Flex Daily misture level problems


#1
  1. How can soil (clay loam) with a capacity of 0.20 in be 100% full at 0.6 in?
    a. I suspect that root depth (6”) has something to do with it, like 6*.2*50%, but that would be 50% full at 6”?
  2. How can soil hold more than 100%? Isn’t that the definition of saturated? I feel that this is a weakness of the database. I think the system will place it in my gas tank and severely delay watering again.
  3. It appears that the moisture graph is expanded, confusing and to some degree wrong. There should be three lines: 1. 0%; 2. allowed depletion at the MAD level, and; 3. saturated field capacity. Instead of going from 50% to 100% as the default, it is expanded to 0% to 100% with the ability to go under 0% and over 100%. The present moisture level of the soil should always fall between the upper and lower lines. There should be a manual method to set the present level in that range beyond zero and saturated if one wants to correct things.

#2

So 100% full really means 50% of the Max. Allowed Depletion (MAD).

FULL (MAD=50%) = 0.2 (in water)/(in soil) * 6 in soil * 0.50 = 0.6 in water

It can’t, and it would indicate roll-off. I don’t know the specifics of why 120% was chosen, but I know that there’s some amount of inaccuracy of what 100% is in the app. versus the reality of what’s happening in your lawn. I don’t know if that has anything to do with it, but I’m OK with it due to that reason.

I guess it’s a matter of opinion to a point. For me, if below 50% means I’m below the permanent wilting point, I don’t plan on seeing many data points there. I always like to see as much of my data on the screen as possible, so 50-100% works well for me.

I’m not sure I’m following. How would that be different from what’s under the adjust button ?


#3

Thank you for the clarity on the MAD math. I would prefer that the range was left as an unaltered ratio from 0% to saturated at 100% with normal operation a range in between 25% to 75%, but so long as I know the math and the range, i can work with it. I was unaware of the 120% limit. I understand that there needs to be a hard limit at some point and that limit is above the wet irrigation point by some amount, so I guess i can see that.

" I’m not sure I’m following. How would that be different from what’s under the adjust button ?"

It would be a minor improvement, adding the ability to calibrate to a measured soil moisture level on a given day, rather than just saying it is wet or dry. Even a subjective squeeze test of a simple core sample could be done fairly well. I think this would be most useful for long roots (24") in the spring and fall when the interval is long (3-4 weeks).


#4

I see what you’re getting at. You can increase your MAD level to see more than 50%, but then the system will let your moisture deplete to that level too, which is probably not what you’re looking for. At that point it requires a display tweak, which it sounds like was your original suggestion.