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1. Some Effects of Soil Compaction on Root GrowthRoot growth and nutrient uptake are obviously related, and yet not well unders tood under field conditions . An oversimplified premise is that plant roots must grow to the site in the soil where the nutrients are retained, or that the nutrient must move to the absorbing root sur-face (or both). Relationships developed under well controlled uniform laboratory conditions of ten do not extrapolate to field conditions. In this respect, progress is often hindered by the fact that root growth measurements... |
2. The Soil Doctor- A Field TrialThe growing environmental concerns of the nation are causing some changes in production agriculture. One of the environmental areas receiving attention is NO,-N in the ground water. A number of universities and private companies have directed attention to this problem. The pre-sidedress nitrate test is the most common approach to reducing excess nitrogen application on corn in the humid eastern U.S. Several researchers have developed systems to use this test. Fields are sampled to a foot depth when... |
3. Returning Conservation Reserve Program Land to Crop Production: Weed Management ConsiderationsThe conservation reserve program (CRP) was formulated in the 1985 Food Security Act and established to help prevent soil erosion on more than one third of the crop acres in the United States (USDA, 1986). Soil erosion represents the greatest threat in agriculture to the environment. Nationally, an estimated 750,000,000 tons of soil have been conserved as a result of CRP representing an estimated annual savings of $2 billion in off-farm clearing of eroded soil. Other benefits of CRP wildlife enhancement,... |
4. Site Specific Nitrogen and Irrigation Management Across Nebraska Agro-ecological ZonesNitrogen leaching below hrrow irrigated ground has caused nitrate contamination in Nebraska's groundwater. Alternate row irrigation and alternate row nitrogen fertilization is proposed as a method to decrease water use and decrease nitrogen leaching. Nitrogen was applied at a uniform and variable rates based on spring grid sampling for nitrate and soil organic matter. The experiment was conducted at three sites in Nebraska that represent a range of growing conditions. At these sites the average growing... |
5. Field Scale Evaluation of Innovative N Management Systems for CornPrevious research has shown that N fertilizer need for corn can vary widely, both between fields and within fields. Producers, however, almost always apply the same N fertilizer rate to whole fields, and vary N fertilizer rates minimally if at all over whole farms. Matching N fertilizer rates more closely to N needs could produce both economic and environmental benefits. Our objective is to test a range of innovative N management systems for their ability to match N rate recommendations to N needs... |
6. Phosphorus and Potassium Effects on Yield Components, Nutrient Accumulation and Persistence of Alfalfa (Medicago Sativa L.)Our objective was to determine why phosphorus (P) and potassiun~ (K) are essential for high yield by analyzing alfalfa yield components. Plots of P treatments (0, 25. 50, and 75 kg/ha) and K treatnients (0. 100, 200, 300, and 400 kgha) arranged in a factorial design were replicated four times. Forage was harvested four times per growi~lg season (1998-2000), and yield. mass per shoot, shoots per area. and herbage nutrient concentrations determined. In May and December, plants were dug to determine... |
7. Site-Specific Nitrogen and Irrigation Management Across Nebraska Agro-Ecological ZonesNitrogen leaching below hrrow-irrigated ground has caused nitrate contamination in Nebraska's groundwater. Alternate row hrrow irrigation and alternate row nitrogen fertilization is proposed as a method to decrease water use and decrease nitrogen leaching. Nitrogen (N) was applied at a uniform and variable rate based on spring grid sampling for nitrate. The experiment was conducted at three sites in Nebraska that represent a range of growing conditions. At these sites, the average growing degree-days... |
8. Site-Specific Manure Application Effects on Corn Yield and N StatusManure, a renewable resource, is an excellent source of nutrients that can be substituted for synthetic types of fertilizers. The organic matter in manure can enhance the physical and chemical properties of soils, especially infertile soils, as these soils typically contain low levels of organic matter and nutrients, and have low water holding capacities. The objective of this study was to evaluate the ability of manure application for improving crop yield and N status in less productive areas within... |
9. The Illinois Nitrogen Soil TestNitrogen fertilizer recommendations for corn production are often estimated on the basis of a realistic yield goal, with adjustments to allow for N credits fiom other sources, such as legumes or manure. A yield-based recommendation may have merit on a long-term basis. but under- or over- fertilization is apt to occur in any given growing season since soil N availability is not taken into account. Insufficient application of N can have serious economic consequences for the farmer, whereas excessive... |
10. Update on the Illinois N TestEstimation of plant-available N is complicated enormously by the dynamic nature of soil N, owing largely to the effects of temperature and moisture supply on N-cycle processes. Numerous biological and chemical methods have been proposed as an index of soil N availability (Brernner, 1965; Keeney, 1982; Stanford, 1982; Bundy and Meisinger, 1994), but none has been adopted widely for soil testing. Biological methods are necessarily time-consuming because of the need for incubation, and the results represent... |
11. Use of Fly Ash as as Alternative Liming Source for Irrigated Corn ProductionFly ash from the Gerald Gentleman Power Station in west central Nebraska can potentially serve as an alternative liming source without reducing corn grain yields. A study was conducted to assess the use of fly ash as an alternative liming source on three acid sandy soils of west central Nebraska where conventional limmg sources can be uneconomical due to transportation costs. Corn grain yield, and soil pH change over time were assessed. Lime sources failed to raise the soil pH in the upper 8 inches... |
12. Variable Rate Nitrogen Fertilizer for Corn Grown in KentuckyIn Kentucky, nitrogen recommendations for corn have historically been based on soil type. soil drainage class, and previous crop rather than on an anticipated yield or yield potential. Because of the growing popularity of yield monitors and GPS technology, corn producers are now accurately mapping yield variations within fields. A three year study was conducted in the karst region of western Kentucky to determine if past yield history (collected with a yield monitor using GPS) could be used as a... |
13. Sustainable Vegetable Crop Production Using Vermi-CompostThis research intends to utili ze earthworm castings as an alternate nutrient source, especially nitrogen, for vegetable crop production. The experiment was conducted in the greenhouse and 'Mountain Fresh' tomato ( Lycopersicon esculentum Mill.) was used as the test crop. The main objectives were (1) to identify the optimum app lication rate of earthworm castings (EC) for tomato growth, and (2) to compare tomato res ponse under different treatments. Three different textural soils, namely sandy soil,... |
14. Assessment Of Enhanced Efficiency Urea Products On Maize In MissouriUrea is the most commonly used N fertilizer worldwide, but can be easily lost to the environment through ammonia volatilization. Enhanced efficiency fertilizers (EEF) have been developed to help prevent these losses. Field studies were conducted from 2009 to 2011 on a Mexico silt loam (fine, smectitic, mesic, Vertic Epiaqualf) to determine the efficacy of five EEF urea products compare to untreated urea when surface applied to no-till maize (Zea mays L.). Treatments included untreated urea, Agrotain,... |
15. Response Surface Models Of Subsoil K Concentration For Loess Over Till Soils In MissouriCrop uptake of potassium (K) has demonstrated sensitivity to subsoil variation in K content. This fact has not been sufficiently considered in K management strategies in part due to logistical difficulties in sampling spatially variable subsoil K. We propose a simplified soil factorial model, a response surface, to enable site-specific accounting of whole root zone K supply for loess over till soils. We compared the performance of two peak functions and a non-parametric local regression procedure... |
16. Searching for Inputs to Increase Soybean YieldCommodity prices and production costs are both at higher levels than in prior periods, encouraging growers to maximize returns by managing costs and raising yields. We conducted experiments at three Illinois sites in 2012 to evaluate foliar fertilizer, foliar insecticide, lactofen herbicide, seed treatment, foliar fungicide, foliar fungicide + foliar insecticide, cytokinin, , and fertilizer N, alone or in combinations of factors, including some deletion' treatments. Serious drought through the first... |
17. Determining Cropping System and Topsoil Depth Effects on Phosphorus and Potassium Nutrient DynamicsUnderstanding the effects of fertilizer addition and crop removal on long-term change in soil test phosphorus (STP) and soil test potassium (STK) is crucial for maximizing the use of grower inputs on claypan soils. Due to variable topsoil depth, nutrient supply from subsoils, and crop removal across fields, accurate P and K fertilizer management can be challenging. Current Missouri fertilizer recommendations rely on a single buffering capacity for all soils throughout the state for P, and are only... |
18. Which Corn Nitrogen Fertilization Rate Tools Preforms the Best in the Midwest?Publicly-available nitrogen (N) rate recommendation tools are utilized to help maximize yield in corn production. These tools often fail when N is over-applied and results in excess N being lost to the environment, or when N is under-applied and results in decreased yield and economic returns. Performance of a tool is often based on the specific soil and weather conditions of a growing season. Research is needed to determine which tools are the most effective at recommending economical optimal N... |
19. Nitrogen and Harvest Impact on Biomass Yield of Perennial Warm-season GrassesUncertainties of the supply of fossil fuels from finite resources and the negative environmental impacts of their use are the two major driving forces for the search of alternative burning fuels. Perennial warm-season grasses have drawn interest as bioenergy feedstocks due to the high yielding capacity with minimal amounts of inputs under a wide range of geography, and the capability to produce multiple environmental benefits. Nitrogen (N) fertility and harvest management are considered as critical... |
20. Topsoil Depth Influences Switchgrass Nitrogen Managment on Claypan SoilsSwitchgrass (Panicum virgatum L.) is an attractive forage or bioenergy crop option for eroded portions of claypan landscapes where grain crop production is marginally profitable. Topsoil depth to the claypan can vary widely within fields and little information exists on the impacts of the topsoil depth on nitrogen (N) management of switchgrass. Therefore, a study was initiated in 2009 at University of Missouri South Farm located near Columbia, MO on a site known as Soil Productivity Assessment for... |
21. Soil Mineralogy and Potassium AvailabilityIn this talk, I will try to answer four questions. The outline below gives the overall framework for the presentation. 1. What are the mineral sources of potassium? Primary minerals crystallize from the magma. Those that contain K are: Feldspars (microcline and orthoclase) Micas (biotite and muscovite) Primary minerals weather decompose by several mechanisms. Chemical bonds are destabilized by acid attack. Al ions are complexed by organic... M.L. Thompson |
22. Assessing Nitrogen Management and Claypan Soil Variability Effects on Switchgrass using Reflectance SensingThe topsoil depth or depth to the claypan (DTC) can be highly variable across the landscape for some Midwest soils. This makes managing crops on these soils difficult because their productivity can be highly variable. In some ar eas of the landscape there can be no topsoil and leave the claypan exposed (e.g., side-slope) while in other areas it can be buried (e.g., toe-slope) (Kitchen et al., 1999). Due to the high variability of theses soils, switchgrass (Panicum virgatum L.) is a potential problem... |
23. 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 |
24. 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 |
25. 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 |
26. An Integrated Approach to Understanding Poultry Litter Use in Corn-Soybean Production SystemsThe majority of poultry litter (PL) in Kentucky is generated in the western third of the state, the same area that produces approximately 80% of corn, soybean, and wheat. This PL is applied to row crop fields as a nutrient source. Producers and commodity board representatives were concerned with reported nutrient availability coefficients, nutrient value, and long-term use of PL. Four field sites in a NT corn-soybean rotation were identified in the fall of 2012 with low to medium soil test values... E. Ritchey, E. Haramoto, C. Bradley |
27. 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 |
28. Soil Health Indicators help with Fertilizer Application Decisions in South Dakota CornFertilizer inputs are an essential part of corn (Zea mays) cropping systems in the United States. In South Dakota, phosphorus and potassium yearly inputs are based on soil test nutrient levels and a yield goal while sulfur is based on soil texture and tillage practices. These 3 plant nutrients have a point called the “critical value” where addition of more of the nutrient as an inorganic fertilizer should no longer result in a yield increase. These fertilizer critical... B. Groebner, J. Clark |
29. Influence of Biological Seed Treatment on Soybean Grain Yield in the U.S.Biological seed treatment in soybean (Glycine max (L.) Merr.) is a growing market in the U.S., with multiple microbially active ingredients and several proposed benefits. Some of the claimed benefits include improving nitrogen fixation, stimulation of root growth, increasing phosphorus, sulfur, and other nutrient absorption, and control of diseases, with the aim to increase soybean grain yield. Farmers are often bombarded with marketing claims about biological seed treatments. In many... F. Colet, R.A. Vann, S.P. Conley, S.L. Naeve, E.G. Matcham, S. Mourtzinis, L.E. Lindsey |