Masters Theses

Date of Award


Degree Type


Degree Name

Master of Science



Major Professor

Horace C. Smith Jr.

Committee Members

W. L. Parks, M. E. Springer


In the humid regions of the world, bases are leached from soils and are replaced by acid forming elements such as hydrogen and aluminum, and the soils become acid in reaction« In order to maintain these soils at a high level of productivity, lime must be added. Although this principle has been known for many years and economical liming materials are available in most of the h\imid regions, many farmers do not use as much lime as needed.

Crop response to lime is often not so striking as that obtained from some other practices such as the use of commercial fertilizers, irrigation, or hybrid varieties. This may be one reason why some farmers have failed to realize the importance of liming and have failed to adopt proper liming procedures as one of their soil management practices. Another probable reason is that only in relatively recent years have methods been developed which adequately predict lime needs.

Much work has been done during the past half century regarding liming and its effects on plant growth. A considerable amount of progress has also been made in methods of determining lime needs and numerous methods have been developed, but no one method has been widely accepted. Some of the methods were based on sound chemical principles and were, or still are, adequate but others were not based on sound chemical principles and were, of course, inadequate. Some methods, although quite precise, are not adaptable for soil testing on a mass basis because of the time involved in the procedure. These methods are usually restricted to laboratory research and often serve as standards of comparison for the development and evaluation of more rapid methods. Rapidity is demanded in any method adapted to mass testing. A compromise between speed and accuracy must be accepted, because those methods which are precise are usually long, somewhat tedious operations and those which are rapid are usually lacking in accuracy to varying extents.

Those methods which are precise enough today in predicting or estimating the lime needs for soils may be wholly inadequate in the near future because of increased technology and intensification of practices in other areas of soil management. With an increasing population farmers will have to produce more and more food on less and less land which means that they will have to manage intensively each acre of land so as to maintain it in a highly productive condition over a long period of time. As a result, more precise measurements of lime needs will be required in order that farmers may obtain maximum production and efficiency in land use. More farmers probably will be using the services of the state soil testing laboratories. use. thus increasing the demand for rapidity in the method or methods used.

The soil properties that affect the lime requirement of soils are varied and complex. Like methods of determining lime needs, these properties have been studied quite intensively, yet the exact nature of their influence on liming is not fully understood. As a result. continued study of these properties as veil as methods of determining the amount of lime needed to cause a desired change in soil reaction is essential. With an awareness of these problems, the objectives of this investigation were to study the various soil properties affecting the lime requirement and to evaluate certain methods of determining the lime requirement of some Tennessee soils to designated pH values.

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