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1. A Brief History of the Great Plains Soil Fertility ConferenceThe Great Plains Soil Fertility Conference began in 1980 as the Great Plains Soil Fertility Workshop at the Denver Sheraton Hotel on Quebec in Denver, CO. This Workshop was patterned off the successful North Central Extension Industry Soil Fertility Workshop which had been in existence since 1971. Several companies provided some initial funding to get the project off and running. The objectives of the Workshop/Conference were to bring together researchers and i... L. Murphy |
2. Accuracy of Quick Soil Nitrate Tests in MontanaAccurate, rapid testing of soil nitrate-N would allow producers to adjust their fertilizer rates when needed and augment their annual soil testing. This study tested the accuracy of three quick test kits on approximately 90 soils. Quick nitrate-N readings were well correlated (P<0.001) with laboratory readings. However there was a fairly high probability (~40%) of over or under estimating total soil N by at least 15 lb N/ac. In addition, regression coefficients between quick test and labor... E. Allison, C. Jones |
3. Acid, Chlorine, Nitrogen, and Phosphorus Management for Subsurface Drip Irrigation SystemsSubsurface drip irrigation (SDI) is expanding at a rapid rate in the western U.S. The efficiency of this irrigation system is higher than with center-pivots. Chemical maintenance, i.e. continuous acidification and periodic chlorination is required to prevent clogging of emitters by precipitates of calcium carbonate, iron or manganese salts, and from bacterial wastes. Fertigation with nitrogen (N) and phosphorus (P) fertilizers is discussed, and current fertigation research in SDI i... K. Bronson, R. Yabaji, W. Multer, C. Stichler, J. Enciso, J. Bordovsky, D. Porter, C. Green |
4. Acidification of Alkaline Irrigation Water: Effects on Nutrient Availability, Yield and Quality of Sweetcorn on Alkaline SoilsMore than 9,000 acres of sweet corn are grown each year in western Colorado with a farm-gate value of approximately $16 million. Over the past decade growers and extension agents have noticed a steady increase in soil pH along with an increase in micronutrient deficiencies. Preliminary soil tests on this calcareous soil showed pH ranging from 7.5 to 8.0. Irrigation water pH is high and increases through the season. In early June irrigation water pH is nea... R. Godin, J. Harold, K. Schultz, J. Rohde |
5. Active Remote Sensing for In-season Precision N ManagementUniform nitrogen (N) fertilizer applications across entire fields have been shown to be inefficient. Recent advances in agricultural technology have led to the development of active remote sensing equipment that can be used to detect crop biomass and potentially be used to improve N fertilizer application rates. The objective of this study was to evaluate the effectiveness of using a hand-held active remote sensing instrument to estimate yield potential in irrigated corn. This study was condu... D. Inman, R. Khosla, R. Reich, D. Westfall |
6. Advances in Slow-release Nitrogen FertilizersControlled- and slow-release nitrogen (N) fertilizers have been commonly used in high-value applications, such as horticultural production. Traditional controlled-release products have not been economical for use in major grain crops because of high cost and low crop prices. New economical, controlled-release fertilizers are available for use in field crops such as corn (Zea mays L.), wheat (Triticum aestivum L.), potato (Solanum tuberosum L.) and oth... A. Blaylock, T. Tindall |
7. Agronomic Implications of Dairy Effluent Water ReuseNew Mexico dairies generate a waste-water stream that is often used for land application. The water contains nitrogen that must be applied according to statutory limits or can be based on agronomic considerations. However, the effluent water also contains other nutrients as well as salinity components that may have a greater impact on crop production and environmental sustainability. A survey of New Mexico dairy lagoons was done in the fall of 2003 in order to... R. Flynn |
8. Antibiotic Transport Via Runoff and Soil Loss from Manured FieldsPrevious research has verified the occurrence of veterinary antibiotics in manure, agricultural fields, and surface water bodies, yet little research has evaluated transport of antibiotics from agricultural fields. The objective of this project is to quantify the transportability of veterinary antibiotics from agricultural fields where manure or effluent is applied. Our hypothesis was that there would be significant differences among antibiotics in the partitioning ... J. Davis, C. Truman, S. Kim, J. Ascough ii, K. Carlson |
9. Apparent Electrical Conductivity As a Tool for Delineating Spatial Patterns in Inherent Soil PropertiesSoil properties affecting crop yield exhibit spatial variability. Apparent electrical conductivity (ECa) can be economically measured and is well correlated with many soil properties. Methods for processing ECa survey data and determining the relationship between ECa and soil properties are needed. An ECa survey was conducted on two fields and processed using the ESAP computer program. Soil samples to calibrate and validate the program were collected. An initial assessment resulted in a succe... B. Wienhold, P. Koerner |
10. Banded P Placement for Sugarbeets in Calcareous SoilPhosphorus (P) is an essential element for sugarbeet (Beta vulgaris) nutrition. Soils in the Western US tend to be calcareous and alkaline, resulting in low P solubility. Sugarbeets have difficulty exploiting soluble P in surface soil due to its tap root system. Research in the North- Central US supports P applied in a band in contact with the seed or below the seed for best results. However, grower concerns about germination problems and seedling vigor have prevented adaptation of these tech... B. Hopkins, J. Ellsworth |
11. Banding 10-34-0 on Sugar BeetsField experiments were conducted over 10 site-years in the Red River Valley of Minnesota on various soil types that tested low in available P. The objectives were to evaluate sugar beet yield response to liquid 10-34-0 and dry 11-52-0 fertilizer banded in-furrow with the seed at planting and to compare those responses to that of phosphorus (P) fertilizer rates broadcast and incorporated prior to planting. Treatments had no effect on net sucrose concentration in the root ... A. Sims, L. Smith |
12. Benefits of Fertilization to Beef Production from Forage WheatWheat (Triticum aestivum L. em. Thell) production in the southern Great Plains is a unique enterprise that provides both high quality forage and a grain crop within the same growing season. However, information on nitrogen and phosphorous management programs to maximize forage and beef production in a winter-active, dual-use wheat production system is lacking. Field-scale production studies were initiated on a Tillman clay loam near Vernon, TX in 1999 to determine i... J. Sij, W. Pinchak, S. Bevers, D. Malinowski, R. Gill, T. Baughman, D. Robinson |
13. Can Existing Sensor-based Technologies Predict Spring Wheat Yield and ProteinSensor-based technologies for in-season application of nitrogen (N) to winter wheat (Triticum aestivum L.) have been developed and are in use in the southern Great Plains. There is little information about the suitability of this technology for spring wheat production in the northern Great Plains. Field experiments were established in Brookings and Gettysburg, SD to evaluate the GreenSeeker Hand Held optical sensor (NTech Industries, Ukiah, CA) for measuring in-seas... S. Osborne, R. Gelderman, D. Beck |
14. Carbon Budget in Dryland Agroecosystems After 12 Years in No-till As Affected by Climate Gradient, Slope Position, and Cropping IntensityBecause available soil water is the most limiting factor in dryland cropping systems in the central Great Plains, summer fallow was implemented to stabilize production by storing two years of soil water for one year’s crop. The traditional dryland cropping system consists of conventional tillage management of a crop-fallow rotation which produced one crop every two years. In order for the fallow period to successfully store soil water, weeds and volunteer plants ne... L. Sherrod, G. Peterson, D. Westfall, L. Ahuja |
15. Changes in Extractable Phosphorus in Amended Soils During a Growing SeasonRecent studies indicate that soil extractable P and P in runoff are greatest immediately after fertilizer and manure applications. Our objective was to evaluate changes in Mehlich 3– and water– extractable P in soils amended with cattle (Bos taurus) manure and monoammonium phosphate (MAP) throughout a single growing season. Cattle manure and MAP were applied at a rate of 184 and 300 kg P ha-1, respectively, on a Pullman clay loam (Fine, mixed, superactive, thermic Torrertic Paleus... R. Schwartz, J. Bell |
16. Chloride Fertility: Small Grain Variety and Disease ResponsesFor spring wheat (Triticum aestivum L.), chloride fertilizer added to low chloride-testing soil results in a positive yield gain 70 % of the time. Some, but not all, of these yield responses have been attributed to chloride interaction with disease susceptibility. Because soil fertility and disease suppression are among the most important management tools used by farmers, additional research on the interaction between chloride fertility and disease suppression is ne... W. Riedell, L. Osborne, S. Osborne |
17. Chloride Response of Corn and Grain SorghumResearch in several states in the United States and in Canada has documented positive small grain responses to chloride (Cl) fertilization, yet little research has been done on corn or grain sorghum. Field research was conducted in Kansas evaluating Cl fertilization on corn and grain sorghum. Chloride rates and sources were evaluated at several farmer-cooperator sites. Corn and grain sorghum yields were consistently increased with Cl fertilization when soil Cl... R. Lamond, K. Rector, C. Godsey, L. Ferdinand |
18. Comparison of Annual and Multi-year N-based and P-based Manure ApplicationsThis 4-yr study (2000-2003) compares beef manure application strategies in their impact on soil and plant nutrient concentrations and nutrient runoff and leaching. The treatments were a fertilizer control, annual N-based manure application, N-based applied every other year, annual P-based, P-based applied every other year, and P-based applied once every four years. By the third year of the study, soil test P levels in the soil surface reflected the amount of P2O5applied ... J. Davis, C. Truman, K. Iversen, K. Doesken |
19. Comparison of Multi-spectral Analog and Imaging Systems for Assessing Plant Nitrogen Status in Irrigated CornUniform applications of nitrogen (N) across a field may result in over fertilization in some areas as well as under fertilization in others. Farmers, consultants, and other end users need rapid, robust techniques to spatially and temporally assess a crop’s N status in order to apply N “as needed” and “where needed”. The objective of this research was to compare the differences in response of a radiometer system and an imaging system for asse... W. Bausch |
20. Composting Problem Wastes Produced on the Csu Campus for Later Beneficial Campus UsesColorado State University’s (CSU) Diagnostic Laboratory (DL), located at the Veterinary Teaching Hospital, diagnoses the causes of animal mortality. Some of the carcasses received by the DL contain prions, the infectious agents of Transmissible Spongiform Encephalopathies (TSEs.). The DL disposes of its mortalities in an alkaline digester, which destroys the infectivity of pathological organisms, including prions, after six hours. The end products of the digestion ... K. Corwin doesken, J. Davis, B. Powers |
21. Correlation of Bray, Olsen and Mehlich 3 Soil Tests with Corn Grain YieldIn the past, the Bray P1 soil test was the most common extractant used to assess the soils relative ability to supply P to growing crops in much of the eastern Great Plains and Midwest. The Olsen P soil test is often used in much of the western Great Plains. In recent years, several states/laboratories, including Kansas State University, have adopted the Mehlich 3 extractant for routine use. The ability to extract multiple elements with a single extractant and its reported utility on bot... D. Leikam, J. Herman, J. Massey, A. Schlegel, L. Maddux, S. Harold |
22. Developing, Delineating, and Managing Production Level Nutrient Management ZonesGrid soil sampling has been used to develop nutrient maps to guide precision fertilizer applications since the inception of precision agriculture. However, the cost and labor associated with collection and analysis of soil samples to accurately describe spatial properties of fields can be prohibitive for most agronomic crops. As a result of these limitations, much interest is now being directed to the use of production level “management zones” (MZ) to allow i... W. Gangloff, D. Westfall, R. Khosla, T. Shaver, H. Farahani |
23. Development and Use of the Soil Management Assessment FrameworkSoils perform a number of critical functions essential to productivity and environmental quality. Management practices affect these soil functions. However, spatial and temporal variation and the slow rate of change in many soil properties make it difficult to assess the effects of management on soil functions. Tools are needed to assist managers in making assessments of the effect their management practices are having on the soil resource. The Soil... B. Wienhold, S. Andrews |
24. Diagnosing B Sufficiency for Fresh Market Tomatoes: Leaf or Flower AnalysisSoil and/or foliar B applications were applied to fresh market tomatoes grown at two Iowa and one Colorado location. Even though there were significant yield responses at all locations the B treatments did not effect leaf or flower B concentrations. Soil B application on Iowa loam soil significantly (P=0.03) increased extractable soil B, but the change was not detected in leaf or flower tissue. At the Iowa coarse sand site leaf B levels were enhanced 11.6%, fr... H. Taber, M. Bartolo, V. Lawson |
25. Dissolution of Granular Fertilizers and Diffusion/lability of P from Fluid and Granular Fertilizers in Alkaline and Calcareous Soils of Southern AustraliaUnlike many soils in Europe and North America, many Australian soils are still responsive to additions of P fertilizer, especially alkaline and/or calcareous soils that dominate the low rainfall zone of southern Australia. Poor responses to granular fertilizers in these areas have recently stimulated a swing by grain growers towards the use of fluid formulations, often resulting in significant yield responses. Laboratory experiments examining P diffusion were undertaken ... E. Lombi, M. Mclaughlin, C. Johnston, T. Mcbeath, S. Stacey, R. Armstrong, R. Holloway |
26. Dryland Strip-till in Western KansasInterest in strip-till has risen over the past few years. Questions about whether strip-till is beneficial on dryland fields is a major concern for producers in western Kansas evaluating this process. To provide answers to some of these questions, a farmer assisted field study was initiated in the fall of 2003. The objectives of this research were to compare no-till to strip-till fertilizer treatments applied at various timings. No response to strip-till was o... B. Olson, R. Aiken, J. Falk |
27. Dynamic Cropping Systems: Implications for Long-term ResearchLong-term cropping systems research provides critical information to producers regarding the sustainability of management practices. Fixed cropping sequences in long-term cropping systems research, while useful from the standpoint of understanding specific crop rotation effects on agronomic and environmental attributes, run the risk of losing relevance with producers over time due to changes in cropping practices brought about by market forces and technological innovations. &n... M. Liebig, D. Tanaka, J. Krupinsky, S. Merrill, J. Hanson |
28. Economics of Variable-rate N Management on CornOver the past several years’ growers have begun to adopt and implement the use of precision farming technologies. Growers and practicing consultants continue to question the profitability of this technology. No data currently exists in the Western Great Plains region demonstrating the economic feasibility of precision farming technology. The objective of this study was to assess the economics of uniform versus variable-rate nitrogen (N) fertilizer applic... R. Khosla, B. Koch, D. Westfall, M. Frasier |
29. Effect of Nitrogen Rate and Timing of Application on Stockpiled BermudagrassFeeding hay through the winter contributes a large portion of the costs associated with cow-calf production. Forage management strategies to lengthen the grazing season and reduce hay consumption would be beneficial in increasing profitability. Stockpiling bermudagrass for livestock consumption in late fall and winter has not been thoroughly evaluated in southern Oklahoma. This study was initiated at Burneyville, Oklahoma in 2000 to determine the effect of N rate and timing of appl... J. Ball, W. Thomason, F. Motal, S. Norton |
30. Effect of Phosphorus Rates on Bermudagrass Yields in Three Southern Oklahoma Locations in 2002-2003Small plot research tests were established on cooperating farmers’ fields in three south central Oklahoma locations in 2002 and continued in 2003. These included a Weatherford soil testing low in extractable P (Mehlich 3), a Port soil testing low in P and a Lela soil testing high in P. Rates of applied P fertilizer were 0, 25, 50, 75, 100 and 200 lbs of P2O5per acre. There were 4 replications of each rate. All plots received 200 lbs N and 120 ... E. Funderburg, D. Annis |
31. Effect of Starter Nitrogen Fertilizer on Nitrogen Fixation of Soybeans in the Northern Great PlainsEnvironmental conditions at the time soybeans (Glycine max (L.) Merrill) are planted in the northern Great Plains are such that nitrogen (N) fixation may not occur immediately, therefore additions of N as starter fertilizer may increase initial growth of soybeans and possibly increase yield and quality. The objective of this study was to evaluate the response of soybeans to low rates of N applied at planting. A field experiment was established within a two-year corn... S. Osborne, W. Riedell |
32. Effect of Zinc Fertilizers of Varying Water Solubility on Long Term Dtpa-zn Soil TestsThere are many zinc (Zn) fertilizer products on the market and these products often vary considerably in water solubility. In general, there are two main types of granular zinc products currently being marketed - zinc sulfate and various zinc oxysulfates. While the zinc in zinc sulfate is generally all water soluble, zinc oxysulfates vary considerably in water solubility. Zinc oxysulfates are typically produced by reacting sulfuric acid with various by-product zinc oxides. Zinc oxide is very ... D. Leikam, D. Seymour |
33. Effects of Alternative Midseason Side Dress Nitrogen Application Methods on Sugar BeetsSplit applications are an effective way to increase N use efficiency in sugar beet production. Research has shown that the efficiency of a midseason N application is greater when N is placed near the plant row than when broadcast. Comparisons of banded and broadcast midseason applications sometimes result in stark visual differences in response. More information is needed regarding the dynamics of this response and its influence on harvested yield. A study was conducted in Powell, WY under a ... S. Skalsky, W. Stevens, J. Jacobs, D. Menkhaus |
34. Evaluation of a Preliminary Algorithm for Increasing Fertilizer Nitrogen-use Efficiency in CanolaA field experiment with canola (Brassica napus L.) was conducted at Indian Head and Scott, Saskatchewan to evaluate the effects of various nitrogen (N) management strategies on grain yield and profitability. The treatment of greatest interest was a variable rate application where we applied a reduced rate of N at seeding and determined N topdressing rates using a preliminary N application algorithm. The algorithm was used to estimate fertilizer N requirements using senso... C. Holzapfel, G. Lafond, S. Brandt, W. May, P. Bullock |
35. Evaluation of Active Optical Sensors for Assessment of Plant N in Irrigated CornNitrogen (N) fertilizer has received attention for a long time as a potential source of ground water pollution. Considerable research has been conducted to investigate use of remote sensing for assessing plant N status to improve N use efficiency. Most of these studies have used passive type sensors which require sunlight. Clouds hinder their performance. Active type sensors provide their own illumination which means they can be used to take measure... W. Bausch, A. Halvorson |
36. Fertility Management for the Pulse-based Cropping Systems in the Semiarid Northern Great PlainsAnnual crop production of the semiarid Northern Great Plains has historically been dominated by cereals, chiefly spring wheat (Triticum aestivum L.) and durum wheat (Triticum turgidum var durum). Low prices for cereal grains, coupled with increasing production problems in wheat- based monoculture systems, are encouraging producers to seek alternative to cereals. In the past two decades, the area devoted to production of annual pulse crops has increased significantly in the semi... Y. Gan, B. Mcconkey, G. Clayton, G. Lafond, F. Walley |
37. Fertilizer Management for Strip-till and No-till Corn ProductionStrip-tillage for corn production can be advantageous over no-till, particularly in areas with heavy soils and high rainfall during spring months. Under these conditions in no-till systems, planting delays and/or slow, uneven emergence are common. Strip-tillage creates a narrow tilled area for the seedbed while maintaining the inter-row residue cover, allowing for erosion protection associated with no-till, yet providing an area in the row where the soil will dry out and... L. Ferdinand, R. Lamond, B. Gordon, K. Janssen, C. Godsey |
38. Field Scale Assessment of Phosphorus Loss to Surface Waters for Planning and Regulation: P IndexesFields identified for manure application by large animal feeding operations need to be assessed for the P loss potential from the field to water bodies before March 30 2007. Many states use a phosphorus index to assess the risk of P loss. Phosphorus indices are intended to be easy to use with modest input data requirements. A P index typically considers source (site and management) and transport factors in assessing risk of P loss. A P index may be a tabular worksheet or a simple computer mod... C. Wortmann, J. Benning, C. Shapiro, D. Tarkalson |
39. Flax Seed Yield and Quality As Affected by N and PFlax (Linum usitatissimum) has the potential to become an important oilseed crop for bio-products and is well adapted to the cropping systems of Montana. Little information on the response of flax to N and P fertilization is available; consequently, nutrient management research was initiated in 2004 and 2005 at four locations each year. Nine treatments consisting of 0, 30, and 60 lbs N/acre in combination with 0, 15, and 30 lbs P2O5/acre were applied at pla... G. Jackson, D. Johnson |
40. Flexible Summer Fallow in the Central Great PlainsSummer fallow has played a significant role in dryland cropping systems in the Central Great Plains for many years. Although it helps to stabilize crop yields, frequent use of summer fallow jeopardizes the long-term sustainability of dryland systems by degrading the soil resource and reducing profitability. We argue that a dynamic system involving flexible summer fallow, whereby a grower’s decision to transition from a summer crop to winter wheat with a short-duration spring crop or sum... D. Lyon, D. Baltensperger, P. Burgener, D. Nielsen |
41. Foliar Fertilization: Improving the Human Wellness Attributes of MelonNetted muskmelon [Cucumis melo L. (Reticulatus Group)] fruit quality (ascorbic acid, beta- carotene, total free sugars, and soluble solids concentration (SSC)) is directly related to plant potassium (K) concentration during fruit growth and maturation. During fruiting, soil fertilization alone is often inadequate due to poor root uptake and competitive uptake inhibition from calcium and magnesium. Foliar applications of Potassium Metalosate during cantaloupe fruit development has been sh... G. Lester, J. Jifon |
42. Functional Significance of Glomalin to Soil FertilityIn the U.S., soil is lost to wind and water erosion at a rate of nearly 2 billion tons yr-1. The formation of aggregates helps stabilize soil and increase soil fertility and water relationships. Organic matter concentration is correlated with the percentage of water-stable aggregates (WSA). The hypothesis of this study was that glomalin, a glycoproteinaceous substance produced by arbuscular mycorrhizal fungi, would be a major fraction of organic C in WSA. Four... K. Nichols, S. Wright, M. Liebig, J. Pikul jr. |
43. Harvest Grain and Crop Residue Yield Differences in Crop Rotation and Residue Management Systems in Tillage Transition in Eastern South DakotaA long-term field study was established in Brookings, SD to investigate the impact of crop rotation, tillage, and residue management on grain yield and crop residue production. These results were compiled when this field was undergoing a transition in the influence of two contrasting tillage systems in the first four years of the study. Initial soil test results indicated that the organic matter levels and pH as well as extractable K and orthophosphate-P (0-6") were high. ... H. Woodard, A. Bly |
44. Impact of Diversified Rotation on Corn N Uptake, Yield, and Soil QualityIncreased length of rotation and increased crop diversity may improve efficiency of water and nitrogen (N) use by corn (Zea mays L.) and soil quality. Objectives were to determine the effect of diversified crop rotation on: 1) N-fertilizer use efficiency (NUE) of corn, 2) water use efficiency (WUE) of corn, and 3) temporal change in soil quality attributes. An experiment was started in 1997 on a Barnes clay loam (fine-loamy, mixed, superactive, frigid Calcic Hapludo... J. Pikul jr. |
45. Impact of Long-term No-till on Crop Yield, Economics, and Soil PropertiesA study was initiated in west-central Kansas near Tribune to evaluate the long-term effects of tillage intensity on soil properties and grain yield in a wheat-sorghum-fallow (WSF) rotation. After 10-yr, water infiltration was 50% greater with no-till (NT) than either reduced tillage (RT) or conventional tillage (CT). Aggregate stability was also better following NT than RT or CT. Grain yields of wheat and grain sorghum increased with decreased tillage intensit... A. Schlegel, T. Dumler, L. Stone |
46. Impact of P Fertility on Dryland Legume N ProductionField pea acreage in Montana has nearly quadrupled since 1997 because of its suitability to the climate and soils of the region and changes in the farm program. Usually in rotation with cereals, field pea provides a means to manufacture nitrogen from the atmosphere by nodulation with Rhizobium leguminosarum. This study attempts to determine whether P fertility has an impact on nitrogen production by the pea crop and the amount of N contributed to the following sprin... J. Waddell, A. Lenssen |
47. Improving the Fermentation Characteristics of Corn Through Optimum N 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 ... G. Reicks, H. Woodard, A. Bly |
48. In Season Crop N ManagementWe 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 CropCircle made by Holland Scientific. It generates its own source of modulate... J. Shanahan, F. Solari, J. Schepers, D. Francis |
49. Initial Studies on Soil Nitrogen Management, Soybean Nitrogen Relations,and Bean Leaf Beetle BiologyBean leaf beetles (Cerotoma trifurcata) are serious insect pests of soybeans (Glycine max). This study was conducted to determine if soil nitrogen (N) input treatments would impact the biology of this emerging pest species. The experiment was conducted in the soybean phase of a long-term corn/soybean rotation study near Brookings SD. Soil N input treatments were: corn fertilized for a yield goal of 8.5 Mg ha-1 (high N input), 5.3 Mg ha-1 (medium N in... W. Riedell, J. Lundgren, S. Osborne, J. Pikul jr. |
50. Innovative Corn and Soybean Production Systems for the Great PlainsIn an eight-year study of twin row planting, our intentions were to see if additional spacing per plant would allow more ear flex and more cubic foot of soil mass per plant. In the first five years of study, over 5000 acres were planted, in five states. In each of those five years, we continually added new and upgraded agronomic facts that we held to be true, i.e. PPI work on deeper P placement, Dr. Barnie Gordons work on high N starters, split applications and precisional placemen... |
51. Intensive Measurements in Single Field Vs. Traditional Multi-location P Rate Studies for Localized P RecommendationsWith the advances in precision technologies over the past decade, there is more interest in individual farmers developing their own individualized research base. There are several stated advantages of individual farmers developing their own research base including; the accumulated data is from their own farm and reflects their environmental conditions, the results reflect an individual farmers cultural practices and rotations as compared to ‘average’ conditions, collecting many da... D. Leikam, J. Herman, J. Massey, L. Maddux, S. Harold |
52. Irrigated Corn Response to Nitrogen Fertilization in the Colorado Arkansas ValleyHigh levels of residual NO3-N are present in the soils in the Arkansas River Valley where alfalfa, grains, and vegetable crops are produced. Nitrogen requirements to optimize yield potential of crops, such as corn, following vegetables needs to be evaluated to reduce NO3-N leaching potential in the Valley where high NO3-N levels have been reported in the ground water. The effects of N source (urea and Polyon®3) and fertilizer N rate on corn yields were evaluated for 4 years.&nb... A. Halvorson, F. Schweeissing, M. Bartolo, C. Reule |
53. Irrigation System Effects on Soil Carbon and Nitrogen Under Sugarbeet and Barley in Northern Great PlainsIrrigation system may influence the growth and yields of sugarbeet (Beta vulgaris L.) and malt barley (Hordeum vulgarisL.), amount of their residue returned to the soil, and soil C and N levels. The effect of two irrigation systems [low energy precision application (LEPA) and mid-elevation spray application (MESA)] was examined on the amount of biomass (stems + leaves) residue returned to the soil from conventional till sugarbeet (CTSB), strip till sugarbeet (STSB), and conventional... U. Sainju, R. Evans, W. Iversen |
54. Is Potassium Limiting No-till Corn Yields?Potassium (K) was thought to be a limiting factor for no-till and ridge-till corn (Zea mays L.) and soybean (Glycine maxL. Merr.) in a long-term tillage and crop rotation study at the Iowa State University (ISU) Agronomy and Agricultural Engineering Research Center (AERC). Our objective in this study was to compare 30 lb K2O/A broadcast, dry subsurface band or liquid surface band applications with a control (0 lb/A). The treatments were applied to the same plots each year for two years, ... D. Karlen, J. Kovar |
55. Is There a Need to Provide N and S to Canola in Any Given Ratio?The importance of N and S nutrition of canola is well recognized (Janzen and Bettany 1984; Bailey 1986; Grant and Bailey 1993; Jackson 2000; Malhi and Leach 2002). Agronomists today are recommending that a N:S ratio of between 5:1 and 7:1 is adhered to when fertilizer N and S are applied. This is also reflected in the provincial recommendations. Thus, Alberta Agriculture, Food and Rural Development (2001) point out that optimum canola requires an N:S ratio of ... R. Karamanos, T. Boon goh, D. Poisson |
56. Kansas State University Fertilizer Recommendation RevisionsSoil testing has long been recognized as the cornerstone for developing cost effective, efficient and environmentally sound nutrient management programs. However, there are still many acres that do not have a sound soil test history. This indicates that there is still much education needed to increase farmer acceptance of soil testing in developing agronomically sound and profitable nutrient management programs. At the same time, USDA is placing increased emph... D. Leikam, R. Lamond, D. Mengel |
57. Making the Most of Fallow Crops – Nitrogen ManagementThe practice of summer fallowing was adopted in the drier areas of the prairies (Brown and Dark Brown Soil Zones) to conserve moisture, afford weed control, allow the soil to “rest”, i.e., mineralize N, maintain stability of crop yields, manage trash and allow for better seedbed preparation and provide a more uniform work load. This practice, however, combined with cultivation encourages wind and water erosion, water percolation and leaching losses in lighter textured s... R. Karamanos, F. Selles |
58. Management Effects on Maturity, Seed Yield, and N2-fixation in Dry BeanThe association between dry beans (Phaseolus vulgaris L) and its associated Rhizobium symbiont (R. phaseoli) has been shown to be inefficient and as such, unable to provide adequate N for maximum bean production. Fertilization with inorganic N is sometimes recommended, but disadvantages of adding fertilizer N include delayed maturity and possible inhibition of N2 fixation. It is unknown whether N fertilizer applications are most beneficial during early growth s... K. Maxwell, B. Stevens |
59. Management of High Yielding Canola CultivarsYield potential of new canola varieties is much higher than older ones, raising questions about whether current management recommendations are adequate to ensure optimum yield. One question that arises is whether such varieties require greater inputs of fertilizer nutrients, particularly nitrogen (N), to realize optimum economic returns. We initiated a three level factorial experiment to investigate the impact of 3 seeding rates, 3 target fertility levels and a fungicide... S. Brandt, D. Ulrich, G. Lafond, R. Kutcher, S. Malhi, A. Johnston |
60. Management of Post-emergence Nitrogen on Spring WheatWhy are Producers Interested in Post Emergence N Applications? Increase in nitrogen (N) fertilizer prices combined with rewards for achieving high grain protein concentration in wheat has led to increased interest in post-emergence applications of N to spring seeded crops. Traditionally, N fertilizer prices decrease in the month of June, thus post-emergence applications may be an economical alternative to applying all the N requirement either in the previous fall or sprin... R. Karamanos |
61. Managing Drought Risk with Post-emergent N Appliactions in Spring Wheat and CanolaFertilizer nitrogen accounts for the largest portion of total fertilizer costs. Unlike other nutrients like P and K, nitrogen is more prone to losses from leaching, nitrous oxide emission and denitrification. Producers are interested in more effective ways of managing the risks associated with N management, especially in the drier areas of the Canadian Prairies. Two separate studies were conducted. The first one examined the feasibility of post-emer... G. Lafond, S. Brandt, A. Johnston, W. May |
62. Managing Soil Acidity in Continous No-tillRecently, management of acidic soils in no-till cropping systems has become an important issue with increasing acreages of no-till and continued surface application of nitrogen fertilizer. Our objectives were to identify vertical movement of surface applied lime, determine the most effective type of lime in changing soil pH, and determine the correct application rate of lime for no-till soils. Two sites were selected for small-plot studies in south-central Kansas in 2000... C. Godsey, R. Lamond, L. Ferdinand |
63. Manganese Nutrition of Glyphosate-resistant and Conventional SoybeansThere is evidence to suggest that insertion of the gene that imparts glyphosate resistance in soybeans may have altered physiological processes that affect manganese (Mn) uptake and metabolism. This study was conducted in order to determine if glyphosate-resistant soybeans respond differently to applied Mn than conventional soybeans. The glyphosate-resistant soybean variety KS 4202 RR and its conventional isoline were grown on a Crete silt loam soil with a pH of 6.9 at the North Central Kansa... B. Gordon |
64. Maximizing Irrigated Corn and Soybean Yields in the Great PlainsThe corn experiment was conducted in 2000 through 2002 on a producer’s field in the Republican River Valley, on a Carr sandy loam soil, and in 2003-2004 on the North Central Kansas Experiment Field, on a Crete silt loam soil. Treatments consisted of two plant populations (28,000 and 42,000 plants/a) and nine fertility treatments consisting of three N rates (160, 230, and 300 lb/a) in combination with rates of P, K, and S. Results from the 3-year study on the Carr sandy loam soil &n... B. Gordon |
65. N Response Functions for Today’s Production CostsBuilding upon a discussion of linear and curvilinear yield response to fertilizer, this research develops a framework where response is fundamentally linear for any particular site-year, but where expected response can become curvilinear in the face of random weather across space and time. We next put forth several functional forms as potential candidates for generalizing expected yield response to N. Functional forms were evaluated using historical N trial data from wes... T. Kastens, K. Dhuyvetter, A. Schlegel, T. Dumler |
66. Next Generation Application TechnologyNew technologies and new applications of new and existing technologies continue to be integrated into equipment for the application of crop production inputs including fertilizer, pesticides and seed. GPS assisted steering now allows “hands off” steering of self-propelled applicators and tractors. Results include better application accuracy, improved machine efficiency and less operator fatigue. Variable rate liquid systems are available to compete... N. Wollenhaupt |
67. Nitrogen and Crop Management Influence Irrigated Corn Yields and Greenhouse Gas EmissionsThe influence of tillage system and N fertility on corn grain yields, residue C inputs to the soil, soil organic carbon (SOC) sequestration, NO3-N leaching potential, and greenhouse gas emissions under irrigated continuous corn production was evaluated. Corn was produced on a Fort Collins clay loam using no-till (NT) and conventional-till (CT) systems at several N fertility levels. Soil and plant data have been collected since the spring of 1999. Corn grain yi... A. Halvorson, A. Mosier, C. Reule |
68. Nitrogen Response in High-yielding Corn Systems of NebraskaIrrigated corn was grown at five different N levels in 34 environments in Nebraska to (1) evaluate the performance of the existing UNL N recommendation algorithm for corn at high yield levels and (2) add adjustments to the N recommendation to account for different application times and varying corn and nitrogen prices. At most sites, maximum corn yields were in the 210 to 275 bu/acre range. Average yield without N application was 166 bu/acre, but ranged from 90 to 247 bu/acre. Yield response ... A. Dobermann, R. Ferguson, G. Hergert, C. Shapiro, D. Tarkalson, D. Walters |
69. Nodulation and Yield Responses to “Starter” N and P in Field Pea, Lentil, and Chickpea in the Semiarid Northern Great PlainsGrain legumes require a high level of N fertility to achieve maximum yield and protein (Sosulski et al., 1974; Sosulski and Buchan, 1978). In these 1970’s and 1980’s studies, nodulation and nitrogenase activity were generally poor even when the legumes were inoculated with rhizobia (Sosulski and Buchan, 1978). Although indigenous populations of rhizobia are often present in the soils, they might be ineffective for inducing N2 fixation under semiarid environments (Kucey and Hy... Y. Gan, G. Clayton, G. Lafond, F. Walley, B. Mcconkey |
70. Nutrient Accumulation and Partitioning by Grain Corn in ManitobaHigh grain yield of corn was produced in a year with normal heat unit and precipitation accumulation without periods of heat or moisture stress. Nutrients varied not only in magnitude of uptake, but in rate, timing and partitioning within the plant. Magnitude of nutrient uptake was: K2O > N > P2O5 > Mg > Ca =S, Fe >>> Zn = Mn > B > Cu. Some nutrients were repartitioned within the plant as the cob and kernels developed... J. Heard |
71. Nutrient Accumulation and Partitioning by Potatoes in ManitobaThe purpose of this study was to document nutrient uptake and partitioning in processing potatoes. Potatoes did take up and remove considerable amounts of macro and secondary nutrients. Nutrients behaved differently in uptake pattern, partitioning in the plant and translocation within the plant. More than half the N, P, K, S and Cu were found in the tuber of the plant. The nutrients Ca, Mg, Fe and Mn were found predominantly in the leaves. B and Zn ... J. Heard |
72. Nutrient Management in Cotton-sorghum Vs. Continuous Cotton RotationsThis study seeks to provide information to High Plains producers on soil fertility requirements for cotton grown in rotation with sorghum. The benefits of rotation on yields and soil properties are also being studied. It is known that the practice of crop rotation benefits the soil and crops from the standpoint of soil fertility, pests, and diseases. In this project we tested cotton-cotton and cotton-sorghum rotations. Within these cropping systems ... K. Bronson, J. Booker, W. Keeling, C. Trostle |
73. Onion Response to Nitrogen Fertilization Under Drip and Furrow IrrigationOnion is a high cash value crop with a very shallow root system that is frequently fertilized with high N rates (>200 lb N/a) to maximize yield. In 2005, we applied six N rates (0, 40, 80, 120, 160, and 200 lb N/a) to existing N plots previously cropped to corn (2000-2003) and chile pepper (2004). The N source was a polycoated urea with a 90 to 120 day release period which was applied prior to planting. The N main plots were split in 2005 to allow irrigation by furrow... A. Halvorson, M. Bartolo, C. Reule, A. Berrada |
74. Outlook on the High Plains Aquifer: What’s in Store for Irrigated Agriculture?The High Plains aquifer is the most intensively used aquifer in the United States, providing irrigation for approximately 14 million acres of crop land. The aquifer recharges slowly in the semi-arid environment of the Great Plains, resulting in significant water level declines in parts of Texas, Kansas, Colorado, Oklahoma, New Mexico and Nebraska over the past 40 years. The recent four year drought on the High Plains, coupled with the Republican River settlement, have pu... R. Waskom, J. Pritchett, J. Schneekloth |
75. Phosphorus Fertilizer Effects on Forage, Beef and Grain Production from Winter WheatPhosphorus fertilizer was surface applied or injected in a NPS solution and compared to a surface-applied NS solution to determine if fall forage production could be increased by P applications and to determine if the additional forage could be captured through beef production to make the P applications profitable. The experimental units were nine 25-acre pastures in which the three treatments were replicated three times and grazed with yearling stocker calves in two management sys... D. Robinson, J. Sij, W. Pinchak, R. Gill, S. Bevers, D. Mallinowski, T. Baughman |
76. Plant Availability of Phosphorus in Swine Slurry and Cattle Feedlot ManureTo utilize manure phosphorus (P) for crop production, the amount of P that is mineralized and subsequently becomes plant available needs to be determined. A laboratory incubation study was conducted to determine P release and availability from applied swine and cattle feedlot manure in three soils. Treatments included incubation temperature (11, 18, 25, and 32 oC), P source (swine and beef cattle feedlot manure, synthetic fertilizer, and no manure or fertilizer), wa... B. Eghball, B. Wienhold, B. Woodbury, R. Eigenberg |
77. Point Vs. Area Grid Soil Sampling in the Great PlainsTraditionally, soil sampling has relied on the approach of collecting multiple cores (or sub-samples) from the entire area of interest (e.g., a field), and then combining them into a single soil sample for analyses. Samples were collected from throughout the area with recognition that soil fertility varied spatially. Where greater spatial variability was anticipated, size of sampling area usually was reduced to provide a better estimate of soil fertility. Unfo... T. Kastens, K. Dhuyvetter, J. Schmidt |
78. Positional Availability of Phosphorus from Surface Fertilizer BandsOur objective in this field study was to determine the relative distribution of P applied as a liquid starter fertilizer in a surface band during the early part of the corn growing season. Research was conducted during three years (2001-2003) at three locations in central Iowa. Exchange-resin membranes were used to characterize P movement. Treatments consisted of a control and 15-30-10 or 60-30-10 starter dribbled (30 gal./A) on the soil surface two inche... J. Kovar, P. Schroeder, K. Washburn |
79. Potassium Fertilization of Corn in Reduced Tillage Production SystemsPotassium (K) deficiency can be a problem on soils that have been managed with reduced tillage practices. The large amount of residue left on the soil surface can depress soil temperature and interfere with plant growth, nutrient uptake, and ultimately grain yield. Soil temperature influences both K up-take by root and K diffusion through the soil. The appearance of K deficiency in fields managed with conservation tillage systems has been reported with greater frequency in resent y... B. Gordon |
80. Predicting Phosphorus Runoff from Calcareous SoilsStudies have shown that as extractable soil P levels increase, runoff P levels also increase. This relationship has been found on many different soils, but tends to be unique for each soil series. Very little research exists evaluating this relationship in calcareous soils. The objectives of this study were to determine soil series specific relationships between soil test phosphorus (STP) and runoff P for three calcareous soils, to compare the use of different... R. Schierer, J. Davis, J. Zimbrunnen |
81. Quantifying Nitrate Leaching in Sandy Soils As Affected by N and Water ManagementEfficient use of nitrogen (N) fertilizer for corn production is important for maximizing economic return and minimizing NO3 leaching to groundwater, especially on irrigated, sandy soils. The objectives of this study were to quantify the NO3leaching for a sandy soil typical of Kansas’ tributaries, under current and alternative N and water management strategies for irrigated corn. Six fields were selected in 2001 and 2002 along the Republican (1), Kansas (2), and... R. Gehl, J. Schmidt, L. Stone, L. Maddux |
82. Rapid Removal of Subsoil N by Conventional and Non-N-fixing AlfalfaNitrate contamination of groundwater is an increasingly serious health issue in the Central High Plains. Although better water and fertilizer management techniques have reduced the rate of leaching from many irrigated fields, high concentrations of residual nitrate accumulating are still observed just below the root zone of irrigated row crops, particularly in fields with a history of animal waste application. Alfalfa (Medicago sativa L.) may be the ideal crop for r... T. Willson |
83. Real-time, In-season Nitrogen Application Using Optical SensorsVariable rate application of fertilizer materials for cereal crop production has been an intense area of research for the last several years. Non-destructive methods of plant analysis, namely crop reflectance based vegetative indices, have been evaluated and researched to determine which provides the best in-season information to make fertilizer recommendations. Because nitrogen (N) fertilizer is typically the largest seasonal crop input (with the exception of water, if ... R. Mullen, W. Raun, G. Johnson, M. Stone, J. Solie, K. Freeman |
84. Recent Advances in P Fertilizer Technologies—Polymer CoatingsPhosphorus fertilizers are an essential part of plant production and have been recognized as such for well over 100 years. Phosphorus utilization by crops is related to both soil availability as well as an individual plants metabolic process that allows P to be taken up by a plant as well as utilized for a wide variety of developmental processes. ... T. Tindall, A. Blaylock |
85. Rejuvenating Old Forage Stands with Liquid FertilizerWe initiated trials on old unproductive forage stands at 2 Saskatchewan locations to determine if their productivity could be restored with fertilizers. Fertilizing with N and P in general agreement with soil test recommendations provided yield responses that more than offset fertilizer costs. Dribble banding liquid urea-ammonium nitrate and ammonium poly-phosphate was an effective way of applying N and P, as was surface broadcasting granular ammonium nitrate plus mono-ammonium phosphate. No ... S. Brandt, G. Lafond, W. May, A. Johnston |
86. Safening Seed Placed Urea with Agrotain®The introduction of no-till and direct seeding in the western Canadian prairies has necessitated placing urea N fertilizer with the seed in the majority of cases. Plant stand reduction due to seed-placement of high rates of urea N fertilizers is attributed to the toxic effects of ammonia/ammonium. Current guidelines for seed-row placement of nitrogen in general and urea in particular to avert seedling damage are based on seedbed utilization, soil texture (Saskatchewan Ag... R. Karamanos, J. Harapiak |
87. Satellite Imagery for Small Plot Research and Precision Farming - Nitrogen Relationships in Irrigated CornHigh quality satellite imagery that recently became available may be useful for predicting the N status of crops, need for additional N fertilization, and crop yield potential. Our objective was to determine if the high-resolution digital images from the QuickBird™ satellite launched in late 2001 had potential in predicting irrigated corn biomass and grain yields and available N at planting as indicated by leaf color on 27 July 2002 from conventional till and no-till research... J. Cipra, A. Halvorson |
88. Site-specific N Application – the Soil Management FactorFields within a site in North Dakota and one in Montana were investigated using variable-rate N based on zone delineation tools. Limited response was observed at either location. Closer examination of the soils within the fields showed that at the ND site, sandier, low organic matter soils might best be managed not through preplant rate, but through a top-dress or sidedress application of N, using lower rates adequate for the lower productivity of the soils. Higher organic matter, heavier tex... D. Franzen, D. Long |
89. Soil Nitrogen Dynamics from Various Legume Crops Used for Fertiliy in Organic Fruit ProductionThe increasing cost of importing animal manures for organic fruit orchard fertility has forced growers to seek alternative sources of organic nutrient inputs. The objective of this study was to evaluate the nitrogen (N) dynamics of several on-farm N sources as a viable supply of organic N fertilizer. The timing of N mineralization is also critical to achieving good fruit production. Four year old organic Suncrest peach trees were used for this study. &nbs... R. Godin, S. Ela, K. Schultz |
90. Soil Test P and P Source Impacts on P Runoff from Calcareous SoilsLong-term application of phosphorus (P) to soils at rates in excess of crop uptake can result in elevated soil P levels (Snyder et al., 1993), which previous research has shown directly influences the amount of P in runoff (Sharpley et al., 1977, 1978, 1995; Daniel et al., 1994; Pote et al., 1996). Because soil test and runoff P concentrations are related, excessive soil P levels may result in significantly high runoff P levels, which accelerate surface-water eutrophication. ... A. Elliott, R. Schierer, J. Davis, R. Waskom, A. Schlegel |
91. Strategies for Maximizing Crop Recovery of Nutrients Applied As Liquid Swine ManureSince the demise in 1996 of the freight rate subsidy for transport of grains by rail from Western Canada to port, there have been increased efforts to develop a local livestock industry to utilize feed grains produced in Saskatchewan and other prairie provinces. This has led to an expansion in the number of intensive livestock operations, particularly swine production systems, on the Canadian prairies. The desire to develop responsible manure management strategies in con... J. Schoenau, S. Mooleki, S. Malhi, G. Hultgreen |
92. The Effect of Low Rates of Commercial Humic Acid on P Availability and Spring Wheat YieldHumic acid (HA), a soluble fraction of humus, has been found to increase crop yields under certain conditions, possibly due to increased nutrient availability. A study was conducted to determine the effects of low rates of commercial HA on P availability and spring wheat yields in both a calcareous soil and non-calcareous soil. In Phase I, soluble P concentrations were monitored at 0.75, 1.5, and 2.25 in. from a MAP band that had either been coated with 1.5 lb HA/ac or l... C. Jones, J. Jacobsen, A. Mungaas |
93. The Effect of Manure and N Rates on Corn Yield and Salt and Nitrate Movement in the Soil Under Furrow and Drip Irrigation in the Arkansas River ValleyA field experiment was conducted at the Arkansas Valley Research Center (AVRC) in 2005 to test the effects of irrigation type and scheduling and fertilizer rate on corn yield and salts and NO3-N movement in the soil profile. Four N fertilizer rates (0, 60, 120, and 180 lb N/a) and four manure rates (10, 20, and 30 t/a) under subsurface drip irrigation (SDI) and furrow irrigation (FrI) with two irrigation scheduling regimes (full and deficit irrigation) were compared. The results show no signi... A. Berrada, A. Halvorson, M. Bartolo, J. Valliant |
94. The Effect of Tillage on Spring Wheat N ResponseFor economic and environmental benefits, more and more producers have adopted no-till practices in Montana, but the nitrogen (N) recommendations for various no-till crop rotation systems have not been well established. The objectives of this study were: 1) to investigate the effects of tillage, number of years of tillage, previous crop, and N input on winter wheat yield, and 2) determine the fertilizer-N needs and establish fertilizer recommendations for Montana growers to produce optimum win... C. Chen, C. Jones |
95. The Future Role of USDA NRCS in Nutrient ManagementSince 1999 USDA Natural Resources Conservation Service has integrated nutrient management planning into the producer’s over-all conservation plan. A nutrient management plan contains the guidance for nutrient rate, form, timing, and method of application. Each action is based on specific local climate, soil, crop, and management conditions. The intent is to improve water quality, as well as soil, plant, air, and animal quality conditions, both on and off... J. Lemunyon |
96. The Interaction of Seed Placed and Side Banded Phosphorous with Nitrogen and Potassium Chloride Fertilizer on the Agronomic Performance of Durum WheatDeveloping knowledge on the effects of nitrogen, phosphorous, and fertilizer placement on durum yield and quality will permit durum producers to implement crop and soil fertility management strategies geared to, improving grain quality, grain protein, yield and achieving a higher grade for the grain they produce. A study was conducted examining the effect of nitrogen and phosphorous, in a two way factorial on durum yield and quality. Several extra treatments w... W. May, G. Lafond |
97. The Role of P Fertility and Mycorrhizae in Flax ProductionEnsuring adequate P nutrition in flax is difficult, because flax is sensitive to seed-placed P and may be less efficient than many crops at using fertilizer P. Studies conducted for three years at two locations in western Manitoba indicated that flax seed yield, mycorrhizal association and Cd concentration were primarily influenced by preceding crop. Early-season P nutrition was enhanced by residual P and by side-banded P fertilizer, but effects on final seed yield ... C. Grant, M. Monreal, B. Irvine, D. Mclaren, R. Mohr |
98. Urea Application Timing Influence on No-till CornFertilizer N for no-till corn in South Dakota is often limited to surface applications of urea. Surface applied urea can volatilize. A study was conducted in 1998, 1999, 2000 and 2002 (four site years) on no-till corn comparing surface broadcast urea timing. Nitrogen rates (50 and 100 lbs N/a) were applied in the fall, winter, early spring, planting, and V-6 stage. Ear leaf samples were analyzed for N concentration in 1999 and 2000 and grain yield was measured each year. Precipitation was mea... R. Gelderman, J. Gerwing, A. Bly |
99. Use of a Crop Canopy Reflectance Sensor for In-season N Management of CornOver-application of nitrogen (N) fertilizer on corn has resulted in elevated levels of N in ground and surface waters. A major factor contributing to decreased N use efficiency and environmental contamination for traditional corn N management schemes is routine pre-season application of large doses of N before the crop can effectively utilize this N. Our long-term research goal is to reduce these over-applications by using remote sensing to direct fertilizer only to areas need... J. Shanahan, J. Schepers, D. Francis, R. Caldwell |