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1. Corn Stem Nitrate N Content-Grain Yield Relationships and Their use as a Basis for Sidedress N Rate RecommendationsThe objectives of this study were to confirm the relationship between nitrate nitrogen (NO3-N) content of basal corn steras and grain yield in Iowa, to establish crltical levels of stem NO3-N content for dtaining various levels of mximum yield, and to perform preliminary calibration of yield responses to sidedressed nitrogen (N) at various levels of st-Rm NO3-N content. Six sites across Iowa with a wide range of physical and environmental conditions were selected. N fertilizer was applied preplant,... |
2. Influence of Soil Nitrate Nitrogen and Fertilizer Nitrogen on Wheat Grain Yield and ProteinWheat producers have recently shown a great deal of interest in grain protein levels. 'Ikis interest has developed prkily because of the relatively lqe protein premium available the last several years (Table 1). Nitrogen is a primary component of protein and needs to be added for most soils to produce high yielding, high protein wheat. The objectives of this study were to detennhe the effects of soil nitrate nitrogen and fertilizer nitrogen on wheat grain yields and protein levels. ... |
3. Nitrogen Soil Test for Corn in OntarioIt is generally believed that for high yielding crops such as corn. the N requirements are much larger than variations in the N supplying capacity of soil. In Ontario, fertilizer N recommendations are based on the requirements of the crop and, for some crops, the expected yield goal. Nitrogen credits are given for past management such as manure application and legumes in rotation. The credits are deducted from the economic rate of N. In a recent analysis of all existing fertilizer N crop response... |
4. The Nitrate Soil Test in South DakotaThe nitrate nitrogen soil test has been used for more than 15 years for making nitrogen fertilizer recommendations in South Dakota. Minimal leaching and denitrification due to a relatively dry climate has helped make this test a good predictor of nitrogen fertilizer needs. The test and nitrogen recommendation system is based on a two foot deep soil sample and a calibrated nitrogen requirement for common crops grown in South Dakota (Table 1). Extensive field plot data shows that the two foot deep... |
5. A Comparison of Point Injected and Knifed Phosphorus for Winter WheatThere are almost 2 million acres of winter wheat grown in South Dakota. Most is produced in the southwest part of the state on residual clay soils in a wheat fallow rotation with only limited, shallow sweep tillage. Very reduced tillage is necessary for wind and water erosion control, and water conservation on the long steep slopes. The continued use of shallow tillage on highly buffered, high pH soils has made broadcast phosphorus fertilizer inefficient in increasing wheat yields, even though phosphorus... |
6. Nitrogen and Phosphorus Fertilization of Cool Season GrassStudies were initiated at two locations on cool season grass in central South Dakota to evaluate the effects of nitrogen and phosphorus on forage and seed yields. Nitrogen rates (0,30,60,90,120,1501b Nacre) and phosphorus rates (0,30,60,90,180 Ib P,Odacre) were applied to established crested or intermediate wheatgrass once and harvested for either two or three years depending on location. Nitrogen increased dry matter yield by 48 and 62% at the two locations and seed yield by 166 percent. Phosphorus... |
7. Influence of Water Treatment Lime Sludge on Soil pH and Crop YieldsSoil pH levels are decreasing in extreme Eastern South Dakota. To test the effectiveness of water treatment lime sludge in raising soil pH and crop yields, a liming study was established at four locations with pH levels of 5.7 or less. The lime sludge applied at 3 tons per acre raised soil pH to neutral and maintained it at neutral for the 4 year duration of the study. Crops grown at the various sites included soybeans, corn, spring wheat, winter wheat and forage sorghum. Although there was a trend... |
8. Regionalizing Fertilizer Recommendations for North Dakota, South Dakota, and Western MinnesotaFertilizer recommendations have varied between adjacent states. The inconsistencies at state lines made educational efforts in soil fertility more difficult for companies doing business across state lines. In an effort to alleviate these problems, the agronomists working with fertilizer calibration data and recommendations from the three states of North Dakota, South Dakota and Minnesota put together a recommendation system which could be used in a large part of all three states. The basic "core"... |
9. Influence of Seed Placed Fertilizer on Corn, Soybean and Sunflower EmergenceSix phosphorous fertilizer materials were placed with corn, soybean and sunflower seed to determine their influence on seed injury and emergence. Fertilizer rates used were 0, 12.5, 25, 50 and 100 Ib/A P,O, as dry TSP (0-46-O), MAP (1 1-55- 0), DAP (18-46-0) or liquid 10-34-0, 7-21-7 and 9-18-9. Seed emergence ranged from 0 to 100% depending on crop, fertilizer rate and materials used. Corn was most tolerant of fertilizer injury while soybean was extremely sensitive with stand reduction with even... |
10. Changes in Iowa's Soil Test P and K Interpretations and RecommendationsResearch results from long-term and short-term experimentation in Iowa have been consistent in the response or lack of response of Iowa field crops to applications of fertilizer phosphorus (P) and potassium (K) at various soil test levels for P and K. Analyses of the research data have established critical soil test values for P and K and the most economic soil test range for P and K to maintain (Mallarino, Webb, and Blackmer, 1991a and 1991 b; Mallarino and Blackmer, 1992 and 1994; Webb, Mallarino,... |
11. Influence of Elemental Sulfur on Soil pH and Soil Test LevelsSoil test summaries from South Dakota State University Soil Testing Lab show that 16 percent of South Dakota soils have a pH of 7.6 or higher. These high pH soils can reduce nutrient availability to plants. A major concern is for reduced phosphorus availability and fertilizer use efficiency. High pH soils also reduce the availability of micronutrients such as iron and zinc. Due to these issues, questions are often asked on how to reduce soil pH. A number of materials such as sulfuric acid, aluminum... |
12. 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... |
13. A Comparison of Producer Adoption of Precision Agricultural Practices in Denmark, The United Kingdom, and Nebraska in the United StatesWhile a lot of research and commercial development has taken place in precision agriculture in recent years there is little information available about the experience and opinions of the producers who are trying to make it pay its way in the field. Information about producer experiences in precision agriculture would be useful in guiding hture research and development in both the public and private sectors. Important questions could include: - what types of precision agriculture practices are producers... |
14. Varying Nitrogen and Seeding Rates of Corn Across Productivity Regions in FieldsA field study was conducted fiom 1999 to 2001 to determine the effects of variable seeding rates and variable nitrogen rates on corn (Zeu muys L.) in southern Ihois. In whole field experiments, variable seeding rates ranging fiom 18,000 to 38,000 seeds ac-' in 4.000 seed increments were planted in randomized strips (in a randomized complete block design) across the field that had soils with varying productivity based upon historical yield maps. From the yield data it was determined that the optimum... |
15. Arbuscular Mycorrhizal Dynamics Throughout Corn Growing SeasonPhosphorous is an essential plant nutrient and is the second most common fertilizer nutrient applied in crop production. The role of mycorrhizal fungi in phosphorous (P) nutrition of corn (Zea mays L.) in high fertility soils in unclear. A study was conducted to determine the effect of extractable P on myco~hizal biomass and to evaluate the temporal dynamics of mycorrhizal fungi during the growing season in two irrigated corn fields in Nebraska. The objectives were addressed by the installation of... |
16. Should We Abandon Soil Testing and Yield Goals in Estimating Nitrogen Rates for CornIf the prices of corn and fertilizer-N and the shape of the N response function relating crop yield to the amount of fertilizer used are known, calculating an economically optimal N rate (EONR) for maximizing the net return to applied N is straightforward: the EONR is the N rate at which no firher increase in net return occurs. In most cropping systems and under common price scenarios, crop yield at the EONR is within 95 to 99% of the maximum yield obtained for the specific management package. In... |
17. Utilizing Existing Sensor Technology to Develop a Late-Season Critical Value for Spring Wheat ProteinA premium is paid to producers for spring wheat with a protein content greater than or equal to 14%. Obtaining that protein content can be problematic without proper nitrogen (N) fertilizer management. Sensor-based technologies have been used for predicting yield. The question is whether ths technology can be used to determine the protein content in-season for spring wheat. Field studies were conducted in South Dakota in 2003 and 2005. Five N treatments (0, 34, 65, 102, 136 kg N ha-') were applied... |
18. Crop Residue Removal Effects on Soil PropertiesThree large challenges facing mankind are the n eed to feed a rapidly growing population, increasing concentration of greenhouse gases in the atmosphere, and reliance on fossil fuels. Expectations from agriculture include produ ction of food and fiber to meet demands, management of agricultural systems to sequester carbon and redu ce emission of other greenhouse gases, and provision of feedstock for a rapidly expanding biofuels industry. Some discussions involving use of crop residue for biofuel... |
19. 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... |
20. 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 relies... |
21. 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 |
22. 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 |
23. 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 |
24. Reevaluating Potassium Recommendations for Soybean Production in KentuckyFertility recommendations from land grant universities are typically lower than private soil test laboratories and lead producers to question the adequacy of current recommendations. Further, soil samples analyzed at UK Regulatory Services Soil Testing Laboratory indicate that average state-wide soil test potassium (K) levels are declining approximately 1 lb K/A/year. The reason for this decline is not known, but some suspect it might be due to increased crop yields while maintaining historical... E. Ritchey, J.H. Grove, J.M. Mcgrath |
25. Corn uptake of soil- and fertilizer-derived nitrogen in response to rate and timing of fertilizer application.While nitrogen (N) fertilizer is essential for high-yielding corn (Zea mays L.) production, over-application or application of fertilizer N before rapid corn N uptake may result in N loss that negatively impacts the environment and reduces fertilizer use efficiency. To better understand how fertilizer rate and application timing impact corn grain yield and fertilizer recovery in the soil-corn system, six two-year field studies were conducted at Minnesota field sites of contrasting soil... |
26. Corporate Sustainability Initiatives and Their Interface with Crop Nutrient ManagementAn increasing number of corporations are establishing sustainability initiatives. For ag/food companies, these interface with nutrient management mainly via nitrogen—a lot of carbon dioxide is produced during nitrogen fertilizer manufacture, and some nitrogen fertilizer is converted to nitrous oxide (a potent greenhouse gas) after application. A corporate sustainability representative, a nitrous oxide expert, and a farmer will present their views and then take questions... P. Carter, R. Sirolli, G. Robertson, M. Hora |
27. Nitrogen Fertilizer and Irrigation Effects on Soil and Plant Nitrogen DynamicsCropping systems can be exposed to different nitrogen (N) and water availabilities for a variety of reasons. Both N and water have been shown to have both positive and negative; direct and indirect effects on soil and plant N dynamics. Given that agronomic crops require large amounts of N to achieve high yields and often acquire a majority of their N from soil nitrogen mineralization (N min), it is important to understand how nitrogen and water interactions alter soil and plant N dynamics. Our... T. Donovan, J. Schneekloth, L. Comas, M. Schipanski |
28. Developing a Sustainable Sufficiency ParadigmSustainable conservation practices must align agronomic productivity and environmental protection goals to facilitate widespread and consistent adoption on-farm. Agricultural phosphorus (P) management is a critical control point for detrimental environmental consequences of P loss in surface runoff from agricultural fields. Reduced P fertilizer inputs are recognized as an effective and necessary control measure to limit P loss; however, current P fertilizer recommendation systems do not support... M.A. Bourns, N.O. Nelson, D. Ruiz diaz, G. Roa |
29. Potentials and Constraints for Successful BioinoculantsBiologicals for agricultural production are receiving much interest, investment, and research. Biologicals offer replacements for chemicals. However, understanding the abiotic and abiotic interactions that affect survival and activity is needed to assess performance. Abiotic factors include soil properties, soil moisture, and temperature. Biotic factors include compatibility with native microorganisms and root characteristics. Given these factors, performance will be more variable than chemical... C.W. Rice |
30. Effects of Cover Crops on Surface Runoff Under Increasing Precipitation IntensitiesWith climate change increasing the frequency of extreme precipitation events, the risks of erosion, nutrient transport and flooding increase as well. Cover crops (CC) are a best management practice for cropping systems that are vulnerable to soil erosion. The objective was to analyze the effects of CC and precipitation intensity on surface runoff and water quality under natural precipitation events. Runoff and water quality data were collected from 2015-2022 from a corn-soybean cropping... S. Moylan, N.O. Nelson, G. Kluitenberg, A. Sheshukov |