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1. A Seed Company Perspective on Use of Crop Canopy Sensors for Making Corn Nitrogen Fertilizer RecommendationsCurrent nitrogen (N) management practices for corn production typically include significant quantities (e.g., 200 to 250 lbs/A) of pre-plant applied N at field-uniform rates. These conventional practices can sometim es result in sizeable N fertilizer losses, especially in extremely wet springs in the Corn Belt. The lo st N not only reduces grower profits through lost fertilizer and reduced yields in N deficien t areas, but can also lead to environmental contamination through nitrate leaching or... |
2. A Smorgasbord of Preliminary Results from Field Trials in OntarioField scale trials may be established to support lo cal needs, but the results seldom reach a wider audience. This paper summarizes two recent fiel d studies by staff of the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) on fertilizer use in soybeans and corn. A study of starter fertilizer response in soybeans found that yield responses to fertilizer tended to be relatively small, and seldom large enough to cove r the cost of the added fertilizer. A second study of ammonia vola... |
3. Active Crop Canopy SensorsActive crop sensor usage for managing crop nitrogen inputs has been an area of intense research over the last decade. The question on the minds of producers, consultants, and policymakers is how well does the technology functi on in the field? And is it robust enough for commercial usage? The goal of this proceedings article and subsequent presentation and panel discussion is to provide a little background on current approaches, research successes and failures, and commercial prospects and chal... |
4. 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 rela... |
5. Agronomic and Nutrient Cycling Responses in a Rotation StudyA twelve-year rotation study was established in the Divide soil near Brookings SD in 2000. Treatments of crop rotations (corn-soybean, s oybean-spring wheat, and corn-soybean-spring wheat), tillage (conservation till vs. no-till), and residue management (post-harvest residue removed vs. residue returned) were established. Grain yield, residue crop residue production, nutrient cycling, and carbon storage responses were documented. Mean grain yield for various crops was not significantly influenc... |
6. Carbon Sequestration: The Lack of Initial Measurement Could Bias Interpretation of Management Effect on Soil CarbonMuch research has been done in the last decades to determine the effect of management practices on the rate of soil carbon (C) seque stration over time. Generally paired fields are sampled and soil organic carbon (SOC) content under each manage ment system is determined. Conclusions about the effectiveness of different management systems in sequestering soil C are established based on the SOC difference and le ngth of the experiment. However, properly archived historic samples are often unavail... |
7. Changes in Soil Test Phosphorus as a Function of Inorganic and Organic Phosphorus in Animal ManureUnderstanding how and why soil test phosphorus (P) levels increase with manure and fertilizer application is important to assist in improvi ng any nutrient management plan. An incubation study investigated the change in soil test P (STP) after 42 different animal manures (dairy, beef, swine, chicken, turkey, goat, sheep, and horse) or fer tilizer were applied at a rate of 40 mg total P kg -1 to 25 different agriculturally important soils of Wisconsin. Both liquid and solid dairy and swine manure... |
8. Drainage Management and Nitrogen LossNitrate-N loss through subsurface agricultural draina ge is of local and regional concern in the Midwest. Good drainage and nitrogen management practices have the potential to reduce nitrate- N concentrations and loss from subsurface drainage systems. The five year (2005-2009) nitrogen management study in Pocahontas County, IA suggests that while fall application of fertilizer may result in higher nitrate-N concentrations than spring application during certain period of the growing season; overa... |
9. Field Evaluations of Nitrogen Ramp Calibration Strips in ManitobaNitrogen Rate Calibration Strips (NRCS) were dem onstrated in some 30 farm fields of cereals, corn and canola. Mid-season assessments of crop yield sufficiency were useful in estimating the adequacy of nitrogen (N) supply. For cereals, rela tive plant height provided a simple and quick indicator of N sufficiency. This NRCS techniqu e has been used to demonstrate the provincial N rate calculator in extension and has been adapted for P de monstrations in alfalfa. ... |
10. Management Zone Delineation Techniques to Aid In-Season Sensor Based Nitrogen ApplicationThe increased efficiency of nitr ogen fertilizer (N) use has been a long-term goal in reduction of nitrate contamination in the stat e of Nebraska. Preliminary rese arch has shown sensor based in- season application of nitrogen has the ability to be economic and environmentally viable. Although benefits have been published there is an opportunity for increased accuracy of N application through the integration of preprocesse d georeferenced management zones. In-season sensor based N application ... |
11. Manure Management Practices to Limit Nutrient Loss from Frozen Agricultural FieldsManure applied to crop areas can be an importa nt source of plant nutrients for crop production and may improve soil quality. Relatively small amounts of nutrients especially phosphorus (P) from manure reaching water bodies can signifi cantly increase eutrophication and impair water quality. Most recommendations indicate not to apply manure to fro zen soils because the risk of nutrient loss to surface water may be increased. Our research objective was to determine the influence of manure applica... |
12. Micronutrient Nutrition for Corn and Sobyean: Emerging Issues in KentuckyIn certain Kentucky regions, corn-Zn and soybean-Mn are well known crop-micronutrient problems. In response to grower observations/c oncerns in another region, soil and leaf tissue sampling indicated that pH P, K, B, Cu and Zn nutrition problems were co-mingled. A series of corn and soybean field studies were conduc ted between 2008 and 2010 to sort out/among possible problems/solutions, relati ve to similar soils in other areas of the state. The results indicate that when P and K nutrition are... |
13. Nitrogen Fertilization Requirement and Corn-Soybean Productivity in a Rye Cover Cropping SystemNitrogen (N) fertilizer inputs for intensive corn-based cropping systems can increase nitrate (NO 3 -N) concentrations in groundwater. Nitrogen tr ansport in surface water to the Gulf of Mexico is also an on-going issu e for the upper Mississippi river ba sin, especially areas with large corn and soybean acreage. Education and policy efforts have focused on i\provement in N application rate, timing, management, and crop N us e efficiency. However, additional means to reduce N loss are needed. R... |
14. Nitrous Oxide Emissions in Claypan Soils Due to Fertilizer Source and Tillage/Fertilizer PlacementNitrogen fertilization for agricu ltural production is a major contri butor to increased soil nitrous oxide emissions. These emissi ons may contribute to global warming and ozone depletion. Nitrogen fertilizer source and placeme nt can influence soil nitrous oxide (N 2O) emissions by affecting the concentration of ammonium and nitrat e available for nitrification and denitrification throughout the growing season. The objectives of this research were to quantify the effect of tillage / fertilize... |
15. One-Time Tillage of No-Till Crop Land: Five Years Post-TillageField research was conducted at two eastern Nebr aska locations to test the hypotheses that one- time tillage of no till (NT) land results in increased grain yield, reduced stratification of available soil phosphorus but reduced wet aggregate stabili ty, and increased soil organic carbon (SOC), without a long term effect on the soil microbial community. Research was conducted in long- term NT fields under rainfed corn [ Zea mays (L.)] or sorghum [Sorghum bicolor (L.) Moench.] rotated with soybea... |
16. Plant Density Consequences on Nitrogen Uptake Dynamics of Maize Plants from Vegetative to Reproductive StagesThere are few studies to date that have inte nsively examined the simultaneous effects of differences in plant crowding and fertilizer N availability for different hybrids and locations on N uptake and maize (Zea mays L.) grain yield. The main research objective was to utilize a quantitative framework to bett er understand the physiological mechanisms that govern N dynamics in maize plants at varying plant densi ties and N rates. Two field experiments involving paired near-isogenic hybrids (i.e... |
17. Quantifying Corn Nitrogen Deficiency and Application Rate with Active Canopy SensorsPrecision agriculture technologies are an integral part of many crop production operations. However, implementation for N application has lagged, primarily due to lack of a viable system for variable N rate decisions. Ac tive canopy sensors have been developed as a tool to determine plant N stress deficiency and provide an on-the- go decision for implementing variable rate. Two general approaches could be implemented. On e is to plan on conducting canopy sensing each year, with a reduced N rate ... |
18. Response of Corn to Residue Management and Nitrogen FertilizationInterest in the production of cellulosic fuel production for bioenergy has identified corn (Zea mays L.) as a suitable option. However, residue removal can affect the growth and yield of a following corn crop and its response to N fertilizer. Residue removal may also influence the optimal tillage system with regard to yield and N-use efficiency. In southern Minnesota, concern about yield reductions due to cool, wet soil conditions, partially attributed to high amounts of crop residue, have limit... |
19. Response to Starter Applied Sulfur in Combination with Nitrogen and Phosphorus Across a LandscapeCorn ( Zea Mays L.) response to starter fe rtilizer combinations containing sulfur were studied using a replicated strip trial methodology. Combinations of ni trogen (20 lbs N), phosphorus (20 lbs P 2O5), and sulfur (25 lbs S) were applied two inches beside and below the seed with the planter and compared with a no-starter control a nd 25 lbs broadcast sulfur. Early plant growth was consistently increased by starter P and so metimes by starter N, while sulfur uptake was increased by S and P app... |
20. Sensing Soybean Canopy Development Responses to and K Nutritional StressNormalized difference vegetative index (NDVI) has been correlated with physiological plant parameters and used to evaluate plant growt h. Recently, active canopy reflectance sensors have been used to determine N nutrition al needs of corn, wheat and forage grasses. There is little information about the use of this technique to detect soybean nutrient deficiencies. The objective of this work was to determine th e ability of the NDVI sensor to detect P and K deficiencies, and grain yield reductio... |
21. Slow-Release Nitrogen Fertilizers and Nitrogen Additives for Field CropsNitrogen management continues to be difficult due to transformations of nitrogen fertilizers that are possible when applied to soil and the uncertainties of weather (Cabrera et al., 2008). Nitrogen fertilizer in the form of urea is subject to ammonia volatilization through the activity of the urease enzyme found ubiquitously in soil (Kissel et al., 2008). Nitrate fertilizer is subject to leaching (Randall et al., 2008) or denitrification (Coyne, 2008) depending on the water content of the soil ... |
22. Soil Test Phosphorus Trends in OhioAgriculture is often sited as th e primary factor for high P loads polluting Lake Erie and Ohio's watersheds, but its exact contribu tion is actually unknown. This proj ect evaluated historical soil phosphorus (P) trends in the state of Ohio by collecting historical soil data from the three largest commercial laboratories servicing Ohio to dete rmine if P levels at a county resolution are changing over time. This helps address to what extent widespread over-applications of P (either commercial ... |
23. Time of Harvest Alters Nutrient Management of SwitchgrassSwitchgrass is one of many cellulosic crops bei ng considered as a biomass feedstock for the production of bioenergy, including ethanol. It is being promoted as a crop that can grow well on marginal lands with low nutrient inputs as well as on more fertile soils. Nutrient removal is important for long-term perennial crop production. A study, establishe d to evaluate the effects of nitrogen rate and harvest management system, was used to evaluate the nutrient removal in switchgrass harvested at ... |
24. Utilizing Fertilizer Technologies to Reduce Nitrate Leaching in the Central Sands Region of WisconsinLeaching of nitrate into the groundwater has been a continuing and extensively researched problem in the sandy soils of Wisconsin. However, no proven solution to this problem has been identified as yet. Research results from our studies in 2009 showed that several products had potential in reducing nitrate-nitrogen (NO 3-N) leaching. Although not always statistically significant, one slow-release fertilizer, Environmentally Smart Nitrogen (ESN), produced greater yields than conventional fertiliz... |
25. What Do You Do When Your N-Rich Reference Fails?In recent years, canopy reflectance sensing has b een investigated for in-season assessment of crop N health and fertilization. Typically, the procedure followed co mpares the crop in an area known to be non-limiting in N (the N-rich area) to the crop in a target area, which may be inadequately fertilized. Measurements from the two areas are used to calculate a relative reflectance to represent the potential need for add itional N fertilizer. Establishing N rich areas or strips is often inconve... |
26. Winter Annual Weeds Effect on Corn Response to NitrogenThe timing to control winter annua l weeds is a management concern for producers. In regards to corn response to nitrogen, the objective was to determine how important the timing of winter annual weed control is for no-till, rainfed co rn production following soybeans by assessing: soil water and nitrate; early growth and nitrogen uptake of corn; nitr ogen status of corn at silking- blister; and grain yield. Field research was conduc ted in 2010 at seven locations in Kansas. There were four diff... |