Fifty instruments were installed at various soil depths and distances from field grown maize plants in order to follow daily moisture changes without disturbing the growing plants. Tensiometer readings were used to study the rate of root penetration, comparative moisture use at different depths, rate of rainfall infiltration in the soil, and to calculate the depth of the water table. The zone of active water absorption progressed downward as much as two inches a day. Within the root zone the rate of moisture absorption was highest near the stalk. Soil moisture classed as equally available by mechanical methods is, in fact, less accessible when situated farther from the base of the plant, even though roots completely ramify the area. Roots seemed to ignore reserves at 24 inches after rainfall had supplied moisture at 12 inches. Two rains of more than one and one-half inches failed to penetrate to the 21 inch soil point. When the soil was sufficiently moist to operate tensiometers, the weekly dry weight increase of 480 maize plants followed closely Lehenbauer's physiological temperature indices.
Proceedings of the Iowa Academy of Science
©1941 Iowa Academy of Science, Inc.
Bair, Roy A.
"Tensiometers for Following Soil Moisture Conditions in the Field (Abstract),"
Proceedings of the Iowa Academy of Science, 48(1), 191-191.
Available at: https://scholarworks.uni.edu/pias/vol48/iss1/20