A soil core probe or auger can be used to sample the soil at the various rooting depths. Guide for judging soil water deficit bases on soil feel and appearance. The tensiometer is a device that measures the energy a plant must exert to extract water from the soil. The amount of energy a plant exerts to extract water is directly related to soil moisture content. Frequent readings are required to track moisture status and to determine when to irrigate.
Tensiometers are relatively expensive to purchase and require regular maintenance.
Moisture readings are obtained from a limited number of locations in the field because of the high cost of the instruments. Resistance blocks are devices, which are constructed of gypsum or nylon, that measure the electrical conductivity of the soil. Electrical conductivity is directly related to the soil moisture content. Frequent readings are required to track moisture status and to determine when to irrigate. Resistance blocks are relatively inexpensive to purchase and easy to maintain when compared to tensiometers.