1816 research outputs found
Sort by
Estimation of infectious risks in residential populations exposed to airborne pathogens during center pivot irrigation of dairy wastewaters
Get PDFIn the western United States where dairy wastewaters are commonly land applied, there are concerns over individuals being exposed to airborne pathogens. In response, a quantitative microbial risk assessment (QMRA) was performed to estimate infectious risks after inhalation exposure of pathogens aerosolized during center pivot irrigation of diluted dairy wastewaters. The dispersion of pathogens (Campylobacter jejuni, Escherichia coli O157:H7, non-O157 E. coli, Listeria monocytogenes, and Salmonella spp.) was modeled using the atmospheric dispersion model, AERMOD. Pathogen concentrations at downwind receptors were used to calculate infectious risks during one-time (1, 8, and 24 h) and multi-day (7 d at 1 h/d) exposure events using a Beta-Poisson dose-response model. This assessment considered risk of infection in residential populations that were 1 to 10 km from a center pivot operation. In the simulations, infectious risks were estimated to be the greatest in individuals closest to the center pivot, as a result of a higher pathogen dose. Based on the results from this QMRA, it is recommended that wastewaters only be applied during daylight hours when inactivation and dilution of airborne pathogens is highest. Further refinement of the dispersion and dose-response models should be considered to increase the utility of this QMRA
Control of curly top in sugar beet with seed and foliar insecticides
Get PDFCurly top in sugar beet is a serious problem that is caused by Beet curly top virus and other closely related species and transmitted by the beet leafhopper. In order to find a means of reducing curly top in sugar beet, 15 combinations of insecticide seed (Poncho, Poncho Beta, and Poncho Votivo) and foliar (Asana, Cyazypyr, Lorsban, Mustang,
Scorpion, and Sivanto) treatments were evaluated versus an untreated check during the 2012 and 2013 growing seasons. An epiphytotic was created by releasing viruliferous beet leafhoppers 58 to 59 days after planting. The foliar sprays were applied 6 to 7 days before and again 6 to 8 days after leafhopper release. Seed treatments (active ingredient:
clothianidin) were able to reduce symptoms by 26 to 42% and increase recoverable sucrose by 16 to 21%. The pyrethroids Asana and Mustang also performed well by reducing symptoms 22 to 56% and increasing yields 13 to 20%. The neonicotinoid seed treatments should be an effective way of supplementing host resistance for early-season (at least 59 days after planting) curly top control in sugar beet. The
pyrethroid foliar applications could be used to extend curly top control during the midseason period and provide resistance management
Livestock GRACEnet: A workgroup dedicated to evaluating and mitigating emissions from livestock production
Get PDFlivestock operations can potentially affect air quality at local, regional, and even global scales. These pollutants, many of which are generated through various anthropogenic activities, are being increasingly scrutinized by regulatory authorities. Regulation of emissions from livestock production systems will ultimately increase on farm costs, which will then be passed onto consumers.
Therefore, it is essential that scientifically based emission factors are developed for on-farm emissions of air quality constituents to improve inventories and assign appropriate reduction targets. To generate a larger database of on-farm emissions, the USDA–ARS created the workgroup Livestock GRACEnet (Greenhouse gas Reduction through Agricultural Carbon Enhancement Network).
This introduction for the special section of papers highlights some of the research presently being conducted by members of Livestock GRACEnet with the intent of drawing attention to critical information gaps, such as (i) improving emissions measurements; (ii) developing emissions factors; (iii) developing and validating tools for estimating emissions; and (iv) mitigating emissions. We also provide a synthesis of the literature with respect to key research areas related to livestock emissions, including feeding strategies, animal housing, manure management, and manure land application, and discuss future research priorities and directions
Experimental sugar beet cultivars evaluated for rhizomania resistance and storability in Idaho, 2013
Get PDFRhizomania caused by Beet necrotic yellow vein virus (BNYVV) and storage losses are serious sugar beet production problems. To identify sugar beet cultivars with resistance to BNYVV and evaluate storability, 24 experimental cultivars were screened by growing them in a sugar beet field infested with BNYVV in Kimberly, ID during the 2013 growing season in a randomized complete block design with 4 replications. At harvest on 11 October 2013, roots were dug and evaluated for symptoms of rhizomania and also placed in an indoor commercial sugar beet storage building. After 123 days in storage, samples were evaluated for surface rot, weight loss, and sucrose loss. Surface root rot ranged from 7 to 76%, weight loss ranged from 6.6 to 11.6%, sucrose losses ranged from 32 to 66%, and estimated recoverable sucrose ranged from 1,643 to 8,308 lb/A. Given these response ranges, selecting cultivars for rhizomania resistance and combining this resistance with storability will lead to considerable economic benefit for the sugar beet industry
Greenhouse gas and ammonia emissions from an open-freestall dairy in Southern Idaho
Get PDFConcentrated dairy operations emit trace gases such as ammonia (NH3), methane (CH4), and nitrous oxide (N2O) to the atmosphere. The implementation of air quality regulations in livestock-producing states increases the need for accurate on-farm determination of emission rates. The objective of this study was to determine the emission rates of NH3, CH4, and N2O from the open-freestall and wastewater pond source areas on a commercial dairy located in southern Idaho. Gas concentrations and wind statistics were measured each month and used with an inverse dispersion model to calculate emission rates. Average emissions per cow per day from the open-freestall source area were 0.10 kg NH3 and 0.47 kg CH4. Average emissions from the wastewater ponds (g m-2 d-1) were 7.8 g NH3 and 22 g CH4. The combined emissions on a per cow per day basis from the open-freestall and wastewater pond areas averaged 0.22 kg NH3 and 0.85 kg CH4. The wastewater ponds were the greatest source of total farm NH3 emissions from spring through fall, contributing 64% of total emissions. The emissions of CH4 were approximately equal from the two source areas from spring through fall. During the winter months, due to decreasing temperatures and freezing of the pond surfaces, the open-freestall source area constituted the greatest source area of both NH3 and CH4 emissions. Data from this study can be used to develop trace gas emissions factors from open-freestall dairies in southern Idaho and potentially other open-freestall production systems in similar climatic regions
Assessment of Phosphorus Retention in Irrigation Laterals
Get PDFIrrigation laterals transport irrigation return flow, including water, sediment, and dissolved nutrients, such as phosphorus (P), back to surface water bodies. Phosphorus transformations during transport can affect both P bioavailability and the best management practices selected to minimize P inputs to waters of the United States. The objective of this study was to determine P retention in three irrigation laterals. Soluble reactive P (SRP) concentrations in lateral waters were increased from 0.08 to 0.25 mg L -1 (0.08 to 0.25 ppm) by constantly injecting a phosphate (PO4) solution for 2.5 hours. Bromide (Br) was used as a conservative tracer to determine dilution effects. Water was sampled at 10-minute intervals, beginning 30 minutes prior to injection and 120 minutes following injection, at one upstream location and various downstream locations to approximately 1,550 m (~1 mi) from injection sites. When at steady state, SRP concentrations only decreased by 5% over the lengths studied, equating to P uptake lengths of over 18 km (11.2 mi), which was one to two orders of magnitude greater than natural streams; the linear SRP uptake rate was 0.011 mg L -1 km -1 (0.018 ppm mi -1 ). Longer P uptake lengths and lower uptake rates in irrigation laterals, as compared to natural streams, may be due to the elevated sediment equilibrium P concentration, greater water velocities, and removal of vegetation causing a reduction in frictional resistance. Reducing water velocities should optimize irrigation lateral conditions to reduce uptake length and maximize P uptake
Site-specific management of meloidogyne chitwoodi in Idaho potatoes using 1,3-dichloropropene; approach, experiences, and economics
Get PDFFumigation for nematode management in irrigated potato production systems of Idaho is widely practiced. Spatially uniform fumigation with large scale soil injection equipment is the only labeled application method for 1,3-dichloropropene. Plant-parasitic nematode species exhibit spatially variable population densities that provide an opportunity to practice site-specific fumigation to reduce chemical usage and production costs. During 2002-2008, 62 fields intended for commercial potato production in eastern Idaho were sampled using a geo-referenced grid sampling system for plant-parasitic nematode population densities. In total, 4,030 grid samples were collected representing nearly 3200 ha of commercial potato production. Collectively, 73% of the grid samples had no Columbia Root Knot (CRN) (Meloidogyne chitwoodi) or CRN densities below the detectable limit. Site-specific fumigation is the practice of varying application rate of fumigant based on nematode population density. In 2007, 640 ha of potato production were site-specific fumigated for CRN nematode control in eastern Idaho. On average, this practice resulted in a 30% reduction in chemical usage and production cost savings of 200 ha-1. Based on farm-gate receipts and USDA inspections provided by potato producers from 2001-2011, potato tuber yield and quality have not been adversely affected using site-specific fumigation
Drought resistant sugar beets
Get PDFTechnical Abstract: Increased water demands and drought have resulted in a need to indentify crop hybrids that are drought tolerant, requiring less irrigation to sustain yields. This study was conducted to assess differences in drought tolerance among a group of genetically diverse sugarbeet hybrids. The study was conducted over three consecutive growing seasons (2008-2010) at the USDA Northwest Irrigation and Soils Research Laboratory in Kimberly, ID on a Portneuf silt loam soil (coarse-silty, mixed, superactive, mesic Durinodic Xeric Haplocalcid). Drought tolerance was evaluated by measuring sucrose yield production of six experimental hybrids of KWS SAAT AG and one commercial hybrid (Betaseed Inc.) under six water input treatments. Hybrid drought tolerance was evaluated by linear regression analysis (slope and intercept) of yield versus water input, calculation of a drought stress index (DSI), and comparison of yield potential under full irrigation. The water input treatments were based on a percentage of estimated crop evapotranspiration (ETc). Water input treatments were 125% ETc (W1), 100 percent ETc (W2), 75 percent ETc (W3), 50 percent ETc (W4), 25 percent ETc (W5) and rain-fed (W6). There were significant differences in overall yield potential and in the sucrose yield response to water among hybrids. Greater drought tolerance or greater difference in sucrose yield between hybrids was seen at the lowest water input treatment (intercept difference). Greater drought tolerance was observed for the KWS-05 hybrid compared to the commercial hybrid. Based on these results it was concluded that there is genetic diversity among existing sugarbeet experimental hybrids
Experimental sugar beet cultivars evaluated for rhizomania resistance and storability in Idaho, 2011
Get PDFRhizomania caused by Beet necrotic yellow vein virus (BNYVV) and storage losses are serious sugar beet production problems. To identify sugar beet cultivars with resistance to BNYVV and evaluate storability, 24 experimental cultivars were screened by growing them in a sugar beet field infested with BNYVV in Kimberly, ID during the 2011 growing season in a randomized complete block design with 4 replications. At harvest on 18 October 2011, roots were dug and evaluated for symptoms of rhizomania and also placed in an indoor commercial sugar beet storage building. Storage samples were evaluated for fungal growth known to correlate with sucrose loss. Depending on cultivar, surface root discoloration (rot and fungal growth) ranged from 2 to 37%. Overall, the experimental cultivars had an average sucrose reduction of 38% after 120 days in storage. Improving cultivar performance for resistance to sucrose loss in storage and rhizomania has the potential to lead to considerable economic benefit to the sugar beet industry
Commercial sugar beet cultivars evaluated for rhizomania resistance and storability in Idaho, 2011
Get PDFRhizomania caused by Beet necrotic yellow vein virus (BNYVV) and storage losses are serious sugar beet production problems. To identify sugar beet cultivars with resistance to BNYVV and evaluate storability, 31 commercial cultivars were screened by growing them in a sugar beet field infested with BNYVV in Kimberly, ID during the 2011 growing season in a randomized complete block design with 4 replications. At harvest on 18 October 2011, roots were dug and evaluated for symptoms of rhizomania and also placed in an indoor commercial sugar beet storage building. Storage samples were evaluated for fungal growth known to correlate with sucrose loss. Depending on cultivar, surface root discoloration (rot and fungal growth) ranged from 1 to 14%. Overall, the commercial cultivars had an average sucrose reduction of 36% after 120 days in storage. Improving cultivar performance for resistance to sucrose loss in storage and rhizomania has the potential to lead to considerable economic benefit to the sugar beet industry