Need complementary units and better PATO quality class for irrigation water quantity

[celineaubert]

Currently the class irrigation water quantity is under the quality class amount. However, this class does not seems to match for a quantity of water. Also, the units currently linked to irrigation water quantity recording protocol are mm et liter. But many other units are used to value the quantity of water http://agriinfo.in/?page=topic&superid=1&topicid=17

[KrishnaTO]

Need to add units (NTR in UO, issue #24), to volume of irrigation water (updated per issues #5 #116)