Master's Theses

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Date of Award

Summer 1961

Degree Name

Master of Science (MS)

Department

Biology

Advisor

G. W. Tomanek

Abstract

A study was made to determine some effects of competition for water on buffalo grass (Buchloe dactyloides (Nutt.) Engelm.). The primary objective of the investigation was to determine if effects of competition on buffalo grass, as determined in a greenhouse study, could be measured. Sods containing buffalo grass, buffalo and blue grama grass (Bouteloua gracilis (H.B.K.) Lag.), buffalo, blue grama, and western wheatgrass (Agropyron smithii Rydb.), and buffalo, blue grama, western wheatgrass, and western ragweed (Ambrosia psilostachya Gray) were planted in phytometers to evaluate competitive effects. Four watering series (from very dry to wet) were arranged to determine effects of varying moisture conditions on buffalo grass. Buffalo grass plants were carefully studied to determine effects of competition with various species and effects of different moisture conditions. Factors included in the study of buffalo grass plants were: (1) leaf length; (2) stolon lengths; (3) root length; (4) date of flower appearance; (5) number of tillers; (6) number of lateral roots per cm. of main root; and (7) production of tops. Greatest variation in growth and production were caused by different soil moisture conditions; however, some changes were caused by competition. Leaf length was greatly reduced in the drier series and some reduction was generally found as competition increased. Buffalo grass plants grown alone produced leaves which averaged 7.02, 7.65, 12.08, and 13.31 cm. long, respectively, from dry series to wet while competition with the three competitors reduced leaf length approximately one to two cm. Competitive effects for the other two competitive series were intermediate. Stolon length was inconsistently affected by moisture conditions and gave no indication of being influenced by competition. Flower appearance was delayed in accordance with moisture conditions, the dry series showing considerable delay. Flower appearance was also delayed as competition increased. Root length increased as moisture increased in practically every case; however, the effects of competition on root length were again quite variable. The number of tillers per buffalo grass plant increased with increased moisture and, strangely, also increased with increased competition. The number of lateral roots per cm. of main root increased with increasing dryness and, generally, also increased with increasing competition. Production of tops was quite variable and indicated little consistent influence of moisture or competition. Generally, production was greatest for those buffalo grass plants growing under moist conditions and without competition. Results obtained from the study indicate that the procedure used to determine competitive effects has many limitations and changes in the method used will be necessary to insure valid results.

Rights

Copyright 1961 Robert Baalman

Comments

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