Available Water Setting


#1

I’m trying to understand the Available Watering setting. In reading your support article, it states that it is the amount of water that can be held in an inch of soil.

In the app. it has a units of inches.

So does that mean that in my snapshot above, my advanced settings are defining 0.2 inches of water for every inch of soil ?

Also, let’s say I create a new zone. Say I start with Sandy Loam. I assume that I get the default AW setting for Sandy Loam. If I go into advanced settings, change Root Depth, and then go back to basic zone info to change my soil type to say Clay Loam, will my AW be stuck at what I had when I originally edited the advanced setting when I had Sandy Loam, or would it use a value appropriate for Clay Loam ? It seems that now as I change the soil types the AW number does not change.

Thanks!


#2

No, it means that your soils holds 8 x .2 inches of water so flex wants to apply 1.6 inches of water to fill your zone. But it also means that flex will need to water for .8 of your pr rate to determine the run time for adequate coverage, so let’s sat, your pr is 1.6 (to keep it easy) 1.6 * .8 = 1.2 inches an hour effective per. so 1.6 * 120% = 72 minutes.

I’m sure ppl are calling bullshit at this moment, but your mad is set to 50% so in your case, flex wants to run when you hit .8 inches. This means it’s trying to apply .8 inches so let’s assume your pr is 1.5, that’s .8 / 1.5 = .53 hour = 32 minutes
32 minutes X 1.2 (120%) = 38.4


#3

I think we’re saying the same thing. 8 in_soil * 0.2 in_water/in_soil = 1.6 in_water. I’m just saying that the 0.2 in setting in the app. is for inches of water in every inch of soil (in_water/in_soil), which is consistent with what the article states. Agreed on that part ?


#4

Yea kind of. It is not garrunteed to be so uniformly distributed like that though.


#5

Understood. On this part, I get what you’re saying for the 32 minute part of the duration calculation, but where does the 120% factor come from ? Is that due to the efficiency ?


#6

Yes, exactly, your efficiency is set to .8 or 80%


#7

Got it, thanks. Do you have any experience on this part ? It seems to me that once you make an advanced setting change, or maybe when you pick the initial schedule, the Advanced Settings don’t get overwritten by a change of soil choice in the main zone setting screen.


#8

I just played with it on a test zone and they do change. But you have to change the soil and click save. THEN go back in and look at it and advanced settings will have changed.


#9

Yes, this is the case.


#10

@Linn @plainsane Thank you both. It seems it depends on your workflow. @Linn I just tried your approach of hitting save (or the <- in the app.) and sure enough I see the AW change. In case you can’t tell I’m trying to work through my soil settings, so this is helpful!


#11

Use that soil database. It’s very accurate.


#12

@plainsane I did, but according to my Mason Jar test it’s way off. WSS says Sandy Loam. My mason jar test as well as @Modawg2k 's, who also lives in Phoenix, shows Sandy Clay or Sandy Clay Loam. I want to believe the WSS but it’s hard to stare at a jar practically half full of clay and use Sandy Loam.


#13

Well, I,would find your soil in that db and use their awc.
I’ll take a quick look.


#14

Sure, if you have time. If I understand it correctly it reports Antho Sandy Loam with a 0.12 AWC. I want to believe it, but it just doesn’t seem to fit. When I was doing the mason jar test, and I was trying to break down a sample that was wet, I put it between to pieces of cardboard and smacked it over and over with a rubber mallet. When I lifted the top piece of cardboard, and I swear I picked the whole thing up like a pancake. And then I end up with somewhere around 10% silt, 40% clay, 50% sand. The other thing is that Sandy Loam tends to lead to more frequent watering frequencies than is the norm out here.

Anyhow, any and all advice is certainly appreciated!


#15

Did you use your address and zone in on your house?
I pulled a list of clays in that area, there are many.

Avondale clay = .18
Primer clay loam = .2
Trip clay loam = .2
Visconti clay = .15


#16

I picked an AOI of about 3000ft x 4000ft, with my house in the center. Otherwise it gives a warning about potential inaccurate results because I’m zoomed in too far.


#17

I would call that a sandy loam.
It has awc at .13.


#18

This is what’s throwing me then. Based on those numbers and this triangle it’s in the clays no ?


#19

I read that as Sandy Clay on the triangle.

Why the quote shows as @plainsane and not as @azdavidr however is beyond me!!!


#20

I see Sandy Clay also