Proceedings
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1. Optimum N Rates for Corn Production as Influenced by Crop RotataionFertilizer N efficiency in corn production has become a'hot' research topic in the 1980's. Increased concerns of nitrate-N entering the groundwater and the potential for improving the profitability of corn producers are the impetus for fine-tuning fertilizer N recarmnendations. Crop production factors such as improved diagnostic techniques, full utilization of symbiotic N fixation, and crop rotation have been gaining widespread research support throughout the United States. The adoption of crop rotations... |
2. Effect of Application N timing and Plant Growth Regulator use in WheatWinter wheat is an important cash crop grown in the Midwestern states. However, progress in yield advancement has been slow compared to advances in other major wheat producing regions, notably Euro~e. This has lead to a competitive disadvantage of USA-produced wheat on the world market. In an effort to enhance wheat productivity and profitability a series of experiments were established in the fall of 1985 to assess the impact of more intensified management practices including the use of multiple... |
3. Alfalfa Response to K Rate, Source and Time of ApplicationThe potassium (K) requirement of alfalfa is greater than that for any other nutrient. Potassium influences several systems within-alfalfa plants, including enzyme activity, carbohydrate production and transport, stomata1 activity: photosynthesis through chlorophyll content and CO, exchange rate, and nitrogen fixation (Munson, 1985). Potassium also markedly influences alfalfa agronomically through yield increases and improvements in forage quality, disease resistance, and overwinter survival. A significant... |
4. Dietary P Management to Reduce Soil P Loading from Pig ManureThe potential use of phosphorus (P) based land application limits for animal manure has increased the importance of optimizing animal feed P management. The specific objectives of this study were to determine the impacts of using high available P (HAP) corn and phytase on 1) P uptake and excretion by young pigs, and 2) total P, PA-P, and water-soluble P (WSP) levels in fiesh manure generated by these pigs during a seven day digestibility trial. Our results show that, compared to the control diet,... |
5. Effect of Tillage on Legume N Credit to Winter WheatAlthough there has been a significant amount of work done on the availability of legume-nitrogen for corn following alfalfa, several questions have arisen as to the sufficiency and availability of the legume N when winter wheat is raised as a following crop. This is especially true if the wheat is planted soon after the alfalfa is killed. The synchrony of nitrogen released from legumes with crop demand for N has been a concern even with crops such as corn, where N uptake can occur through- out the... |
6. 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... |
7. Estimating Second- and Third Year Nitrogen Availability from Dairy manure: It is common practice to repeatedly apply dairy manure to the same fields. To accurately assess the total plant availability of rnanure nutrients, it is necessary to account for the nutrients remaining in soil fiom previous years applications. A corn (Zea mays) field experiment has continued since 1998 on a Plano silt loam. Residual manure N availability was estimated for two and three years after a single rnanure application fiom differences in whole-plant N uptake using 1) fertilizer N equivalence... |
8. Sulfur Responses and the Wisoconsin Alfalfa Sulfur SurveyFor more than 30 years, agronomists, soil scientists, consultants and farmers have recognized the potential for significant responses to applied sulfur fertilizer in northern and western Wisconsin on lighter textured, low organic matter soils that had not recently received manure (Rand et al., 1969; Hoefi and Walsh, 1975; Schulte, 1976; Peters and Kelling, 1987). More recently, crop consultants and others have reported seeing sulhr responses on soils or in locations where they typically were not... |
9. Starter Fertilizer for Row Crop Production Under No-till Conditions in Eastern NebraskaStarter fertilizer application often results in increased corn and sorghum yield under no-till conditions, probably due to lower soil temperatures as compared to tilled soil. Five dryland and 5 irrigated corn trials. and 12 dryland grain sorghum trials were established after soybean in 2002 and 2003 on rolling land in eastern Nebraska with different soil types and topographic positions. Three placement positions were compared: in the seed furrow. over the row. and 2" to the side and 2" deep (2x2).... |
10. 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... |
11. 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... |
12. 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... |
13. Nitrogen and Phosphorus Recalibration for Sunflower in the Northern Great PlainsSunflower producers in the northern Great Plains states of North Dakota, South Dakota, and Minnesota are presently directed to N and P recommendations that originate from research performed in the late 1960s and early 1970s. These three states alone produce more than 80% of the sunflowers in the United States on a yearly basis (USDA-NASS, 2015). The current general formulas determining N and P fertilizer rate in these top-producing states are equivalent. The N recommendation is represented here by... |
14. 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 unavailable.... |
15. Variable Fertilizer Nitrogen Application Based on the Delta Yield Index- A Field StudyA quick review of the both the scientific and popular literature indicates that many different approaches have been suggested for the prediction of variable fertilizer N applications in the field. In previous meetings of this conference we have presented the general outline and approach taken for our site-specific crop management project in Ontario. Briefly, historical data sets of grain corn response trials to fertilizer N (encompassing some 300 site-years worth of data) indicated that most yield... |
16. Understanding Spatial Variability in Cover Crop Growth and DecompositionIn many agricultural landscapes, topographic variability leads to downslope movement of soil, water, and nutrients, causing heterogeneity in both crop yield and soil fertility throughout production fields. Cover crops can slow these processes, but the impact of topography on cover crop growth and residue persistence is uncertain. We measured the growth, mixture biomass composition, and decomposition of a cereal rye (Secale cereale L.) cover crop, and cereal rye /crimson clover (Trifolium... S.J. Leuthold, M. Salmeron, O. Wendroth, E. Haramoto, H. Poffenbarger |
17. Not All Litter is Created Equal: Differences in Nitrogen Mineralization Among Broiler Litter TypesOver three fourths of U.S. broiler chicken production is located in the Southeast and generates a substantial amount of broiler litter (BL). Broiler litter is a mixture of bedding material and manure that can be a valuable nutrient source for row crop production when properly used. New technologies provide farmers with the opportunity to use a combination of BL and inorganic fertilizers with minimal environmental impact. The first part of the project evaluated integrated N management systems that... L. Fitzgerald, E. Ritchey, J. Mcgrath, J. Shockley, H. Poffenbarger |
18. Corn Yield Response to Sub-Surface Banded Starter Fertilizer in the U.S.Sub-surface fertilizer application at planting (i.e., starter fertilization) is a common practice in U.S. corn (Zea Mays L.) production to improve early-season nutrient uptake, nutrient use efficiency, and plant growth, especially under cool and moist spring soil conditions. However, yield increases from starter applications can vary across production systems and environments. Here, we use a meta-analysis approach to quantify and generalize corn yield responses to sub-surface starter... D. Quinn, C. Lee, H. Poffenbarger |
19. 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... |
20. Effects of Silicon Supplementation on Growth and Silicon Accumulation in Tall Fescue (Festuca arundinacea) and Bentgrass (Agrostis stolonifera)This study assessed the effect of silicon (Si) supplementation on biomass production and Si accumulation of tall fescue (Festuca arundinacea) and bentgrass (Agrostis stolonifera). Plants were grown in buffered Hoagland’s media (pH 6) with four Na2SiO4 treatments (0, 0.5, 1, 2, 4 mM). The two species responded differently to Si supplementation in terms of biomass. For bentgrass, biomass was enhanced by Si supplementation, but only significantly (p... S. Qian, J. Unrine, H. Poffenbarger |
21. Comparison of Wheat and Barley to Rye as a Cover Crop for CornWinter cereal cover crops have become an essential management practice for sustainable corn production. Rye is the most popular winter cereal for cover crop, but wheat and barley may provide a comparable value due to their similar fibrous root systems. Winter cereals provide organic matter, scavenge residual nutrients, and protect the soil from erosion. Winter cereals can immobilize nutrients for the corn crop and can reduce corn stands in some situations, reducing corn yield. The primary objective... R. Nalley, C. Lee, H. Poffenbarger |
22. An Evaluation of Summer Cover Crops for Agroecosystem Services in Small Grain SystemsCover cropping has been gaining popularity in recent years, specifically for its ability to improve soil properties and suppress weeds. However, cover crop species differ in the agroecosystem services they provide. Our objective was to evaluate a variety of summer cover crop treatments and their ability to provide soil physical protection, increased yield and quality of subsequent small grains, nitrogen input reduction, and weed suppression. Six summer cover treatments were evaluated for these... S. Watkins, H. Poffenbarger, D. Van sanford |