Master's Theses

Date of Award

Spring 1981

Degree Name

Master of Science (MS)

Department

Biology

Advisor

G. K. Hulett

Abstract

Grazed and ungrazed limy upland range sites of the Mixed Prairie in west-central Kansas were studied from August, 1973 to August, 1974, to estimate litter and cellulose decomposition rates above and below ground. The rate of decomposition of litter in the grazed treatment exceeded that in the ungrazed by about 1.5 times. Mean daily losses of litter were 1.108 mg/g/day in the grazed treatment and 0.750 mg/g/day in the ungrazed. Subsurface cellulose losses were 7.87 mg/g/day in the grazed, and 7.57 mg/g/day in the ungrazed, with monthly rates ranging from 0.09 to 20.42 mg/g/day. Most litter decomposition was probably due to leaching by precipitation because decomposition of litter above the ground totaled about 85% as much as decomposition on the ground. Most subsurface decomposition was due to biological activity, primarily by arthropods. Arthropod populations in the litter and the soil were highly variable, but it was concluded that they were important in affecting a loss of surface litter and most subsurface decomposition. The rate of carbon dioxide evolution was estimated in the laboratory at selected levels of soil water and soil temperature. Carbon dioxide production ranged from 0.0045 to 0.018 milli-equivalents/gram of soil/hour, but differences between the soils of the grazed and ungrazed treatments were not significant except at one point, which was due to temperature and soil water differences. It was concluded that if any differences in microbial populations did occur, they did not significantly affect subsurface decomposition rates.

Rights

Copyright 1981 John G. Mai

Comments

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