Agronomy and Crop Sciences Commons^™

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.

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 …

Manipulation Of High Spatial Resolution Aircraft Remote Sensing Data For Use In Site-Specific Farming, Gabriel B. Senay, Andrew D. Ward, John G. Lyon, Norman R. Fausey, Sue E. Nokes

Biosystems and Agricultural Engineering Faculty Publications

Three spatial data sets consisting of high spatial resolution (1 m) remote sensing images acquired in 12 spectral bands, an on-the-go yield map, and a Digital Elevation Model were co-registered and evaluated for spatial variability studies in a Geographic Information Systems environment. Separate on-the-go yield maps were developed for 3, 5, and 12 statistically significant mean yield classes. For each yield class, the corresponding mean spectral and elevation data were extracted. The relationship between mean spectral and yield data was strongly linear (r = 0.99). Also, a strong linear relationship between mean yield and elevation data (r = 0.92) was …

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) …

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; …

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 …

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.

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 …

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 …

Influence Of Dibble Shape And Depth On The Germination And Seedling Establishment Of Burley Tobacco In The Float System, Robert C. Pearce, M. Cui, Lowell P. Bush

Agronomy Notes

Direct seeding of pelleted tobacco seed into the float transplant system has become common in Kentucky. Direct seeding reduces labor compared to the plug and transfer method, but it increases the risk involved and requires more management by the producer. Uniform germination, and ultimately a high percentage of useable transplants are the keys to success with direct seeding.

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 his reason, many states have long recommended that producers periodically grow a crop of SCN-susceptible soybeans within a crop rotation when SCN populations are too low to cause yield reductions. In Kentucky, the UK Plant Pathology Department recommends a four year rotation in SCN-infested fields [PPA3; "Wanted: …

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 …

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.

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 …

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.

Evaluation Of The Crop Growth Component Of The Root Zone Water Quality Model For Corn In Ohio, Sue E. Nokes, Feliks M. Landa, Jon D. Hanson

Biosystems and Agricultural Engineering Faculty Publications

The Root Zone Water Quality Model (RZWQM) is a computer model developed to simulate water, chemical, and biological processes in the root zone of agricultural management systems. As of this writing RZWQM is in the beta-testing phase of development. This article reports on a parameterization and evaluation study performed in Ohio on field corn for the crop growth component of RZWQM. The generic crop growth model in RZWQM had not previously been parameterized or tested on field corn. This article reports the results of such a study. One year of data was used to calibrate RZWQM, and two additional years …

Cultivar Selection, Seed Stratification And Surface Cover Effects On Switchgrass Establishment On Coal Mine Spoil, David C. Ditsch, Michael Collins, T. P. Demond, Timothy D. Phillips

Agronomy Notes

Surface mining in the Appalachian region of Kentucky often involves steep slopes and spoil limitations for revegetation not encountered in other reclamation situations. Herbaceous species (mono cultures or mixtures) provide quick cover required in revegetation of mined land for control of erosion as well as promoting soil development, improving wildlife habitat, and livestock production through hay and pasture production as well as a potential use as renewable energy for cofiring with high sulfur coal. However, due to the many challenging chemical and physical characteristics of mine spoil, selection of adaptable herbaceous species should be carefully considered.

Variability In Soil Testing, Kenneth L. Wells, Vern Case

Agronomy Notes

Many factors can influence the accuracy of soil test results, ranging from field sampling technique, sample preparation, and quality control in the laboratory. Many people expect that if a field is sampled more than once, the soil test results should be identical. When identical results are not obtained from successive sampling, much concern about soil test reliability is of ten expressed.

We have analyzed soil test results from some controlled field experimental sites which help provide an understanding of variability which can occur naturally in the field, how various field sampling techniques influence soil test readings obtained, and how laboratories …

An Evaluation Of Twelve Maturity Group Ii Soybean Varieties At Lexington, Kentucky, Larry J. Grabau, Colleen C. Steele

Agronomy Notes

In both 1993 and 1994, the Kentucky Soybean Promotion Board funded an on-farm test of a small set of Maturity Group (MG) II varieties. Those studies showed that several MG II varieties were competitive with a high-yielding MG IV variety. However, other MG II varieties did not perform as well in those tests, indicating that variety selection is an important management consideration if this early maturing cropping system is to be successful in Kentucky soybean producers' fields. MG II varieties used in past University of Kentucky tests have been chosen based on their performance in university variety trials where such …

Kentucky County Soil Sample Summaries, Vern Case

Agronomy Notes

The UK Soil Testing Labs at Lexington and Princeton, KY test 50,000 to 60,000 soil samples each year. Samples are submitted through the county Extension offices for agronomic (Ag) crops, commercial horticulture, home garden/lawn, greenhouse media, and surface mining reclamation. The Mehlich III extractant (M-3) is used for routine determination of phosphorus (P), potassium (K),calcium (Ca), magnesium (Mg) and zinc (Zn). Amounts of these nutrients extracted are determined by either ICP methodology or by color for P and atomic absorption for K, Ca, Mg and Zn. Soil pH is determined on a 1:1 soil:water mix using appropriate electrodes and pH …

Planting Dates For Early Maturing Soybean, M. V. Kane, Colleen C. Steele, Larry J. Grabau

Agronomy Notes

Early maturing soybean cropping systems have been gaining in popularity with producers across the southeastern US, as well as in Kentucky. To our south, some producers in Texas, Arkansas, and Mississippi are using varieties that are two or three Maturity Groups (MG) earlier than those traditionally grown. The main intent in those states has been to avoid late summer drought by using early maturing varieties coupled with early planting. Previous Kentucky research in this area has also emphasized early planting(late April). However, a number of Kentucky growers have had good success using later planting dates for early maturing varieties, particularly …

Growth Of Early Maturing Soybean, M. V. Kane, Colleen C. Steele, Larry J. Grabau

Agronomy Notes

Production of early maturing soybean varieties has grown in popularity across the southeastern US in recent years. Many growers in Mississippi, Arkansas, and Texas have seen this system as a way to avoid late season drought. However, several Kentucky growers have had good success with the use of Maturity Group (MG) II soybeans in the recent seasons which had generally good rainfall patterns. Some growers are glad to get competitive yields from MGII soybean while gaining the opportunity to harvest some of their soybean acreage before corn is ready to harvest.

Sodium In Pasture Species And Grazing Livestock, C. T. Dougherty, Kenneth L. Wells, G. E. Mitchell

Agronomy Notes

Concern among some dairy nutritionists has recently been expressed that "high potassium" content of hay and silage is reducing milk production in some high-producing dairy herds. Alfalfa and grass hay and com and grass silage, which have been heavily fertilized, are the objects of this concern. The nutritional question being considered in this article is whether an animal diet excessively high in potassium (1

Crude Protein, And Other Chemical Constituents Of Corn Hybrids Evaluated In The 1994 Kentucky Hybrid Corn Performance Tests, C. G. Poneleit, K. O. Evans, Michael Collins

Agronomy Notes

Grain samples have been collected each year since 1990 from three locations of the Kentucky Hybrid Corn Performance Test and analyzed for crude protein (CP). The objective was to provide an unbiased comparative evaluation of the CP concentration of com hybrids sold in Kentucky. The results indicate that while management and environment at each test location may have significant influences, CP does differ among hybrid genotypes. The feeding value of specific hybrid genotypes based on their protein concentration may have significant influence in diet formulation for non-ruminant animals due to the amount of supplement needed to properly balance the diet, …

Grain Quality Of Early Maturing Soybean Grown In Kentucky, M. V. Kane, Colleen C. Steele, Larry J. Grabau, C. T. Mackown, David F. Hildebrand

Agronomy Notes

Interest in grain quality of US soybean has grown in recent years. For example, in 1990, there was much interest in "component pricing" of soybean grain, Under that plan, growers would be paid a price for their grain that reflected the value of the protein and oil it actually contained, rather than the common price paid to all growers, regardless of any variation in protein and oil content. However, the soybean processing industry is evidently not excited about the complexity of testing individual lots for protein and oil and keeping track of pricing structures depending on those results. As a …

Lime Source And Rate Effects On Corn Production On An Acid Soil, Kenneth L. Wells, James E. Dollarhide, V. W. Case

Agronomy Notes

Quality of lime available for use in neutralizing soil acidity can be quite variable in Kentucky. This sometimes raises questions of which locally available source is most effective. Information about the quality of individual lime sources is necessary to make such determinations.

On-Farm Testing Of Early Maturing Soybean, Colleen C. Steele, Larry J. Grabau, N. Gift

Agronomy Notes

Maturity Group (MG) II soybean varieties have performed well in University of Kentucky tests over the past several years. Early planted (late April/early May) tests in the relatively dry years of l986 through 1989 showed MG II yields to exceed those of MG III or MG lV. Over the generally wetter years 1990 through 1993, MG III and lV yields were slightly better than those of MG II varieties. Across eight years of data, MG II yield averages were virtually identical to those of MG III and lV. Perhaps growers could plant a portion of their soybean acreage to MG …

An Evaluation Of Twelve Maturity Group Ii Soybean Varieties At Lexington, Kentucky, Larry J. Grabau, Colleen C. Steele

Agronomy Notes

In 1993, an on-farm study funded. by the Kentucky Soybean Promotion Board showed that the best Maturity Group (MG) II variety tested was quite competitive with the best available MG IV variety. However, other MG II varieties did not fare as well, indicating that careful variety selection will be essential for on-farm success with this MG II cropping system. MG II varieties used in past University of Kentucky tests have been chosen based on their performance in university variety trials where they are normally grown, for example, in Iowa, Illinois, Indiana, and Ohio. Such tests include relatively large numbers of …