Proceedings
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| Filter results6 paper(s) found. |
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1. Changes in Nitrogen use Efficiency and Soil Quality After Five Years of Managing for High Yield Corn and SoybeanAverage corn gain yields in the USA have increased linearly at a rate of 1.7 bulacre over the past 35 years with a national yield average of 130 bdacre. Corn yield contest winners and simulation models, ho ~ever, indicate there is -100 bda in exploitable corn yield gap. Six years (1999-2004) of plant development, grain yield and nutrient uptake \yere compared in intensive irrigated maize systems representing (a) recommended best management practices for a yield goal of 200 bdacre (Ml) and (b) intensive... |
2. Soil Carbon and Nitrogen Distribution and Gaseous Flux Due to Landscape Position and Temperate Alley-Cropping Practices in an Agricultural WatershedSoil NzO and COz efflux can be stimulated by agricultural practices whlch may contribute to an enhanced global warming effect. However, the efflux of these two gases in response to landscape position and soil conservation management practices such as contour strips in a temperate agoforestry alley cropping system has not been extensively studied. The objective of this study was to assess the effects of alley cropping and landscape position on soil total organic C and total N distribution and N20... |
3. Hybrid Maize A Simulation Model for Improving Corn ManagementHybrid-Maize (www.hybridmaize.unl.edu) is a computer program that simulates the growth and yield of a corn crop under non-limiting or water-limited (rainfed or irrigated) conditions. The model can be used to (1) assess the overall site yield potential and its variability based on historical weather data, (2) evaluate changes in attainable yield using different combinations of planting date, hybrid maturity and plant density, (3) analyze yield in relation to silking and maturity in a specific year,... |
4. Should We Abandon Soil Testing and Yield Goals in Estimating Nitrogen Rates for CornIf the prices of corn and fertilizer-N and the shape of the N response function relating crop yield to the amount of fertilizer used are known, calculating an economically optimal N rate (EONR) for maximizing the net return to applied N is straightforward: the EONR is the N rate at which no firher increase in net return occurs. In most cropping systems and under common price scenarios, crop yield at the EONR is within 95 to 99% of the maximum yield obtained for the specific management package. In... |
5. A Nitrogen Rate of Return Calculator for Wheat, Barley, and Canola in ManitobaNitrogen (N) general guidelines in Manitoba ar e reviewed by a panel of government, industry and university experts on an annu al basis and revisions as well as additions and corrections are reflected in the Soil Fertility Guide that is published (as well as posted on the web-site) by Manitoba Agriculture, Food and Rural Initiatives. However, a comprehensive review of the N databases for barley, wheat and canola has not been undertaken since September 1990. Post 1988 database of experiments conducted... |
6. Overview of Manure Handling on Steroid Movement in Agricultural Fields from Beef Cattle SystemsManure generated from concentrated animal feeding operations may serve as a source of steroids in surface water and potentially in groundwater. The objectives of this research were to determine the amount of steroids and metabolites in runoff from beef cattle production pens, and from runoff and leaching from crop production fields. Cattle were fed a synthetic progestagen, MGA or melengestrol acetate and treated with zeranol, trenbolone acetate, and estradiol implants, while a second group was not... |