The rooting depth of various vegetable crops is listed in the table. It is important that shallow-rooted crops receive more frequent irrigations. Preferred Minimum Soil Moisture. Soil moisture is measured with a tensiometer or soil block. The former is preferred for sandy soils and the latter for clays and loams.
Tensiometers report soil moisture in centibars.
Suggested soil tensions for various vegetables are reported below. Irrigation amounts and the time between irrigations are critical to efficient irrigation practices. Some suggestions for amount and timing of irrigations are presented in the table. Critical Moisture Periods. This is not to say that it is the only time in the life of the crop that moisture stress reduces yield.