Field Estimation of Soil Water Content: A review

Excerpt

Field Estimation of Soil Water Content delves into the workings of a number of devices that measure soil water content (generally volumetric). Though the authors realize that instruments are often purchased based on convenience or economics, they aimed the book as a guide to help readers find the soil water measuring devices that perform best under given circumstances and to give readers information on how to use the devices. The most accurate, although destructive, form of measurement is physical sampling. Using that as the baseline, the authors listed several conclusions about less invasive measurement techniques. Their conclusions can be briefly listed as follows: all sensors must be field calibrated (with the possible exception of time domain reflectrometry [TDR]); the field-calibrated neutron moisture meter (NMM) is the most accurate and precise indirect form of measurement; electromagnetic sensors are too sensitive to nonwater related variability in the field; all sensors are too inaccurate, too costly, or too difficult to use for on-farm scheduling (with the possible exception of tensiometers or granular matrix resistance sensors); NMM, TDR, and physical measurements are the only methods accurate enough for research; and more research is needed to overcome device limitations.

Though the conclusions above seem definitive,…