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Smallaxe
03-27-2011, 09:15 AM
So we all know that the actual Impervious Black Thatch is formed by improper cultural practices... i.e. too much fertilizer(especially in the Spring) and too much water...

So my question is:

What is a simple practical way to come onto a lawn and see if it is getting low enough on water that it can be irrigated again without creating thatch?

This is an exact opposite approach of "Better Safe Than Sorry" mentality, in which the rule of thumb is to keep it moist... Is it necessary to plug the soil or have it monitored wth meters? or can we just wait until the turf feels dry 1/2 hour after sunup and the dew is gone?

Kiril
03-27-2011, 10:38 AM
So we all know that the actual Impervious Black Thatch is formed by improper cultural practices... i.e. too much fertilizer(especially in the Spring) and too much water...

So my question is:

What is a simple practical way to come onto a lawn and see if it is getting low enough on water that it can be irrigated again without creating thatch?

This is an exact opposite approach of "Better Safe Than Sorry" mentality, in which the rule of thumb is to keep it moist... Is it necessary to plug the soil or have it monitored wth meters? or can we just wait until the turf feels dry 1/2 hour after sunup and the dew is gone?

This is not really an issue of field capacity, but rather an issue of management allowed depletion (MAD). Irrigation management is complex issue with many variables to consider and cannot be reasonably covered on a forum.

That said ... if you want to wing it .... wait until your turf starts showing signs of water stress, then irrigate an appropriate amount. This is not something I would recommend doing on a regular basis, nor is it appropriate for an LCO. I will sometimes use this method as a easy way to determine potential problem areas on a given site (ex. compaction), but not as a means to determine an appropriate irrigation interval.

You can also learn how to use the feel method to estimate soil moisture, or buy a low cost Lincoln meter, the latter being preferred over the former. These methods however only address soil moisture levels at a given point in time and when you might want to irrigate a particular hydrozone .... assuming you have determined an average effective rooting depth of the plants in the hydrozone and know what depth(s) to measure you soil moisture.

Oh ..... and thatch is not impervious.

Smallaxe
03-28-2011, 09:39 AM
Thanks Kiril,

I realize that water depletion to the point of stress is not a good idea, and only my non-irrigated lawns are ever close to that b4 I bother with 'sprinklers'. I hate sprinklers...

What I tend to see as an issue is that the thatch layer sits like a dried sponge and 'puddles' water for a long time, before it starts soaking into the soil underneath...

You are probably correct, in that there is no visual or 'feel' for lawn moisture that appears b4 stress sets in...
Thought maybe someone had a clever insight that I'd missed... :)

I used the word 'impervious' to contrast with brown mulch that most people think of as thatch. It is more descriptive than definitive...