HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Cannell, G. H. Search for Related Content PubMed Articles by Cannell, G. H. Agricola Articles by Cannell, G. H.

Effect of Drying Cycles on Changes in Resistance of Soil Moisture Units¹

ABSTRACT

Several different types of electrical resistance units were tested for displacement of calibration curves using a wetting-drying regime. The experiment was carried out in a temperature-light controlled growth chamber, and was designed to simulate field conditions with respect to moisture treatments; (1) excessive-leaching, and (2) slight-leaching.

A cover crop of oats was used as a means to reduce the moisture content to near the wilting percentage in each drying cycle. Growth of the crop was controlled by clipping which permitted drying periods with intervals of nearly 7 days. Changes in moisture content during the drying cycle were obtained by use of a solution balance. Block resistance readings were recorded at the time weights were taken.

Statistical analyses were made at several soil suctions for the 1st, 6th, and 11th drying cycles. The differences between drying cycles were statistically significant.

Analyses of variability were calculated and comparisons made between blocks of a given type and between different block types at various soil suctions. In general, variability between blocks of one type increased with soil suction. However, the increase was not always consistent between different types of blocks.

¹ Contribution from the Soil and Water Conservation Research Division, ARS, USDA.

² Assistant Soil Physicist, Univ. of California Citrus Exp. Sta., Riverside; formerly Soil Scientist, Western Soil and Water Management Research Branch, SWC, ARS, USDA, Northern Great Plains Field Station, Mandan, N. Dak.

Received for publication January 10, 1958. Accepted for publication April 17, 1958.