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1. DAP vs MAP Manufacturing/Marketing ImplicationsOver the past several years, discussions on the suitability of monoammonium phosphate (MAP) and diammonium phosphate (DAP) as P sources for crop production have been common. In addition to agronomic principles, these discussions have often focused on what the future holds on the availability of these two materials in the marketplace. This discussion will deal with manufacturing and marketing influences on future availability/use, while agronomic comparisons will be made elsewhere. To some, phosphate... |
2. Assessing Crop Nitrogen Needs with Chlorophyll MetersTissue testing of corn leaves for nitrogen (N) concentration is not widely used because it is easier and perhaps more economical to apply sufficient fertilizer than to risk a yield reduction because of an N deficiency. Environmental concerns related to N fertilizer will require producers to improve N management practices to reduce the potential for nitrate leaching. Applying fertilizer N on an "As Needed" basis rather than using a "Lump Sum" approach has both environmental and economic implications.... |
3. Phosphorus Placement and Tillage Effects on Corn and Soil P LevelsIncreasing crop production costs have producers scrambling to gain the greatest efficiency possible from added fertilizers. A field study was conducted at two locations in southern Illinois is assess the effect of phosphorus (P) rates and placement methods on yield and P uptake by corn under no-till (NT) and conventional (chisel and disk) tillage (CT) systems. Phosphorus rates consisted of 0, 20, and 40 pounds P205/Ac with placement methods of surface broadcast, dribble and 2x2 at planting. After... |
4. Early Season Stresses in CornSpatial variability in corn yield is frequently associated with lost yield potential caused by plant stresses. Early-season stresses are difficult to recognize because growing conditions (soil temperature and water status) are not ideal and seldom uniform throughout a field. The impact that climate has on plant growth is dificult to determine because it also affects nitrogen (N) availability. Nitrogen stress was imposed sequentially until the V8 growth stage and then all plots were sidedressed with... |
5. Strategies for Establishing Management Zones for Site Specific Nutrient ManagementRecent precision agriculture research has focused on the use of management zones as a method to define areas for variable application of crop inputs. The goal of our work was to determine the relative importance of terrain information, aerial photographs, magnetic induction maps, and yield maps to define management zones. This work was conducted on a center-pivot irrigated field located near Gibbon. NE that has been planted to continuous corn for at least five years. Remotely sensed bare-soil images,... |
6. Nutrient Management Implications of Relay Cropping on the EnvironmentResidual nitrogen (nitrate-N) remaining in the root zone after seed corn production is frequently greater than under commercial corn production. This nitrate is subject to leaching into the shallow ground water of the Platte River Valley in South-Central Nebraska. as noted by elevated nitrate-N concentrations under seed cornfields compared to other fields. Hard-red winter wheat was planted into seed corn residue in early October of 2001 as a cover crop to scavenge residual- N from the root zone and... |
7. An Update on Crop Canopy Sensors for In-Season N ManagementRemote sensing in agriculture has focused 011 the spectral and spatial properties of plants. Remote sensing provides the capability for rapid collection of vast quantities of spatial data that can be analyzed quickly for use in detel-mining a course of action. This creates the potential for using remote sensing to assess and manage in-season production practices. Past research has shown that a change in canopy rel-lectance inay not be unique for a given stress. Also, other agents may have effects... |
8. In Season RecommendationsWe are testing a prototype high-clearance tractor configured with active crop canopy sensors, drop nozzles with electronic valves, and a variable rate controller as means to deliver in-season variable rates of liquid N fertilizer based on crop needs as an alterative to preplant uniform applications of N. The active sensor we're evaluating is the model ACS-210 Crop Circle made by Holland Scientific. It generates it's own source of modulated light in the amber and near infrared (NIR) bands and then... |
9. In-Season Nitrogen Recommendations for CornMaking fertilizer N recommendations involves a great deal of guess work and uncertainty because much, essentially all, of the fertilizer N is applied before the crop is planted and the amount is based on estimated crop use from historical data. In addition, producers, consultants, and fertilizer dealers try to anticipate how much N might be lost because of untimely or excess precipitation or how much additional N might be required if the weather conditions are favorable. Sidedress and in-season... |
10. Organic Farming in Nebraska: Establishing Organic Research for the Organic Farming CommunityFour sites in Nebraska were developed to have land available to conduct research on certified organic land. All sites will be certified organic by the end of 2008. The goal of the project is to conduct research relevant to the organic farmi ng community and not to compare organic systems with conventional systems. Resear ch is being conducted on the use of flaming to control weeds, winter wheat variety development and selection for the organic market, variety testing of organic winter wheat, proso... |
11. Field to Market: The Alliance for Sustainable AgricultureField To Market®: The Alliance for Sustainable Agriculture Field To Market® is a diverse alliance working to create opportunities across the agricultural supply chain for continuous improvements in productivity, environmental quality, and human well-being. The group provides collaborative leadership that is engaged in industry-wide dialogue, grounded in science, and open to the full range of technology choices.... |
12. Switchgrass Rhizobacterial Community Structure as a Function of Cultivar and Nitrogen Fertility at Two Sites in MinnesotaBiofuel production using native perennial grasses such as switchgrass (Panicum virgatum) has potential to reduce U.S. dependence on foreign oil and curtail greenhouse gas emissions. Switchgrass can also provide significant ecosystem services, such as nutrient loss reduction and carbon sequestration. Best management practices (BMPs) for switchgrass fertility are being established on a regional basis, yet little work has been done to examine the intersection of soil fertility with soil biology in switchgrass-for-biofuel... |
13. Nitrogen Management: Unraveling the Effect of Timing and FormImprovement of nitrogen use efficiency by co rn production would decrease the potential for nitrogen loss into the environment. A study ha s been conducted in Ames, Iowa on 16 different forms and rates of nitrogen in both a continuous corn and corn-soybean production systems. There were differences among treatments; howeve r, the most consistent treatment was the SuperU applied as a 150 lb A -1 preplant or as 50 lb A-1 preplant and 100 lb A-1 sidedress and UAN with Agrotain adde d to both the 50... |
14. Root Growth and Phosphorus Uptake Affected by Fertilizer Management in Soybean and WheatPlant root growth patterns can be affected by nutrient and water availability. The objective of this study was to assess the effect of phosphorus (P) fertilizer management on soybean (Glycine max. L) and winter wheat (Triticum aestivum L.) root system growth and macro and micronutrients uptake. Two greenhouse studies were carried out at Kansas State University, Manhattan, Kansas under controlled environment. The experimental design... F. Hansel, D. Diaz |