Agronomy and Crop Sciences Commons^™

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.

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 …

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

Agronomy Notes

Maturity Group (MG) II soybean varieties have performed well in University of Kentucky tests over the past several years. Six tests from 1986 to 1989 showed MG II varieities to outyield MG I, III, or IV varieties. During those relatively dry years, MG II may have been able to better utilize limited soil moisture than did later maturing varieties. Across the years 1990 to 1993, four planting date tests showed continued strong performance by MG II' varieties, although MG III and IV varieties had slightly higher yield averages during those wetter years. In summary, over the last eight years of …

Crude Protein Of Hybrid Corn Varieties Evaluated In The Kentucky Hybrid Corn Performance Tests From 1990 To 1993, C. G. Poneleit, K. O. Evans, Michael Collins, Gary L. Cromwell

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. The objective was to provide an unbiased comparative evaluation of the crude protein content of corn hybrids sold in Kentucky. The results indicate that while management and environment at each test 1ocat i on may have significant influences, crude protein does differ among hybrid genotypes. The feeding value of specific hybrid genotypes based on their protein content may have significant influence in diet formulation for non-ruminant animals owing to the amount of supplement needed to properly …

Wetlands: Mechanisms For Treating Acid Mine Drainage, David C. Ditsch, Anastasios D. Karathanasis

Agronomy Notes

A great deal of attention has been given to wetlands in recent years. Research suggests that natural and/or constructed wetlands may play a valuable role in flood flow moderation, sediment retention and stabilization, and waste water treatment while providing habitat for game and nongame wildlife. Only within the last 10 years have wetlands received serious attention in the treatment of acid mine drainage (AMD).

1994 Kentucky Timothy Variety Test Report, L. M. Lauriault, Timothy D. Phillips, Jimmy C. Henning

Agronomy Notes

Timothy (Phleum pratense) is the fourth most widely sown cool-season perennial grass used in Kentucky for forage, ranking behind tall fescue, orchardgrass, and Kentucky bluegrass. It is a late-maturing bunchgrass that can be used for grazing but is mainly harvested as hay, particularly for horses. For hay production, timothy can be sown with alfalfa or red clover, while white clover or birdsfoot trefoil make good mixtures with timothy for grazing. Management is similar to that for other cool-season grasses. Harvesting at the mid- to late-boot stage is needed to assure good yields and high forage quality. Quality of …

1994 Kentucky Bluegrass Variety Test Report, L. M. Lauriault, A. J. Powell, Jimmy C. Henning, Paul B. Burrus Ii, Paul C. Vincelli, Timothy D. Phillips

Agronomy Notes

Kentucky bluegrass (Poapratensis) is the third most prominent cool-season grass used in Kentucky for forage, behind tall fescue and orchardgrass. As with all cool-season grasses, Kentucky bluegrass does best in cooler weather, becoming relatively non-productive in hot, dry conditions. It is a high quality, long-lived, rhizomatous grass that is used for both turf and forage. Compared to other cool-season grasses, Kentucky bluegrass is slower to germinate (2-3 weeks) and generally is lower in seedling vigor and herbage yield. Most recent varieties have been developed for turf use. Several have been used in horse pastures even though they were …

1993 Kentucky Bluegrass Variety Test Report, L. M. Lauriault, A. J. Powell, Timothy D. Phillips, Jimmy C. Henning

Agronomy Notes

Kentucky bluegrass (Poa pratensis) is the third most prominent cool-season grass used in Kentucky for, forage, behind tall fescue and orchardgrass. As with all cool-season grasses, Kentucky bluegrass does best in cooler weather, becoming dormant in hot, dry conditions. It is a high quality, long-lived, rhizomatous grass that is used for both turf and forage. Compared to other cool-season grasses, Kentucky bluegrass is slower to germinate (2-3 weeks) and generally is lower in seedling vigor and herbage yield. Most recent varieties of Kentucky bluegrass have been developed for turf use; therefore, primary emphasis has been placed on improving …

1993 Kentucky Timothy Variety Test Report, L. M. Lauriault, Timothy D. Phillips, Jimmy C. Henning

Agronomy Notes

Timothy (Phleum pratense) is the fourth most widely grown cool-season perennial grass used in Kentucky for forage, ranking behind tall fescue, orchardgrass, and Kentucky bluegrass. It is a late maturing bunchgrass that can be used for grazing but is mainly harvested as hay, particularly for horses. Management is similar to that for other cool season-grasses. Harvesting at the proper stage of maturity (mid- to late-boot) is needed to assure high forage quality; otherwise, quality of timothy declines more rapidly than other cool-season grasses as it overmatures. In Kentucky, timothy behaves like a short-lived perennial with stands lasting for …

Using Poultry Manure From Layers As A Supplemental Nitrogen Source For Corn, Lloyd W. Murdock, R. Darrell Simpson, Tim Gray

Agronomy Notes

The objectives of this study were to try to find an effective inorganic nitrogen (N) fertilizer rate to apply to a corn crop when poultry manure has been used on the field and to see if an N soil test at sidedress time could help predict the amount of N needed.

Growth, Yield, And Efficiency Of Potassium Fertilizer Use In Burley Tobacco Production, J. L. Sims, William O. Thom, Kenneth L. Wells, J. D. Clark

Agronomy Notes

For many crops, band placement of fertilizer offers agronomic, economic, and environmental advantages over commonly used preplant broadcast applications. Drill banding most of the nitrogen (N) fertilizer 12 inches to both sides of the row for tobacco shortly after transplanting greatly aIleviates manganese toxicity and other nutrient imbalances, improves early growth and yield, and offers increased efficiency of N use. Nitrogen fertilizers applied after transplanting are less likely to be leached during excess rainfall events that commonly occur in April and early May in Kentucky.

Effect Of Topping Time On Dark Tobacco Yield, Bill Maksymowicz

Agronomy Notes

When the terminal bud is removed from tobacco by topping, a number of changes are triggered in the plant: increased root growth, nicotine synthesis, improved drought tolerance, and leaf expansion and increased thickness. These changes are affected by topping time; generally there will be less crop response to topping as topping is delayed. The most important changes, from a producer's perspective, are continued leaf expansion and thickening, with a commensurate improvement in quality and increase in yield. Topping at the proper time of plant development is often difficult on a field scale since uneven crop growth, particularly when tobacco is …

Sucker Control Performance In Dark Tobacco, Bill Maksymowicz

Agronomy Notes

Poor sucker control adversely affects tobacco yield and quality. Suckers serve as a "sink" for nutrients and dry matter that otherwise would go to the expanding leaves intended for harvest, resulting in lower yields. Hand removal of large suckers can cause leaf damage, and failure to remove suckers may result in spoilage during the curing process, resulting in lowered quality. Use of chemical sucker control measures used in burley production can produce lower yields or W1desirable cured leaf color of dark tobacco. These studies were conducted to compare the effects of recommended sucker control practices for dark tobacco with systems …

A Survey Of The Content Of Some Heavy Metals In Soil And Corn Grain In The Pond And Lower Green River Bottoms, Kenneth L. Wells, Greg Henson, George Kelley

Agronomy Notes

Corn is intensively grown along the Green and Pond Rivers in McLean, Hopkins, and Webster Counties, Kentucky, representing a major source of income to producers in those areas. However, producers in McLean County have experienced poorer corn production than expected for many years. This has been observed more on the Pond River bottoms and the Green River bottoms below the confluence of the Pond than upstream on the Green above the Pond. Some producers have speculated that their poor production may be associated with chemical pollution from the Pond River and/or nearby industrial sources. On this basis, an assumption was …

Reduced Scepter Rates For Broadleaf Weed Control In Soybean, D. S. Jones, H. Lin, M. V. Kane, Larry J. Grabau

Agronomy Notes

Public agencies are placing greater scrutiny on herbicide applications by farmers. For example, the corn herbicide atrazine is now classified as a restricted use pesticide, with limits placed on allowable rates. While soybean growers may share some of this concern for the environment, rate reduction is more likely to be attractive for economic reasons. Some growers are already cutting back on herbicide rates. For example, Missouri data shows that the average application rates for soybean herbicides were only 75% of the labelled rate. While reduced rates might save growers money, and may be kinder to the environment, there is a …

Hybrid Variation For Yield, Crude Protein, Feed Value And Percent Lysine Of Corn Grown In The 1991 Kentucky Hybrid Corn Performance Test, C. G. Poneleit, K. O. Evans, Michael Collins, D. O. Liptrap

Agronomy Notes

These data are the results from the second year of protein analyses of corn hybrids grown at three locations in the Kentucky Hybrid Corn Performance Test. These analyses were supported. by a grant from the Kentucky Corn Growers Association.

Trends In Cropland Acreage And Fertilizer Use In Kentucky Since 1980, Kenneth L. Wells

Agronomy Notes

Cropland acreage and patterns of fertilizer use varied considerably during the period 1980-1991. Variation in cropland acreage is largely related to commodity prices, available markets, land ownership patterns, and government programs. Patterns of fertilizer use are affected by cropland acreage, the nature of the fertilizer supply industry in Kentucky, weather, and improved efficiency in use of time and labor by farmers. The situation in the early 1990's is different than it was in 1980, and the following discussion highlights changes that have taken place. Fertilizer use data are those reported by the University of Kentucky's Division of Regulatory Services in …

Growing Soybean Varieties From Multiple Maturity Groups Can Reduce Yearly Yield Volatility, Todd W. Pfeiffer

Agronomy Notes

In the Kentucky Soybean Performance Test program, varieties of maturity groups (MG) 3, 4 and 5 are tested to provide information on their relative yields. The difference in maturity between the earliest and the latest maturing variety in the test in any year is approximately 30 days. In general, although some regional differences appear, the long-term state-wide and within region yield of the different maturity groups (average yield of a 11 varieties in a maturity group) is equal (Table 1). As I've inspected results from the Kentucky Soybean Performance Tests for the last decade, it appeared that some of the …