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1. What's Ahead- Soil Conservation Service Nutrient Management PlansFarmers have been going through a major change in their relationship with Government during the past ten years. Many in the agricultural community are anticipating possibly more changes in the future from such Legislation as the Clean Water Act and the Endangered Species Act. Each act has potential of having even more impact on the agricultural community. Immediately following those two acts will be the 1995 Farm Bill. The last two Farm bills have been slanted more to environmental concerns than... |
2. Soil pH and Corn-Soybean Rotation Yield Responses to Limestone Applications and TillageFarmers growing corn and soybean in northwest Iowa must carefully consider liming needs and economics. This is because of high liniestone material cost and the fact that soils in northwest Iowa have high pH subsoil, which can moderate negative effects of acid surface soils. Another factor that must be considered is the variable effect from limestone mixing depth associated with different tillage systems. An experiment designed to evaluate six rates of aglime (0 to 6,000 Iblacre of effective calcium... |
3. In-Season Nitrogen Fertilization of SoybeanNitrogen (N) fertilization is not a traditional nutrient management practice for soybean production in Iowa. Soybean is a legume plant and is assumed to adequately obtain needed N through symbiotic fixation. However, there has been interest over the years in using N fertilization to increase yield and grain protein due to the recognition of the large N requirement associated with high yields. Depending on the soil residual inorganic N level and soil N mineralization characteristics, approximately... |
4. Corn and Soybean Response to Sulfur Applications on Iowa SoilsHistorically sulfur (S) application has not been recommended on Iowa soils for corn and soybean production. Prior research has not determined a consistent need for S fertilization in Iowa, with field research indicating no corn or soybean yield response to applied S at virtually every site studied (Thorup and Leitch, 1975; Webb, 1978; Alesii, 1982; Killom, 1984; Sexton et al., 1998; Mallarino et al., 2000). The soil supply, in combination with sources such as manure and atmospheric deposition has... |
5. Using Chlorophyll Meter Readings to Determine N Application Rates for CornOne method for refining nitrogen (N) application in corn is use of in-season crop sensing. To aid producers in making decisions regarding N rate adjustments, a calibrated relationship between sensor-derived information and expected N application need should be established. Nitrogen rate trials were conducted at multiple sitcs across Iowa in 2001-2003. Nitrogen was applied at or shortly after corn planting. Minolta SI'AD chlorophyll meter (CM) readings were collected at the R1 growth stage fiom the... |
6. Assessment of Nitrogen Supply From Poultry Manure Applied to CornThe production of poultry in the state of Iowa is one of the largest in the nation and growth has continued the past few years. Currently Iowa is the number one egg producing state in the USA (USDA, 2005). This increase in production also implies an increase in manure production from poultry sources. The common end use of manure is application for crop production. Concerns exist- regarding application at rates higher than needed for crop use, with potential for contamination of water bodies due... |
7. Evaluation of the Illinois Soil Nitrogen Test in the North Central RegionData from 96 locations across the North Central Region was complied to evaluate the usefulness of the Illinois soil nitrogen test (ISNT) in identifying fields where corn will not respond to additional N fertilizer and predicting the yield optimizing N rate (YONR) for each field. The ISNT could not accurately predict non-responsive sites, nor could it predict YONR. Sub-setting the data based on soil drainage class and previous crop did not improve the predictive capability of the ISNT. The ISNT was... |
8. Winter Rye Cover Crop Biomass Production, Degradation, And N RecyclingWinter rye (Secale cereale L.) as a cover crop can take up residual inorganic N between annual row crops and therefore be used to help reduce NO 3--N loss from fields and movement to water systems. However, does the rye N uptake affect N recycling to soil and add to plant available N? The rye carbon:nitrogen (C:N) ratio could also influence N recycling. The objectives of this study were to evaluate rye biomass degradation and N recycling after spring rye termination in a no-till corn (Zea mays L.)... |
9. 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 |
10. Corn Residue Harvesting Effects on Yield Response to N FertilizationProducers have many choices of diverse tillage practices for their corn (Zea mays L.) production systems. However, no-till has become an important soil management practice to help reduce water and wind erosion, as well as nutrient runoff, while conserving soil moisture for crop use. No-till systems also help farmers by saving labor and time, as well as reducing farm costs due to less equipment and fuel consumption. Nevertheless, no-till production is typically more successful and has higher crop... |
11. 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 application.... |
12. 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. Recent... |
13. 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 applied... |
14. Soil pH and Lime Management for Corn and Soybean: An Ongoing On-farm ProjectSoil acidity can affect plant growth directly and indirectly by affecting the plant-availability of nutrients, levels of phytotoxic el ements, microbial activity, and ot her soil properties. Soils may become acidic in the long term as a result of several natural processes. In the short term, however, soil acidity develops mainly due to application of N fertilizers or manure, primarily those having high concentrations of ammonium or urea because nitrification releases hydrogen (H) ions. Soil pH decreases... |
15. Dealing with Sulfur Deficincies in Crop Production: The Iowa ExperienceResearch conducted for more than forty years (pri or to approximately 2005) in Iowa rarely noted improved crop yield with sulfur (S) fertilization. Studies during that time period with corn and soybean found yield increase from S fertilizer application only three times out of approximately 200 trials. Research in the early 1980's had also documented sufficient plant available S in the soil profile for crop production on most Iowa soil associations. Results of recent studies (2000- 2005) in corn and... |
16. Re-Evaluating Rate, Time, and Placement of Urea and Other Nitrogen Sources in MinnesotaUrea is increasingly an important nitrogen (N) source in Minnesota. Approximately 43% of our farmers use urea as their major N source. In the southwestern, south-central and west-central areas approximately 45% of the N is applied in the fall, 50% is applied in the spring, and 5% is applied at sidedress. While most of those that use urea as the major N source apply it in the spring, approximately 4% do the major application with urea in the fall and there are others that apply some of their N... F. Fernandez, K. Fabrizzi, J. Vetsch, D. Kaiser |
17. 4R Nutrient Management for Corn Production on Upper Midwest SoilsCorn (Zea mays L.) demand for nitrogen (N) is often met using inorganic fertilizer on Upper Midwest soils. While applying the right rate of fertilizer N normally has the greatest impact on yield and N use efficiency (NUE), selection of the right fertilizer source, placement, and application timing can fine-tune rate recommendations, improve NUE by matching soil N availability to corn demand, and minimize loss to the environment. Given the diversity of corn production environments, the... J. Spackman, F. Fernandez, K. Fabrizzi |
18. 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 |
19. Nitrogen Management in Minnesota as Influenced by Soil Drainage and TillageTile-draining, conventional tillage and pre-plant applications of nitrogen (N) fertilizer are prevalent practices among Minnesota corn growers. However, climate change and increasingly warmer and wetter spring conditions have called for a re- evaluation of the appropriateness of these practices for continued sustainable corn production. The objectives of this study are to determine the influence of drainage, tillage and N application timing on (1) corn grain yield and N uptake, (2) corn N demand... G. Paiao, F. Fernandez |
20. Cover Crop and Nitrogen Fertilizer Rate Effects on Mitigating Soil Nitrate Leaching in Irrigated Sandy Soils in Corn and Soybean ProductionCoarse textured soils are very productive when supplemented with irrigation and nitrogen (N); however, they are susceptible to nitrate (NO3–N) leaching. Nitrate leaching not only reduces fertilizer efficiency but has costly environmental impacts to the groundwater supply. The majority of NO3–N loss occurs in the fall and spring or when nutrient and water uptake from corn (Zea mays L.) and soybean (Glycine max Merr. L.) is limited but precipitation is frequent.... N. Ricks, F. Fernandez |
21. 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 |
22. 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 |
23. Can a Winter Rye Cover Crop Mitigate Nitrate Leaching from Corn Production on Irrigated Coarse Textured Soils?Minnesota has approximately 500,000 acres of irrigated coarse textured soils. These soils are very productive but are highly vulnerable to nitrate (NO --N) leaching and ground water contamination. In these soils, most of the NO --N leaching losses take place in early spring and late fall, when precipitation is high and crops have limited water and nutrient uptake. The objectives of this study are 1) quantify the capacity of rye (Secale cereal L.) as a cover crop to mitigate... N. Ricks, F. Fernandez, J. Baker |
24. 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 |
25. In-Season Soil Nitrogen as a Predictor of Corn Grain YieldCorn (Zea mays L.) grain yield is closely linked to plant available soil nitrogen (N). Our objectives were to (i) examine the influence of N rate, source, and time of application on N use efficiency with relation to grain yield and total plant N uptake, and (ii) evaluate in-season soil N testing as a tool to determine N rate needs and predict grain yield. During the 2014-2015 growing seasons, 12 fields across Minnesota varying in soil and climate conditions received 1) pre-plant urea (0 to 204... J. Spackman, F. Fernandez |
26. 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... |