Starting irrigations in this range assures soil aeration and ensures maintaining readily available soil moisture at all times. For tensiometers, atmospheres of tension are multiplied by 100 to obtain corresponding tensiometer readings. For resistance blocks, atmospheres of tension are converted to meter readings by referring to a calibration chart for the models of blocks and meter being used. Resistance blocks are less accurate than tensiometers for tensions of less than 0.5 atmospheres. Tensiometers should not be used where tensions of more than 0.7 atmospheres are expected.
Ranges are due to variations in soils and in crop response.
Resistance blocks should not be used for sandy soils. Tensiometers are not desirable for fine-textured soils unless the Crops require maintenance of low moisture tensions. 1 D.L. Miles, Colorado State University Cooperative Extension irrigation engineer, retired. Revised by I. Broner, Cooperative Extension irrigation specialist, chemical and bioresource engineering. Go to top of this page.