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1. A Case for the use of Limestone in North DakotaFarmers in North Dakota have long believed that nearly all of the cultivated land in the state was alkaline in pH. A recent survey of the state revealed that between 27% and 50% of the fields tested below pH 7, depending on landscape position, with about 17% of the state with pH less than 6.5. In site-specific studies in fields with dominant pH above 7, nearly all fields contained at least one area with pH below 7. Herbicide carryover studies have shown that areas of even slightly acid pH can re... |
2. A Crop-Based Approach for In-Season N Management of CornOver-application of nitrogen (N) fertilizer on corn has resulted in elevated levels of N in ground and surface waters. A major factor contributing to decreased N use efficiency and environmental contamination for traditional corn N management schemes is routine pre-season application of large doses of N before the crop can effectively utilize this N. Our long-term research goal is to reduce these over-applications by using remote sensing to direct fertilizer only to areas needing N at times when... |
3. Ammonium Thiosulfate as a Urease Inhibitor- A suggested MechanismA great deal of interest, ard sca~ controversy, has been generaw by my observations (Goos, 1985a; Goos, 1985b; Fairlie and Goos, 1986) that ammonium thiosulfate (ATS, 12-0-0-265) can inhibit soil urease activity when mixed with fertilizers such as urea-ammonium nitrate (UAN) . Preliminary field research (Gascho and Burton, 1987; Fox and Piekielek, 1987; Lamond et al. 1986) has shown some increase in crop yields or N uptah by adding ATS to surface-applied UAN. However, the use of ATS as a urease ... |
4. Can we Afford Not to Ridge Till?A typical farmer response to ridge till is that it is just another method of tillage. My contention is that it is much, much more than that. In my career in this I have had three cbjectives. One is to attapt to create as much balance between famkq ad the enviroment as possible. ?he second is to rrake farming profitable. The third is to make farming easier and fun. I believe with the proper approaches in regards to fertility, chemicals and water management along with the ridge till technique the... |
5. Changes in Crop Production Efficiency with High Yield ProductionIncreases in crop yields are due to changes in the genetic efficiency in the use of inputs. However, there are constraints on efficient use of resources, e-g., water, nitrogen, solar radiation, that limit consistent high yield response. The interactions of water, nitrogen, and light form a basis for understanding how crop production efficiency can be improved. Carbon dioxide is an input to crop production that has been overlooked and understanding this environmental component will help identify... |
6. Changes in Extractable P and Mineral N from Soil Recieving Fertilizer or Manure from Swine Fed Tradional or Highly Available Phosphorus Corn DietsWe compared extractable P and mineral N from soils receiving inorganic fertilizer or manure from swine fed either traditional (TC) or Highly Available Phosphorus (HAP) corn diets. The study was conducted at two sites, one with conventionally tilled irrigated corn and the other with no-tillage dryland sorghum. Manure application to a no-tillage site resulted in volatilization losses of N and greater variation in nutrient availability when cornpared to incorporated manure. When expressed as a per... |
7. Compaction - K Fertility Interactions in Corn ProductionSoil compaction is recognized as a significant factor affecting yield in crop production today. The pressure to produce crops profitably has often led gruwers to farm greater acreages, with larger equipment under soil conditions which favor compaction. Effects of compaction are not limited to the surface lay- of a soil but often may be apparent cut much of the root zone. With the interest in soil compaction and its effects on crop growth, a research project was initiated to accomplish the fol lo... |
8. 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 ha... |
9. Corn and Soybean Yield Response to P and K at Different Landscape PositionsSoil sampling for fertilizer recommendations is most often from the surface 15 to 20 cm (6 to 8 inches). The nutrient pool available to crops however might be quite variable when considering the spatial variation in the sub-soil nutrient pool. The objective of this research was to assess the potential interaction between claypan soil topsoil thickness (i.e., depth to the claypan) and soil-test phosphorus (P) and potassium (K) on corn and soybean crop response. Plots were established in 1996 on a... |
10. 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 prepla... |
11. Delivering Continuing Education to Ag Professionals- The Crop Adviser InstituteContinuing education is essential for agricultural professionals, whether required by a certifjmg organization or completed voluntarily as a supplemental educational opportunity. Agricultural continuing education has traditionally been delivered on-site, but temporal, geographical, and other constraints often prevent individuals from attending these courses. The Crop Adviser Institute (CAI) has been established to provide an alternative method of delivering continuing education. Implementation o... |
12. Developing a Natural Resource Web Site as a Training Tool for Students and AgronomistsSouth Dakota State University. Brookings SD Introduction South Dakota agronomists, agricultural workers, and students often require visual aids to demonstrate a field procedure or understand the interaction among natural resources that contribute to agricultural production. Suitable commercial products are available to serve this purpose, but they may be neither readily accessible to the public, nor particular to the state. An Internet site accessible to the public is required to display aspects... |
13. Do Hybrids Differ in Response to Differential Levels of Nitrogen Fertilizer?In the absence of other limiting factors, maize yield increases with nitrogen fertilizer application to very high levels. In fact, researchers attempting to maximize maize production have reported a yield -rise at levels of N greater than 300 lbs/acre. Because there are many limiting factors in addition to nitrogen, nitrogen fertilizer must be mged to minimize costs and maximize response. In addition to mging the crup's proctuctivity, recent concerns about high levels of nitrates and other farm... |
14. Do We Really Need a Soil Test for SulfurThe importance of sulhr (S) in a fertilizer program for crop production has been recognized for over 50 years. The need for fertilizer S was not universal. Measured responses were limited to special or localized situations. Since S in a fertilizer program was not needed for all crops and all soils, it was only logical to attempt to develop a soil test that would accurately predict the need for the addition of this essential nutrient. Development of a soil test for S that would accurately predic... |
15. Effect of Alum Water Treatment Residuals on Soils with Very High Bray P1 Soil Test LevelsAs point discharges of phosphorus (P) and other pollutants to surface waters from industrial and municipal wastewater systems have been reduced, nonpoint sources of P are now contributing a greater portion of P inputs into freshwater resources. Agricultural runoff and/or erosion can be a main contributor to this nonpoint source pollution. Continued inputs of fertilizer and manure P in excess of crop requirements have led to a build-up of soil P levels which are of environmental, rather than agro... |
16. Effect of Ammonia Knife Spacing on Corn YieldExperiments were conducted at DeKalb on a Drummer sicl, Dixon Springs on a Alford silt loam and Elwood on a Blaunt sicl to evaluate the effect of ammonia knife spacing at varying N rates and on different tillage systems on the yield of corn Nitrogen was awlied at 180 1bs N/acre at bath DeKalb and El& and at 210 lbs N/acre at Dixon Springs in the knife spacing by tillage study. In the rate by knife spacing by time of application study at DeKalb, the preplant nitrogen was placed under where the ro... |
17. 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 object... |
18. Effect of Intensive Management Practices on Wheat Yields and ProfitabilityConsiderable interest in improving wheat yields and profitability has been shown throughout the U.S. over the past ten years. Much of this interest has resulted from the dramatic yield increases achieved by English producers during that time - an annual increase of 5.0 bushellacre per year (Figure 1). During that same time period, wheat producers in the U.S. have shown a much lower rate of increase in wheat yields - 1.02 bushellacre per year (Figure 2). Missouri growers have been no exception to... |
19. Effect of Three Tillage Systems on Soil Bulk Density and Porespace DistributionMany grain producers in Kentucky use a 3 crop in 2 year rotation of corn fol lowed by small grain-soybeans, and commonly no-ti1 1 the soybeans and corn in order to intensively use sloping land for continuous grain production. Because of the intensity of machinery traffic in this system, grtwxs. are concerned that continuw no-till management may cause compaction, and that such fields may need occasional primary tillage. In order to obtain information regarding this situation, we conducted a test ... |
20. 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 t... |
21. Effects of Soil Test, Tillage, and Manure and Fertilizer Application Method on Phosphorus RunoffLoss of phosphorus from agricultural lands into surface waters is of growing environmental concein. Phosphorus transported by surface runoff often ends up in streams and lakes and accelerates eutrophication, which affects the ability to use the water for drinking, fishing. recreation. etc (Foy and Withers, 1995). The niajor mechanisms by which agriculture contributes phosphorus to surface water is through runoff and erosion (Sharpley et al., 1994). Controlling run~ff and erosion from agricultura... |
22. Energy and Nutrient SuppliesA study by the Potash and Phosphate Institute on 2.5 million North American soil samples has determined that soil nutrients have been withdraw without adequate replacement for several years. Soil fertility levels have dropped below optimum. At the same time, energy prices have skyrocketed, increasing fertilizer production costs. The presentation explains natural gas supplyfdemand, and how it affects both the price for natural gas and the production costs for fertilizers. The impact of this price... |
23. Enhancing Alfalfa Production Through Improved Phosphorus and Potassium ManagementAddition of phosphorus (P) and potassium (K) fertilizer is vital to maintain alfalfa productivity. The objective of this study was to examine how P and K fertilizer application increases alfalfa yield. nutrient use, and plant persistence. Replicate plots of P (0, 50, 100, 150 1bs P205/acre) and K (0. 100, 200, 300, 400 Ibs K20/acre) treatments were arranged in a factorial design. Forage harvests occurred four times annually for 5 years and yield, mass per shoot, shoots per area, and herbage nut... |
24. 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 equiv... |
25. Fall Applied Controlled-Release Nitrogen as a Nitrogen Source for Soft Red Winter WheatSoil conditions are often not conducive for timely spring N applications on wheat. Fall applications may save labor and be more economical when blended with other nutrients such as phosphorus. However, many N sources may be susceptible to loss before uptake by the wheat plant. This study evaluated fall applied controlled-release N as a N source for wheat. ... |
26. Fertilizer and Manure Management Comparisons for Corn-Soybean Rotataions in MinnesotaA study was designed to evaluate the impact of P sources (fertilizer and manure), nutrient application methods (broadcast and subsurface bands), P rates (crop removal and twice crop removal), and tillage systems (no-till and conventional) on corn-soybean response. Results to date show higher yields using manure as compared to fertilizer as the P source. This could be attributed to a higher rate of P being applied using the manure. No-till systems measured greater yields in 1999 and 2000, primari... |
27. Fertilizer Recommendations Based upon Nutrient Removal or Soil Testing- A Spatial AnalysisCosts for nutrient management are generally high in crop production systems. Those costs are associated with activities related to: a) gathering information regarding soil fertility and plant nutrition for a field, b) acquisition of the actual soil amendments intended to improve the field's fertility and future crop nutrition, and c) application of the purchased soil amendments at the right rate in the appropriate place within the field. Information gathering usually consists of plant tissue and... |
28. 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 nee... |
29. Greenhouse Gases and Carbon Sequestration Where They Fit With the Fertilizer IndustryFew things elicit more debate than the weather, and whether it is changing. Farmers in Nebraska are klly convinced that global warming is real. while farmers in Michigan arid Ontario aren't nearly as sure after this growing season. I am not going to debate whether climate change is real, or whether it is good or bad, but rather provide some background on the whole issue and how farmers and the fertilizer industry may be affected. Current scientific consensus is that greenhouse gas levels in the ... |
30. Improved N Use Efficiency for Wheat in Southwest IndianaAbout one-third of the wheat acreage in Indiana is grown in southwest Indiana. During most years this area of Indiana receives exoessive precipitation during the late winter and spring gruwth period for wheat. This presents problems with losses of available soil nitrogen (N) through leaching and/or denitrification and law uptake of N by the crop even on fields which have been well-fertilized. These experiments were condtucted in 1986 and 1987 to evaluate fall, mid-winter and late-winter topdress... |
31. 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. ... |
32. Insuring Nitrogen Best Management PracticesWhether real or perceived, the risk of losing profit by implementing best management practices (BMPs) is a major barrier in a farmer's decision process to adopt these environmentally and economically positive practices. Farmers have come to rely on agri-chemicals and fertilizers to reduce risk. Even when scientific evidence proves they are unneeded, many are slow to reduce their reliance on these inputs. Farmers need assurance that the occasional failure of best management practices will not cau... |
33. Interaction of Potassium Fertilization and Row Width for SoybeansIn the past several years the row width of soybeans has decreased substantially. As row width decreases the amount of soil between rows for soybean roots to explore and from which to extract nutrients has decreased. Also many acres in the Midwest have little or no fertilizer added in the soybean year but rely on residual nutrients left from the previous crop. In this study the effect of row width and method of potassium fertilization for soybeans was investigated. ... |
34. Iowa Soil-Test Field Calibration Research Update- Potassium and the Mehlich-3 ICP Phosphorus TestIowa soil-test interpretations and fertilizer recommendations for phosphorus (P) and potassium (K) were last updated in 1999. The only change from previous recommendations (Voss et al., 1996; Voss and Mallarino, 1996) was to add interpretations for the Mehlich-3 (M3) P and K tests to existing interpretations for the Bray-1 P, Olsen P, and ammonium-acetate K tests (Voss et al., 1999). The interpretations for the ammonium-acetate and M3 K tests are similar because comparisons of amounts of K extra... |
35. Iowa's 1987 Groundwater Protection ActThe law is the result of public concern about contamination of Iowa's groundwater resources. Data from all over the state have shown that agricultural chemicals are finding their way into -ter. The law calls for spending $64.5 million over 5 years on programs to prevent groundwater contamination from agricultural chemicals, sinkholes, agricultural drainage wells, municipal and irdustrial wastes, landfills, household chemicals, and buried chemical and petroleum storage tanks. Three fourths of the... |
36. Manure Treatment and Handling OptionsManure treatment and handling will need to be an integral part of the nutrient management systems on livestock farms. No one manure system will meet the varied needs of farms with their specific nutrient management situations. The method of manure handling that will best suit each farm will vary depending on labor, land and capital resources and the manure itself. Several criteria that each farm manager will need to evaluate the treatment system that will best meet their needs are presented. A v... |
37. Nitrate Leaching Characteristics for Various Nitrogen Management Strategies on Irrigated CornEfficient use of nitrogen (N) fertilizer for corn production is important for maximizing economic return to the producer and minimizing NO3 leaching to groundwater. This is especially important on irrigated, sandy soils due to the high infiltration and saturated conductivity and potential risk to the local water supplies. This study is being conducted to quantifL the NO3 leaching potential in the irrigated sands along Kansas' waterways under current and alternative N and water management strateg... |
38. Nitrogen Availability, Time of Release and Movement in RotationsPrevious studies have found that N is released through the decomposition of sugarbeet tops (Moraghan and Smith, 1996: Reitmeier et a]., 1999). There is also evidence that N credits may be justified following other broadleaf crops, such as potato and sunflower. This evidence follows work by Vanotti and Bundy (1995) and Bundy et al. (1 993) suggesting that N credits from annual legumes are provided not by decomposition ofthe roots or release ofN directly into the soil from the roots as some might ... |
39. Nitrogen Management and its Influence on N Losses to Surface Water Through Subsurface Tile LinesSubsurface tile drainage from row-crop, agricultural production systems on high organic matter soils has been identified as a major source of nitrale entering surface waters in the Mississippi River Basin. Tile drainage studies have been conducted on three drainage research facilities at two locations in Minnesota since 1973. Nutrient and crop management systems including rate and time of N application. N sources (fertilizer, dairy manure and hog manure), nitrification inhibitors, cropping syste... |
40. Nitrogen Management for no-till Grain SorghumField experiments evaluating the effects of nitrogen management for no-till dryland grain sorghum were coacted in 1985 and 1986. Nitrogen rates (0, 50, 100 lbs N/A and placement methods for urea ammonium nitrate solution (UAN) have been evaluated in eastern Kansas. Placement methods have included surface broadcast, surface banded, pressure injected, and knifed. Results to date shm that nitrogen consistently increases yields and tissue and grain N contents, and that method of UAN placement produc... |
41. Nitrogen Recommendations and Optimum Nitrogen Rates- How Do They CompareThe goals of University N recommendations for corn are to suggest adequate amounts of N to maximize economic return to the grower and simultaneously avoid excess N additions that can contribute to water quality problems. With increasing concerns about the contributions of aoricultural N to groundwater nitrate and to hypoxia in the Gulf of 3 Mexico. the appropnateness of N recomn~endations and their research basis are increasingly questioned. In addition, University N recommendations are often be... |
42. No-till Corn Response to N Fertilizer Sources and Placement Methods- A Summary of Southern Illinois ResultsExperiments were conducted in southern Illinois from 1984-1986 to evaluate the placement efficiency of several N fertilizers used in no-till corn production. Such information has become of meaningful importance as producers strive to obtain the greatest possible returns from their N fertilizer investment and to obtain yields and a level of profitability equal to that of more conventionally produced corn. Also, in the near future, no-tillage will become an important tool for many farmers in south... |
43. On-The-Go Sensors for variable rate Nutrient Management- Determining Soil K Status with a Flat-Surface Ion-Selective ElectrodeTraditional soil sampling approaches are frequently not sufficiently spatially dense to characterize within field variability in soil fertiiity. Recent technology advances have demonstrated the feasibility of using automated soil sampling systems and tractor mounted sensors to create nutrient availability maps from more continuous measurements. Our objective was to determine if a flat-surface ion selective K electrode could measure soil K status at field moisture content. Twenty-four agricultura... |
44. 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 ... |
45. 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 determin... |
46. Phosphorus Runoff From Incorporated and Surface-Applied Fertilizer and ManureContinued inputs of fertiher and manure in excess of crop requirements have led to a build-up of soil phosphorus (I?) levels, creating an environmental rather than agronomic concern (Sharpley et al., 1994). The objective of this study was to evaluate the effects of soil test P level, source of P amendments, tillage, and manure application method on P runoff from agricultural soils. The treatments consisted of swine manure surface applied and injected at rates of 29 and 59 Ib acre-' of P, and tri... |
47. Phosphorus Stratification- is it Relevent to P uptake by SoybeanStratification of nutrients, observed in soils under continuous no-till management, remains an issue. Two experiments were conducted during 2001 and 2002 to evaluate the effect of stratification on P nutrition of soybean (Glycine nzax (L.) Merr.). At the fist site there were five blocks with stratified and unstratified main plots and five levels of soil test P as subplots. In the second trial there were four blocks with two stratification treatments as main plots, the absence and presence of in... |
48. Potassium Deficiency in South DakotaSouth Dakota soils are typically very high in plant available potassium (K). However in the last several years there have been increasing reports of K deficiency on corn. A number of observations have been made concerning where K deficiency occurs and what factors are involved. A few research studies have been initiated to answer frequently asked questions by producers on K management for corn and soybean rotations in the state. Preliminary results indicate differential corn variety response to... |
49. Predicting Fertilizer Nitrogen Requirements for Corn in OntarioThe nitrogen fertilizer requirement of a crop under field conditions is influenced by numeraus factors including soil, climate and managanent variables. Most of these factors are very difficult, if not impossible to predict in advance. The major factors influencing nitrogen fertilizer nquhment are (Gch and Haynes, 1986); 1. the requirement of the crop for N as determined by its yield (or yield patential) , 2. the availability of fertilizer N or the fertilizer use - efficiency, and 3. the amount ... |
50. Preplant vs. Weekly Applications of N-P-K FertilizersMany studies have compared time of fertilizer application to corn, but few have looked at weekly applications of complete N-P-K fertilizers. Often only one nutrient is looked at individually making sure that the other nutrients of concern are adequately supplied. In some instances the ratio between the nutrient in question and other nutrients may be greatly out of proportion, thus resulting in an imbalance ard less than maximum response. Is it possible to add N-P-K nutrients in a certain ratio o... |
51. Relationship Between Soil P and P in Surface Runoff and Subsurface Drainage- An Overview of Ongoing ResearchNonpoint source pollution fiom agricultural fields has the potential to accelerate eutrophication of fieshwater ecosystems. In a report of water quality in the United States, the Environmental Protection Agency sited agriculture as the primary source of pollution in 60% of impaired river miles, 30% of the impaired lake acres and 15% of estuarine square miles @PA, 1998). Phosphorus, in particular, has received much attention due to its role as limiting nutrient in many fieshwater ecosystems (Cor... |
52. Remote Sensing of Corn Canopy Dynamics and Biophysical Variables Estimation in MichiganThis study was initiated to evaluate sensor-based nitrogen and water application for corn (Zea mays L.) in Michigan. The specific objectives of this study were: 1) to identi@ wavelengths that are more sensitive to N deficiency in corn, 2) to determine when to predict corn grain yield fiom spectral remote sensing data, and 3) to estimate biophysical variables ofcorn such as leafareaindex (LAI) and fractional cover (Fc) fiom spectral vegetation indices (SVI) obtained fiom radiometric measurements ... |
53. Response of Corn to N Fertilization in Fall, Spring, and (or) SummerPrecision farming technologies (remote sensing of canopy reflectance and yield monitoring) were used to study the response of corn after soybean to fertilizer N applied at different times in three field-scale trials in central Iowa in 1999. Weather conditions were unusually favorable for losses of fall-applied N and crop responses to N indicated that substantial losses occurred. Yields of corn could be maintained by adding a nitrification inhibitor or additional N, but the greatest profit was at... |
54. 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... |
55. 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 ... |
56. 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 calc... |
57. Soil Phosphorus Spatial Distribution in Pastures Receiving Poultry Litter ApplicationsEnvironmentally-based P management strategies could be improved by debeating management zones incorporating the effects of landscape position on soil morphology, hydrology, and soil P distribution. Three farm pasture sites in SW Missouri receiving long-term poultry litter applications were sampled by landscape position (summit, shoulder, upper backslope. middle backslope, lower backslope, footslope, drain) for soil P (Bray 1 P, CaCl2 P, total P) at two depths (0-5 cm, 5- 15 cm). Low landscape po... |
58. Soybean Response to Nitrogen ApplicationsSoybean yield increases due to N fertilizer have been reported recently, particularly for N applications during the reproductive stages. It is also known that nitrate inhibits nodulat ion and nodule activity and could potentially reduce yield. Our objective was to evaluate the effect of N fertilizer on soybean yield. Forty-six experiments were conducted with N fertilizer applied at times ranging fiom planting to late reproductive stages. Some experiments had significant positive or negative resp... |
59. Spatial Variability of Soil Test Phosphorus, Potassium, pH and Organic Matter ContentAs part of a larger study investigating the potential for variable fertilizer N application in corn production, 18 field sites were established on farms across Ontario intensively sampled in the 1995 and 1996 field seasons to assess the spatial variability of soil test P, K, pH and organic matter content. Soil parameters typically display a log-normal distribution (positive skew) which would generally result in the under-fertilization of a greater area of a field if the rate of fertilization wa... |
60. Starter Fertilizer Application Effect on Reduced and No-tillage Grain Sorghum ProductionThis experiment was conducted at the North Central Kansas Experiment Field, located near Belleville, on a Crete silt loam soil. Soil test P was in the high@ range. Treatments consisted oftillage systems and starter fertilizer placement and composition. Tillage systems were no-tillage and minimum tillage (spring disc and harrow treatment). Methods of starter fertilizer application included placement 2 inches to the side and 2 inches below the seed at planting (2x2) and dribbled in a band on the s... |
61. Starter, Nitrogen Management and Nitrogen Calibration- Localizing Management PracticesWhen I first started consulting with some of the fertilizer dealerships in my area, they hired me to make them different from the dealership down the road. The best way to do this was to become a local expert on scientifically-based best management practices for growing corn and soybeans in my territory. This included knowing how best to manage nutrients to grow productive and profitable crops. University and soil test laboratory recommendations provided a good starting point. However, these dat... |
62. Strategies for Establishing Management Zones for Site Specific Nutrient ManagementRecent precision agriculture research has focused on the use of management zones as a method to define areas for variable application of crop inputs. The goal of our work was to determine the relative importance of terrain information, aerial photographs, magnetic induction maps, and yield maps to define management zones. This work was conducted on a center-pivot irrigated field located near Gibbon. NE that has been planted to continuous corn for at least five years. Remotely sensed bare-soil i... |
63. Strip till Nitrogen Placement, and Starter Fertilizer Effects on Corn Growth and YieldStrip tillage, a system where residue is removed and small ridges are formed in the fall in the position of next year's rows, has become an increasingly popular alternative to 0-till for corn in Illinois. Over three years and eight environments in Central and Northern Illinois, tillage had no effect on grain yield: conventional tillage, strip tillage, and 0-till produced 1 1.67, 11.67, 1 1.57 Mg/ha, respectively. There were also no differences in yield due to N timing, N placement, or starter fe... |
64. Sulfur Influence on Corn and Soybean Yields in Eastern South DakotaClean air legislation, the increasing use of conservation tillage, and the manufacture of phosphorus fertilizers without sulfur have all contributed to lowering soil sulfur (S) availability to crops. Soil S availability has been affected to some extent by all three issues in eastern South Dakota. Hilltop erosion has exposed subsoil in which the pH is higher and organic matter content is lower than at lower landscape positions. In some eroded shoulder positions of the landscape in no-till fields.... |
65. 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 no... |
66. Supplemental N on Soybeans After FloweringThis one year study evaluated the yield response of soybeans to three urea-N sources applied at R3 (early pod), R5 (early bean fill), and R6 (late bean fill) growth stages. Nitrogen sources were urea, urea plus a urease inhibitor (~grotain~) and a controlled-release N (POLYON AG@ polymer-coated urea). Seventy-five Ib per acre of actual N was applied by hand to 10 x 40 foot plots. Experimental design was a completely randonlized block with four replications. Analysis was a 3 x 3 factorial and a z... |
67. The Effect of Tillage and P Fertilizer Placement on P Runoff from Sugar Beet Production SystemsThe objective of this study was to determine the differences in the amount of phosphorus (P) in runoff fiom land under sugar beet production caused by different management practices and phosphorus fertilizer placement. The study was set up as a split plot experimental design, replicated three times. The whole plot treatments were: 1 ) codsoybean rotation, with moldboard plow as primary tillage before soybean; 2) corntsoybean rotation, with chisel plow as primary tillage before corn; 3) sugar bee... |
68. The Growth of MEY in Spring Wheat CountryAny ag orientated news source looked at in recent weeks in North Dakota or western Minnesota has had some kind of a MEY related story. The MEY usually has been identified as 19naximum economic yield," but recently some use of I1most efficient yield" has been seen. Yes, spring wheat country has a new buzz acronym - MEY. How did such a buzz term for tbis amount of press/news coverage develop in the spring wheat region? The kickoff for MEY club deve1-t ocaured on November 25, 1986. Before that was ... |
69. The Influence of Variably Applied Potassium Fertilizer on Yield Variations in Two Southern Illinois Farm FieldsThe basis of Variable Rate Technology (VRT) is to apply nutrients where they are needed and to reduce the application of nutrients where they are not needed. However, there is considerable uncertainty as to whether the variable application of nutrients to farmers fields should be on the basis of soil test levels or yield potentials. A field study was conducted at two locations in southern Illinois from 1997 to 1999 to evaluate VRT as a management tool for corn and soybean production on fields w... |
70. The Total Maximum Daily Loads Process in KansasThe Clean Water Act of 1972 required states to establish Total Maximum Daily Loads (TMDLs) for surface water bodies that contain one or more pollutants that exceed water quality standards. A TMDL is a written, measurable assessment of a specific stream segment and its water quality problems and contributing pollutants. This assessment outlines the amount of a pollutant that needs to be reduced to meet water quality standards. allocates control responsibilities among pollution sources in a waters... |
71. 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 ... |
72. Use of Chlorophyll Flourescence Techniques to Detect Stresses in CornIncreased efficiencies in the use of water and fertilizer will require better methods of monitoring crop stress. This study was conducted to determine whether chlorophyll fluorescence was more sensitive to detecting water and nitrogen stress than chlorophyll meters in corn (Zea mays). The experiment was carried out near Shelton, NE in 2000, 200 1, and 2002. Treatments consisted of a factorial combination of 12 corn hybrids (1 1 Pioneer Hi-Bred internationali and B73 x M017), two water levels (de... |
73. 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 in... |
74. Variable Nitrogen Rate ManagementIt is now more or less acknowledged that lime and N are potentially more profitable than P and K variable rate management. There is a lot of variability in optimal N rates within fields so that there is a need for variable N management. The benefits related to variable N management are generally ranked as: o Less N fertilizer used per unit yield. Savings of 15 USDIac on average for small grains. up to 41 USDIac. o Greater uniformity in crop stand, yield, grain humidity, specific weight and prot... |
75. 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... |
76. Variable Seeding Rates in Twin Row Planting and Micro Management of NutrientsA large scale study to determine if twin row planting, utilizing particular fertility concepts and conservational practices, out produces conventional methods of planting and fertilizing. The primary goal of the study was to increase fmer profitability and promote methods of conservational tillage. ... |
77. 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 opti... |
78. Visual Correlation of Aerial Imagery with Topography and Crop YieldA study is currently being conducted on several farms to evaluate the usefulness of aerial imagery of soil and of a growing crop to delineate within-field management zones for the purposes of site-specific management. Presented is information for one site in Kent county Ontario for which correlations between aerial images taken of the soil and of the growing crop with the spatial patterns of measured topography, soil texture, and corn yield were examined. Visual interpretation indicated a very g... |
79. Water Quality Issues and Activities in MinnesotaWithin the last few years there has been considerable public concern over the occunrence of nitrates (NO;) in bath ground and surface waters. ?his is especially significant since 50% of drinking water for the U.S. tames fm g-muthter supplies and this increases to 85% in the rural areas (CAST, 1985). The issue has at tirrres becaw emotioml and fingers have been pointed regarding the cause of nitrates in our water supply. Consequently, steps are being taken to establish the relationship between N... |
80. Water Quality Issues in NebraskaThe primary water quality issue in Nebraska at this the is related to groundwater as opposed to surface water. Groundwater provides irrigation for over 7 million acres of land in Nebraska and is the drinking water source for almost a1 1 of Nebraska's domestic and municipal water users. In rural areas groundwater provides about 85% of the drinking water (Cast, 1985). Numerous reports of groundwater contamination led to its emeqence as a major environmental issue for the 1980,s. Govenrment agenci... |
81. Winter Annual Legume Cover Crops in a Wheat Grain Sorghum Rotation in South Central KansasWinter annual legumes in humid regions ofthe country can have a positive effect on subsequent corn (Zea mays) and grain sorghum (Sorghum bicolor) crops, mainly through N contribution of the legume and. in some cases, soil improvement. However, water use by the cover crop in drier regions has the potential to reduce yields in subsequent crops. This study was initiated in south-central Kansas to look at the agronomic implications of adding a winter annual legume cover crop to a winter wheat (Triti... |
82. Zinc Deficiency Response of Sorghum, Wheat, and CornZinc (Zn) deficiency in corn (Zea mays L.) is more common than in sorghum (Sorghum bicolor (L.) Moench) or wheat (Triticum sp.). The ability of wheat to withstand low soil Zn conditions is related to increased release of phytosiderophore, a natural chelate, fiom its roots. The reasons for sorghum's ability to utilize low levels of soil Zn have not been adequately explored. The objective of this research was to: 1) ascertain if Zn deficiency can be induced with sorghum, wheat, and corn grown in a... |