(10-22-2021, 07:18 PM)Jags Wrote:

(10-22-2021, 03:51 AM)Senor Fantastico Wrote: ET is a measurement of the transfer of water vapor from plant tissue to the atmosphere. I guess you can think of it like a plant sweating. It's a method used to measure both plant water needs and plant water use. 

Currently, there's 3ish good methods to determine water needs. You can measure the water in the soil with a tensiometer, crush green plant tissue and see how much water you can extract from it, or use ET measurement. I use ET myself because doing math is a lot cheaper than tensiometers and pressure bombs. 

To do that, UC Davis keeps something like a 1 inch tall plot of grass and measures its water use by weighing it in a lysimeter. That gives you a Reference ET. Then I would need to calculate a coefficient based on the crop I grow, canopy size, growth stage, a bunch of junk. 

That will give me a crop ET that I can use to determine how many gallons either an acre or per vine to apply. Then I take a reading of how many gallons per minute my pump is putting out and can figure out how long it needs to run to apply the correct amount of gallons per vine. Just a lot of time consuming math and conversions.

This program gives a daily output of specific ET needs. It already knows I grow grapes and it'll just tell me each day, put on 6 inches of water dummy. So it does help make life easier. I've already used it just today to determine my irrigation system has terrible uniformity. I can also see the sandy streaks in the field because they're dryer, kinda crazy. 

But... we also have quite a few water laws going into effect in January. So the other side of this program is EVERYONE can can see to the inch how much water every other person is using on a daily, weekly, monthly and annual basis. 

Personally, I've been under the current limit for a few years so I'm mostly good with it, but there's a lot of "water barons" that probably aren't going to be very happy next year.

Also, I think it's just kinda cool that they can measure how much water you're using from space by what the plants sweat off.

That’s pretty slick there.  I’m sure as a farmer, you’re very well aware of how much you need to water your crops.  But I find it pretty damn cool there is such high tech gadgets and satellites making life easier.  Have you done your normal math against this yet,  how much, if any, did it vary?

Looks like I had myself down for 24.5 acre-inches of water and they had me at 22.76 and 25.52 on the smaller block. But my pump meter is like an analog speedometer type dial. So guessing between 10-15 gallons per minute on the dial can be tough and that can add up over the course of the year. 

It has a more accurate odometer type reading too so I'll have to add that up and get a more accurate reading. Sounds like it's pretty damn close though.

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