Proceedings
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1. Corn Nitrogen Rate Response and Crop Yield in a Rye Cover Crop SystemWater quality impairment related to N loss from crop production fields continues to be a concern in Iowa, including meeting the USEPA nitrate-N drinking water standard and reducing N export to the Gulf of Mexico. Therefore, in-field production practices would be helpful to aid in reduction of nitrate leaching and movement to water systems. One practice identified in the science assessment for the Iowa Nutrient Reduction Strategy is use of a winter cereal rye (Secale cereal L.) cover crop, where a... |
2. Effect of Ammonia Knife Spacing on Corn YieldExperiments were conducted at DeKalb on a Drummer sicl, Dixon Springs on a Alford silt loam and Elwood on a Blaunt sicl to evaluate the effect of ammonia knife spacing at varying N rates and on different tillage systems on the yield of corn Nitrogen was awlied at 180 1bs N/acre at bath DeKalb and El& and at 210 lbs N/acre at Dixon Springs in the knife spacing by tillage study. In the rate by knife spacing by time of application study at DeKalb, the preplant nitrogen was placed under where the rows... |
3. On-Farm Nitrogen Fertilizer DemonstrationsThe Magdoff Pre-Sidedress Nitrate Test (PSNT) has been successful 1y used in the Northeast and humid parts of Midwest to improve N fertilizer recommendations. A modified version of the Magdoff PSNT was evaluated in 1989 and 1990 in Michigan. Fifty-three large scale on-farm corn N demonstrations were carried out. Two rates of N (a reduced rate and a high rate) were rep1 icated 3 to 6 times in each field. Forty-six sites showed no significant (p=.05) yield reduction due to the reduce N rate. Forty-nine... |
4. Using Soil Properties to Predict Soluable Phosphorus Losses from Indiana SoilsEscessive phosphorus (P) levels in surface water can degrade water quality by causing algal blooms and accelerating the eutrophication process. Agriculture has bceri implicated as a major nonpoint source of P, so many states have considered restricting P applications from inorganic fertilizers, manures, and other Pcontaining materials once soil test P levels esceed "threshold values". Relationships between soil properties and soluble P loss potential have not been welldocumcnted. This laboratory... |
5. Changes in Extractable P and Mineral N from Soil Recieving Fertilizer or Manure from Swine Fed Tradional or Highly Available Phosphorus Corn DietsWe compared extractable P and mineral N from soils receiving inorganic fertilizer or manure from swine fed either traditional (TC) or Highly Available Phosphorus (HAP) corn diets. The study was conducted at two sites, one with conventionally tilled irrigated corn and the other with no-tillage dryland sorghum. Manure application to a no-tillage site resulted in volatilization losses of N and greater variation in nutrient availability when cornpared to incorporated manure. When expressed as a percentage... |
6. Use of Enhanced Efficiency Nitrogen Fertilizers To Reduce Leaching And Volatilization LossA laboratory study was conducted to explore interactions of N source and treatment with precipitation events on a coarse-textured soil. Nitrogen sources included urea-ammonium nitrate solution (UAN), UAN with additives of either nitrapyrin (Instinct �) or a carboxylated polymer (Nutrisphere-N�), or a polymer-coated dry urea (PCU) (ESN�). These products were applied to soil chambers which allowed measurement of ammonia (NH 3-N) volatilization or nitrate leaching over 31 days. Precipitation events... |
7. Integrating Multiple-Input Management Systems to Improve Soft Red Winter Wheat Grain YieldContinued improvements in wheat (Triticum aestivum L.) grain yield have cast greater interest on utilizing multiple inputs within enhanced management systems. Less than recommended seeding rates of modern varieties may utilize inputs more efficiently when subjected to enhanced management. The objective of this study was to evaluate plant growth, grain yield, and expected economic profitability for multiple agronomic and nutrient inputs across different production intensity levels.... K. Steinke, S. Purucker |
8. Overview of Biostimulant Classification and Industry PerspectiveThere are many but what is the definition of biostimulant? How are these products categorized? We will start off with definitions of commonly used terms around biostimulant products used in agriculture. The current categories in which biostimulant products fit, or do not fit into, are continually evolving as industry and regulatory work towards fine-toning definitions. As more products become commercially available, producers need to be aware of their advantages, as well as challenges, to maximize... C. Preston |