Estimating Soil Moisture Depletion

The chart below is a compendium of years of experience by researchers and consultants.   It is used to gauge soil moisture depletions by observing the look and feel of soil samples.  Many consultants would prefer to work with a sample from a coring tool rather than a screw auger or bucket auger.  The National Resources Conservation Service has published similar guidelines with full-color pictures for some areas.  Check with your local NRCS (the old Soil Conservation Service).
Soil Texture Classification
Moisture
Deficiency
in/ft		 Coarse
(loamy sand)		 Sandy
(sandy loam)		 Medium
(loam)		 Fine
(clay loam)



.0


.2


.4


.6


.8


1.0


1.2


1.4


1.6


1.8


2.0

(field capacity)

--Leaves wet outline
    on hand when
    squeezed.

    Appears moist,
    makes a weak ball.

__ Appears slightly
   moist, sticks
   together slightly.

   Dry, loose, flows
   through fingers.
   (wilting point)

--






__







---
(field capacity)

--Appears very dark,
   leaves wet outline
   on hand, makes a
   short ribbon.

   Quite dark color,
   makes a hard ball.
___

   Fairly dark color,
   makes a good ball.

   Slightly dark color,
   makes a weak ball.

--Lightly colored by
   moisture, will not
   ball.

   Very slight color
   due to moisture.
   (wilting point)
__







---
(field capacity)

--Appears very dark,
   leaves wet outline
   on hand, will ribbon
   out about one inch.

   Dark color, forma a
   plastic ball, slicks
__ when rubbed.

   Quite dark, forms a
   hard ball.


   Fairly dark, forms
   a good ball.
--

   Slightly dark, forms
   a weak ball.


   Lightly colored,
__small clods crumble
   fairly easily.

   Slight color due to
   moisture, small
   clods are hard.
   (wilting point)

---
(field capacity)

--Appears very dark,
   leaves slight moisture
   on hand when
   squeezed, will ribbon
   out about two inches.

   Dark color, will slick
__and ribbons easily.


   Quite dark, will make
   a thick ribbon, may
   slick when rubbed.


--Fairly dark, makes a
   good ball.

   Will ball, small clods
   will flatten out rather
   than crumble.

__Slightly dark, clods
   crumble.


  Some darkness due to
  unavailable moisture,
  hard & cracked clods
  (wilting point)
---