Preliminary Field Investigations of Electrical Resistance-Moisture Stress Relations in Cotton and Grain Sorghum Plants

Box, J. E.; Lemon, E. R.

Preliminary Field Investigations of Electrical Resistance-Moisture Stress Relations in Cotton and Grain Sorghum Plants

1958

Box, J. E. | Lemon, E. R.

It is recognized that there is a need for a simple method of determining when to apply irrigation water to a growing crop. To this end a preliminary study was made, using cotton and grain sorghum plants under field conditions, of the relation between the moisture stress in the plant stems and electrical resistance between two electrodes inserted in their stems. The results suggest that this simple electrical measurement is largely related to hydration in the plant stem tissue. Electrical resistance measurements in grain sorghum and cotton under various soil moisture regimes in the field demonstrated that: (a) resistance in cotton was closely correlated with soil moisture, these relationships were not so clearly demonstrated in sorghum; (b) resistance measurements in cotton underwent diurnal fluctuations, but always continued an upward trend during a drying-out cycle following an initial lag after irrigation; and (c) the coefficient of variation ranged from about 10% for 8 a.m. measurements to 24% for 2 p.m. measurements, depending upon soil moisture conditions. The results indicate that the method has promise as a tool to indicate moisture stress in certain plants. However, additional research is needed to completely evaluate the method.

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