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1. No-till Nitrogen Management Research in MissouriNo-till nitrogen management research on corn in Missouri has focused on the field response of N sources and placement. Results suggest consistent significant response to the use of a non-volatile N source when broadcast on the soil surface compared to N sources that contain urea and potentially can lose ammonia through volatilization. Knifed application of N in no-till has . consistently provided higher yields and N uptake compared to either surface band or broadcast application of potentially volatile... |
2. Assessing Crop Nitrogen Needs with Chlorophyll MetersTissue testing of corn leaves for nitrogen (N) concentration is not widely used because it is easier and perhaps more economical to apply sufficient fertilizer than to risk a yield reduction because of an N deficiency. Environmental concerns related to N fertilizer will require producers to improve N management practices to reduce the potential for nitrate leaching. Applying fertilizer N on an "As Needed" basis rather than using a "Lump Sum" approach has both environmental and economic implications.... |
3. Nitrogen and Water ManagementIt is difficult to separate N and water management when developing improved management systems for irrigated corn production. This is because adequate supplies of both N and water are critical for crop growth, but excesses of either or both can threaten ground water quality. Several N and water management systems were established at the Nebraska Management Systems Evaluation Area (MSEA) project to evaluate the impact of improved irrigation and N fertilizer management practices on production and/or... |
4. Survey of Corn Response to Fertilizer Sulfur in MissouriAbstract Fertilizer sulfur (S) rate studies were conducted during 1991 and 1992 at 53 sites located throughout Missouri on soils that were primarily silt loam or heavier. Sites were selected on the basis of a high yield potential since a common belief among farmers and fertilizer dealers is that the greater crop S requirement of high yields exceeds the S supply from the soil and incidental sources. Either ammonium sulfate or ammonium thosulfate were applied at planting or wihn four weeks following... |
5. Remote Sensing Techniques to Identify N Deficiency in CornNitrogen management remains a primary concern for corn production. Environmental consciousness has increased the need for diagnostic techniques to identify N deficiencies to guide corrective measures or to provide feedback on management practices. This study was designed to evaluate several techniques that measure reflectance from corn plants to detect N stress. The experiment was located in Central Nebraska and involved four hybrids and five N rates. Leaf reflectance, canopy reflectance, and aerial... |
6. Remotely Sensed Crop Indices for Nitrogen StressCrop nitrogen (N) stress has a strong influence on plant vigor and growth. Under field conditions, crop N stress is frequently expressed through spatial variability in biomass production and grain yield. Remote sensing serves as a useful tool to monitor crop N status by characterizing canopy reflectance because certain wavebands (i-e., colors) are sensitive to chlorophyll and crop growth. Unfortunately, interpreting reflectance data in terms of crop stress is still an inexact science. Several indices... |
7. Early Season Stresses in CornSpatial variability in corn yield is frequently associated with lost yield potential caused by plant stresses. Early-season stresses are difficult to recognize because growing conditions (soil temperature and water status) are not ideal and seldom uniform throughout a field. The impact that climate has on plant growth is dificult to determine because it also affects nitrogen (N) availability. Nitrogen stress was imposed sequentially until the V8 growth stage and then all plots were sidedressed with... |
8. Vegetative Assessment of Phosphorus and Nitrogen Status in Maize Using Remote SensingAssess spatial variability of soil P and N is not only costly but also a time consuming processes. Remote sensing measurements of canopy spectral reflectance can provide a rapid and non- destructive method for assessing plant-canopy nutrient status. The main objective of this research was to detect P and N stress during the early corn growth by selecting specific wavelengths, or combinations of them, using narrow band field sensors. In 2001, two corn experiments were planted over an old manure experiment... |
9. Use of Chlorophyll Flourescence Techniques to Detect Stresses in CornIncreased efficiencies in the use of water and fertilizer will require better methods of monitoring crop stress. This study was conducted to determine whether chlorophyll fluorescence was more sensitive to detecting water and nitrogen stress than chlorophyll meters in corn (Zea mays). The experiment was carried out near Shelton, NE in 2000, 200 1, and 2002. Treatments consisted of a factorial combination of 12 corn hybrids (1 1 Pioneer Hi-Bred internationali and B73 x M017), two water levels (deficit... |
10. Long-Term Measurement of Nitrate Leaching Below Corn Agreosystems and a Restored PrairieMany studies have evaluated nitrogen leachmg from tile drained agricultural soils, but less research has been performed on many well drained soils also common throughout the Midwest. This study measured nitrate leaching fiom chisel-plow (CP) and no-tillage 0 agroecosystems in order to determine the effects of common agricultural practices on the quality of water that drains past the root zone of crops. In an effort to obtain background levels of nitrate leaching from a natural ecosystem, measurements... |
11. Nutrient Management Implications of Relay Cropping on the EnvironmentResidual nitrogen (nitrate-N) remaining in the root zone after seed corn production is frequently greater than under commercial corn production. This nitrate is subject to leaching into the shallow ground water of the Platte River Valley in South-Central Nebraska. as noted by elevated nitrate-N concentrations under seed cornfields compared to other fields. Hard-red winter wheat was planted into seed corn residue in early October of 2001 as a cover crop to scavenge residual- N from the root zone and... |
12. Relationship Between Response Indices Measured In-Season and at Harvest in Winter WheatCurrent methods for making nitrogen recommendations in winter wheat (Triticum aestivurn L.) do not adjust for in-season temporal variability of plant available non-fertilizer nitrogen (N) sources. The purpose of this study was to compare the use of different nitrogen response indices determined in-season @INDVI and RIPLANTHEIGkm) to the nitrogen response index measured at harvest (RIHARvEST). In addition, this study evaluated the use of the in-season response indices for determining topdress nitrogen... |
13. Active Sensor Orientation Over Corn Rows and Effect on Assessment of BiomassOur long-tern mresearch goal is to develop practical N application systems that use on-the-go remote sensing as a nleans to assess crop N status and only apply N where needed at times when the crop can most efficiently utilize N. Our preliminaty testing of two active sensor systems has shoxl-11 considerable promise for rapid and accurate assessment of canopy N status and crop biomass. In this work, the effect of sensor positioning and orientation over the canopy and their effects on assessment of... |
14. An Update on Crop Canopy Sensors for In-Season N ManagementRemote sensing in agriculture has focused 011 the spectral and spatial properties of plants. Remote sensing provides the capability for rapid collection of vast quantities of spatial data that can be analyzed quickly for use in detel-mining a course of action. This creates the potential for using remote sensing to assess and manage in-season production practices. Past research has shown that a change in canopy rel-lectance inay not be unique for a given stress. Also, other agents may have effects... |
15. 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... |
16. 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 converted... |
17. 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 design,... |
18. In Season RecommendationsWe are testing a prototype high-clearance tractor configured with active crop canopy sensors, drop nozzles with electronic valves, and a variable rate controller as means to deliver in-season variable rates of liquid N fertilizer based on crop needs as an alterative to preplant uniform applications of N. The active sensor we're evaluating is the model ACS-210 Crop Circle made by Holland Scientific. It generates it's own source of modulated light in the amber and near infrared (NIR) bands and then... |
19. 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... |
20. Effect of Phosphorus and Potassium Fertilization on Corn Development and Root Distribution in Conservation TillageIn conservation tillage systems, like no-till (NT) and strip-till (ST), phosphorus (P) and potassium (K) typically become vertically and/or horizontally stratified in the soil. This stratification has the potential to make P a nd K less available and to limit corn yield. The objective of this study is to determine the infl uence of tillage and P and K placement and rate on soil P and K content, soil water status, root and shoot development, and grain yield of corn. The experiment was arranged in... |
21. Weed Control Timing Effects on Corn Yield Response to NitrogenNitrogen (N) rate guidelines for corn are under c ontinued scrutiny to maximize N use efficiency in order to minimize potential N losses to th e environment while maximizing economic returns to growers, especially with significant N fertilizer price increases in recent years. In-season crop stress can potentially affect corn N needs for optimum production. Recently, postemergence weed control has become more common with th e availability of glyphosate resistant corn hybrids. Delaying weed control... |
22. Can Soil Information Better Inform Canopy Sensor Algorithms for Corn?Corn production is often limited by the loss of nitrogen (N) due to leaching, volatilization and denitrification. The use of canopy sensors for making in-season N fertilizer applications has been proven effective in matching plant N requirements with periods of rapid N uptake (V7-V11), reducing the amount of N lost to these processes. However, N recommendation algorithms used in conjunction with canopy sensor measurements have not proven accurate in many fields of the U.S. Cornbelt, resulting in... , N.R. Kitchen, J. Camberato, P.R. Carter, R.B. Ferguson, F.G. Fernandez, D.W. Franzen, F.G. Fernandez, E.D. Nafziger, C.J. Ransom, , J. Shanahan, G.M. Bean |
23. Comparison of Canopy Sensing Technologies for Corn Nitrogen Management in MinnesotaVarious crop canopy sensing tools are being used to manage nitrogen, but their utility to predict N needs in Minnesota remains unclear. The objectives of this study are to compare the effectiveness of different canopy sensing technologies at predicting corn (Zea mays L.) yield at different development stages, and compare their capability to determine in season N deficiency. Six to seven N rates at 35 to 45 kg N ha -1 increments were pre-plant applied in six fields throughout Minnesota and a rate... |
24. Starter Fertilizer and High Yield Management Impacts on Corn Production... |
25. Micronutrients Fertilization for Corn and Soybean: A Research UpdateEssential plant nutrients such as boron (B), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), zinc (Zn), and others are absorbed by crops in very small amounts and are referred to as micronutrients. A deficiency can have a large impact on crop yield, however, because they perform important physiological functions. The soil parent material and soil formation processes over time along with effects of soil moisture, aeration, and temperature can significantly influence the amount of plant-available... |
26. Evaluation of Crop Canopy Sensors as a Tool for Soybean Research and ProductionDetermining the variables that consistently increase yields in soybean  [Glycine max (L.) Merr.] continues to challenge researchers, agronomists and growers alike. Crop canopy sensors have emerged as a technology used in other cropping systems to monitor and manage agricultural inputs. The sensors measure reflectance in selected wavebands that are used to calculate vegetation indices that relate to unique leaf or canopy characteristics. The objectives of this study were to determine if a commercially... |
27. Which Corn Nitrogen Fertilization Rate Tools Preforms the Best in the Midwest?Publicly-available nitrogen (N) rate recommendation tools are utilized to help maximize yield in corn production. These tools often fail when N is over-applied and results in excess N being lost to the environment, or when N is under-applied and results in decreased yield and economic returns. Performance of a tool is often based on the specific soil and weather conditions of a growing season. Research is needed to determine which tools are the most effective at recommending economical optimal N... |
28. Effects of Nitrogen Managemetn on Maize Yield and Nitrate Leachingon Irrigated Sandy SoilsIrrigated sands are some of the most productive and environmentally sensitive areas in Minnesota. Reducing nitrate leaching is critical for corn (Zea mays L.) production as ground water is a major source of drinking water in these soils. The objective of this study was to evaluate agricultural technologies that may improve nitrogen (N) management for profitable corn production and mitigate negative effects in groundwater. A randomized complete block design with four replications was established... |
29. iPhone Apps: Corn Nitrogen Fertilizer Rate Calculator and Nitrogen Fertilizer Price Comparison CalculatorAs communications technology advances, there is a need for Extension to deliver information and decision- making tools that leverage these new technologies to engage existing and new clientele groups in new wa ys. Smart technologies allow ac cess to pertinent information on-the- go and out in the field, right when it's needed. ... |
30. Active-Crop Sensor Calibration Using the Virtual-Reference ConceptCalibration of laboratory and field instruments usually involves collecting data from some type of accepted standard materials or compounds. This approach works well for most physical and chemical measurements; however, such procedur es become problematic when dealing with biological systems like plants that go throug h a number of physiological states during the growing season. In addition, genetic composition differences between cultivars can affect the architecture of plant canopies a nd relative... |
31. Soybean Growth Components as Influenced by No-till and Strip-till Systems and Different P and K Rates and PlacementsReduced tillage and broadcast phosphorus (P) a nd potassium (K) applications can lead to accumulation of these nutrients in the soil surfa ce. The objective of this study was to determine the impact of conservation tillage (no-till and strip-till) and rate/placement of P and K on soybean production. The experiment was arranged in a split-split-block design with three replications with tillage/placem ent no-till broadcast (NTBC), no-till deep placement at 15 cm (NTDP), and strip-till deep placement... |
32. Current Perceptions on Soil Fertility Recommendations and Status of Soil Fertility in IllinoisWhile most soils in Illinois are generally recognized for their high productivity, regular application of phosphorus (P), pot assium (K), and limestone are necessary to maintain their productivity. Determination of soil P, K, and pH levels through soil analysis is necessary to guide application of these nutrients and limestone. Due to recent high fertilizer prices there has been interest from producers to temporarily reduce or eliminate P and K applications without reducing crop yield. In an effort... |
33. Remote Sensing as a Tool for AgricultureThe tendency for nearlv everything in our society to be bigger, better, faster, easier, cheaper, and safer than in the past has resulted in many challenges. Agriculture is not immune from these trends, and in some cases agriculture even leads the way. Incorporation of remote sensing into site- specific management activities is one area where technologies are being merged to develop a new array of products that are intended to help producers and consultants make better and more timely management decisions.... |
34. Nitrogen Source and Application Timing to Improve Corn Yield and Reduce Nitrate in Tile-Drain WaterNitrogen (N) fertilizer is among the most important inputs for corn because of this crop’s large N requirements. When N fertilizer applications exceed crop needs, that N can be lost to the environment or be incorporated into the soil organic matter Many farmers in the US Midwest install subsurface drainage to remove excess water from the soil. The drained water leached from the farms contains nitrate-N (NO3), which poses risks to surface waters. Midwest agriculture has... S. Menegaz, F. Fernandez |
35. Active-Optical Reflectance Sensing Evaluated for Red and Red-Edge Waveband SensitivityUncertainty exists with corn (Zea mays L.) N management due to year-to-year variation in crop N need, soil N supply, and N loss from leaching, volatilization, and denitrification. Active-optical reflectance sensing (AORS) has proven effective in some fields for generating N fertilizer recommendations that improve N use efficiency. However, various sensors utilize different wavebands of light to calculate N fertilizer recommendations making it difficult to know which waveband is most sensitive... G. Bean, N. Kitchen, J. Camberato, R. Ferguson, F. Fernandez, D. Franzen, C. Laboski, E. Nafziger, J. Sawyer, P. Scharf, J. Schepers, J. Shanahan |
36. Do Split-Nitrogen Applications in the Midwest Affect Corn Nitrogen Uptake and Grain Yield?It is hypothesized that split-nitrogen (N) relative to single near-planting applications improve corn (Zea mays L.) grain yield and nitrogen recovery efficiency, which can lessen environmental impacts of fertilization. However, these hypotheses have not been fully tested. A 49-site-year study across eight US Midwestern states over three years was conducted to compare near-planting (Single) and split-N (Split) applications. Three N application timings were evaluated [Single near planting, 40... J. Clark, F. Fernandez, J. Camberato, P. Carter, R. Ferguson, D. Franzen, N. Kitchen, C. Laboski, E. Nafziger, J. Sawyer, J. Shanahan |
37. The Anaerobic Potentially Mineralizable Nitrogen Test as a Tool for Nitrogen Management in the MidwestThe anaerobic potentially mineralizable nitrogen (PMNan) test is a tool that can improve estimations of mineralizable nitrogen (N) and enhance nitrogen use efficiency. This tool may also help improve predictions of N uptake, grain yield, and the economic optimum nitrogen rate (EONR) of corn (Zea mays L.). A 32 site-year study across eight US Midwestern states was conducted to 1) compare the effect of incubation length (7-, 14-, 28-d), soil sampling timing, N fertilizer rate, and their... J. Clark, K. Sloan veum, F. Fernandez, J. Camberato, P. Carter, R. Ferguson, D. Franzen, N. Kitchen, C. Laboski, E. Nafziger, J. Sawyer, J. Shanahan |
38. Topsoil Thickness Effects on Phosphorus and Potassium Dynamics on Claypan SoilsDue to variable depth to claypan (DTC) across landscapes, nutrient supply from subsoils, and crop removal, precise P and K fertilizer management on claypan soil fields can be difficult. Therefore, a study was performed to determine if DTC derived from soil apparent electrical conductivity (ECa) could be used to improve P and K management for corn (Zea mays L.) and soybean (Glycine max [L.]). Research was conducted on a claypan soil at the University of Missouri’s... L. Conway, M. Yost, N. Kitchen, N. Kitchen, K. Sudduth |
39. Phosphorus and Potassium Response In No-Till Corn and Soybean ProductionCurrent UWEX fertilizer recommendations and plant analysis interpretation guidelines were developed prior to the release of GMO corn. There is some concern amongst University soil fertility specialists and industry agronomists that corn and soybean response to P and K fertilizer applications may be different with modern corn hybrids and soybean varieties. In addition, in the UW recommendation system, an estimate of the amount of nutrients removed in the harvested portion of the crop is used to... C. Laboski, T. Andraski |
40. Nitrogen source and application timing for corn to mitigate leaching and gaseous N lossesNitrogen (N) is an important nutrient for corn, but N fertilizers are associated with contamination of surface waters through leaching and gas emissions through denitrification and volatilization. A comprehensive N loss study was conducted at the University of Minnesota Southwest Research and Outreach Center (SWROC) in Lamberton, MN from 2014 to 2020. The objectives were to quantify the effects of traditional (pre-plant urea) and advanced N management practices (split-N applications and... |
41. Implementation and Validation of the MRTN Recommendation System in WisconsinThe maximum return to N (MRTN) recommendation system for corn was implemented in Wisconsin in 2006. In many ways, MRTN is a dynamic extension of N response-based N recommendation that was implemented in 1991. Vanotti and Bundy (1994) demonstrated the utility of using N rate response trials as the basis for N recommendations. And that grouping soils by N response and soil characteristics was useful could improve N recommendations. In Wisconsin recommendations, relative yield potential was qualitatively... C. Laboski |
42. A Minnesota-Wide Assessment of Critical Pre-Plant and in-Season Soil Nitrate for Adjusting Nitrogen Rate GuidelinesThe pre-plant (PPNT) and pre-sidedress (PSNT) soil nitrate tests are often used as indicators of soil nitrogen (N) availability in Minnesota. The assessment of available soil nitrogen (N) provides corn (Zea mays L.) growers with key information on N credits to adjust their N fertilizer rates. However, current N management recommendations in Minnesota were based on research conducted 40-yr ago and did not specify differences between environments and management. Through a comprehensive... E. Souza, F.G. Fernandez, J. Coulter, M. Wilson, J.A. Vetsch, P.H. Pagliari, R.T. Venterea, D.E. Kaiser, K.P. Fabrizzi, D. Bernau, C.J. Rosen, K. Mizuta, Y. Miao, V. Sharma |