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1. 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 |
2. Project Sense: Sensors for the Efficient Use of Nitrogen and Stewardship of the Environment. An On-Farm Research Effort to Increase Adoption of Sensor Based N ManagementLow nitrogen use efficiency (NUE) has been attributed to several factors including asynchrony between nitrogen (N) fertilizer application, crop demand, and spatial variability (Shanahan et al., 2008). Sidedress applied N synchronizes crop uptake demand for N, but does not address the spatial and temporal variability that exists in a field year to year. Active crop canopy sensors provide an ability to monitor and respond to spatial and temporal N variability for a given field. A three-year project,... B. Krienke, R. Ferguson, J. Luck, L. Thompson, J. Parrish, N. Mueller, T. Mieno, J. Crowther, T. Shaver, T. Ingram, D. Krull, K. Glewen |
3. Accuracy of Credits and Soil Indicies for Predicting Nitrogen Response in Corn Following AlfalfaCorn is the most frequent first- and second-year crop following alfalfa in the upper midwestern United States. In the majority of reported cases, there is little need for additional fertilizer N to optimize yield of first-year corn following alfalfa. For second-year corn following alfalfa, fertilizer N is needed in about one-half of cases and the economically optimum N rate (EONR) has varied greatly in responsive fields. The objective of this research was to use literature data to evaluate the accuracy... |
4. Stand Age Affects Fertilizer Nitrogen Response in First-Year Corn Following AlfalfaThrough a symbiotic relationship with soil bacteria, alfalfa can acquire nitrogen (N) from the atmosphere, use the N for its own growth, and contribute large amounts of N to subsequent crops. To estimate this N contribution, most land-grant universities use book-value N credits based on alfalfa stand density at termination. However, a recent literature analysis indicated that alfalfa stand density is not a reliable predictor of grain yield response to fertilizer N in first-year corn. That analysis... |
5. Site Specific Nitrogen and Irrigation Management Across Nebraska Agro-ecological ZonesNitrogen leaching below hrrow irrigated ground has caused nitrate contamination in Nebraska's groundwater. Alternate row irrigation and alternate row nitrogen fertilization is proposed as a method to decrease water use and decrease nitrogen leaching. Nitrogen was applied at a uniform and variable rates based on spring grid sampling for nitrate and soil organic matter. The experiment was conducted at three sites in Nebraska that represent a range of growing conditions. At these sites the average growing... |
6. Site-Specific Nitrogen and Irrigation Management Across Nebraska Agro-Ecological ZonesNitrogen leaching below hrrow-irrigated ground has caused nitrate contamination in Nebraska's groundwater. Alternate row hrrow irrigation and alternate row nitrogen fertilization is proposed as a method to decrease water use and decrease nitrogen leaching. Nitrogen (N) was applied at a uniform and variable rate based on spring grid sampling for nitrate. The experiment was conducted at three sites in Nebraska that represent a range of growing conditions. At these sites, the average growing degree-days... |
7. Soil and Site Factors Responsible for Yield Variations in Two Southern Illinois Farm FieldsYield variability within a field is largely influenced by the soil physical. chemical. and topographic features of that field. On-farm field research studies were conducted from 1997 through 1999 on two southern Illinois farm fields (one in Jefferson County and the other in Pope County) with varying soil physical, chemical, and topographic features to determine which factors most influenced crop yield variability. Each location was GPS-gridded utilizing a grid cell size of 0.45 acres. Detailed topographic... |
8. The Influence of Variably Applied Potassium Fertilizer on Yield Variations in Two Southern Illinois Farm FieldsThe basis of Variable Rate Technology (VRT) is to apply nutrients where they are needed and to reduce the application of nutrients where they are not needed. However, there is considerable uncertainty as to whether the variable application of nutrients to farmers fields should be on the basis of soil test levels or yield potentials. A field study was conducted at two locations in southern Illinois from 1997 to 1999 to evaluate VRT as a management tool for corn and soybean production on fields with... |
9. Soil Electrical Conductivity Map Quality- Impact of Interpolation Search Neighborhood ParametersSpatial predictions of soil electrical conductivity (EC) measurements may be improved by adjusting the search neighborhood criteria. The objective of this study was to investigate how varying search parameters impacted the quality of soil EC maps. The three fields cl~osen for this study were from the Inner and Outer Blue Grass physiographic regions of Kentucky. Soil EC was measured by direct contact at all locations. The prediction datasets included EC measurements along transects that were separated... |
10. In-Season Nitrogen Management for Sub-Surface Drip Irrigated CornIrrigation water and nitrogen @I) management for subsurface drip irrigated (SDI) corn was evaluated from 2004 through 2006 at the South Central Agricultural Laboratory of the University of Nebraska. SDI irrigation and N management strategies to increase both water and N use efficiency were compared to preplant N application for hrrow irrigation, commonly used in the area. Irrigation water levels of 100, 75 and 50% of measured evapotranspiration (ET) were applied with SDI, and N was applied in treatments... |
11. Evaluation of Nitrate Leaching Potential from Slow and Controlled Release Nitrogen Fertilizer Application to Irrigated CornThe use of slow and controlled release nitrogen (N) fertilizers as a practice to reduce nitrate leaching from irrigated corn was evaluated on coar se-textured soils in the Central Platte River Valley of Nebraska in 2007 & 2008. Slow-releas e methylene urea (MU) and polymer-coated urea (PCU) were compared to a standard fertil izer of urea ammonium nitrate (UAN) solution. Flooding in 2007 severely impacted the study site, and results are not reported here. Saturated soils were common at the site in... |
12. Validating Potassium Fertilizer Guidelines in Alfalfa-corn RotationsIn 2008 to 2010, on-farm research was conducted on 10 fields with medium soil test K (STK) to validate Minnesota K fertilizer guidelines by determining the effect of K fertilizer applications on alfalfa yield and quality in its last production year, and estimating the carryover of excess fertilizer K to first-year corn. We were surprised to find that no K fertilizer was needed to maximize alfalfa yield or overall forage feed value and quality. Luxury consumption of K occurred because as K application... |
13. Assessment Of Enhanced Efficiency Urea Products On Maize In MissouriUrea is the most commonly used N fertilizer worldwide, but can be easily lost to the environment through ammonia volatilization. Enhanced efficiency fertilizers (EEF) have been developed to help prevent these losses. Field studies were conducted from 2009 to 2011 on a Mexico silt loam (fine, smectitic, mesic, Vertic Epiaqualf) to determine the efficacy of five EEF urea products compare to untreated urea when surface applied to no-till maize (Zea mays L.). Treatments included untreated urea, Agrotain,... |
14. Predicting Fertilizer Nitrogen Response In Corn Following AlfalfaCorrect prediction and application of alfalfa N credits to first-year corn can reduce fertilizer N costs for growers, reduce over-application of N, and reduce the potential for water contamination. For decades, researchers have found that first-year corn following alfalfa often requires no fertilizer N to maximize grain yield. However, a review and analysis of nearly all the research on this topic in North America and Spain (442 site-years of research) indicates that corn following alfalfa can respond... |
15. Geographic Trends in Alfalfa Stand Age and Crops that Follow AlfalfaTo gain perspective on alfalfa-annual crop rotations in the upper Midwest, USDA-National Agricultural Statistics Service cropland data layers and Soil Survey Geographic Database layers were combined for six states (North Dakota, South Dakota, Nebraska, Minnesota, Iowa, and Wisconsin) and seven years (2006-2012). Soil texture and geographic location both significantly affected the length of the alfalfa phase (stand age), and alfalfa stand age, soil texture, and year all significantly affected the... |
16. Impact of sulfur and its interaction with N rates on wheat and barley in North Dakota and Western MinnesotaEffects of S, N, and their interactions were assessed on grain yields and protein of spring wheat and barley, across eight site years in Western Minnesota (MN), and ten site years (hereafter, sites) in North Dakota (ND) from 2015 to 2019. The studies were to determine if S improves yields and protein in wheat, and if the effects were dependent on N rates. Treatments included all combinations of five N rates of N (0, 60, 120, 180, and 240 lbs/ac) and three rates of S (0, 10, 20 lbs/ac) in MN. In... J.M. Teboh, S. Yuja, B.G. Schatz, G. Pradhan |
17. Does Starter Fertilizer Benefit Late Planted Corn?Starter fertilizers are used by producers to help overcome wet and cool soils often encountered with early planted corn. Early planted corn in no-tilled fields and limited drainage typically have the greatest chance of response from starter fertilizers. Starter fertilizers can range from a mixture of UAN, ammonium polyphosphate (APP), and other fertilizers to low salt (LS) formulations containing N, P, K and various micronutrients. Some that promote LS starter fertilizer products claim that UAN... E. Ritchey, H. York |
18. How Late Can Nitrogen Be Applied to Corn?Delaying some of the N supplied to the corn crop is considered a way to increase N uptake and yield and to limit N losses, but the length of the delay may increase the risk of yield loss. We conducted a 3-year experiment at Urbana, Illinois in which half of the N (112 kg N/ha) was injected as UAN at planting and the other half or all (224 kg N/ha) of the N was dribbled UAN next to the row, at each of eight stages ranging from V3 to R3. In corn following soybean, when half of the N was applied... B. Yoder |
19. Lower Soil Test P Values Do Not Affect Crop Yield Values when Under Conservation PracticesSustainable P management in cropping systems is a challenge in modern agriculture. Phosphorus moving from agricultural fields to aquatic ecosystems resulting in eutrophication and other water quality problems continues to be a challenging issue for the agricultural community to solve. Despite the large amount of P in agricultural soils, most P is held within insoluble complexes, making this pool of P unavailable to plants. The implementation of conservation practices of no-till and high residue... C. Winter, D. Clark, S. Ireland, D. Beck |
20. Conservation Practices Lower Soil Test Phosphorus Requirements and Optimize Crop YieldSustainable P management in cropping systems is a challenge in modern agriculture. The implementation of conservation practices of no-till, retaining high levels of residue in the field, and diverse crop rotations may create a more suitable environment for arbuscular mycorrhizal fungi (AMF) to accumulate. A greater AMF population may subsequently increase the P available to crops, lowering the soil test P amount needed to optimize crop yield. At the Dakota Lakes Research Farm in Pierre, South... C. Winter, J. Clark, M. Lehman, S. Xu, S. Ireland |