both an environmental and public health perspective.