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Herbivory And Eutrophication Mediate Grassland Plant Nutrient Responses Across A Global Climatic Gradient, T. Michael Anderson, Daniel M. Griffith, James B. Grace, Eric M. Lind, Peter B. Adler, Lori A. Biederman, Dana M. Blumenthal, Pedro Daleo, Jennifer Firn, Nicole Hagenah, W. Stanley Harpole, Andrew S. Macdougall, Rebecca L. Mcculley, Suzanne M. Prober, Anita C. Risch, Mahesh Sankaran, Martin Schütz, Eric W. Seabloom, Carly J. Stevens, Lauren L. Sullivan, Peter D. Wragg, Elizabeth T. Borer

Plant and Soil Sciences Faculty Publications

Plant stoichiometry, the relative concentration of elements, is a key regulator of ecosystem functioning and is also being altered by human activities. In this paper we sought to understand the global drivers of plant stoichiometry and compare the relative contribution of climatic vs. anthropogenic effects. We addressed this goal by measuring plant elemental (C, N, P and K) responses to eutrophication and vertebrate herbivore exclusion at eighteen sites on six continents. Across sites, climate and atmospheric N deposition emerged as strong predictors of plot‐level tissue nutrients, mediated by biomass and plant chemistry. Within sites, fertilization increased total plant nutrient pools, …

Evaluating P And K Fertilizer Prescriptions From Site-Specific Technologies, John H. Grove, E. M. Pena-Yewtukhiw

Soil Science News and Views

Developing a field's fertilizer prescription as a part of a site-specific nutrient management plan can be one of the more costly tasks undertaken. Those costs are traditionally associated with gathering of a number of plant and/or soil samples, their testing, as well as acquiring and applying amendments. Soil sample analysis is particularly important for traditional phosphorus (P), potassium (K) and soil acidity (pH) management. Soil sampling requires skill and time, time that may be in short supply when crop harvest is to be soon followed by establishment of a succeeding crop. Soil test results are not always timely, further delaying …

Effect Of Avail® Polymer Applied To Phosphorus Fertilizers On Dry Matter Production And P Uptake Of Fescue At Princeton, Ky, Lloyd W. Murdock, John James Olson, Gene Olson

Soil Science News and Views

A study was conducted near Princeton, KY to determine if a polymer (AVAIL^®) applied to diammonium phosphate (DAP, 18- 46-0) and mono ammonium phosphate (MAP, 11-52-0) would increase (P) phosphorus use efficiency in fescue production on a low P testing soil, when compared to an untreated phosphate fertilizer. AVAIL^® (Specialty Fertilizer Products, Belton, MO) is presently being sold in Kentucky as a product to improve phosphorus fertilizer efficiency.

The Effect Of Rate And Source Of Potassium Fertilizer On Cured Leaf Yield Of Burley Tobacco And Leaf Content And Soil Test Levels Of Potassium And Magnesium, Kenneth L. Wells, James E. Dollarhide, Mark Reese

Soil Science News and Views

In response to questions being asked by tobacco growers about the effectiveness of sulfate of potash magnesia (SPM; 21% K₂O and 11% Mg) as coinpared to sulfate of potash (SP; 50% K₂O), field studies were conducted during 1993-1994 to compare the two potassium (K) sources for use on burley tobacco. Any effect of SPM on yield of tobacco should be due to Mg since the only difference between the two sources in kind of nutrient contained is the presence of magnesium (Mg) in SPM. To compare the two K sources, we selected field sites low enough …

Managing Soil Content Of Nitrate Nitrogen, Kenneth L. Wells

Soil Science News and Views

The concerns about leaching of fertilizer nitrogen (N} into groundwater which were raised in the late 1960's were largely silenced during the 1970's as our agricultural economy was massively expanded. But since the early 80's they have been raised again to the point that national legislation (the Clean Water Act) was put into place to bring purity of the nation's water supplies into compliance with EPA-established standards. Beyond the apprehension largely about nitrate (NO₃) levels in groundwater, the groundwater issue today also includes concerns about pesticides. At the current time, the public is apprehensive about drinking water and …

Fertilizer Value Of Cattle Dunghills In A Pasture Field, Kenneth L. Wells, Steve D. Davis

Soil Science News and Views

There were nearly 2.5 million cattle and calves in Kentucky in 1988. Most of these were maintained under pastureland conditions. Nutrients taken up by pasture plants, consumed by cattle, and re-cycled back onto fields by fecal and urine excretions can be a major source of nutrients for maintaining pastureland productivity. In order to estimate the value of this under grazing conditions, observations were made on a pasture field in Casey County, Kentucky, following stocking of the field with cattle.

How Much Fertilizer Ls Needed For Corn?, Kenneth L. Wells, Keenan Turner

Soil Science News and Views

Corn producers are faced each year with the decision of how much money to invest in fertilizer for use on their crop. Differing philosophies used by those who make fertilizer recommendations often leave the grower bewildered as to what is best to do. It is not unusual for a producer to be told by his agricultural extension agent that he doesn't need any phosphate and potash on fields which test high in these nutrients while other sources may recommend fertilizer use. The philosophy behind the zero P-K recommendation made by extension agents in such cases is based on University of …

Using Residual Soil Fertility Effectively, Grant W. Thomas

Soil Science News and Views

During the past 30 years, the use of commercial fertilizer in Kentucky has resulted in increases in the levels of phosphorus and potassium in soils. As might be expected, the soil test levels are higher with tobacco than with any other crop. but all soils for all crops show increases in fertility levels. Comparisons between 1975 and 1985 (the latest year available) show the proportion of samples sent to the University of Kentucky that are medium or high in soil test phosphorus has increased considerably. Even more striking is the decrease in very low values of phosphorus.

Basic Fertilizer Facts, Monroe Rasnake

Soil Science News and Views

The "foods" used by green plants for growth and life functions are referred to as nutrients or fertilizer elements. There are 16 nutrients required for plant growth and development (See Table l). Although carbon, hydrogen, and oxygen are found in plants in the greatest quantities. they are obtained by plants from air (carbon dioxide) and water rather than from fertilizers or the soil. Of the nutrients provided by the soil or from fertilizers. those required in large amounts are called PRIMARY nutrients. Those required in smaller amounts are called SECONDARY nutrients, while those needed in very small amounts are called …

Timing N-P-K Fertilizer To Burley Tobacco, J. L. Sims

Soil Science News and Views

Recent changes in the Federal tobacco program (causing reduced income to growers} coupled with high fertilizer and other production costs have stimulated interest in fertilization practices that increase efficiency of tobacco production. Practices that increase yields and/or quality of cured leaf without increasing production costs should result in increased profit. Research conducted by Agronomists at the University of Kentucky indicates increased yield is possible through proper timing of fertilizer applications, split applications, and in some cases by banding applications.

Fertilizer Use Changes In The U.S. And Kentucky, Monroe Rasnake, Dan Kirkland

Soil Science News and Views

The use of inorganic fertilizers for crop production is perhaps the most successful educational program ever attempted by Land-Grant Colleges, the Tennessee Valley Authority and other agencies. Not many producers in the United States or the world will attempt to grow a crop without the use of fertilizers. In fact, some producers over fertilize and in recent years, the educational program has been aimed at teaching producers to limit fertilizer applications to what is actually needed based on soil tests and cropping conditions.

Fall Application Of Fertilizer, Kenneth L. Wells

Soil Science News and Views

Fall application of fertilizer offers the advantages of (1) getting a job done which can delay early spring planting, (2) being able to get over fields when they are usually drier and less likely to compact, and (3) more often getting a price break from fertilizer dealers. Several crop-related advantages also apply and are discussed below. In terms of nutrients which can be fall applied, phosphate and potash are well adapted, Both these nutrients react strongly enough with soil to resist overwinter leaching. and the requirements for next year's production can safely be applied in the fall. Fall use of …

Efficient Use Of Fertilizer On Tobacco, J. L. Sims

Soil Science News and Views

Recent increases in fertilizer prices and other productions costs have stimulated interest in ways to increase the efficiency of fertilizer use while maintaining or increasing yields and quality of tobacco. Growers currently spend about $250 per acre for fertilizer. Although this represents only 15 to 20 percent of the total cash costs per acre, it is one category of cash expenses that can be decreased.

Using Urea Nitrogen As A Fertilizer, Kenneth L. Wells

Soil Science News and Views

Solid granular or prilled urea (45-46% N) has become widely available in Kentucky, as has 28% nitrogen solution (UAN solution) which is half urea and half ammonium nitrate. When applied to a field, urea is transformed to ammonium N soon after application. The rate of transformation is greatly increased by urease, the enzyme found to varying degrees in soil and on plants and plant residues. Due to the chemical reactions involved as urea nitrogen undergoes transformation, there is some degree of likelihood for volatilization loss of some N. Whether such a loss will occur, and how much N will be …

Developing A Fertilizer Program For Tobacco, J. L. Sims

Soil Science News and Views

Use of adequate amounts of required fertilizer nutrients are necessary to increase both yield and quality of tobacco if they are lacking in a soil. However, to insure maximum profits from the tobacco crop, careful consideration must be given to fertilizer management (kinds, rates, and methods and times of fertilizer application), the chemical and physical characteristics of the soil, and the crops grown in rotation with tobacco. To develop a profitable fertilization program for tobacco requires thoughtful planning on the part of the grower. Late summer and early fall is a good time to make these plans for the future.

Weed And Feed, William W. Witt, Harold B. Rice

Soil Science News and Views

Fertilizer and herbicide combinations are often applied prior to planting, at planting, or after crop emergence, a procedure sometimes called "weed and feed". The opportunities for utilizing this system are numerous with the major advantage being saving an extra trip across the field. In order for the system to work, it must ensure that both fertilizer and herbicide are present when needed. When both the crop plant and weedy plant are at growth stages which allow for compatible applications with a single treatment, this can be highly successful. Conversely, when these two plant systems are not at compatible growth stages, …

Use Of Urea For Crop Production In Kentucky, Wilbur W. Frye

Soil Science News and Views

Current trends indicate that urea will become the major source of solid and liquid N fertilizer in the future. Although urea has several advantages over other N fertilizers, especially in manufacturing, transporting, and marketing, there are some potential agronomic problems that farmers should keep in mind when using urea.

Anhydrous Ammonia Use For Corn, William O. Thom

Soil Science News and Views

Anhydrous ammonia is the most concentrated form of nitrogen fertilizer available to corn producers in many areas of Kentucky. It is a simple chemical compound made up of one part nitrogen and three parts hydrogen (NH₃), existing as a gas at normal outdoor temperatures. This makes it necessary to store and handle the material in closed containers under pressure. The product contains 82% nitrogen, making it one of the highest analysis and most economical fertilizers available for corn production.

Current Research On Band Application Of Fertilizer To Burley Tobacco, J. L. Sims

Soil Science News and Views

Present Status: Generally, past research conducted in the United States has shown that only one-half to two-thirds as much fertilizer is required to produce maximum crop yields when the fertilizer is properly banded as when it is broadcast. However, the magnitude of plant response to banding compared to broadcast applications varies widely with soil nutrient levels, soil temperature, soil pH, and the mobility of the nutrient being applied. Greatest benefits from banding result from (a) applications to soils having low or very-low soil test levels of the nutrient in question, (b) applications to crops grown in cool climates, (3) applications …

Effect Of Fertilizer Salts On Crop Production, V. P. Evangelou

Soil Science News and Views

Soil consists largely of mineral and organic matter, air, and water. Plants obtain nutrients from mineral and organic matter, oxygen from air, and they use water as a carrier of nutrients from the soil into the root and to the above ground portion of plants.

Since soil water functions as a carrier of nutrients from solid fractions of soil into and through plants, it plays a very important role in plant nutrition. Because of this importance, correct chemical balance of the soil solution is necessary for best crop performance. This means that pH of the solution should be in the …

Energy Conservation In Corn Production, Wilbur W. Frye

Soil Science News and Views

On-farm production of food and fiber uses about 3% of the annual U.S. energy consumption. About one-third of this energy is directly from fossil fuels used in farm tractors and trucks and for crop drying, while about one-fourth is used in manufacturing and transporting fertilizers. Tillage and N fertilizers are the two largest uses of energy in non-irrigated product ion of crops which are not dried artificially. Thus, the greatest effects of energy conservation can be achieved in these two areas.

Band Vs. Broadcast Application Of Fertilizer, Kenneth L. Wells

Soil Science News and Views

Current fertilizer prices coupled with other increased production costs have renewed interest in band applications of fertilizer as a means of lowering fertilizer costs while maintaining crop yields. Fortunately, much basic soil fertilizer research has been conducted over the years which provides an understanding of the relative merits of band and broadcast placement. The following discussion outlines the basic considerations involved in deciding which of these two placement methods may be more economically useful for specific crop production systems. To better understand these considerations, certain principles related to adding fertilizer to the soil should be kept in mind. These are …

Fertilizing Soybeans, Monroe Rasnake

Soil Science News and Views

Soybeans need a fertile soil with a pH of about 6.4 for maximum production. This condition is best attained through a regular soil testing and fertilization program. A fertility program based on fertilizer and lime. use as determined by soil testing is more economical and more effective than applying large amounts of fertilizer at planting. Soil testing is the key.

Fertilizer Recommendations, William O. Thom

Soil Science News and Views

Fertilizer recommendations are interpreted from a soil test value. The interpretations are based on field research that compares crop yield to soil test levels and the amount of fertilizer applied. These field studies provide data to compare relative yield of a crop for a measured soil test value and fertilizer recommendations are then calibrated to these soil test values.

Delayed Nitrogen Applications On Corn, Grant W. Thomas

Soil Science News and Views

A method of fertilizer application that was standard practice 30 to 50 years ago has become important once again, and for the same reason. When nitrogen fertilizer was expensive and corn was cheap, it was considered prudent to save back some of the nitrogen fertilizer and apply it when the corn was "knee-high." This was thought to be safer because some of the nitrogen added at planting might be lost before the corn was big enough to take advantage of it. The increasing cost of nitrogen fertilizer has made efficient use of this product important again.