Proceedings
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1. A Different Approach to Managing Nitrogen in SorghumResearch conducted over the past fifty plus years has been used to develop a Nitrogen Fertilizer Recommendation "formula" for grain sorghum which considers factors such as Yield Potential, Residual Nitrate N in the soil Profile, the amount of N mineralized fi-om Soil Organic Matter and Previous Crop Residue, and other potential sources of N such as animal manure or N in irrigation water. The current formula used is as follows: N Rec = Yld x (1.6) - (20 x %SOM) - PNST - PCA - Manure N - Water N W... |
2. An Environmental Assessment of Sensor-Based Variable-Rate Nitrogen Management in CornIn order to address the problem of nitrate contamination of surface and ground waters, various methods have been used to try to account for spatial variability of N within agricultural fields. One approach to account for this variability and thereby reduce nitrate pollution is in-season site- specific N application according to economic optimal N rate (EONR). Recently, active crop canopy sensors have been tested for mid-season, on-the-go N fertilizer application in corn. This 2004 and 2005 stud... |
3. Assessment of the Combined Effects of Soil pH and Carbonates on Soybean Yield and Development of Iron Deficiency ChlorosisSoybean is extensively grown in areas of the Midwest where fields often have areas of acid to calcareous soils intermingled in complex spatial patterns. Soil pH is highly buffered by carbonates, and measured pH usually ranges from 7.5 to 8.3 depending on the concentration of C02 and other factors. Soybean grown on high-pH calcareous soils often shows iron (Fe) deficiency chlorosis (IDC). Symptoms of IDC include yellowing of interveinal areas of young leaves and, as the deficiency becomes severe,... |
4. Corn Hybrid Responses to Nitrogen Fertilizer RatesEfficient use of nitrogen (N) fertilizer is becoming increasingly important in modem corn (Zea mays L.) production due to rising nitrogen fertilizer prices and growing concerns about NO3- contamination of ground and surface waters. Interest has arisen in whether nitrogen management can be improved by choosing hybrids that respond better to nitrogen. In order to see if hybrids respond differently to varying rates of N fertilizer, we grew nine hybrids at five N rates for three years at Urbana: Ill... |
5. Corn Yield Response to Fall and Spring Applied Controlled- Release Urea vs. Spring Conventional UreaNitrogen (N) application to corn has been proven to increase yields, but concerns about nitrate-N in ground and surface water have led to investigation of controlled-release N fertilizer. The objective of these experiments is to compare corn grain response to controlled-release urea (ESN) and conventional urea. Two field studies are being conducted at two locations in Iowa and corn yield data will be reported from 2003-2005. All N treatments were hand broadcast in 30 lb N/a increments from 0 lbs... |
6. Corn Yield Response to Residual Forage Crop Rotation and Manure Amendment Effect in Potato RotationsAccurate prediction of multiple-year N availability froin organic sources is difficult and can complicate nitrogen management for producers using these sources. The objective of this study was to use corn yield and soil N monitoring to evaluate long-term nutrient availability from rotational systems on an irrigated Alfisol in central Michigan. Over a 5-year period, multiple crop sequences were grown with either annual liquid dairy manure at 12,260 L ha-' or conventional mineral fertilizer applic... |
7. Cropping Systems Management Effects on Soil N Mineralization DynamicsChanges in soil organic matter (SOM) content due to cultivation also impacts the amount of indigenous soil nitrogen (IN) supply. Crop management practices designed to achieve high yields also result in high residue inputs, which can contribute to SOM build up and enhanced indigenous N supply. The objective of this study was to evaluate the long term effect of crop rotation and nutrient management in conventional and intensive maize based systems on the change in soil N supply. Soil samples fiotn... |
8. Development of Field InSite as an Effective Nutrient Management ToolNitrogen. phosphorus, and potassium are essential nutrients for crop production. Crop nutrient management is critical to the success of any farming operation. Land stewardship is a concern for most producers as long as yields and profitability are not affected significantly. While farmers are eager to improve the efficiency with which they apply nutrients, maintaining expected crop revenue per acre is equally important. Higher fertilizer costs have increased the desire to find better ways to ap... |
9. Evaluation of the Illinois Soil Nitrogen Test in the North Central RegionData from 96 locations across the North Central Region was complied to evaluate the usefulness of the Illinois soil nitrogen test (ISNT) in identifying fields where corn will not respond to additional N fertilizer and predicting the yield optimizing N rate (YONR) for each field. The ISNT could not accurately predict non-responsive sites, nor could it predict YONR. Sub-setting the data based on soil drainage class and previous crop did not improve the predictive capability of the ISNT. The ISNT w... |
10. Fertilizer Industry Update- Price, Availability, HistoryThis talk will review world and local factors that have been affecting fertilizer demand, pricing, and supply. The speaker will review fertilizer trends and usage in the world markets as well as discuss trends in the U.S. fertilizer industry. Due to the proprietary nature of most of the information, a paper is not included in the proceedings. Select slides may be available upon request. however. ... |
11. Hypoxia in the Northern Gulf of Mexico- a 2006 UpdateBased on several science reports and opinions, hypoxia (dissolved oxygen of -Mexico was previously thought to be caused by excessive loads or discharge of nitrogen (N) - primarily as nitrate plus nitrite-N (hereafter referred to as nitrate-N), and exacerbated by fertilizer N inputs (CENR, 2000). These science reports estimated lhat about 90% of the nitrate load to the Gulf was from nonpoint sources in the Mississippi and Atchafalaya River Basin (MARB). They also estimated about 56% of the nitrat... |
12. Impact of Nitrogen and Sulfur Fertilization on Wheat Yield and Quality in 2006Historically, wheat has not responded to supplemental sulfur (S) on fine to medium textured soils with adequate organic matter. However, improved sulfur scrubbers in the industrial sector have decreased the amount of S contributed annually by rainfall. Annual S deposition in Ohio has decreased by 50% over the last twenty-seven years (NADP, 2005). This may lead to greater demand for S in Ohio crops. Recent Oho research showed a positive response to ammonium sulfate but did not have the parameter... |
13. In-Season Nitrogen Management for Sub-Surface Drip Irrigated CornIrrigation water and nitrogen @I) management for subsurface drip irrigated (SDI) corn was evaluated from 2004 through 2006 at the South Central Agricultural Laboratory of the University of Nebraska. SDI irrigation and N management strategies to increase both water and N use efficiency were compared to preplant N application for hrrow irrigation, commonly used in the area. Irrigation water levels of 100, 75 and 50% of measured evapotranspiration (ET) were applied with SDI, and N was applied in tr... |
14. 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... |
15. Manure Source and Rate Effects on Soil Test Levels and Corn GrowthNutrient management planning has become an important tool in an effort to improve water quality. In Wisconsin, nutrient management regulations are in the process of moving to a phosphorus (P) based standard. As such, P budgeting and the P index will greatly influence manure applications. Thus, there is a need to better understand how soil test P changes with respect to a P based manure application. In Wisconsin, only 60 % of the total P applied in manure is considered to be available to the crop... |
16. Nitrogen Fertilization for Wheat Grown on Wet SoilsKentucky wheat production has declined fiom 530,000 acres in 1996 to 320,000 acres currently. During this time, the state average yield has increased at a rate of approximately 1.5 bushels per acre per year reaching a record high of 71 bula this year (USDA NASS, 2006). While some of the increased yield can be attributed to genetic improvements, much of the positive yield response is due to producers removing marginal soil from production. With the projection of higher wheat prices, many Kentucky... |
17. Nitrogen Mineralization Estimates for N Rate SuggestionsTo improve the accuracy of N rate recommendations for corn, reliable estimates of soil N supplying capability are needed. The important influence of soil N supplying capability on estimating corn N needs is illustrated by a recent compilation of data on corn yield response to N fertilization fiom over 300 experiments in Illinois, Iowa, Minnesota, and Wisconsin showing that 50 to 70% of the observed corn yield was produced with N supplied by the soil alone (Sawyer et al., 2006). The soil availabl... |
18. Nutrient Uptake and Partioning by Soybeans in ManitobaSoybean plants were analysed for nutrient uptake and removal through the growing season. The 45 bufac crop took up some 200 lb Nlac and removed 88% in the grain, leaving little residual N for following crops in the surprisingly high C/N ratio leaf, stem and pod material. Typical rate of N, PzOj and K20 uptake during the growing season were 4, 1 and 4 lb/ac/day, respectively. Much K was lost from senescing leaves. Nutrient translocation from vegetative parts to seed was observed for N, P, K, S, Z... |
19. On-the-go Sensing Technology for Improved Crop Nutrient ManagementOne of the major objectives of precision agriculture technologies is the site-specific management of agricultural inputs to increase profitability of crop production, improve product quality, and protect the environment. Information about the variability of different soil attributes within a field is essential to the decision-making process. The inability to obtain soil characteristics rapidly and inexpensively remains one of the biggest limitations of precision agriculture. Numerous researchers... |
20. Periodic Deep Tillage of No-till Corn and Soybean Systems in Southern IllinoisLow organic matter and low available moisture supplying soils in southern Illinois lend themselves to no-tillage crop production, but concern about compaction and rooting depth have led some to employ the use of periodic tillage. A field study was conducted at two locations in southern Illinois between 2000 and 2006 to evaluate the effects of periodic deep tillage (ripping 16-18 inches [40-45 cm] with minimum surface disturbance style shanks) prior to corn or soybean production. Deep tillage occ... |
21. Short-Term Stability of Soil Test Phosphorus in Agricultural FieldsThe spatial and temporal stability of soil test values is important to the use of soil testing for nutrient management. A study was conducted to evaluate the spatial and temporal stability of soil test phosphorus (P). Five sites ranging in size fiom 9.1 to 10.8 acres were soil sampled in the same locations in a 60 X 60 ft. grid either three or four times over a two year period. Bray 1 -P values were similar or decreased over time while Olsen-P values at two of five sites decreased. One site show... |
22. 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. ... |
23. Silage Specific Corn Hybrids for Silage Production in KentuckyFour corn hybrid types at three plant densities and two nitrogen rates were evaluated for forage yield, forage quality and ensiled quality. The four hybrid types included nutri-dense (ND), waxy (WX), leafy (LF), and dual-purpose (DP); while the three target plant densities were 54 000, 68 000, and 81 000 plants ha; and the nitrogen rates were 134 and 224 kg ha". WX consistently had low forage and grain yields compared with the otl~er types. When averaged over nitrogen rate and hybrid: plant dens... |
24. Slow Release Nitrogen Fertilizer and its Impact on Sustainable Turf Grass GrowthThe methodology of this project aims at developing an efficient, yet effective, means of providing various nitrogen (N) fertilizer sources to turf grass with the ultimate goal of maintaining sufficient biomass production while minimizing the use of excess fertilizer that may eventually end up contaminating our groundwater and waterways. Nitrogen is the nutrient required in the largest quantity by plants, and also poses the greatest threat when nutrient leaching and water contamination are consid... |
25. Strip-Tilled Corn Responses to Deep Placement of Phosphorus and Potassium- 2005 UpdateReduced tillage systems modify some of the most important variables related with the plant-soil- weather environment and consequently affect the last expression of this relation: yield. A possibly more restrictive root growth scenario (due to lower soil temperatures and higher mechanical impedance), as well as pronounced horizontal and vertical stratification in nutrients within the soil profile (particularly for no-till systems) could lead to a reduction in root uptake of nutrients. This sit... M. Cánepa, T.J. Vyn |
26. Sulfur and Nitrogen Starter Fertilizer for Corn in Northern ClimatesThe combination of cool and wet weather in early spring can reduce the amount of S and N released in soil by decomposition and mineralization of organic matter, particularly in reduced- tillage or no-till cropping systems. Recent changes to S emission regulations have decreased the amounts of S that is deposited to the soil through attnospheric channels. Field studies were initiated in 2005 at five corn (Zea mays L.) sites in Michigan to evaluate the effects of S and N starter fertilizer on nutr... |
27. Tillage and Nitrogen Application Methodology Affects Corn Grain YieldMore efficient use of fertilizer nitrogen (N) is essential for improved yields and environmental stewardship. While university N recommendations for corn are based on observations typically made in conventional tillage systems, few universities have established research to evaluate if N recommendations should be different for alternative tillage systems. Generally spealung, no-till or minimum tillage systems have been identified as needing additional N to compensate for microbial immobilization ... |
28. Use of Yield Goals for Providing N Rate Suggestions- General ConceptsRecent studies in the North Central region have shown a poor relationshp between optimum yield of individual sites and optimum fertilizer N rate (Sawyer et al., 2006). The outcome has been the development of fertilizer recommendation approaches that do not consider site yield goal (Vanotti and Bundy, 1994a; Sawyer and Nafiiger, 2005). This causes one to ponder how so many recommendation programs utilizing yield goal were developed in the fist place and have continued in use for more than 40 year... |
29. Utilizing Existing Sensor Technology to Develop a Late-Season Critical Value for Spring Wheat ProteinA premium is paid to producers for spring wheat with a protein content greater than or equal to 14%. Obtaining that protein content can be problematic without proper nitrogen (N) fertilizer management. Sensor-based technologies have been used for predicting yield. The question is whether ths technology can be used to determine the protein content in-season for spring wheat. Field studies were conducted in South Dakota in 2003 and 2005. Five N treatments (0, 34, 65, 102, 136 kg N ha-') were appli... |
30. Utilizing the Greenseeker to Evaluate Spring Wheat Growth and YieldThere is currently little information on the use of existing sensor-based technologies for in- season application of nitrogen (N) to spring wheat (Triticttm aestivztm L.) in the northern Great Plains. Over the past decade researchers in the southern Great Plains have developed the Greenseeker as a tool for on-the-go N application to winter wheat. Field experiments were established in Brookings and Gettysburg, SD to evaluate the Greenseeker Hand Held optical sensor (NTech Industries, Ukiah, CA) ... |
31. What's New with Micronutrients in our Part of the WorldThe importance of micronutrients for production of a variety of crops in the North-Central region of the U.S. has been recognized for many years. When needed, these essential nutrients can have a substantial positive impact on production. However, neither the need for nor the importance of each micronutrient is universal across the reg~on. Importance (need) is greatly affected by crop. soil properties, and production environn~cnt. With traditional thinking over the years, thoughts have focused o... |