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1. Alternative Approaches to Making Fertilizer RecommendationsThe objective of this research project was to evaluate, both agronomically and economically. some common altcrnative methods of making fertilizer recornmcndations for corn, soybeans, and soft-red winter wheat used in Indiana. Over a period of six years ( 1992- 1997) the effect of seven alternative fertilizer recommendation philosophies on soil test levels, crop yields, plant tissue analysis, and fertilizer additions were measured in an attempt to determine differences in performance between thes... |
2. Assessing the Variability of Corn Response to NitrogenBecause results of experiments designed to test the response of corn to N rate tend to vary considerably with the environment. repetitions of such studies over time are essential. It is not clear, however, what number of repetitions are needed in order to deduce sound recommendations for application of N fertilizer to succeeding crops. We used the results from 16 years of a crop rotation x N rate study conducted at Monmouth, Illinois to assess the effect of duration of such an experiment on the ... |
3. Basic Concepts of Soil Acidity and LimingMost midwestern soils require periodic applications of aglitne or other liming materials for optimum crop production. Liming has several beneficial effects: I ) it reduces harmhl or potentially tosic conditions which can develop in acid soils; 2) it increases the availability of some of nutrients: 3) it replaces the supply of calcium and magnesium essential for plant growth which is depleted as soils become acid; 4) it ensures favorable conditions for the activity of certain herbicides; and 5) i... |
4. Challenges for making intensive soil sampling and VRT Pay. Ongoing Iowa Studies with PhosphorusSoil fertility evaluation and management can be greatly improved with the use of precision agriculture technologies. Differential global positioning systems @GPS), yield monitors, various forms of remote sensing, geographical information system (GIs) computer software, and variable rate technologies are available for use to producers. Intensive soil sampling, crop scouting, and other practices complete the new technological package. Soil testing is a diagnostic tool especially adapted for site-s... |
5. Chloride Fertilization on Wheat, Corn, and Grain SorghumResearch in the Pacific Northwest and the Northern Great Plains has documented positive cereal grain responses to chloride (CI) fertilization. Field research was conducted in Kansas evaluating CI fertilization on winter wheat, corn, and grain sorghum. Chloride fertilization consistently and significantly increased plant CI concentrations in all crops. Chloride fertilization increased grain yields or one or more winter wheat cultivars at 3 of 4 sites. The most dramatic yield increases were at th... |
6. Comprehensive Nutrient Management Plan from a USDA PerspectiveLivestock manure has emerged over the past few years as a major political, as well as an environmental issue. As the Congressional Research Service described the situation in a May 1998 report: "Social and political pressure to address the environmental impacts of livestock production has grown to the point that many policy-makers today are asking what to do, not whether to do something." It added: "The bulk of current policy debate on animal waste issues, both legislative and regulatory, is occ... |
7. Cover Crop Impacts on Corn and Soybean Nitrogen Accumulation and YieldThe need to retain soil N between economic crops has renewed interest in cover crops for the eastern cornbelt but their management remains a barrier to widespread adoption. We conducted a 3 site-yr study to determine effects of cover species (wheat or rye) and biomass management (burndown 40 d, 20 d, or 2 d preplant) on corn and soybean yields. Sites included a very poorly drained (wland wlo tile drainage) and a well drained silt loam. With adequate drainage, cover biomass 40 d preplant averaged... |
8. Deep Banding Phosphorus and Potassium for No-till Corn and SoybeanThe information presented is part of ongoing research to identify effective fertilizer placement methods and diagnostic tools lor phosphorus (P) and potassium (K) in no-till corn and soybeans. There is uncertainty about soil test interpretations and cost-effective methods of fertilizer application for the no-till systcni. Moreover, producers are uncertain about the value of soil testing in conservation tillage because of large variability and lack of knowledge concerning techniques for collectio... |
9. Early Season Stresses in CornSpatial variability in corn yield is frequently associated with lost yield potential caused by plant stresses. Early-season stresses are difficult to recognize because growing conditions (soil temperature and water status) are not ideal and seldom uniform throughout a field. The impact that climate has on plant growth is dificult to determine because it also affects nitrogen (N) availability. Nitrogen stress was imposed sequentially until the V8 growth stage and then all plots were sidedressed w... |
10. Effect of Nutrient Combinations and Nitrapyrin in Starters on CornExperiments were conducted from 1994 to 1996 at the Belleville Research Center of Southern Illinois Univerity and the Dixon Springs Agricultural Center of the University of Illinois to evaluate the effect of starter fertilizers. nitrapyrin (N-Serve) amendment of the starters, and tillage on conn. The soil at the Belleville site was an Iva silt loam, a low organic matter soil with relatively high P and K soil test levels. At Dixon Springs a Bonnie silt loam (bottomland) soil was used and the soil... |
11. Effect of Time of N Application for CornThe economic benefit associated with the application of N fertilizers for corn has been known for over 5 decades. As a result, over 99 % of the farmers in Illinois apply N fertilizers when corn is grown. Unlike phosphorus and potassium, there is no good soil test to predict the amount of N needed, instead, farmers use a factor times yield potential with appropriate credits for legume and other N sources to set N rates. While this works well over a number of years, there are years when less N wil... |
12. Effects of Phosphorus Application Method and Rate on Furrow-irrigated Ridge-tilled Grain SorghumThe objective of this research was to investigate the effects of method of phosphorus (P) placement and rate on inigated grain sorghum grown in a ridge-tillage system on a soil low in available P. This experiment was conducted from 1993-1 995 on a producer's field near the North Central Kansas Experiment Field Experiment Field at Scandia, Kansas on a Carr sandy loam soil. Treatments consisted of fertilizer application methods: surface broadcast, single band starter (2 inches to the side and 2 in... |
13. Evaluation of Nitrogen Management Practices in No-till Corn ProductionExperiments were conducted fiom 1995 to 1998 at the Dixon Springs Agricultural Center of the University of Illinois and the Belleville Research Center of Southern Illinois University to evaluate agronomically and economically several nitrogen (N) management options, including the use of the urease inhibitor Agrotaii, in no-till corn production. Compared in these studies were N sources (urea, UAN, ammonium nitrate, and anhydrous ammonia), placement (dribble vs. broadcast for surface-applied N and... |
14. Hypoxia in the Northern Gulf of Mexico- Causes and ConsequencesSeasonally severe and persistent hypoxia, or low dissolved oxygen concentrations, occur on the inner to mid-Louisiana continental shelf to the west of the Mississippi River and Atchafalaya River deltas. The areal extent during mid-summer surveys of 1993- 1997 ranged from 15.800 to 18,200 km2. The shelfwide distribution in mid-summer for 1985 to 1992 averaged 8,000 to 9,000 km2. Hypoxia occurs below the pycnocline from as early as late February through early October, but is most widespread, persi... |
15. Influence of Nitrapyrin on Nitrate Concentrations in SoilsIn central Ohio most of the water used for d&g comes from the Scioto River Watershed. This water shed in primarily composed of farmland in which corn and soybeans are the dominant crops. Periodically the nitrogen in the Scioto River exceeds safe drinlung water standards of 10 ppm nitrate nitrogen. Several EPA studies have concluded the high nitrate nitrogen levels are the results of nitrate flushes through the underground tile in agricultural fields. These flushes of high nitrates usually from l... |
16. Intensive Nitrogen Management of Soft Red Winter WheatThe current system of making nitrogen recommendations for wheat in the Eastern cornbelt assumes that nitrogen fertilizer required is a simple function of yield potential. The higher the yield potential, the more N fertilizer needed. The problem with this assumption is that factors such as soil type and ability of a site to release N through mineralization, climate, variety. disease pressure and managetnent practices all affect nitrogen use efficiency, and are not considered in making nitrogen re... |
17. Interaction of Soil Applied Herbicides with Soil pHManagement of soil pH is important in enhancing the availability of certain plant nutrients and in minimizing toxic levels of other elements to crops. However, the reaction of herbicides with soils under varying soil pH levels can affect both crop growth and herbicide performance. Soil pH affects herbicide performance in several ways. When crops are under stress due to nutrient imbalance from unfavorable soil pH levels, application of certain herbicides may increase risk of crop injury. When soi... |
18. Limestone Sources and Factors Affecting Their QualityAddition of liming materials to correction soil acidity is an age old practice. According to Barber (1984). Cato and Varro used lime to correct soil acidity about 200 B.C. In America. benefits derived from liming acid soils were docuniei~ted in the early 1800's (Ruffin, 1821). In a sunfey conducted in 1980. all but two of the North Central States (North Dakota and South Dakota) reported that research had shown a need !'or limc (Whitney, 1980). The need has not changed over the last 17 years, i.e... |
19. Liming in No-till SystemsIn 1985 a study was initiated at Penn State to look at the effects of surface application of lime on a very acid, long-term no-till soil. Since 1977 this field had been in no-till corn production with no limestone applied. The initial pH of "plow layer" was 5.1 and the surface 2 inch pH was 4.5. The limestone recommendation, based on the SMP buffer pH and a target pH of 6.5, was 6000 Ib calcium carbonate equivalent (CCE) per acre. The study included four limestone rates (0. 3000, 6000.9000 Ib CC... |
20. Methods and Limitations of Zone Sampling Using Topography as a Logical BasisTwo forty-acre fields in North Dakota were sampled in a 110 foot grid. Each field was measured for elevation in the same 110 foot grid. Topographic sampling zones were identified in each field and a correlation of the sampling based on these zones was compared to the correlation values from a 220 foot grid. Nitrate-N and the 220 foot grid were both correlated to the 110 foot sampling values for nitrate-N and P. A map of field nitrate-N levels from topography sampling compared to the 220 foot gr... |
21. Nitrate Concentrations in Drainage Water from a Continuous Corn Production System- Impacts of Tile Spacing and Precipitation EventsCharacterization of agricultural drains as point sources for nitrates in surface waters has generated keen interest in regional grab-sample monitoring programs. Grab sample tile drain monitoring programs are being explored by numerous public and private organizations interested in encouraging BMPYs for nitrogen and/or implementation of TMDL policy. Our objective was to determine if nitrate concentrations in water collected from individual tile lines could be interpreted independent of informatio... |
22. Nitrogen Availability to Corn Following Small GrainsNitrogen rate recommendations for corn are generally reduced following legumes compared to following corn or small grains. A 4-yr field study was conducted on a Plano silt loam soil in southern Wisconsin to evaluate the capability of soil NO3 tests to predict N availability to corn follo~b-ing small grains. Previous crop small grains included \vinter wheat, winter qe. and oats harvested for grain and straw. Nitrogen fertilizer was applied to corn at rates of 0 to 180 Ib/a in 30 Ib increments. Gr... |
23. Nitrogen in the Mississippi River Basin- Sources and Factors Affecting Loss of Nitrate to the RiverNitrogen (N) is a naturally occurring element that is essential to plant growth and crop production. In a soil system, nitrate-N is continually supplied through mineralization of soil organic matter. Other sources of N include fertilizers, animal manures, municipal sewage wastes, agricultural and industrial wastes, atmospheric deposition. and dinitrogen fixation, all of which either occur as nitrate-N or can be converted to nitrate-N through mineralization and nitrification. ... |
24. No-till Corn Response to Starter Ffertilizer in MissouriEarly research on starter fertilizer showed that it usually increased early season crop growth, but in Missouri and adjacent states this only occasionally translated into a yield advantage. With widespread changes in tillage practices over the past twenty years, this conclusion may be changing. Recent starter fertilizer trials from other states are frequently showing corn yield responses in no-till systems. Dave Mengel at Purdue University found a yield response to starter in 8 of 11 no-till sit... |
25. Optimal Phosphorus Response in Site-specific FarmingSite-specific farming has provided an opportunity to collect large amounts of field data, but traditional agronomic yield response models have not been developed to exploit this mformation. This research presents a yield model that incorporates detailed site-specific field information (e.g., soil pH. soil test P, K, and N, fertilizer rates), providing improved fertilizer decision making. A quadratic yield response function and a modified asymptotic Mitscherlich function are compared for irrigate... |
26. Performance of Early vs. Late Maturing Corn Hybrids in MichiganThe planting of fill-season, or late maturing hybrids in Michigan is encouraged by their tendency to produce higher yields. Full-season hybrids can take advantage of the entire growing season available at a particular location. Shorter season hybrids reach physiological maturity sooner and generally yield less. Recent experience with cool, wet springs resulting in delayed planting, and growing seasons that provided less growing degree days (GDD) than normal has caused corn producers to question ... |
27. Phosphate Management for the Corn Soybean RotationThe evaluation of rate, Frequency, and placement of phosphorus (P) fertilizer on production in the codsoybean rotation was evaluated for two contrasting tillage systems. A primary objective of this study was to evaluate both yield and economic response for the full crop rotation. Tillage systems compared were fall chisel plow and no-till. Application rates ranged from 0 to 92 Ibs P205 ac-' yr-l and were fall applied either annually or at double the rate on a biennial basis. The biennial applicat... |
28. Potassium Placement in Conservation Tillage- cropping System ConsiderationsSoil fertility specialists have repeatedly observed that significant stratification of both P and K occurs on fields which are kept in no-till production, even if that time period is as short as three years. The actual degree of K stratification is affected by soil texture, the method of fertilizer application, crop rotation history, precipitation levels and surface residue management. Potassium stratification isn't inherently deleterious to crop production in a given environment. Crop yield los... |
29. Precision Phosphorus Management for SoybeanSoybean responds to phosphorus fertilization in the Midwest. Most correlation and calibration data suggests that soybean is less responsive than corn. Because of this. normal management in the Upper Midwest is to fertilize before the corn crop in a corn-soybean rotation for both the corn crop and following soybean crops. This saves the cost of one application and the logistical problem of fertilization with P after a corn harvest. This management works well in soils tvith a pH less than 7.4 and... |
30. Predicting N Fertilizer Rates for CornSixteen N rate experiments were carried out in farmer fields in 1995 and 1996. The objective was to measure optimum N fertilizer rates and see whether they could be reliably predicted ahead of time. Yield response to N was measured in each experiment along with soil N measurements (planting and sidedress), and tissue N and chlorophyll meter reading at sidedress time. A very wide range of economically optimum N fertilizer rates was found, fairly evenly spread from 0 to 200 Ib N/acre, with an aver... |
31. Relationship of Seed-placed Phosphatic Fertilizer Salt Index to Crop EmergenceThe role of fertilizer salt index in salt injury to germinating seeds has been recognized for over 60 years. Recent increased use of direct seed placement of fertilizer P has produced a need for a simpler method of making seed-placed fertilizer recommendations. Numerous field studies were conducted utilizing seed-placed P fertilizers. Published fertilizer salt index values were multiplied by the PtOs/ha application rate to give a salt indexha value. Relative plant stand (dependent variable) was ... |
32. Remote Sensing as a Tool for AgricultureThe tendency for nearlv everything in our society to be bigger, better, faster, easier, cheaper, and safer than in the past has resulted in many challenges. Agriculture is not immune from these trends, and in some cases agriculture even leads the way. Incorporation of remote sensing into site- specific management activities is one area where technologies are being merged to develop a new array of products that are intended to help producers and consultants make better and more timely management ... |
33. Response of Minimum-till Corn to Starter Fertilizer and ACAStarter fertilizer containing N and P often increases grain yield under no-till management. but yield responses to starter have riot been consistently observed under conventional tillage. Experiments were established in 1996 and 1997 at six sites varying in latitude, soil type. fertility, and crop rotation to evaluate the effect of starter fertilizers on corn grown under high-residue minimum-till systems. In one experiment, a factorial combination of 3 N. 2 P, and 2 K rates placed in a 2x2 band ... |
34. Sidedress N applications for corn based on corn colorNitrogen-deficient corn reflects more light over the entire visible spectrum than nitrogen-suff icient corn. Our objective was to calibrate the relationship between remotely-sensed corn color and the nitrogen need of the corn. Corn color measurements were made two ways: Aerial photographs In-field spectral radiometer A successful calibration would allow: Variable-rate sidedress nitrogen applications that precisely meet the needs of the crop. Precise response to in-season N loss (Figure 1). Data ... |
35. 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 ... |
36. Soil Fertility for Functional FoodsIn the agri-food industry today, two trends cannot be ignored. First, the health conscious "baby boom" generation is demanding and will continue to demand foods that enhance their wellness. Crop producers must increasingly focus on the goal of producing crops that meet their needs. Second, the tools of molecular biology give agricultural scientists the opportunity to attain that goal. Biotechnology involves not only genetic engineering, but also includes tools that enhance the traditional select... |
37. Soil Fertility Trends in a Long Term Crop Rotataion-Soil Fertility TrialPenn State soil test recommendations are based on fertilizing for crop response at soil test levels below the critical level for response, maintenance fertilization based on expected crop removal in the optimum range just above the critical level, and finally no fertilizer recommended in the high range. Using a sufficiency level approach, a soil that was at the critical level would have a zero recommendation, however this zero recommendation would not be valid for 3 or 4 years until a new soil t... |
38. Soil Phosphorus Chemistry- Agronomic and Environmental ApplicationsPhosphorus (P) has been a heavily researched topic in soil science for many years. For example, a search of the AGMCOLA database from 1970 to present turned up nearly 6000 citations under the key words soil and phosphorus. The fact that P is essential to all forms of life has promoted these research activities. as one would expect. In addition, the complexity of the soil P cycle has yet to be fully understood and appreciated by the scientific community. Further, while early research focused on c... |
39. Soybean Chlorosis in North Dakota- Causes, Severity and Possible SolutionsSoybean acres continue to increase in northwestern Minnesota and North Dakota in spite of severe problems with iron chlorosis in some years. Soybeans often turn yellow within a few weeks of emergence and remain yellow for up to 8 weeks before plants green up and mature. Iron chlorosis tolerant soybeans available today are somewhat effective in reducing chlorotic acreage, but are not tolerant enough to counteract the soil conditions in this area. Several researchers have found that iron chlorosis... |
40. Spoke Injection of Fertilizer Phosphorus for GrassesFertilization of forge grasses with phosphorus has shown limited forage increases in South Dakota, even with low soil tests. Lack of response to added phosphorus may partially be due to fertilizer placement on established grass stands. Traditionally broadcasting fertilizer has been the only placement method available. Since P moves very iiiile in the soil, root feeding from tne added P must occur very ciose to the soil surface. A dry soil surface could limit P uptake by grasses, limiting any yie... |
41. Subsoiling No-tillage CornCurrently, over half of the corn in Kentucky is no-till planted. Many fields have received little tillage in the last 10 to 20 years. Many producers wonder if soil compaction increases with time on these long term no-till fields due to annual trafficking with heavy equipment. Subsoiling implements are available that allow subsurface tillage while preserving the surface mulch layer. This allows for continued no-till planting while introducing some tillage into the cropping system. Some producers ... |
42. Topsoil Thickness Influence on Phosphorus and Potassium Availability and Crop ResponseSoil testing to estimate nutrient availability and fertilizer needs is a widespread management practice for cropping systems in the United States. as well as in other countries. The purpose of soil testing is to simulate the ability of the plant roots lo uptake these various nutrients critical for normal growth. Crops generally uptake a s~nall amount of phosphorus (P) compared to potassium (K). The portion of soil P that is readily available for plant growth maybe limiting due to the small quant... |
43. Using Soil Properties to Predict Soluable Phosphorus Losses from Indiana SoilsEscessive phosphorus (P) levels in surface water can degrade water quality by causing algal blooms and accelerating the eutrophication process. Agriculture has bceri implicated as a major nonpoint source of P, so many states have considered restricting P applications from inorganic fertilizers, manures, and other Pcontaining materials once soil test P levels esceed "threshold values". Relationships between soil properties and soluble P loss potential have not been welldocumcnted. This laboratory... |
44. Variable Fertilizer Nitrogen Application Based on the Delta Yield Index- A Field StudyA quick review of the both the scientific and popular literature indicates that many different approaches have been suggested for the prediction of variable fertilizer N applications in the field. In previous meetings of this conference we have presented the general outline and approach taken for our site-specific crop management project in Ontario. Briefly, historical data sets of grain corn response trials to fertilizer N (encompassing some 300 site-years worth of data) indicated that most yi... |
45. Yield of Sugar Beet, Soybean,Corn, Field Bean and Wheat as affected by Lime Applications on High Soil pHLime from sugar beet processing plants has been stockpiled for 100 years. Environmental regulations and limited storage space provide an impetus for the removal of the material. Land application on alkaline soils is one alternative for disposal of this material. This study was undertaken to evaluate the effect of applying sugar beet processing lime on crop production on these soils. Studies were conducted at seven sites representing four alkaline soil series in Michigan. Lime was applied at rate... |