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1. A Nitrogen Soil Test for CornIn the past decade, many states have started including a soil test when making N recommendations. In order for a soil N test to be useful, it must provide information that is not known or incorporated when making N recommendations without a test. If a test does not provide explainable, qunlltifiable infarmation. the tcs: !cses its usefghess. In Minnesota, a falllspring preplant N test has been used in the western tier of counties, which have lower rainfall than the rest of the state, for many ye... |
2. A Novel Use of Data Translation Allows 3D Prediction of Soil Fertility LandscapesSoil fertility managers need better estimates of the subsoil contribution to the nutrient pool. Thls need could be achieved through 3-D predictions of subsoil fertility using a novel method of soil- profile data translation in relation to a controlling genetic horizon. For this translation, the depth of a controlling pedogenic feature is used as the origin and the rest of the profile is linearly scaled to it. When applied to a group of soils, from across a local or regional landscape, with varyi... |
3. Aerial Photos Can Predict Corn Yield Loss Due to N DeficiencyFields that experience wet weather after N fertilizer is applied may lose N and consequently lose yield. Replacing N may be difficult or expensive after corn is too tall for tractor clearance. A tool to assess the degree of potential yield loss would help corn producers decide how much expense is justified in making late N applications. ... |
4. Alfalfa Responses to PotassiumThe potassium requirement of alfalfa is greater than that for any other nutrient. Potassium influences several systems within alfalfa plants including enzyme activity, carbohydrate production and transport, stornatal activity, photosynthesis through chlorophyll content and C02 exchange rate, and nitrogen fixation. Excellent reviews on the role of K in physiological processes are provided in the most recent potassium monograph (Munson, 1985). Potassium also markedly influences alfalfa agronomical... |
5. An Overview of the Thompson/Baker Farming Systems StudyThere is a general lack of quantitative information, collected from field-scale studies, that can be used to assess long-term effects of alternative farming systems. The objective of an on-going study in central Iowa is to quantitatively evaluate several chemical, physical, biological, and economic parameters on the Richard Thompson (alternative) and Eugene Baker (conventional) farms. This project was initiated in 1989 on adjacent 32-ha tracts of land, that have Clarion loam, Nicollet loam, Cani... |
6. Arbuscular Mycorrhizal Dynamics Throughout Corn Growing SeasonPhosphorous is an essential plant nutrient and is the second most common fertilizer nutrient applied in crop production. The role of mycorrhizal fungi in phosphorous (P) nutrition of corn (Zea mays L.) in high fertility soils in unclear. A study was conducted to determine the effect of extractable P on myco~hizal biomass and to evaluate the temporal dynamics of mycorrhizal fungi during the growing season in two irrigated corn fields in Nebraska. The objectives were addressed by the installation ... |
7. Assessing the Source of Groundwater Nitrates- And You Thought Good Wine Took TimeControversy continues with elevated groundwater nitrate concentrations being attributed to N fertilizer use. Current research defining best management practices in farming system K management seldom addresses the influence these practices have on groundwater. Why? The results of this Missouri research show that the influence of management on groundwater nitrates may last for decades. The study provides support for time requirements when assessing farming system impact on groundwater quality. ... |
8. Assessment of Nitrogen Supply From Poultry Manure Applied to CornThe production of poultry in the state of Iowa is one of the largest in the nation and growth has continued the past few years. Currently Iowa is the number one egg producing state in the USA (USDA, 2005). This increase in production also implies an increase in manure production from poultry sources. The common end use of manure is application for crop production. Concerns exist- regarding application at rates higher than needed for crop use, with potential for contamination of water bodies due... |
9. Balancing Agronomy and Environment: N Recommendations in Ontario for the 21st CenturyThe goal of a fertilizer program may be to maximize yields from each ficld, or to maximize profit, or to minimize environmental impact. Recent instances of groundwater contamination with nitrate have focused attention on the need for source water protection, and agriculture has been implicated as one of the sources of nitrate contamination. This has lead to concerns that environmental rules could reduce the profitability of crop production, by limiting fertilizer use and hence, crop yields. Addi... |
10. Certified Crop Adviser (CCA) ProgramThe Certified Crop Adviser (CCA) Program is being developed under the auspices of the American Society of Agronomy (ASA). The ad hoc steering committee is comprised of industry and university agronomists, state dealer associations, independent crop consultants, several organizations (including T.F.1, P.P.I., ARA, TVA) and ASA staff. This is a broad group representing wide geographic parts of the U.S., and has also included USDA officials, representing SCS and Extension. The purpose of the CCA pr... |
11. Determining Economic Optimum Nitrogen Rates with the Illinois Soil Nitrogen Test and Soil Organic Nitrogen FractionsDevelopment of a diagnostic test to estimate soil N supplying capability is a continuing research need. The Illinois soil nitrogen test (ISNT) has been proposed as a method for adjusting corn (Zea Mays L.) N recommendations for to account for soil organic N contributions. We evaluated the ISNT as a tool for predicting corn N response in Wisconsin by comparing ISNT values and corn N response data from-81 experiments conducted between 1984 and 2004 with a range of crop rotations, management histo... |
12. Economic Optimum Rates of N for Corn Production in IowaProper nitronen (N) fertilizer is essential if crop producers are to maximize profits and minimize environmental contamination. A study to determine 'economic optimum N fertilizer rates was conducted in Iowa from-1987 to 1991. The results show that Iowa crop producers over-applied N during those years primarily due to not considering residual N in the soil. This was especially true following the drought year of 1988.... |
13. Effect of Timing of Broadcast Potassium (K) on Soybean Yield and Seed K ContentIn Indiana, the common practice is for K fertilizer to be applied in advance of the corn crop for both crops in the rotation, relegating soybean to feed on the application residual. Producers are concerned that current University guidelines and common practices for K management in corn- soybean rotations do not fully recognize the particular K needs of the soybean crop as differentiated from the corn crop. A four-location, six-year field study was conducted to investigate the effects of rate and... |
14. Effects of Residue Density Levels on the Response of No-till Corn to N Fertilizers and InhibitorsExperiments were conducted from 1989-91 at tho southern Illinois locatio~ls (~elle\?ille and Car*bcrndale) to evaluate the effect of residue levels un the perfor-mance of N fertilizers, urease inhibitors, and placenient on the response of no-till conl. Levels of 0, 50, 100, and 200 percent of existing (pre-plant) amounts were established in the crop residues of previous corn. Kitrogen fertilizers were urea-ammonium nitrate (UAN) solution (dribble, injection. and split-applied) and urea (broadcas... |
15. Evaluation of Slow Release Nitrogen Materials in Corn ProductionStudies were conducted over a two year period to evaluate two slow release urea nitrogen carriers with regular urea for the production of corn on iirigated Spinks loamy sand. Because nitrogen availability in the soil is quite transient fiom one season to the next, annual addition of nitrogen is important for maximu~n corn yields. Many corn producers prefer to apply most of the nitrogen prior to planting corn. Once incorporated into the soil, nitrogen containing materials, such as urea, are conve... |
16. Evaluation of Three N Recommendation Systems for Corn Yield and Residual Soil NitrateProper N application rates are required for continued economic and environmental viability of U.S. agriculture. Application at rates below that required for economic optimum will place U.S. farmers at a competitive disadvantage in the world market. On the other hand, excessive rates of N fertilizers may result in contamination of ground water. ... |
17. Fertilizer Nitrogen Source and Management Impacts on Greenhouse Gas EmissionsAgricultural soil management accounts for nearly 6.3% of all greenhouse gas emission in the U.S. Although fertilizer nitrogen is an essential coinponent of nearly all agricultural systems, the addition of reactive N to soils and the emission of nitrous oxide (N20) via soil microbiological processes (nitrification and denitrification) makes U.S. agriculture the largest source (62%) of total U.S. N20 emissions. Because N20 is a potent greenhouse gas with a forcing potential more than 300 times gre... |
18. Hybrid Maize A Simulation Model for Improving Corn ManagementHybrid-Maize (www.hybridmaize.unl.edu) is a computer program that simulates the growth and yield of a corn crop under non-limiting or water-limited (rainfed or irrigated) conditions. The model can be used to (1) assess the overall site yield potential and its variability based on historical weather data, (2) evaluate changes in attainable yield using different combinations of planting date, hybrid maturity and plant density, (3) analyze yield in relation to silking and maturity in a specific yea... |
19. Impact of Nitrogen and Sulfur Fertilization on Wheat Yield and QualitySulfur (S) contributed by rainfall has decreased by 50% over the last twenty-seven years and may increase the need for S supplementation by fertilization. Nitrogen (N) application is typically split applied in Ohio with some applied in the fall and remainder applied in the spring near first green-up. The objective of this study was to compare N application source and timing with and without S fertilization. Two experimental locations were established in the fall of 2004. Urea and urea-ammonium n... |
20. Impact of Stratified Potassium and Water Content of No-Till Soils on Soybean Growth and YieldLow potassium (K) concentrations in subsurface soil and reduced water content in the K- enriched surface soil are thought to cause K-related yield reductions in rain-fed soybean (Glycine max L. Merr.). Our objectives were to examine root-to-shoot ratios through ontogeny and yield components in relation to stratified soil water and K. Soil and plant samples were collected at V6, R2, R4, and R6 from a 2-year field study. Additionally, a greenhouse split-root ot study in P a complete factorial des... |
21. Importance of Subsoil PotassiumRecent information has emphasized the importance of nutrient distribution by depth in soils. Information from across the Cotton Belt in the U.S. has demonstrated that cotton yields have been affected by accumulation of potassium (K) near the soil surface with subsequent depletion of subsoil K. This condition combined with changes in K demand by new, high-yielding cotton varieties has led to a change in cotton K deficiency symptoms and delayed diagnosis of the actual problem. Recent studies have ... |
22. Improving the Fermentation Characteristics of Corn Through Optimum Fertilization and Hybrid SelectionEthanol processors could increase production efficiency if they had access to corn grain better- suited for fermentation. The objective of this study was to determine the influence of hybrids and N fertility rates on fermentable starch content that will be used for dry-mill ethanol production. Six hybrids were grown under four N fertility levels at two locations in eastern SD. Ethanol yields increased as N fertility levels increased. Higher ethanol yields were achieved by hybrids that produced b... |
23. In Search of EAN of Spring WheatMany spring wheat varieties respond reliably to enhanced ammoniunl nutrition (EAN) in the greenhouse. Three field studies were established in 1992 to determine if similar responses could be obtained in the field. Butte 86 spring wheat was fertilized (100 Ib N/A) with calcium nitrate, urea, urea + DCD, forestry-grade (0.1 g) urea pellets and forestry-grade urea pellets + DCD. The goal was to provide wheat with a large range of a1nmonium:nitrate ratios and to determine the effect 011 wheat develop... |
24. 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 the... |
25. In-Field Determination of Anhydrous Ammonia Applicator Accuracy in NebraskaLiquid and dry fertilizer applicators have been studied for their application patterns and precision. However, anhydrous ammonia (AA) applicators are generally considered less accurate. Due to the difficulty of calibration, actual application errors have not been documented. In order determine if AA applicators were delivering the intended application rate, a standard AA nurse tank was fitted with load cells, temperature, pressure, travel speed and travel distance sensors. Initial data from 55 f... |
26. Influence of Phosphorus Soil Test Level on the Probabaility of Corn Yield ResponseData from a long term residual phosphorus study was analyzed to determine the probability of a corn yield response at low, medium, high and very high soil test levels. Analysis of 55 rate-site years showed a corn yield increase 59, 22, 43 and 17% of the time respectively for low, medium, high and very high soil test categories. The very high soil test category is defined as a Bray P soil test of greater than 20 ppm. The results suggest that the current South Dakota State University recommendatio... |
27. Introgressing Unique Sources of Germplasm to Improve N Use in Temperate MaizeThe vast majority of maize breeding efforts have been conducted under high N environments that primarily select for only one component of NUE, N uptake. Furthermore, these studies have employed US. and European genotypes, which have been selected for performance at high N. Historically, maize was grown in numerous low N tropical environments, suggesting that evaluation of adapted maize lines containing tropical germplasm may harbor useful genetic variation and novel alleles for improving NUE. Th... |
28. Long Term Outlook On Nitrogen and Potassium SupplyThe North American fertilizer industry is operating in world market today. Worldwide fertilizer demand, competition for transportation, and natural gas prices are all putting pressure on North American fertilizer prices. The themc of this mornings' session is on strategies the supply industry and fanners may adopt to manage these pressures. This talk is about the near future outlook nitrogen and potassium fertilizer. Fertilizer sales figures indicate that nitrogen, phosphorus. and potassium fer... |
29. Long Term Phosphorus Research on Corn and Grain SorghumPhosphorus fertilizer is needed for optimum production and economic returns from irrigated corn and grain sorghuni in western Kansas. A long term study shows that the yield benefit from P increases over time from no yield difference initially to over 100 butacre higher corn yields after 30 years. Without fertilizer P, soil P levels declined from 17 pprn Bray- 1 P to less than 10 pprn within five years, where they stabilized for both corn and sorghurn. The addition of fertilizer P at 40 Ib P205la... |
30. Long-Term Alfalfa Study With K RatesA long-term potassium rate study was conducted on a Maury silt loam as part of the soil test calibration program to develop data for more soils in Kentucky. Beginning soil test K levels were established with initial applications of either 0, 150 or 300 lb of K20 per acre. Annual applications of 0, 120, 240 and 360 lb of K20 per acre were applied about 1 month before fall freezedown. Results indicated (1) there were significant yield responses to annual applications after the first year; (2) the ... |
31. Making Urea Work in No TillNo-till and reduced tillage production systen~s are widely used today in the United States as well as around the world due to their capacity for reducing soil erosion and topsoil loss, reducing phosphorus movement to surface water, and reducing labor, fuel, and equipment requirements. In no-till systems, an average of 25% of the N applied as broadcast urea can be lost via ammonia volatilization. Therefore, N losses due to ammonia volatilization will decrease corn and wheat yields. independently ... |
32. Managing Continuous Corn for High YieldsMany "contest-winning" corn yields have historically been produced in fields where corn is grown continuously, often with extensive tillage, hgh soil test values of P and K, high N rates, and high plant populations. We are conducting a series of research trials at four sites in Illinois, in whlch we are varying tillage, fertilizer rates, and plant population in a factorial experiment at several Illinois locations. Over ten site-years to date, tillage deeper than normal increased yield at two sit... |
33. Near Seed Application of Fluid Fertilizer for Corn Soybean and Sugarbeet ProductionIn recent years, crop producers in Minnesota have shown increased interest in placing fertilizer near the seed at planting. The more traditional 2x2 "starter" band was not an option. Guidelines were needed for banded placement of fertilizer near the seed at the time of planting. This study was conducted in 2004 and 2005 in fields of cooperating crop producers. Three fluid . materials (10-34-0, 4-10-10, 3-18-18) were applied at two rates for corn, soybeans and sugarbeets. In 2004, the materials w... |
34. Nitrogen Management Systems for Ridge-tilled Corn ProductionThe use of conservation tillage methods, including ridge- tillage, increases crop residue cover which can lead to loss of urea-based fertilizers applied broadcast. ~ield tests were conducted during 1987-1991 at the ~rrigation ~xperiment Field, located near Scandia, Kansas, on a Crete silt loam soil (fine, montmorillionitic, mesic, Panchic, Arguistoll). Treatments included anhydrous ammonia (AA) applied preplant knife-injected; 28% urea-ammonium nitrate solution (UAN) applied preplant knife- inje... |
35. Opportunities and Limitations of Automatic Steering TechnologiesIn the short span of 10 years we have gone from using the Global Positioning System (GPS) to locate ourselves in a farm field, to automatically steering a machine working in the field. This application requires about 15 conlponents with each component evolving at a rapid pace. A number of conlpanies have formed to provide automatic steering packages as aftermarket retrofits. At a slightly slower pace, the main equipment manufactures are engineering machines that will be factor ready or factory e... |
36. Phosphorus and Potassium Place in Corn-Soybean Systems in the Midwest: Possibilities with Automatic Guidance TechnologyGlobal positioning system teclmology available to the public has become more accurate in recent years. Current Real Time Kinematic (RTK) techniques allow relative positions of equipment to be recorded with 3/8 - 2 in. precision (Dana, 1991). Being able to return to the same location in the field year after year with high precision may have implications for corn-soybean systems where banded applications of phosphorus (P) and/or potassium (K) are made at a time other than at planting. The importan... |
37. Phosphorus Management on Extremely Acid Soils in South Central KansasResearch was conducted to evaluate the effectiveness of phosphate fertilizer in reducing the toxicity of soluble aluminum (Al) on very acidic soil for production of winter wheat. Banded P fertilizer increased wheat grain yields significantly with the response being greater on unlimed compared to lime conditions. Based on the findings of this research coupled with Oklahoma State University research, banded P is an alternative to liming for wheat production on extremely acidic soils with consider... |
38. Potassium RecommendationsMost soils have relatively large contents of total K but relatively small amounts of plant- available K+. Potassium is found as a component of several minerals that release it to soluble and exchangeable forms by weathering at greatly differing rates. These forms are shown in the adjacent figure. Some of these minerals also have the capacity to reabsorb (fix) added K+ back into their structures in nonexchangeable form. Even the exchangeable K+ is bonded with different strengths depending on the ... |
39. Preplant Soil Nitrogen Test for CornSoil ammonium N and nitrate N were measured at the pre-plant and sidedress stages on 59 Michigan fields in 1992. Total inorganic soil N (ammonium N plus nitrate N) at pre-plant stage averaged to 12.6 ppm, about 50% of which was present in the nitrate form and 50% in the ammonium form. Total inorganic N at sidedress stage was 18.9 ppm, of which the nitrate N component was 12.2 ppm. The NH JNO, ratio decreased from 1.06 at prep1 ant stage to 0.54 at sidedress stage. Multiple correlation analysis ... |
40. Regional Approach to Making Nitrogen Fertilizer Rate Decisions for CornNitrogen fertilizer is one of the largest input costs for growing corn. Across the Corn Belt, N is typically the most yield-limiting nutrient. Facing record high N fertilizer prices and potential supply problems, producers are concellled about N fertilization rates. Soil fertility researchers and extension specialists froin seven states across the Corn Belt (see list in acknowledgements section) have been discussing corn N fertilization needs and evaluating N rate recommendation systems for appr... |
41. Response of Ridge-till Corn to Potash FertilizationIn recent years there has been an increased interest in growing corn with either ridge-till or no-till planting systens. This interest has been stimulated by concern for conservation compliance, farm profitability and the environment. Many problems have surfaced as these tillage systems are adopted by more and more farmers. The appearance of potassiu,~ deficiency symptoms has been a major concern for those who grow corn and soybeans with these tillage systems for the past four or five years. For... |
42. Role of Land Tenure-Other Factors in Soil P InterpretationsSoil test interpretation should recognize the residual value of applied PI the inherent limitations of soil P tests, and utilize an approach that can be easily personalized at the local level. These criteria were used to develop an interpretation approach utilizing a computer spreadsheet to estimate the optimum soil test level for an individual grower. The spreadsheet requires the following inputs: a calibration curve, acceptable marginal return, interest rate, land tenure, soil test buffer pote... |
43. Scale of Measurement Effects on Phosphorus Runoff Losses from CroplandAs phosphorus (P)-based nutrient management planning becomes necessary for some farms in Wisconsin, it will be critical to have reliable, research-based planning tools. The Wisconsin P- hdex provides one method for preparing P-based nutrient management plans. The P-Index was developed largely from small plot-scale data showing the relationships between various site and management variables and runoff P losses. Thls study was conducted to compare runoff composition measurements at the subwatershe... |
44. 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 ... |
45. Strip Tillage and No Tillage Fertilization Systems Evaluated for Eastern Kansas Rain Fed CornRow-crop agriculture in East-Central and Southeast Kansas is facing increasing pressure to reduce sediment and nutrient losses via runoff. Edge-of-field measurements show that no-tillage with fertilizers placed below the surface of the soil has significantly less sediment and total P losses in runoff compared to conventional tillage (Janssen et al., 2000). However, for rain-fed corn, no-tillage in these regions can provide serious challenges some years because of frequent spring rains and an abu... |
46. Study on Phosphorus and Nitrogen Concentration of Corn Adapted in South DakotaThough nitrogen (N) and phosphorus (P) are vital in several physiological and developmental processes in plants and animals, they pose several environmental, nutritional and health problems, if present in excess amounts. Reduction in the excess input of these nutrients into the soil, thereby reducing environmental problem and consequently nutritional and health problem, can be achieved by balancing their concentration in animal feed. Therefore, this research aims to quantify the nitrogen and pho... |
47. Summary of P Fertilizer use Effects on Soil Test PhosphorusOver the years, much research has centered on the use of various soil P extractants for developing soil fertility programs. While P soil test values are most reliable for estimating the historical probability of obtaining a crop response from fertilizer P application and tracking the effects of past P fertility programs - P soil tests are more commonly used as to estimate future fertilizer P rate requirements. Depending on the objectives of a grower, P soil testing is used to predict future P ra... |
48. Swine Manure Phosphorus Use for Crop Production in IowaImproving manure phosphorus (P) management guidelines should result in a more efficient use of thls resource for crop production and in lower risk of P loss to surface water resources. Phosphorus fertilizers are widely used in crop production, there is a great deal of information about their use, and farmers have little doubt about their value to improve crop yield in low- testing soils. However, there is a great deal of uncertainty concerning the value of manure nutrients for crops and about co... |
49. The Influence of Nitrogen Rate and Foliar Fetilization on Yield and Nitrosamine Levels in Burley TobaccoMany burley tobacco (Nicotiana tabactm~ L.) producers believe that additions of nitrogen (N) rates greater than those recommended by university extension senices will result in increased yield and income. In addition to high rates of N, many producers feel that additional foliar fertilizer will further increase yield and quality of burley tobacco and result in greater revenue. Concerns with excessive N additions include improper curing, elevated levels of tobacco specific nitrosamines (TSNA's), ... |
50. Tillage, Fertilizer Placement Equipment and Residue Compliance- Is There a ConflictConservation compliance is no longer a nightmare for crop producers farming highly erodible land. Instead, it is rapidly becoming reality if those crop producers plan to participate in USDA agricultural assistance programs. In Missouri, farmers are adopting conservation and no-till cropping practices at a very rapid rate. Though not verified, it appears that no-till acres in many north Missouri counties more than doubled from 1991 to 1992. The most cost effective means of reducing soil erosion r... |
51. Validating the Wisconsin P Index with Measured Runoff P Losses From Agricultural FieldsPhosphorus (P) indices have been developed by most states in the USA for use as planning tools to assess the risk of P loss and identify appropriate management alternatives to control these losses where needed. Little information is available on the relationshp between P index values and actual P runoff losses in the field. We compared annual P losses in runoff measured at 2 1 field or sub-watershed locations with Wisconsin P index values calculated for the same areas. The research sites include... |
52. What's Ahead- Soil Conservation Service Nutrient Management PlansFarmers have been going through a major change in their relationship with Government during the past ten years. Many in the agricultural community are anticipating possibly more changes in the future from such Legislation as the Clean Water Act and the Endangered Species Act. Each act has potential of having even more impact on the agricultural community. Immediately following those two acts will be the 1995 Farm Bill. The last two Farm bills have been slanted more to environmental concerns than... |
53. Zone Delineation for Nitrogen ManagementManaging nitrogen through zone soil sampling has been shown effective in revealing residual soil nitrate patterns in North Dakota. Zone delineation has been constructed using several types of data, including yield maps, remote imagery, topography and soil EC sensor data. A study was conducted in North Dakota, Montana and Minnesota to evaluate zone delineation methods. Across the region, yield frequency maps, topography, remote inlagery and soil EC data were effective in helping to construct zon... |