Date of Award:

1963

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Plants, Soils, and Climate

Advisor/Chair:

Howard B. Peterson

Abstract

Water requirement was defined by Briggs and Shantz in 1911 as the ratio of the weight of water absorbed by a plant during its growth to the weight of dry matter produced. Ballard (1933) and Williams (1935) defined water requirement as the ratio of the amount of water transpired to the amount of dry matter produced. Ballard (1933) and Williams (1935) defined water requirement as the ratio of the amount of water transpired to the amount of dry matter formed during the whole or any part of the life cycle of the plant. Miller (1938) and Kramer (1959) postulated that the water requirement is the ratio of water used to the dry matter produced, and therefore could more accurately be termed transpiration ratio because it is largely controlled by transpiration. Regardless of specific definition, the dry matter considered in such ratios is generally the amount harvested, including the entire plant except the roots. The amount of water measured is the amount lost during growth since the amount of water retained within the plant is insignificant when compared with either total water intake or the amount transpired. The water requirement thus constitutes a useful way to characterize the plant and soil-water conditions and plant growth.

The availability of soil water to a plant is one of the factors that vitally affects its water requirements. In turn, the availability of soil water is affected by soil moisture tension and the salt content of the soil. Thus it seems likely that a significant relationship may exist between a plant's water requirement and its degree of salt tolerance.

The relation between water requirement and salt tolerance could not be established based on the information found in the literature at this time. the study reported here was undertaken in an attempt to determine the effect of salt on the water requirement of plant species known to have different degrees of salt tolerance.

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