Master's Theses

Date of Award

Summer 1985

Degree Name

Master of Science (MS)

Department

Biology

Advisor

Robert Nicholson

Abstract

Herbage production of winter annual grasses often is correlated with environmental conditions. To examine the effects of defoliation, light intensity, and density on the production of tillers, biomass, and regrowth in Japanese brome (Bromus japonicus), a greenhouse and field experiment was conducted for one year in Hays, KS. In the field experiment, 5 clipping intervals (1, 2, 3, 4 weeks and control) and 3 light treatments (basal, plot, and no shading) were used. Clipping intervals of 1, 2, 3, and 4 weeks produced more tillers than no clipping. Unshaded plants produced the most tillers at the beginning but, during the middle and end of the season, shaded plants produced the most tillers. Plants not clipped produced the most regrowth and plants clipped weekly the least amount of regrowth. Unshaded plants produced the most regrowth, and the amount of regrowth decreased throughout the experiment. Unclipped plants produced the most biomass, and the amount of biomass produced was not affected by light treatment. The amount of biomass produced increased and then decreased to nothing at the end of the experiment. In the greenhouse experiment, 3 density levels of Japanese brome were planted (high= 1/sq. cm, intermediate=½ sq.cm, and low= 1/4 sq. cm). Three light treatments (same as field), and 4 clipping intervals (1, 2, 3 weeks and control) were used. Low density produced the most tillers and high density the least. Plants not shaded produced the most tillers. Tiller number was not affected by clipping interval and increased throughout the season. Low and intermediate densities produced the most biomass and regrowth. The amount of biomass produced was not affected by light intensity. Clipping intervals of 1, 2, and 3 weeks produced the most biomass and controls the least. The rate of biomass production decreased throughout the season. The amount of regrowth produced was not related to clipping frequency. Plants not shaded produced the most regrowth. The amount of regrowth decreased until the last date when it increased because of seed production. Treatments affected the number of plants germinating in the fall of 1984 and the spring of 1985.

Rights

Copyright 1985 Theresa Ann Pfeifer

Comments

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