Proceedings
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1. Minnesota Long-Term Phosphorus Management Trials: Phase I, The Build PeriodPhosphorus (P) fertilizer recommendations are usually made using one of two philosophies, Build and Maintain or Sufficiency. In recent years, the Sufficiency approach has been questioned because of concerns of reducing soil test levels and yield sustainability and whether it has the same yield potential as the Build and Maintain approach. Trials were initiated in 2010 at six locations across Minnesota to develop various soil test P Interpretation Classes in replicated experiments. The initial phase... |
2. Effect of Intensive Management Practices on Wheat Yields and ProfitabilityConsiderable interest in improving wheat yields and profitability has been shown throughout the U.S. over the past ten years. Much of this interest has resulted from the dramatic yield increases achieved by English producers during that time - an annual increase of 5.0 bushellacre per year (Figure 1). During that same time period, wheat producers in the U.S. have shown a much lower rate of increase in wheat yields - 1.02 bushellacre per year (Figure 2). Missouri growers have been no exception to... |
3. Sidedress N applications for corn based on corn colorNitrogen-deficient corn reflects more light over the entire visible spectrum than nitrogen-suff icient corn. Our objective was to calibrate the relationship between remotely-sensed corn color and the nitrogen need of the corn. Corn color measurements were made two ways: Aerial photographs In-field spectral radiometer A successful calibration would allow: Variable-rate sidedress nitrogen applications that precisely meet the needs of the crop. Precise response to in-season N loss (Figure 1). Data reported... |
4. Field Scale Evaluation of Innovative N Management Systems for CornPrevious research has shown that N fertilizer need for corn can vary widely, both between fields and within fields. Producers, however, almost always apply the same N fertilizer rate to whole fields, and vary N fertilizer rates minimally if at all over whole farms. Matching N fertilizer rates more closely to N needs could produce both economic and environmental benefits. Our objective is to test a range of innovative N management systems for their ability to match N rate recommendations to N needs... |
5. Manure Application Technology and Impact on Nitrogen DynamicsA field study was carried out ne ar Elora, Ontario to assess the impact of manure application timing and method on ammonia volatilization a nd nitrogen availability to the crop. A novel method was developed and calibrated for quan tifying ammonia volatilization using passive dosimeter tubes, which promises to provide an economical alternative to other methods. Ammonia loss was negligible from injected manure treatments, and when manure was incorporated immediately it had smaller losses th an when... |
6. Effect of Phosphorus and Potassium Fertilization on Corn Development and Root Distribution in Conservation TillageIn conservation tillage systems, like no-till (NT) and strip-till (ST), phosphorus (P) and potassium (K) typically become vertically and/or horizontally stratified in the soil. This stratification has the potential to make P a nd K less available and to limit corn yield. The objective of this study is to determine the infl uence of tillage and P and K placement and rate on soil P and K content, soil water status, root and shoot development, and grain yield of corn. The experiment was arranged in... |
7. 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... |
8. Determining In-season Nitrogen Requirements for Maize Using Model and Sensor Based ApproachesThere is great value in determining the optimum quantity and timing of nitrogen (N) application to meet crop needs while minimizing losses. Applying a portion of the total N during the growing season allows for adjustments which can be responsive to actual field conditions which result in varying N needs. Two methods of determining in-season N needs were evaluated, a model-based approach and a crop canopy sensor approach. The Maize-N model was developed to estimate the economically optimum N fertilizer... |
9. A 2020 Vision on Nutrient Use DecisionsMany farmers this fall are facing significant financial stress due to several factors including low crop prices and weather-induced crop losses. Crop prices are currently much lower than they were in the first half of this decade but we have been here before … time tested principles continue to apply. Past studies of the characteristics of the most profitable farmers show that they tend to have higher yields, lower costs, and are more rapid adopters of technology than their less profitable... P.E. Fixen |
10. Effect Of High Carbon Char in Conjunction with Composted Manure and Urea on Corn YieldAn integrated approach to optimize fertilizer input through use of high carbon char (also called cinder), a by-product from a local industry in Western Nebraska, was set up for determination of optimal rate of char along with a given nitrogen (N) fertilizer or composted manure on corn (Zea mays L.) yield. Char is a potential soil amendment, since it contains around 30% total carbon (C) in addition to many essential plant nutrients. The experiment was started in 2016 in sandy loam... D. Panday, B. Maharjan |
11. Assessment of Plant Nitrogen Uptake with Late Fertilizer Applications in CornPrevious research in Kansas and other regions has shown that split applications of N fertilizer with early side-dress can increase yield compared to applications at planting in some site years. Split applications are typically done using the traditional side dress at the V6-V8 growth stage. However, late N applications (late-vegetative or early reproductive stage) is generating interest as one alternative to improve nitrogen use efficiency and possibly increase yields,... D. Diaz, A. Stammer, F. Hansel |
12. Estimation of Nitrogen Losses from Char Amended Fertilized Soils: a Laboratory StudyMore than 50% of nitrogen (N) fertilizer added to agricultural soil is lost to the environment through volatilization, denitrification, and leaching. Proper management of soil carbon (C) may reduce N losses since soil C affects soil properties and N cycling. There are a wide range of soil C management practices, including direct addition of high C content materials to the soil. A 30-day laboratory study was conducted to evaluate effects of char on N losses from fertilized loam and sandy loam soils.... D. Panday, B. Maharjan |
13. Comparative Effects of Herbicide, Nitrogen Inhibitors and Nitrogen Source on Nitrification and Corn YieldNitrogen management in crops can be challenging due to nitrogen transformations and losses in soil, such as nitrification and denitrification. Nitrification is the conversion of ammonium (NH4+) to nitrate (NO3-) by ammonia oxidizing bacteria (AOB), Nitrosomonas and Nitrobacter. Nitrates can be lost through leaching during heavy precipitation. Nitrification inhibitor products are used to temporarily slow the nitrification process by... W. Neels, A. Jhala, B. Maharjan, R. Little, J. Iqbal |