Proceedings
Authors
| Filter results22 paper(s) found. |
|---|
1. Nitrogen Management for Winter Wheat in MissouriEight site years of data have been collected to evaluate nitrogen rate and timing for intensively managed winter wheat in Missouri. Variables have included rates up 160 lbs N per acre applied as all fall, all spring, or split in a fall and spring or fall plus two spring applications. Results have pointed to the split applications of rates at 80 to 120 lbs N per acre as providing greatest consistency and economic return to the grower. Maximum yield has generally been obtained with the 3 way split... |
2. Corn Yield Response to the Urease Inhibitor N-n-Butyl Thiophosphoric Triamide (NBPT) When Applied with UreaUrease inhibitors are applied to reduce ammonia volatilization and immobilization losses from surface-applied urea or urea-ammonium nitrate solutions (UAN). The urease inhibitor N-(n-buty1)thiophosphoric triamide (NBPT) was evaluated at rates of 0.25 to 1.0 % (w/w) in 78 U.S. trials conducted with corn (Zea mavs L.) during the period 1984 to 1989. When averaged over N rates for all locations and years, NBPT increased grain yields by 4.3 bu/acre when compared to similar rates of unamended urea. Average... |
3. Evaluation of Soil Profile NO3-N for Prediction of N Fertilizer RequirementsCurrent N recommendation systems based on yield goal with adjustment for previous legume crop or manure applications have worked well in many situations. In the example given in Table 1, multiplying the 8 year average yield times 1.2 lb N/bushel would result in a recommendation within 20 Ibs N/acre of the optimum in 6 of the 8 years. As expected, this system resulted in significant over recommendation in the 1988 and 1989 drought years. While these results provide confidence that the system works... |
4. Evaluation of Three N Recommendation Systems for Corn Yield and Residual Soil NitrateProper N application rates are required for continued economic and environmental viability of U.S. agriculture. Application at rates below that required for economic optimum will place U.S. farmers at a competitive disadvantage in the world market. On the other hand, excessive rates of N fertilizers may result in contamination of ground water. ... |
5. Zone Delineation for Nitrogen ManagementManaging nitrogen through zone soil sampling has been shown effective in revealing residual soil nitrate patterns in North Dakota. Zone delineation has been constructed using several types of data, including yield maps, remote imagery, topography and soil EC sensor data. A study was conducted in North Dakota, Montana and Minnesota to evaluate zone delineation methods. Across the region, yield frequency maps, topography, remote inlagery and soil EC data were effective in helping to construct zones.... |
6. Corn Yield Response to Residual Forage Crop Rotation and Manure Amendment Effect in Potato RotationsAccurate prediction of multiple-year N availability froin organic sources is difficult and can complicate nitrogen management for producers using these sources. The objective of this study was to use corn yield and soil N monitoring to evaluate long-term nutrient availability from rotational systems on an irrigated Alfisol in central Michigan. Over a 5-year period, multiple crop sequences were grown with either annual liquid dairy manure at 12,260 L ha-' or conventional mineral fertilizer application... |
7. Nitrogen Loss from Sprinkler Applied Beef Feedlot EffluentLoss of nitrogen from sprinkler applied beef feedlot effluent can be costly for both the producer and the environment. Sprinkler application of effluent is common throughout the Great Plains, though little work has focused specifically on N losses from beef feedlot effluent. We quantified ammonia (NH 3) and nitrous oxide (N2O) losses from beef feedlot effluent applications under field conditions including variations in soil pH, soil water content, ammonium (NH 4+) concentration of the effluent, and... |
8. Nutrient Reduction StrategiesThe Hypoxia Task Force (HTF) 2008 Action Plan set a goal or reducing the nitrogen and phosphorus load reaching the Gulf by 45% in order to reduce the size of the hypoxic zone to 5,000 km 2. Each of the 12 states along the main stem of the Mississippi and Ohio rivers were to develop a state specific strategy by 2013 to achieve the goal by 2015. These plans have been developed and work is underway to implement the strategies, but the time line was not realistic. In February 2015, the HTF announced... |
9. Roto and Shoot Biomass and Nutrient Composition in a Winter Rye Cover CropNitrogen loss from applied fertilizer can be a significant environmental quality issue if NO 3 moves to surface or ground water. The Iowa nutrient reduction strategy science assessment identified winter cereal rye (Secale cereal L.) cover crop as a practice that can significantly reduce N and P loss (41% NO 3-N and 21% P reduction) from corn (Zea mays L.) and soybean [Glycine max. (L.) Merr.] fields. Cereal rye, when used as a cover crop, through its fibrous root system is able to explore the soil... |
10. 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... |
11. Biochar: Waste, or Product?Nutrient losses following summer and fall manure applications result in economic and water quality problems. We tested the potential of biochar (BC) and ammonium thiosulphate (ATS) as manure additives to retain nutrients by reduci ng nitrate pool size and runoff of N and P. To determine appropriate rates to use in field expe riments, the compounds were initially added at different rates to liquid swine manure (LSM) then the slurry mixed with soil and incubated. The selected rates, based on N transformations,... |
12. Nutrient Management Studies in Bio-Fuel Cropping SystemsResearch was conducted to determine the effect of nutrient management practices on bio-fuel crop production, and to evaluate long term effects of bio-fuel crop production on selected chemical, physical and microbiologi cal properties. Experimental plots for research on bio-fuel crops production were established in 2008 at two sites in Missouri. The experimental design was an 8x3 factorial laid out in a sp lit plot design. The main plots were eight bio-fuel cropping systems including: 1) continuous... |
13. Evaluation of Sulfur Fertilizers In Corn ProductionSulfur deficiencies and corn yield increases from S fertilization have been documented in Iowa since the mid-2000’s. Therefore, S fertilization management is an important component of high yield corn production. Many S fertilizers are available for use in correcting deficiencies. However, specific product evaluations have not been widely conducted in Iowa. In addition, a new S fertilizer has recently become available in the Midwest U.S., the mineral polyhalite. The research objectives were... J. Sawyer, M. Castellano, A. Sassman, J. Lundvall |
14. Winter Cereal Rye Nitrogen Response and Fertilization RequirementWinter cereal rye (Secale cereale L.) has been a common cover crop choice due to seed cost, winter hardiness, and rapid spring growth. It could also be an alternative grain crop to include in a corn-soybean rotation. Also, a rye crop would provide soil coverage during the springtime when corn and soybean do not. No known research has investigated the N fertilization requirement for winter cereal rye seed production in Iowa. The objectives of this study were to evaluate N response in cereal... C. Martins, J. Sawyer, J. Lundvall |
15. Manure, Phosphorus, and 125 Site-Years of Edge-of-Field Runoff MeasurementsPhosphorus export from agricultural fields continues to create water quality concerns in Wisconsin. The UW Discovery Farms program, along with Discovery Farms Minnesota have collected 125 site-years of edge-of-field monitoring datawhich can be used to better understand the relative effects of inherent soil properties (slope, drainage class, texture), management practices (manure application, tillage, crop rotation, cover cropping), and soil test P values on seasonal (frozen and non-... M. Ruark, A. Thompson, Z. Zopp, T. Radatz, A. Radatz, E. Cooley |
16. 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 |
17. 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 |
18. The Effect of Agricultural Management Practices on Labile Soil Carbon and Nitrogen in WisconsinAmid ever-increasing enthusiasm for soil health there remains uncertainty about how best to measure it, to interpret the results, and to adapt agricultural management accordingly. One factor of particular interest to farmers is the capacity of a soil to mineralize organic matter, making nutrients available to crops. This research takes a survey-based approach to identify how labile carbon (C) and nitrogen (N) – as permanganate oxidizable carbon (POxC), potentially mineralizable carbon (PMC)... G. Richardson, M. Ruark, E. Silva, M. Chawner, E. Olson, A. Radatz, C. Zegler |
19. 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 |
20. 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 |
21. Impact of Nitrogen Application Timing on Corn ProductionWater quality issues have renewed interest in timing of nitrogen (N) application as a means to improve use efficiency in corn and reduce losses. Improved economic return is also desired as N fertilization is one of the most costly inputs to corn production. Time of fertilizer application is a component of the site-specific 4R nutrient management stewardship programs. In Iowa, the Nutrient Reduction Strategy has a 7% (37% std. dev.) nitrate-N reduction with a 0% (3% std. dev.) corn yield change... J. Sawyer, D. Barker, J. Lundvall |
22. The MRTN Approach: Past, Present, and FutureThe method of using crop N response data assimilation, now called the “MRTN approach”, was conceived at a September, 2004 meeting in Bettendorf, Iowa of scientists from several Corn Belt states. This meeting was prompted by findings in field trials that showed substantially lower optimum N rates than those based on using corn yield goal to predict crop N needs; most also showed no correlation between EONR and yield at EONR across trials. The MRTN method is straightforward: yield data... E. Nafziger, J. Sawyer |