Plant Sciences Commons^™

Nitrapyrin (N-Serve) With Anhydrous Ammonia At/Near Corn Planting, John H. Grove

Agronomy Notes

Higher prices for energy are driving corn fertilizer nitrogen (N) prices higher as well. This increases interest in alternative management practices and products that optimize corn’s N nutrition, but maintain grower profit. Alternatives permitting fertilizer N rate reductions include: a) changes in N application timing and placement; b) using alternative sources of N (ex. poultry litter) to meet part of corn’s N need; and c) using fertilizer N additives that improve N use efficiency by inhibiting one or more N loss processes in the soil N cycle (biological N transformations).

2002-2003 Kentucky Canola Variety Performance Test, Greg Schwab, Lloyd W. Murdock, James H. Herbek, Chad Lee, David Van Sanford

Agronomy Notes

Winter canola is a crop that is well suited for Kentucky’s climate and crop rotation, but production peaked at 20,000 acres in 1989and has since declined mainly due to winter hardiness concerns. Changes in the 2002 farm bill have once again caused farmers to consider converting some of their wheat acreage to canola production. For the past several years, plant breeders have been working to improve canola’s winter hardiness and have released several varieties that seem to be better suited for Kentucky’s variable winters than the varieties grown in the late 1980s. A study was initiated in the fall of …

Stripping Burley Tobacco Into Grades, Gary K. Palmer

Agronomy Notes

Stripping burley tobacco into different grades has been a controversial topic for many years. The one-price years in the mid to late 80’s provided no incentive to the producer to strip into the appropriate grades. However, with the advent of contracting in the year 2000, many companies are suggesting four grades but still get a high percentage of three-grade tobacco. Tobacco companies can utilize a small percentage of mixed stripped tobacco, but the handling characteristics of the four stalk positions differ substantially during processing. As the companies make their blends, they look for specific characteristics that differ from grade to …

Phosphorus Soil Test Change Following The Addition Of Phosphorus Fertilizer To 16 Kentucky Soils, William O. Thom, James E. Dollarhide

Agronomy Notes

When applying phosphorus to soils it is important to know how much the soil test P changes with the addition of various rates. Soils are different in how they respond to varying rates of application, and only limited information is available for Kentucky soils.

“Burn Down” Management Of Winter Cereal Cover Crops For No-Tillage Burley Tobacco Production, Robert C. Pearce, David C. Ditsch, Jack M. Zeleznik, Wade Turner

Agronomy Notes

Recent developments in the design of no-till transplanters and significant improvements in weed control have made no-till tobacco production a feasible option for burley tobacco growers. No-till production reduces soil erosion when tobacco is grown on sloping land. This helps maintain the long term productivity of the soil and may provide the grower with more options for crop rotation, by allowing sloping land to be utilized for tobacco production.

Zinc Fertilizer Rates And Mehlich Iii Soil Test Levels For Corn, Lloyd W. Murdock, Paula L. Howe

Agronomy Notes

Zinc (Zn) is the micronutrient most often deficient for corn in Kentucky. This problem occurs every year but is more commonly seen in years with a cool, wet spring. Although the environment, soil type and past erosion each have an effect, the most important factors controlling plant available Zn are the soil pH, extractable soil phosphorus (P) and extractable soil Zn. While the amount of Zn in the plant increases as the available soil Zn increases, increasing levels of soil P and pH are strongly associated with reduced levels of Zn in the plant.

Effect Of Seed Pellet Modification On Spiral Root Formation Of Tobacco Seedlings, L. V. Caruso, Robert C. Pearce, B. Gilkinson, Lowell P. Bush

Agronomy Notes

Tobacco seeds are often pelleted to facilitate precision seeding into float trays. Pelleting consists of the application of solid particles, such as clay, to seeds with a binder in a coating pan or tumbling drum to form spherically shaped dispersal units. One of the several advantages of pelleting is to provide seeds with a vastly enlarged bulk size to ensure proper placement of the seed at the surface of the growing medium.

Root Growth And Development Of Float Tobacco Transplants Before And After Transplanting, L. V. Caruso, Robert C. Pearce, Lowell P. Bush

Agronomy Notes

In the production of float tobacco transplants, the seedling produces at least two different kinds of roots. The “media” roots are those that grow in the soilless medium within the float tray cell. They have a normal branched appearance similar to roots produced on soil-bed grown transplants. The “water” roots grow through the soilless medium in tray cells and into the nutrient solution below the float tray. They tend to be very fragile and less branched than roots growing in the soilless medium. In removal of seedlings from tray cells during transplanting, “water” roots are usually badly damaged or destroyed, …

Escherichia Coli Pathogen O157:H7 Does Not Survive Longer In Soil Than A Nonpathogenic Fecal Coliform, D. N. Mubiru, Mark S. Coyne, John H. Grove

Agronomy Notes

Survival rates for individual types of fecal organisms are quite different. Although some pathogens may persist as long as 5 years in soil, most fecal pathogens from human and animal waste usually die very quickly. Two to three months is sufficient in most cases to reduce pathogens to negligible numbers once they have been excreted or land-applied in animal wastes.

It is expensive and time- consuming to test for individual pathogens. Consequently, nonpathogenic fecal indicator bacteria, which are easily and inexpensively detected, are often used to study pathogen survival in soil and water. Current methods for rapidly detecting fecal indicator …

The Effect Of Drying Soil Samples On Soil Test Potassium Values, Kenneth L. Wells, James E. Dollarhide

Agronomy Notes

Extreme temporal and spatial variability of soil test potassium values (STK) was measured on small plots (12-ft x 40-ft) being used for a STK correlation and calibration study on a Crider soil in Larue County, Kentucky. Twelve periodic samplings of the 20 small plots in this study over a period of 18 months showed as much as two-fold temporal differences in STK within individual plots, many of which had received no potassium (K) fertilizer during the study. Spatial variability of STK also varied as much as two-fold among the individual small plots at any given sampling time for similar treatments. …

Trends In Alfalfa Production And The Beef And Dairy Industries In Kentucky During 1989-98, Dennis Hancock, Michael Collins

Agronomy Notes

On suitable soils, alfalfa produces the highest yield of nutrients possible from a perennial forage crop. However, high production costs and restrictive soil requirements have limited the production of alfalfa in Kentucky. High producing dairy cows respond well to premium quality forage, so alfalfa is a preferred forage crop in dairy production. Thus, alfalfa production is primarily contingent on the producer’s method of marketing the crop.

Comparison Of Weed Management Strategies With Roundup Ready® Corn, J. A. Ferrell, William W. Witt

Agronomy Notes

Corn weed management during the past several years in Kentucky has centered around two herbicide families, the chloroacetamides (Dual, Frontier, Harness, Micro-Tech, Surpass) and the s-triazines (AAtrex, Bladex, Princep). These products have been used widely because they offer acceptable, full season control of many common warm season annual weeds at a reasonable price. This combination has been so popular that several premixtures that contain these types of herbicides (Bicep II, Bullet, Guardsman, Harness Xtra, Surpass 100, FulTime) are used commonly used in Kentucky. The key to this efficacious and economic program is atrazine because it controls most annual broadleaf …

Small Scale Temporal And Spatial Variability Of Potassium Soil Test Values On A Crider Soil, Kenneth L. Wells, James E. Dollarhide, Frank J. Sikora

Agronomy Notes

An on-farm, small plot study conducted in 1996, on a Crider soil in Larue County, Kentucky, resulted in unanticipated wide variability of soil test potassium (STK) values between spring and fall sampling. Because of this, the small plots were sampled monthly over a period of time with the objective of determining if such variability in STK values was real.

Aphanomyces-Resistant Alfalfa: A Solution To A Common Problem In Spring Seedings, Paul C. Vincelli, Jimmy C. Henning, Tim Hendrick, Gerald D. Brown, L. J. Osborne, Beth Prewitt, Val Shields, Don Sorrell, Kim Strohmeier, Ray Tackett, Joe Wyles

Agronomy Notes

For several decades, farmers have experienced a common stand-establishment disease syndrome when spring-seeded alfalfa was followed by extended periods of wet weather. Seedlings affected by this syndrome exhibit severe stunting as well as yellowing and reddening of seed leaves (cotyledons), but they do not wilt or collapse, as they might from a damping-off disease. Commonly, the problem affects most or all of the field.

Based on research that began in the 1980's, we suspected that a fungus called Aphanomyces euteiches (hereafter simply called Aphanomyces) was responsible. This root-rot fungus can be found in the majority of alfalfa fields we …

Common Pokeweed Management In Corn And Soybeans With A Conservation Tillage Cultivator And Herbicides, Jonathan D. Green, William W. Witt

Agronomy Notes

Common pokeweed (Phytolacca americana L.) is a warm-season perennial that grows well in nondisturbed areas such as fence rows and woodland borders. In recent years it has begun spreading to com and soybean fields where no-tillage practices are used. The deep taproot that is characteristic of common pokeweed, makes this weed difficult to manage, particularly in no-till plantings. The green leaves, fleshy stems, and purple berries of common pokeweed can inhibit the harvesting process and lead to discounts at the elevator for high moisture and stained seed.

The equipment industry has developed cultivators with large sweeps capable of operating …

Do Cover Crop Residue And No-Till Increase Poultry Litter Runoff?, M. A. Cooprider, Mark S. Coyne

Agronomy Notes

Manure and litter produced during broiler production are an environmental issue in Kentucky. The most common and practical disposal method is to apply the poultry wastes to pasture and crop land. If the wastes are incorporated by tillage immediately after application to crop land, nitrogen that might otherwise be lost by ammonia volatilization is conserved. However, incorporating wastes is not possible in no-till, which is a best management practice (BMP) used by 51% of Kentucky's farmers to control soil erosion. One question is whether surface application of poultry wastes onto no-till fields could increase fecal bacteria contamination of surrounding waterways …

Evaluation Of Soilless Media Used In Tobacco Float Systems, Robert C. Pearce, Jack M. Zeleznik

Agronomy Notes

A wide range of soilless media is currently available to tobacco growers utilizing the float system for transplant production. Most of the media are predominantly made up of peat moss with varying amounts of perlite, vermiculite,and coconut fibers (coir). One of the most difficult problems for growers has been inconsistency in the media from year to year. Because peat is a natural product, some year to year variability is unavoidable. However, many manufacturers of soilless media have procedures in place to ensure that the final product is as consistent as possible.

Field Evaluation Of Super Urea® For Production Of No-Till Corn, Kenneth L. Wells, James E. Dollarhide, H. E. Burkwhat

Agronomy Notes

Nitrification inhibitors and urease inhibitors have been commercially available to farmers for several years. Nitrification inhibitors are intended to minimize losses of nitrate nitrogen (NO₃-N) from soil due to leaching and denitrification, by slowing the activity of soil bacteria which convert ammonium nitrogen (NH₄-N) to the more easily lost NO₃-N. This has the potential to make NH₄-N or urea fertilizer sources of N more effective, particularly during late spring and early summer when soil and climatic conditions are usually more favorable for leaching or denitrification of NO₃-N. Urease inhibitors slow …

Effectiveness Of Tile Drainage On A Fragipan Soil In An Orchard Site, Gerald D. Brown, Dwight E. Wolfe, Lloyd W. Murdock

Agronomy Notes

Orchards require a well-drained soil in order for roots to have good aeration and to function properly. The soil is unsatisfactory for orchard purposes if the water table remains within six inches to a foot of the soil surface for a week after a heavy spring rain, or within three feet of the surface for several weeks after growth starts. Poor internal water drainage is a limiting factor for many sites. In Kentucky, many orchards are on soils with a fragipan which result in perched water tables near the surface during winter and spring months. Perched water tables exist above …

Early Maturing Varieties And Soybean Cyst Nematodes: Will This Marriage Work?, Colleen C. Steele, Larry J. Grabau

Agronomy Notes

Soybean cyst nematode (SCN) is widely distributed in Kentucky’s soybean growing areas. The use of SCN-resistant varieties has long been a recommended production practice for infested fields. However, continuous use of such varieties can result in a shift to a race of SCN which is able to vigorously attack previously resistant varieties. For this reason, many states recommend that producers periodically grow a crop of SCN-susceptible soybeans within a crop rotation when SCN populations are at minimal levels (causing less than a 5% loss in yield). The UK Plant Pathology Department recommends a four year rotation in SCN-infested fields [PPA3; …

Influence Of Topping And Harvest Management On The Evaluation Of Data From Burley Tobacco Variety Trials, Robert C. Pearce, Jim Calvert, Gary K. Palmer

Agronomy Notes

Tobacco producers are always interested in new tobacco varieties, and are continually searching for the "best" variety. Producers receive information about varieties from a number of sources including; research and extension publications, county extension agents, neighbors, farm supply workers, and seed producers. To help producers evaluate varieties, county agents in cooperation with tobacco specialists conduct many burley tobacco variety trials at the county level.

Potassium Soil Test Correlation And Calibration For Burley Tobacco Grown On An Allegheny Loam Soil, Kenneth L. Wells, James E. Dollarhide, Val Shields

Agronomy Notes

Burley tobacco removes large amounts of potassium (K) from soil. A 2,600 pound/A cured leaf crop removes around 200 lbs K/A/yr, with about 110 lbs of that in the leaf and 90 lbs in the stalk. Because of such a heavy soil demand for K, growers are always concerned that application of fertilizer K be sufficient for top production. The University of Kentucky's Soil Testing Laboratory (Division of Regulatory Services) provides a statewide soil testing service. The Mehlich-3 soil extractant is used by the UK lab, and soil test K values from use of this extractant (reported as lbs K/A) …

Can Denitrification Reduce No3 In Shallow Ground Water?, Mark S. Coyne, E. Montgomery, Grant W. Thomas

Agronomy Notes

Systematic sampling of springs, tiles, and wells in Kentucky, as part of a recent statewide program to assess agricultural impacts on water quality, showed that NO₃ concentrations in these shallow ground water sources varied tremendously. The NO₃ concentration could be correlated with flow rate; higher when ground water recharge flushed NO₃ from soil in winter and spring, and lower or non detectable in summer and fall when less NO₃ leaching occurred. Depending on the season, NO₃ concentrations ranged from < 1 to > 10 ppm NO₃-N in almost half of the sites. For example, the water in …

Establishment Of Kura And Red Clover On A Soil And Mine Spoil, David C. Ditsch, Michael Collins, Norman L. Taylor

Agronomy Notes

Numerous benefits result from the addition of forage legumes to livestock diets. Superior nutritive value and intake of legume forage generally increase individual animal productivity compared with grass alone. This is particularly important with tall fescue where dilution of the diet with legumes can partially alleviate toxicosis associated with endophyte fungus infected fescue (Acremonium coenophialum). Unfortunately, short-term persistence of most legumes requires periodic reestablishment, adding to the cost of forage production and complicating pasture management.

Nitrogen Source Effects On The Growth And Development Of Burley Tobacco Transplants In The Float System, Robert C. Pearce, Gary K. Palmer

Agronomy Notes

During the spring of 1996, many tobacco producers used a water soluble 20-10-20 fertilizer in their float beds, only to have to throw out the stunted sickly plants that resulted, and start over. The fertilizer that caused the problems turned out to have 100% of the nitrogen (N) as urea-N. It was hypothesized that the poor growth was related to with the conversion of the urea-N to other forms of N. There have been numerous other cases where producers using fertilizers high in urea-N or ammonium-N (NH4-N) have had problems with stunted plant growth. Further study of nitrogen transformations is …

Particle Size And Temperature Affect Fecal Bacteria Survival In Sediment, Mark S. Coyne, J. M. Howell, P. L. Cornelius

Agronomy Notes

When cattle have direct access to streams, fecal bacteria concentrations in stream sediments increase. If these bacteria persist, and if the sediments are resuspended, fecal bacteria may also appear in surrounding water for extended periods. Why do fecal bacteria persist, since dry conditions, high acidity or alkalinity, sunlight, competition from native microbes, and extreme temperatures all diminish their populations in soil? The effects of these environmental factors are much reduced in sediment. Water protects fecal bacteria from desiccation and ultraviolet light. High temperatures can promote their regrowth in wet environments. Fecal bacteria also survive on fine-sized sediments in streams because …

Differential Black Walnut Growth On A Recommended Soil Map Unit: Investigation Of Related Soil Chemical And Physical Properties, David C. Ditsch, Jeff Stringer, D. Mcintosh

Agronomy Notes

Black walnut (Juglans nigra L.) is one of the best known and most valuable trees in Kentucky. However, due to its high value, the species has been aggressively harvested from natural stands, creating a limited supply of quality black walnut trees. Many landowners recognize this as an investment opportunity and have placed small tracts of unused land into black walnut production.

Effect Of Boron Fertilization On Alfalfa, Monroe Rasnake, Garry D. Lacefield

Agronomy Notes

The need for boron (B) fertilization of alfalfa has been known for many years. An annual application of 1.5 to 2.0 ·pounds of elemental B per acre on alfalfa has been the general recommendation of the University of Kentucky's, Department of Agronomy for at least 20 years. Most states surrounding Kentucky have similar recommendations; however, some indicate that B needs to be applied only once every two years. There has been very little recent research to verify the need for B on alfalfa.

Als Resistant Smooth Pigweed In Western Kentucky, R. E. Schmenk, Michael Barrett, William W. Witt

Agronomy Notes

Pigweeds The pigweed, or Amaranthus, family contains some of the most commonly occurring weeds of midwest agriculture. Species from this family that occur in Kentucky include smooth pigweed (Amaranthus hybridus, most common), tumble pigweed, prostrate pigweed, spiny amaranth,Palmer amaranth,common waterhemp, and tall waterhemp. Research has shown that some pigweed species respond differently to various herbicides, therefore, proper identification is necessary to achieve acceptable control. Pigweed identification in early stages of seedling growth can be difficult because the distinguishing physical characteristics do not appear until plants are mature or have produced seed. Also, some pigweed species may cross-pollinate to …

Preliminary Maturity Group Ii Soybean Variety Trials, Colleen C. Steele, Larry J. Grabau

Agronomy Notes

On-farm research with early maturing soybean varieties in Kentucky in both 1993 and 1994 has indicated that Maturity Group (MG) II varieties yield competitively with our traditional MG IV varieties. In those tests, four MG II varieties were compared with a single, high yielding MG IV variety (Asgrow A4715) over a range of planting dates on a total of 27 farms across both years. Asgrow A4715 averaged 43 bu/A, while the best MG II variety (Jack) averaged 39 bu/A. Such on-farm strip tests are valuable for comparing varieties under true production conditions. However, strip tests can effectively compare only a …