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| Registros recuperados: 12 | |
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| Wortmann, C.S.; Tarkalson, D.D.; Shapiro, C.A.; Dobermann, A.R.; Ferguson, R.B.; Hergert, G.W.; Walters, D.T.. |
| Nitrogen use efficiency (NUE) is of economic and environmental importance. Components of NUE were evaluated in 32 irrigated corn (Zea mays L.) trials conducted across Nebraska with different N rates and where the previous crop was either corn (CC), drybean (Phaseolus vulgaris L.) (CD), or soybean (Glycine max L.) (CS). The mean grain yield with adequate nutrient availability was 14.7 Mg ha–1 . When no N was applied, measured soil properties and irrigation water N accounted for <20% of the variation in plant N uptake (UN). Mean fertilizer N recovery in above-ground biomass was 74% at the lowest N rate compared with 40% at the highest N rate, a mean of 64% at the economically optimal N rate (EONR), and least with CD. Agronomic efficiency of... |
| Tipo: Article |
Palavras-chave: Corn / maize; Nitrogen. |
| Ano: 2011 |
URL: http://eprints.nwisrl.ars.usda.gov/1414/1/1384.pdf |
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| BARTELT-HUNT L, SHANNON; SNOW D, DANIEL; KRANZ L, WILLIAM; MADER L, TERRY; Shapiro, C.A.; VAN DONK J, SIMON; SHELTON P, DAVID; Tarkalson, D.D.. |
| Supplements and growth promotants containing steroid hormones are routinely administered to beef cattle to improve feeding efficiency, reduce behavioral problems, and enhance production. As a result, beef cattle manure will contain both synthetic steroids as well as a range of endogenous steroids including androgens, estrogens, and progestogens. A two-year controlled study was conducted in which beef cattle were administered steroid hormones via subcutaneous implants and feed additives and the occurrence of sixteen endogenous and synthetic steroid hormones and metabolites was evaluated in runoff from beef cattle feedlots and in manure and soil collected from feedlot surfaces. Samples were extracted and analyzed using liquid chromatography tandem mass... |
| Tipo: Article |
Palavras-chave: Animal; Runoff; Manure. |
| Ano: 2012 |
URL: http://eprints.nwisrl.ars.usda.gov/1450/1/1415.pdf |
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| Bartlelt-Hunt, S.L.; De Vivo, S; Johnson, L.C.; Snow, D.D.; Kranz, W.L.; Mader, T.L.; Shapiro, C.A.; Van Donk, S.J.; Shelton, D.P.; Zhang, T.C.; Tarkalson, D.D.. |
| In this study, the fate of steroid hormones in beef cattle manure composting is evaluated. The fate of 16 steroids and metabolites was evaluated in composted manure from beef cattle administered growth promotants and from beef cattle with no steroid hormone implants. The fate of estrogens (primary detected as estrone), androgens, progesterone, and the fusarium metabolite and implant a-zearalanol were monitored in manure compost piles. First-order decay rates were calculated for steroid half-lives in compost and ranged from 8 days for androsterone to 69 days for 4-androsterone. Other steroid concentration data did not fit first-order decay models which may indicate that other microbial processes may result in steroid production or synthesis in... |
| Tipo: Article |
Palavras-chave: Feed preference; Animal; Manure. |
| Ano: 2013 |
URL: http://eprints.nwisrl.ars.usda.gov/1563/1/1519.pdf |
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| Tarkalson, D.D.; Payero, J.O.; Ensley, S.M.; Shapiro, C.A.. |
| Nitrate leaching from agricultural soils can increase groundwater nitrate concentrations. The objectives of the study were to assess the accumulation and movement of nitrate in the soil profile over a 2-year period under deficit irrigation conditions following a one time application of N in cattle feedlot manure and commercial fertilizer to corn at rates to achieve yield goals expected under conditions of full irrigation. Cattle manure and ammonium nitrate were applied in 2002 at the University of Nebraska recommended rate (1M and 1F ; respectively) and cattle manure was applied at twice the recommended rate (2M) for N for the 2002 corn (Zea mays L.) crop. The recommended rate was based on expected yields under full irrigation. The manure N... |
| Tipo: Article |
Palavras-chave: Chemistry; Fertilizer; Nitrogen; Mass Import - autoclassified (may be erroneous). |
| Ano: 2006 |
URL: http://eprints.nwisrl.ars.usda.gov/59/1/1220.pdf |
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| Biswas, S; Kranz, W.L.; Shapiro, C.A.; Mamo, M.; Bartlelt-Hunt, S.L.; Snow, D.D.; Tarkalson, D.D.; Shelton, D.P.; Mader, T.L.; van Donk, Simon J.; Zhang, T.C.. |
| Beef feedlot manure distributed to row crop production areas is a potential surface water contaminant source of the steroid hormones commonly used in beef cattle production. This article reports on research conducted at the University of Nebraska Haskell Agricultural Laboratory near Concord, Nebraska, in July 2009. Manure, collected from beef feedlot pens, was stockpiled for ten months prior to application to a row crop field. Previous research identified that the detection frequency of steroid hormones in beef manure varies greatly. Thus, a surrogate (17 alpha-ethynylestradiol, EE2) was applied at a rate of 75 g per ha to ensure detectable concentrations in surface runoff samples. EE2 was applied directly to beef cattle manure and to bare soil. The EE2... |
| Tipo: Article |
Palavras-chave: Manure Management; Tillage; Soil. |
| Ano: 2013 |
URL: http://eprints.nwisrl.ars.usda.gov/1554/1/1510.pdf |
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| Biswas, S; Shapiro, C.A.; Kranz, W.L.; Mader, T.L.; Shelton, D.P.; Snow, D.D.; Bartlett-Hunt, S.L.; Tarkalson, D.D.; vanDonk, S.J.; Zhang, T.C.; Ensley, S.M.. |
| Growth promoting steroids and steroid-like compounds (GPSC) used by the US beef cattle industry are potential contaminants to water resources. Manure generated in concentrated animal feeding operations contains GPSCs that may enter the environment. Several studies have focused on off-site impacts of GPSC in aquatic life and suggest possible adverse impacts such as abnormal blood hormone levels, masculinization of females, feminization of males, altered sex ratios, intersexuality and reduced fertility. Other studies point to potential human health impacts including increased incidence of human cancers, sexual disorders, and decline in male: female ratio in human beings. However, the use of GPSCs in beef production provides benefits to both cattle producers... |
| Tipo: Article |
Palavras-chave: Animal health; Animal. |
| Ano: 2013 |
URL: http://eprints.nwisrl.ars.usda.gov/1500/1/1463.pdf |
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| Zhang, T.C.; Ma, Rui; Bartelt-Hunt, S.L.; Qi, Yong; Kranz, W.L.; Snow, D.D.; Mader, T.L.; Shapiro, C.A.; Shelton, D.P.; Van Donk, S.J.; Tarkalson, D.D.. |
| In this study, batch sorption and desorption experiments were conducted for testosterone using four agricultural soils and five clay minerals. Significant differences in sorption behavior were observed between abiotic and biotic systems. The Freundlich sorption coefficient Kf (µg per g)/(µg per mL) ranged from 8.53 to 74.46 for soils and from 35.28 to 1243 for clays. The maximum sorption capacity (µg per g) of soils ranged from 25.25 to 440.61 for soils and 168.46 to 499.84 for clays. Correlation of sorption model parameters with soil properties indicated that both clay content and soil organic matter are important variables in predicting testosterone sorption behavior. Observed testosterone desorption from agricultural soils ranged from approximately 14... |
| Tipo: Article |
Palavras-chave: Soil water (soil moisture); Soil; Water. |
| Ano: 2015 |
URL: http://eprints.nwisrl.ars.usda.gov/1606/1/1564.pdf |
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| Tarkalson, D.D.; Shapiro, C.A.; Petersen, J.L.. |
| Fly ash (FA) produced from subbituminous coal combustion can potentially serve as a lime material for crop production in acidic soils. A five-year study was conducted to determine if FA was an effective liming material in an acid sandy soil under corn and soybean grain production. Fly ash and pelletized lime (PL) were surface applied at rates ranging from 3,200 to 6,400 and 1,416 to 5,658 kg/ha (0.5 to 2 times the recommended rate) at two sites near Brunswick, NE, respectively. At Site A, lime source additions increased soil pH by 0.7 units and decreased soil exchangeable Al by 7.3 mg/kg to a depth of 20 cm. Lime applications resulted in pH increase during the first year (2004) at the 0 to 10-cm depth, and in 2007 at the 10 to 20-cm depth. At Site B, soil... |
| Tipo: Article |
Palavras-chave: Soil; Chemistry. |
| Ano: 2010 |
URL: http://eprints.nwisrl.ars.usda.gov/1363/2/1340.pdf |
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| Dobermann, A.R.; Wortmann, C.S.; Ferguson, R.B.; Hergert, G.W.; Shapiro, C.A.; Tarkalson, D.D.; Walters, D.T.. |
| Nitrogen management recommendations may change as yield levels and efficiency of crop production increase. The mean yield with adequate nutrient availability in 32 irrigated corn (Zea mays L.) trials conducted across Nebraska to evaluate crop response to split-applied N was 14.8 Mg per ha. The mean economically optimal N rates (EONR) for irrigated corn varied with the fertilizer N to grain price ratio. At a fertilizer N:corn price ratio of 7, the EONR was 171, 122, and 93 kg per hectare, respectively, for cropping systems with corn following corn (CC), soybean (Glycine max L.) (CS), and drybean (Phaseolus vulgaris L.) (CD). At this price ratio the present University of Nebraska (UNL) recommendation procedure gave mean N recommendations that were 17.2,... |
| Tipo: Article |
Palavras-chave: Corn / maize; Nitrogen. |
| Ano: 2010 |
URL: http://eprints.nwisrl.ars.usda.gov/1415/1/1385.pdf |
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| Wortmann, C.C.; Shapiro, C.A.; Dobermann, Achim; Ferguson, Richard; Hergert, G; Walters, Daniel; Tarkalson, D.D.. |
| Alarm is expressed about the environmental impact of the increasing amount of reactive N in the atmosphere and in terrestrial and marine ecosystems around the globe. Much of this increase is attributed to production and use of N fertilizer. Use of fertilizer N is essential to meet growing global demand for agricultural commodities. Management is key to increasing productivity while also increasing N use efficiency and reducing N losses. A team of University of Nebraska-Lincoln scientists, with partial funding from the Nebraska State Legislature, addressed this challenge. They conducted 32 irrigated trials across diverse production conditions of Nebraska from 2002 to 2004 to evaluate corn response to rates of split-applied N. The results were reported in... |
| Tipo: Article |
Palavras-chave: Air Emissions; Chemistry; Fertilizer; Nitrogen; Soil. |
| Ano: 2011 |
URL: http://eprints.nwisrl.ars.usda.gov/1579/1/1535.pdf |
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| Van Donk, S.J.; Bigas, S; Kranz, W.L.; Snow, D.D.; Bartlelt-Hunt, S.L.; Mader, T.L.; Shapiro, C.A.; Shelton, D.P.; Tarkalson, D.D.; Zhang, T.C.; Ensley, S.M.. |
| A variety of naturally occurring steroid hormones are regularly excreted by livestock, while additional steroid hormones have been used as growth promoters by the livestock industry. Depending on manure age and storage conditions, both groups of compounds are likely to be present during application to crops. Recent research suggests that some estrogens, androgens and progestagens in surface waters may originate from runoff after land application of livestock manure. Groundwater may also be impacted by livestock manure when used as a nutrient source to crops and may be indicated by excess nitrate in water. Few studies have been conducted to investigate the potential of steroid hormones contamination of groundwater. The objective of this study was to monitor... |
| Tipo: Article |
Palavras-chave: Feed preference; Chemistry; Fertility. |
| Ano: 2013 |
URL: http://eprints.nwisrl.ars.usda.gov/1591/1/1548.pdf |
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| Registros recuperados: 12 | |
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