Physical Sciences and Mathematics Commons^™

Hydrology And Sedimentology Of Dynamic Rill Networks Volume Ii: Hydrologic Model For Dynamic Rill Networks, Lindell E. Ormsbee, George E. Blandford, John S. Montgomery, Laura B. Terrell, Billy J. Barfield, Daniel E. Storm

KWRRI Research Reports

A comprehensive model has been developed for use in modeling the hydrologic response of rill network systems. The model, which is called HYMODRIN, is composed of both a hydrologic runoff component and a hydraulic channel routing component. The hydrologic component of the model uses a Green Ampt infiltration approach linked with a nonlinear reservoir runoff model. The channel routing component of the model is baaed on a finite element solution of the diffusion wave equations. In order to account for backwater effects the model employs a dual level iteration scheme.

The model may be used in either a stand alone …

Hydrology And Sedimentology Of Dynamic Rill Networks Volume I: Erosion Model For Dynamic Rill Networks, Daniel E. Storm, Billy J. Barfield, Lindell E. Ormsbee

KWRRI Research Reports

No abstract provided.

Modeling Mass Transport In Aquifers: The Distributed Source Problem, Sergio E. Serrano

KWRRI Research Reports

This report presents a new methodology to model the time and space evolution of groundwater variables in a system of aquifers when certain components of the model, such as the geohydrologic information, the boundary conditions, the magnitude and variability of the sources or physical parameters are uncertain and defined in stochastic terms. This facilitates a more realistic statistical representation of groundwater flow and groundwater pollution forecasting for either the saturated or the unsaturated zone. The method is based on applications of modern mathematics to the solution of the resulting stochastic transport equations. This procedure exhibits considerable advantages over the existing …

Urease Inhibitor Reduces Ammonia Loss From Surface-Applied Urea, Wilbur Frye, Lloyd W. Murdock, Robert L. Blevins

Soil Science News and Views

Urea is the world's leading N fertilizer, and its use continues to grow. In the USA, for example, the use of urea increased 50 fold from 1955 to 1986. During that same time, its use in Kentucky increased from 214 to more than 112,000 tons per year, which was 28% of the N used in Kentucky in 1986. The increasing popularity of urea is due to advantages over other N fertilizers in its manufacture and to its use in making most N solutions, another rapidly growing form of N fertilizer. Desirable qualities of urea include the highest N content of …

Effectiveness Of Two Lime Sources With Different Relative Neutralizing Values (Rnv), Greg Henson, Lloyd W. Murdock

Soil Science News and Views

Quality of agricultural lime (ground limestone) is an important factor in maintaining proper soil pH. The quality of lime is determined by its purity and fineness of grind. Purity is the amount of calcium and magnesium carbonate present in the limestone. Clay, silt, sand, organic matter, and other materials present in limestone rock dilute its purity. Since limestone is slowly soluble, it must be finely ground to be effective. The more finely ground the lime, the more rapidly it will dissolve in the soil.

Sulfur And Magnesium Trials With Wheat In West Kentucky, Monroe Rasnake

Soil Science News and Views

Interest in fertilizing wheat with sulfur and magnesium has increased recently in West Kentucky. This has been due primarily to positive test results in adjoining states and recommendations being made by some commercial people. Previous-testing in Kentucky has shown no response by wheat to sulfur, or to magnesium. However, in order to have current data on which to base recommendations, research plots were established in the fall of 1987 in Todd and Hopkins counties. They were repeated on different farms in 1988, making a total of 4 different sites studied.

Effectiveness Of Surface Application Of Phosphorus And Potassium On Yield Of No-Till Corn Grown On Soils Testing Low Or Medium Below A Depth Of 3 Inches, Grant W. Thomas

Soil Science News and Views

When crops are grown continuously under no-tillage or very minimum tillage, there is a tendency for phosphorus (P) and potassium (K) to become concentrated at or near the soil surface. This occurs when P and K fertilizers are broadcast on the surface and not mixed with the soil as would occur with plowing. The result is a stratification of P and K such that the surface few inches become very high in those nutrients, but soil test levels remain largely unaffected below that. The question is whether high yields of no-till crops can be obtained under these conditions.

Has The Nitrate-Nitrogen In Streams Draining Agricultural Watersheds In Kentucky Changed In The Last 18 Years?, Grant W. Thomas, Gerald R. Haszler, James D. Crutchfield

Soil Science News and Views

In 1971 and 1972, we sampled streams across Kentucky for nitrate-nitrogen (NO₃-N) during the high-water flow months of January through June. The results were variable and showed a dominant effect of geology and lesser effects of both time and land use on the results. Since that time, use of fertilizer nitrogen (N) has nearly doubled in Kentucky and, further, there is a high degree of concern among the public that NO₃-N from fertilizer use may be contaminating streams. The US Environmental Protection Agency has set a maximum of 10 ppm NO₃-N in water as …

The Effect Of Fall And Spring Tillage Of A Compacted Soil On Corn And Tobacco Yields, Kenneth L. Wells, Roy V. Catlett

Soil Science News and Views

Soil compaction is being diagnosed in increasing instances as the cause of poor crop performance in Kentucky. While the basic causes of compaction can usually be identified, it is much more difficult to prescribe techniques to solve the problem. Following identification of compacted soil as being the cause of poor corn growth in a field in Shelby County, Kentucky, a study was conducted to compare three tillage tools on production of corn and tobacco. The compacted zone was within the top 6-inch layer of soil.

Movement Of Triazine Herbicides In Conventional, Reduced Tillage, And No-Tillage Corn Production, William W. Witt, K. W. Sander

Soil Science News and Views

Herbicides are applied to over 90 percent of the corn acreage in Kentucky and triazine herbicides are used the most. Conservation tillage methods are often used to prevent soil erosion and to conserve soil water. However, as tillage is decreased the dependence on herbicides for weed control often increases. Minimizing herbicide movement from the application sites to non-target areas, such as ground and surface waters, is necessary to maintain optimum water quality.

Production Of No-Tillage Burley Tobacco, Jack M. Zeleznik, R. E. Phillips

Soil Science News and Views

In the early 1970's, researchers at the University of Kentucky produced burley tobacco by using no-tillage methods. These studies were abandoned a few years later due to poor growth, poor plant survival, and the lack of adequate weed control as the contributing factors. In 1984, the experimental production of no-tillage burley tobacco was reinitiated with the hopes that the newer herbicides would perform more effectively for no-tillage tobacco production. Burley producers could realize several potential advantages to no-tillage tobacco production if the yields produced by no-tillage were equal to or near those of conventional tillage. These potential advantages would include: …