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1. Effect of Ammonium to Nitrate Rations of Fertilizers Applied at Various Times Throughout the Growing Season on Yield and Nitrogen Concentrationof CornA number of recent investigations have produced evidenm that the ionic form of N taken up by roots affects the growth of plants. While soil- plants generally take up rest of their N as nitrate, there is evidence that increasing the relative proportion of ammonium in the culture (or soil) solution can enhance growth and yield. Owing to difficulties in prevent* the rapid miaxbial conversion of ammonium to nitrate in soil, this response has nat been well demnstrated in a field situation. The objective... |
2. Nitrogen Test Development Soil N Levels in 1989The developnent of a N test that can be used for fertilizer recamrendations of corn in the eastern areas of Minnesota is needed for environmental and econcmic reasons. A multi-site project was initiated in 1989 to extensively examine soil sampling time and depth as well as N forms in the soil. This will then enable statistical models to be develaped using one or mre of the variables. A subset of the entire project is reported--concentrating on the sites allowing the calibration of the soil N tests... |
3. Selected Soil Chemical Properties and Corn Grain Yield Under Different Manure SystemsThe Iowa Department of Agriculture and Land Stewardship estimated 1987 farm animal populations to be 4.6 million cattle and calves and 13.8 million hogs and pigs (26% of the nation's hogs). The animals produced about 141,987 tons of plant available N if 50% of the excreted N is available the first year of application. This amounts to 22 lb of N for every corn acre in Iowa. Most of the livestock operations are intensive with high populations of animals on a sniall land area. Nutrients in feed are... |
4. Spacial Variability of Soil Test Phosphorus in a Northern Corn Belt FieldFor some time, an increasing number of fertilizer dealers, crop consultants, and farmers have reported substantial year-to- year variability in soil test values for phosphorus (P) and potassium (K). Frequently, this variation could be explained by such factors as extremes in soil moisture content at the time of sample collection. In many situations, however, this variation was due to the fact that soil samples were not collected from the same location in the field in two consecutive years. The introduction... |
5. Aerial Photos Can Predict Corn Yield Loss Due to N DeficiencyFields that experience wet weather after N fertilizer is applied may lose N and consequently lose yield. Replacing N may be difficult or expensive after corn is too tall for tractor clearance. A tool to assess the degree of potential yield loss would help corn producers decide how much expense is justified in making late N applications. ... |
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. Swine Manure Phosphorus Use for Crop Production in IowaImproving manure phosphorus (P) management guidelines should result in a more efficient use of thls resource for crop production and in lower risk of P loss to surface water resources. Phosphorus fertilizers are widely used in crop production, there is a great deal of information about their use, and farmers have little doubt about their value to improve crop yield in low- testing soils. However, there is a great deal of uncertainty concerning the value of manure nutrients for crops and about cost-effective... |
8. Sulfur and Nitrogen Starter Fertilizer for Corn in Northern ClimatesThe combination of cool and wet weather in early spring can reduce the amount of S and N released in soil by decomposition and mineralization of organic matter, particularly in reduced- tillage or no-till cropping systems. Recent changes to S emission regulations have decreased the amounts of S that is deposited to the soil through attnospheric channels. Field studies were initiated in 2005 at five corn (Zea mays L.) sites in Michigan to evaluate the effects of S and N starter fertilizer on nutrient... |
9. Using Reflectance Sensors to Predict Nitrogen Needs of CottonObjectives 1) Develop on-the-go N recommendations based on analysis of the reflectance sensor readings. 2) Determine the sensor model, height, and wa velength that give the best prediction for sidedress N. 3) Determine the best growth stag e for sensor-based sidedressing Relevance There is great spatial variability of N in the soil. Cotton fields that receive a blanket rate of nitrogen, ignoring the vari ability, will have areas of excessi ve growth. This unnecessary growth raises production cost... |
10. Agronomic and Environmental Assessment of Cover Crops in IllinoisCrop production systems have been changing for thousands of years and new ideas and practices are being implemented every day. In recent years, the practice of cover cropping systems has come into the spot light, and though research has been in effect, the practice has been slow to take root for producers in Illinois. Benefits of cover crops primarily center around increases in soil organic matter, which can lead to higher soil productivity, but the long-term agronomic, environmental, and economic... |
11. Corn and Soybean Response to Phosphorus Placement under Minimum Tillage SystemProducers often question the need for better fertilizer placement methods in reduced tillage systems. The objective of this study was to evaluate the effects of different placements and rates of phosphorus (P) fertilizer for corn (Zea mays) and soybean (Glycine max). The study was conducted at 3 locations from 2005 to 2012 (8 years). This paper presents results from one irrigated location. Tillage system was strip till before planting corn; and soybean was planted without previous tillage. Fertilizer... |
12. Comparison of the MRTN and Adapt-N Derived N Rates for CornNitrogen application to corn is a large determinant for high yield, and rate has important implications for economic profitability and off-field movement of nitrate-N. Nitrogen rate recommendation systems have varied over time. A popular system was yield-goal based, with grain yield multiplied by a per-bushel factor and then rate adjusted for previous crop and other N inputs. Modifications of this system are still used today in some states. Seasonal (site-year) variability in economic optimum N rate... |
13. Evaluation of Fertilizer Placement for Corn with Contrasting Rooting SystemCorn genetic improvements in recent year⤙s generated hybrids adapted for water limited conditions (drought tolerant-DT). Drought tolerant hybrids were developed with conventional breeding selection process, and therefore selected based on certain characteristics such as growth habits and root system. New transgenic DT corn hybrids are also becoming available to producers. A previous study demonstrated that corn response to starter fertilizer application can vary by hybrid (Gordon et al, 1997).... |
14. Evaluating the Interaction between Chelated Fe Source and Placement on Phosphorus Availability in SoybeanIn agriculture, chelating agents are used to supplement micronutrients, such as iron (Fe). However, little research has been conducted on a field scale to evaluate chelating agent effects on phosphorus (P) uptake. The objectives of this study were to evaluate four commercially available chelated Fe sources on early soybean growth and nitrogen (N), P, and potassium (K) uptake. The study was conducted at two locations, and the experimental design was a randomized complete block with four replications... |
15. Evaluation of Secondary and Micronutrient for Soybean Production in KansasSecondary and micronutrients are being increasingly studied for their potential to contribute to yield increase. The objective of this study was to evaluate soybean response to secondary and micronutrient fertilizer application to maximize yields. A randomized complete block design was employed with four replications, at five locations during 2013 and five locations in 2014. Treatments consisted of micronutrient fertilizer as individual nutrient for B, Cu, Mn, S and Zn, in addition to a mix of these... |
16. Evaluation of Weed Management Strategies on Grain Sorghum Nitrogen Status and Grain Yield Using Optical SensorsInformation on weed management options and relation to nutrient status is very limited for grain sorghum production. The objectives of this study were: (i) determine the effects of different weed management strategies on grain sorghum yield; and (ii) evaluate the impact on nitrogen (N) status and development of the crop. This study was established at two locations in 2014 (Smith and Reno Co in Kansas). The study used a randomized complete block design with 4 replications. Two main factors evaluated... |
17. Fertilizer Placement and Tillage Interaction in Corn and Soybean ProductionDifferent tillage systems can affect the availability of phosphorus (P) in the soil. The objective of this study was to evaluate the effects and interaction of fertilizer placement, tillage, and varieties/hybrids for corn and soybean. The experiment was established at two locations in Kansas in 2014. The experimental design was a factorial in a randomized complete block with four replications. Three fertilizer treatments were combined with two tillage systems and two varieties/hybrids of soybean... |
18. 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... |
19. 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... |
20. Winter Annual Weeds Affect Nitrogen Availability for No-Till CornWinter annual weeds effects on nitrogen availability have not been adequately studied. The objective of this study was to determine winter annual weed s effects on nitrogen availability for rainfed no -till corn (Zea mays L.) following soybeans ( Glycine max L. Merr.). Field research was conducted in 2010-2011 at 14 sites with heavy winter annual weed pressure in eastern Kansas. A two -factor factorial arrangement in a randomized complete block design with three replications included t hree herbicide... |
21. 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 different... |
22. 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 limited... |
23. Can CRP Serve As a Soil Health Benchmark: A Minnesota Case Study Utilizing SMAFSoil health is an important concept relating to sustainable agriculture and food security. However, the absence of a universally accepted benchmark for soil health complicates its application as a tool to measure soil functional capabilities. Here we propose the use of Conservation Reserve Program (CRP) soils as a potential benchmark for soil health in Southern Minnesota. The Soil Management Assessment Framework (SMAF) was used to evaluate soil health indicators and quantify the soil health gap... O. Hoffman, C. Chorpenning, C. Buchanan, T. Trimarco, N. Carr, J. Ippolito |
24. Nitrogen Application Timings in No-Till Dryland Corn Production SystemRight timing of nitrogen application is one of the practices of the 4 R nutrient stewardship. Three independent trials using a randomized complete block with 4 replications were conducted to determine the optimal (1) split rate, (2) proportion and (3) timing for sidedress N application in non-irrigated corn. In trial 1 (13-site years), five N rates were examined: 60, 120, 180, 240, and 300 lb N/A, which were applied at two split-applications. Split-applications included single- and split-application.... N. Adotey, R. Blair, R. Adotey, N. Montgomery |