Miscellaneous thoughts 
concerning all methods of 
irrigation scheduling
Several different techniques are available 
which can be used to effectively monitor or 
directly measure soil water content. Some are 
extremely simple and are well worth the 
investment of time and labor. Many irrigation 
scheduling consultants are using these 
different methods
Table 5.  (Thomas W. Ley, Robert G. Stevens, Richard R. 
Topielec and W. Howard Neibling)
Qualitative evaluation of soil water monitoring devices. 1 is 
Least favorable while a score of 10 is most favorable.
NP Neutron Probe; 
TDR Time Domain Reflectometry;
GS Gravimetric Sampling;
AP Troxler Sentry 200
-
AP;
AQ Aquaterr Probe;
TM Tensiometer;
GB Gypsum Block;
WB Watermark Block;
Disadvantages of Fixed Point Soil 
Moisture Monitoring:
Several locations and depths must be monitored to 
make sure your measurements are representative of 
the entire field.  Irrigation systems often are 
extremely variable 
Movement of water on the surface of the soil leaves 
wet and dry spots, often within a few feet of each 
other.  Moving a water mark sensor or tensiometers 
a few meters away might give very different 
readings.  Moving to a different location in the field 
will likely encounter a completely different soil.