Proceedings
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| Filter results12 paper(s) found. |
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1. Spatial Variability of Soil Test Phosphorus, Potassium, pH and Organic Matter ContentAs part of a larger study investigating the potential for variable fertilizer N application in corn production, 18 field sites were established on farms across Ontario intensively sampled in the 1995 and 1996 field seasons to assess the spatial variability of soil test P, K, pH and organic matter content. Soil parameters typically display a log-normal distribution (positive skew) which would generally result in the under-fertilization of a greater area of a field if the rate of fertilization was... |
2. Impact of Liquid Hog Manure and Inorganic Phosphorus (P) Fertilizer Additions on Soil Test P and P Uptake by RyegrassOntario recently introduced a phosphorus (P) index to assess the relative risk of surface water contamination resulting from P application to cropland, and to suggest possible management strategies and application restrictions to reduce this risk. The index incorporates various soiVsite characteristics (soil test P level, erosionlmnoff potential etc.) as well as management practices (rate and method of P application). Within the development of the P index, questions were raised regarding the relative... |
3. 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... |
4. Relationship of Mehlich-3 ICP and Mehlich-3 Colorimetric Phosphorus Determinations with the Bray-P1 ExtractantThe Bray P1 extractant has traditionally been the common extractant used for soil testing in the Midwest and Great Plains. while the Olsen P tests has been the dominant phosphorus (P) extractant used in many westem states. The use of the Meldich-3 extractant for determining soil test P in private and state operated soil test laborato~ies becotne more commonplace in recent years. The ability to extract multiple elements is a 11lajor advantage of the Mehlich-3 test. While the Mehlich-3 test is often... |
5. Soil Electrical Conductivity Map Quality- Impact of Interpolation Search Neighborhood ParametersSpatial predictions of soil electrical conductivity (EC) measurements may be improved by adjusting the search neighborhood criteria. The objective of this study was to investigate how varying search parameters impacted the quality of soil EC maps. The three fields cl~osen for this study were from the Inner and Outer Blue Grass physiographic regions of Kentucky. Soil EC was measured by direct contact at all locations. The prediction datasets included EC measurements along transects that were separated... |
6. Tank-Mixing Micronutrients Fertilizers with Glyphosate- Potential Problem or Efficient SolutionsTANK-MIXING MICRONUTRIENT FERTILIZERS WITH GLYPHOSATE - POTENTML PROBLEM OR EFFICIENT SOLUTION Mark L. Bernards, Kurt D. Thelen, Donald Penner Michlgan State University, East Lansing, MI Summary: Many agribusinesses are currently promoting the application of micronutrient foliar fertilizers in tank-mixtures with glyphosate for increased efficiency in glyphosate-resistant soybean production. This practice is inconsistellt with data which shows decreased glyyhosate efficacy in the presence of the hard-water... |
7. Slow Release Nitrogen Fertilizer and Dynamics in Soil Systems Part I Incubation StudyA lab study was conducted at Southern Illinois University soil fertility research facility to investigate the effects of soil type on the nitrogen (N) release dynamics. The objective of this study was to identify the effect of soil type on the release rate of N from slow release nitrogen (SRN) fertilizers under controlled conditions (moisture and temperature). Two contrasting soils from Iowa and Georgia (pH and mineralogy) were combined with 500 mg kg-, of SRN or urea and kept for 90 days under growth... |
8. 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... |
9. Response Surface Models Of Subsoil K Concentration For Loess Over Till Soils In MissouriCrop uptake of potassium (K) has demonstrated sensitivity to subsoil variation in K content. This fact has not been sufficiently considered in K management strategies in part due to logistical difficulties in sampling spatially variable subsoil K. We propose a simplified soil factorial model, a response surface, to enable site-specific accounting of whole root zone K supply for loess over till soils. We compared the performance of two peak functions and a non-parametric local regression procedure... |
10. 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... |
11. How Agronomic Management Affects Soil Nitrous Oxide EmissionsThe effects of crop and soil management practices on soil emissions of non-carbon dioxide (CO2) greenhouse gases (GHGs) such as nitrous oxide (N2O) are highly variable, and long-term field data are limited. Management strategies that impact nitrogen (N) mineralization are also likely to affect how N is lost to the atmosphere as N2O gas. This presentation covers the agroecosystem soil N cycling concepts leading to losses as N2O as well as... V.L. Jin, M.R. Schmer, B.J. Wienhold |
12. Project Sense: Sensors for the Efficient Use of Nitrogen and Stewardship of the Environment. An On-Farm Research Effort to Increase Adoption of Sensor Based N ManagementLow nitrogen use efficiency (NUE) has been attributed to several factors including asynchrony between nitrogen (N) fertilizer application, crop demand, and spatial variability (Shanahan et al., 2008). Sidedress applied N synchronizes crop uptake demand for N, but does not address the spatial and temporal variability that exists in a field year to year. Active crop canopy sensors provide an ability to monitor and respond to spatial and temporal N variability for a given field. A three-year project,... B. Krienke, R. Ferguson, J. Luck, L. Thompson, J. Parrish, N. Mueller, T. Mieno, J. Crowther, T. Shaver, T. Ingram, D. Krull, K. Glewen |