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| Filter results6 paper(s) found. |
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1. Field Scale Variability of Corn Yield response Functions to Fertilizer Nitrogen ApplicationVariable rate nitrogen (N) application assumes that corn response to N fertilizer varies within a field. However, this hypothesis has not been formally tested yet. Field variation of corn response to N fertilizer and economically optimum N fertilizer rates (EON) were assessed in on- farm experiments throughout central Illinois. Fields (16 to 32 ha.) were subdivided into 13 to 20 areas. Five nitrogen rates were randomized within these areas in 28 kg N increments (2 rates) and decrements (2 rates)... |
2. 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... |
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. 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... |
6. Nitrogen Non-Cycling from Cover Crops Grown Before Corn and Spring Wheat-Unexpected Early Project ResultsNitrogen credits in North Dakota State University fertilization recommendations include those anticipated from the previous year annual legume crops (field pea, lentil, soybean, chickpea) and from terminated alfalfa. In addition, it was established in the region that sugarbeet tops returned to the soil may have an N credit potential of up to 80 pounds of N per acre (Crohain and Rixhon, 1967; Moraghan and Smith, 1994a; Moraghan and Smith, 1995a; Moraghan and Smith, 1995b; Franzen et al.,... D. Franzen, A. Wick, H. Bu, L. Ressler, J. Bell, M. Berti, C. Gasch |