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1. A Systems Approach to High Yields, Efficiency and Profits in Corn, Wheat and Doublecropped Soybean RotationUsing a systems approach friendly to the environment, a three-crop/two-year no-till system has shown significiant yield increases in a three-year research project conducted at the Poplar Hill Research and Education Facility in Quantico, Maryland. In each case, corn, wheat, and doublecropped soybean yields exceeded average yields produced on Maryland's Delmarva Peninsula. Instrumental in producing these superior yields were enhanced fertility, supplemental water, and appropriate variety selection... |
2. 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... |
3. Comparing the Performance of Preplant and Presidedress Soil Nitrate Tests for the North-Central RegionSoil nitrate (NO3-N) testing is a recommended best management practice (BMP) for adjusting corn N fertilization rates across the North-Central region. Several approaches to soil NO3-N testing are used and vary in both recommended time and depth of sampling (Hergert, 1987). Nitrate is very mobile in soil and is subject to either loss from leaching and denitrification or gain from net mineralization of crop residue and manure. The processes that govem nitrate accumulation in soils are most active ... |
4. Comparison of Mehlich-3, Olsen, and Bray-P1 Procedures for Phosphorus in Calcareous SoilsFertilizer recommendations for P generally are based on soil testing. Although a variety of soil tests are reliable for evaluating plant available P of neutral or slightly acid soils. there is still uncertainty about appropriate soil tests and soil-test interpretations for calcareous soils. The Bray-P 1 and Olsen methods are the most widely used soil-test P methods in the North Central region. Extensive research has shown that the Bray-P1 test is reliable on neutral or acid soils but that it ten... |
5. 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... |
6. Corn Production as Affected by Daily Fertilization with Ammonium, Nitrate, and PhosphorusManipulation of N fertilization to control NH,+/NO,' ratios in the soil can affect corn (Zea mqs L.) growth and yield. Field study of these effects, however, has been difficult to conduct because nitrification of NH,+ andlor NO, leaching often occurs during the growing season. The objectives of this 4-year field experiment, were to investigate the effects of daily fertilization with various N sources and P on corn growth and yield. Pioneer 3343 was fertilized with solutions of urea (U), NH,CI, C... |
7. 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... |
8. 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... |
9. 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... |
10. Effects of Residue Density, Strip Tillage, and Starter K on No-till Corn Grown in Wheat StubbleField studies were conducted in 1992 to 1994 at 2 locations in southern Illinois to evaluate the influence of wheat straw residue density and stl-ip-tillage vs no-tillage on corn growth and yield. Corn growth and resultant yield is frequently reported by producers to Se depressed in the residues of a previous wheat crop. Allelopatliy is thought to be at least partially involved. The objective of the research was to evaluate straw level (removed, remain non-modif ied, and doubled), strip tillage,... |
11. 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... |
12. 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. ... |
13. 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... |
14. 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... |
15. Forage Quality Management- A Key to Successful Cattle Nutrition ProgramsIn 1992, the USDA reported 59.6 million acres were harvested for hay with an average yield per acre of 2.5 ton per acre. These values gave a projected total yield of 149.1 million tons of harvested hay. Using an average market price of $72.10 per ton, total value of hay produced exceeded 10.5 billion dollars. Also in 1992, alfalfa production represented over 50 percent of the forage harvested with 79.6 million tons produced. In addition to stored forage. pasture is also a significant source of f... |
16. 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 ... |
17. Improving PSNT Based Sidedress N Recommendations for Corn with Site Specific FactorsThe pre-sidedress soil nitrate test (PSNT) has been found to be a valuable tool for improving nitrogen recommendations for corn grown in humid regions of the country. The PSNT has been especially useful for nunaging N on fmls where organic sources of N, like animal manures are important. This test was proposed by Magdoff et al. in 1984 and has been studied extensively since then (Magdoff et al., 1990; Roth et al., 1992; Fox et al., 1989; Blackmer et al., 1989; Klausner et a]., 1993, and Meisinge... |
18. Influence of Potassium, Sulfur, and Zinc Fertilizer on Corn and Soybean Grown on High Tetsing SoilThe influence of potassium, sulfur and zinc fertilizer on corn and soybean yields grown on high testing soils was studied at two locations in Eastern South Dakota over a period of six years. Treatments were 50 Ibla K,O, 25 Ibla sulfur and 5 Ib/a zinc. The treatments were applied to the same plots at each location every year. Soil test levels were in the high range for all elements in question and additional nutrients would not have been recommended by the South Dakota State University Soil Testi... |
19. 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... |
20. 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... |
21. 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 ... |
22. 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... |
23. 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... |
24. Nutrient Management and Starter Fertilizer for No-till CornNo-till corn acreage has steadily increased in Illinois. No-till presents unique problems of nutrient stratification, increased surface residue, and cool, wet soils which may influence nutrient availability. Two experiments were initiated in 1993 at 4 locations to evaluate the response of no-till corn to: 1) primary N applications of anhydrous ammonia preplant, UAN broadcast preplant, and ammonia sidedressed at V6; 2) starter fertilizers with factorial combinations of N, P, and K banded 2 inches... |
25. Nutrient Management Following CRP- Concerns and On-Going ProjectsThe future of the Conservation Reserve Program (CRP) is uncertain as this paper is being prepared, however, most agree that at some point a significant acreage currently in CRP will be brought back into production. The peak of contract expirations for the 36 million acres of CRP will occur in the fall of 1996 with the first contracts originally due to expire in 1995 (Figure 1). Many of the Northcentral states have substantial CRP acreage's making post-CRP management an important topic for this r... |
26. 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... |
27. 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... |
28. Planting Equipment for No-tillPlanters or drills have to cut and handle the residue, penetrate the soil to desired seeding depth, and establish proper seed-to-soil contact. Keeping these three items in mind, a producer can evaluate the strengths or weaknesses of any piece of planting equipment and make any adjustments or changes necessary to make no-till planting successful. Fortunately. most currently available planters and drills can be used for no-till with few, if any, modifications. In the early days of no-till, produce... |
29. 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... |
30. Preparing for No-till Planting into CRP LandAs CRP contracts expire, many producers are considering bringing the land back into crop production. In order to conserve soil and water, and to keep the soil building benefits of idling the land for ten years, no-till is the best production system to use. Tillage will destroy the soil structure that has built up from the freeze-thaw and wetting-drying cycles. In addition, it will plant surface weed seeds and stimulate seeds which have been buried for the last ten years. Tillage will also fluff ... |
31. Real-Time Soil Nitrate SensingIon-selective field effect transistors (ISFETs) have inherent features such as small dimensions. low output impedance. high signal-to-noise ratio, low sample volumes and the potential for mass production, which are required for a real time soil sensor. However, ISFETs have the disadvantage of long-term drift, which is diminished by the use of a Flow Injection Analysis (FIA) system. In fact, FIA and ISFETs are complementary since the small sample volumes and rapid response of ISFETs allow the mi... |
32. 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... |
33. 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 enha... |
34. Seed Inoculations and Nitrogen Fertilizer Trials with SoybeansCurrently there is a lot of interest in soybean seed inoculation. There are some new products on the market that are creating renewed interest in seed inoculation even on fields that have a history of soybean production. Some of the new inoculants have claims for higher potency, new and better strains of Rhizobium. higher numbers of Rlzizobiurn per gram of material, sterilized peat media, seed sticker additions and etc. Many companies are beginning to pay more attention to storage and handling o... |
35. Site-Specific Management of N Fertilization in OntarioSignificant within field variability of soil properties, such as soil fertility, and plant growth have been well docome~ited. Standard soil testing practices and fertilizer recommendations which enco~npass an average soil test value for a field and a constant rate of fertilization will obviously result in certain areas of a field being either over or under fertilized. As indicated by Kachanoski and Fairchild (1995), for a single (constant) rate of fertilizer application, reconimendations based o... |
36. Site-Specific Management Research in MIssouri- Swamped in Spatial DataWith a maturing GPS technology, we have over the past couple of years become very enamored with producing maps on crop production fields. It wasn't long ago that the only map available was the soil map from county soil surveys. Continued sensor development and aerial photography and sensing, along with decreasing costs to store and manipulate spatial data, will mean that in the future measuring and mapping data will be the rule. There have been a lot questions raised regarding the minimum amount... |
37. 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... |
38. Site-Specific Research in North DakotaSite specific fertilizer application is currently being practiced in the Red River Valley of North Dakota/Minnesota A study has been initiated to determine sampling practices suitable for North Dakota producers using sitespecific farming both within and west of the valley. Two forty acre fields were sampled in 1994 in a 110 ft. grid, separating each sample into 0-6" and 6-24" subsamples. Smaller grid sizes were also obtained at 10 and 2 ft. grid distances in selected areas of each field. Nitrate... |
39. 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 ... |
40. 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... |
41. 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... |
42. Starter Fertilizer Interactions with Corn HybridsThe objective of this study was to evaluate the response of corn hybrids grown in a dryland, no-tillage production system on a soil high in available phosphorus to starter fertilizer. Treatments were corn hybrids (5 in 1993 and 6 in 1994) grown with or without starter fertilizer. Starter fertilizer (30 Ib N and 30 Ib P,O,) was applied 2 inches to the side and 2 inches below the seed at planting. Nitrogen was balanced on all plots to give a total of 180 IbIA. Bray-I P level in the experimental ar... |
43. 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... |
44. 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... |
45. The Conservation Reserve Program- Changes on the HorizonTen years ago, Congress passed the foundation of current conservation programs--the Food Security Act of 1985. Today, one program in particular, has exceeded many peoples' expectations. The Conservation Reserve Program (CRP) yas designed to take 40 - 45 million acres of highly erodible cropland out of production for a 10 - 15 year period. As the first CRP contracts begin to expire, Congress and the Administration are grappling with the program's future in the context of the 1995 farm bill. Will ... |
46. 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... |
47. 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... |
48. Trapping Function of Grassed FiltersThe potential to contaminate rivers, streams, and other natural water bodies with sediment, nutrients, pesticides and bacteria in runoff from agricultural land is a very important water quality issue. Conservation tillage has proven to be effective in decreasing soil exposure to rainfall, thus decreasing water runoff and erosion potential. Vegetative filters slow down runoff that allows sediment, nutrients, pesticides and bacteria to be deposited. Combining conservation tillage with vegetative f... |
49. Using High-Tech Media Tools to Transfer the Principals of System Research to FarmersBeginning in 1981, research and extension personnel at Virginia Tech and the University of Maryland formed Intensive Wheat Management Teams. Over the next six years these Teams developed a higher yielding, more profitable and environmentally superior soft red winter wheat production system. Yields greater than 100 bu/a were achieved every year. This was at a time when average wheat yields were in the 40 bu/a range (Table 1). Intensive wheat research continues today to refine and update the syste... |
50. What Grid Cell Size is Best for P and K Soil Testing in MinnesotaA study to evaluate the best grid cell size and best soil san~ple system for immobile nutrients was conducted in South-Central Minnesota from 1993 to 1995. A corn/soybean cropping system was used. The soils at the research sites were formed in glacial till. Three grid cell sizes, 60 x 60 ft., 180 x 180 ft., and 300 x 300 ft. were evaluated. The sampling patterns included a mid-plot sample, a 60 x 60 ft. grid all-point pattern. and five to nine sample pattern. The smaller the grid cell the better... |
51. 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... |