Masters Theses

Date of Award

8-1981

Degree Type

Thesis

Degree Name

Master of Science

Major

Plant, Soil and Environmental Sciences

Major Professor

Russell J. Lewis

Committee Members

W. L. Parks, G. M. Lessman

Abstract

Two experiments were conducted to study the effects of adding wheat straw, corn stalks, and alfalfa to acid Sequoia (Typic Hapludult) and Tellico (Typic Rhodudult) soils on chemical changes occurring in the soils, growth of the Harrison variety of barley (Hordeum vulgare L.)» 3nd the accumulation of selected nutrients in barley tops. The effects on root growth were studied in a soil slurry experiment, and the effects on growth, ion uptake, and soil properties were studied in a greenhouse pot experiment. In both experiments, the plant materials were added at 0, 3, and 6% rates (soil weight basis). In the greenhouse pot experiment, the effects of mixed and surface application methods were also compared. The surface application method provided greater concentration of plant materials in sampling zone than did the mixed application method. The Sequoia soil contained a high level of A1 whereas the Tellico soil contained a high level of Mn. There were no differences in the root lengths among the rates and plant materials in the Sequoia soil. The root lengths in the Tellico soil treated with wheat straw or corn stalks were longer than those of the untreated, though the differences between 3 and 6% rates were not significant. However, there were no differences in the root lengths measured in the Tellico soil treated with different rates of alfalfa. In both soils, pH values in solution and sediment of the slurries increased with increasing amounts of plant materials added, though not consistently. Root weights were not respon-sive to the various treatments. In the greenhouse pot experiment, pH and exchangeable Mn of both soils increased with increasing amounts of plant materials applied. The reverse effect was observed on exchangeable A1. Among the plant materials, only alfalfa reduced the A1 and Mn toxicities suffered by barley plants. Plants receiving this treatment grew vigorously and their heights and weights were the greatest. However, the greater amount of alfalfa applied to the Tellico soil caused Mn toxicity. The accumulation of A1 in barley tops was without a pattern. Contrastingly, large amounts of Mn was present in the tops of plants suffering Mn toxicity. Adding wheat straw, corn stalks, or alfalfa to Sequoia soil increased the K and P contents but decreased the Ca and Mg contents measured in barley tops. Adding these materials to Tellico soil increased the Mg, K, and P contents but had no effect on the Ca content measured in barley tops.

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