American Falls press. [volume] (American Falls, Idaho) 1907-1937, 1910-12-03
CRUST UNDER MULCH
Nothing Can Prevent Formation II
Drouth Lasts Long.
Cannot Be Broken Up Without De-
strcylns Crop, but Can pc Rem
dersd Harmless by Right
Kind Of Flowing.

Every dry yoar some one asks:
What can we do when a crust forms
under mulch7
Nothing can prevent this crust
forming n the dyou.h lasts long
enough. writes II. r. Parsons In Dry
Farming Bulletin.
The top inch Of the mulch dries
first. then the second. then the third.
and then the Inevitable crust begins
% form underneath and becomes
thicker and thicker with every day OF
drouth.
We cannot break up this crust with
out destroying the crop. but W. can
render this crust perfectly harmless
by the right kind Of blowing. and that
II all that Ia necessary.
The formation Of this crust depends
on two different factors. the drouth
about and the moisture conditions be-
low.
People sometimes talk and write in
magazines about tho dry farmer max
ing a cistern for moisture and putting
the lid on and SO forth, as II he had
all the water he could handle. but the
fact OF the matter il we can wet up
our land by conserving moisture to a
certain percentage to n certain limit
only, which Is determined by the cap
ollAriiy Of the soil In question, and
above that limit. which is more or
less constant, It IL impossible to raise
II ~ long as there IL a dry subsoil
below. which In the true condition Of
the dry farm soil. What / g Is
this: When q storm I'M the water
goes down hy capiiarity or gravity, or
both combined. until II IL loo diffused
20 90 any further; capilIarity ceases
for the time being until another storm
comes and starts 1t again: then II
goes down again until It stops for lack
Of water. Now, II we make a test Of
this soil for moisture a day or SO after
. storm. when capillarity has ceased
working. VIZ md We have no more
moisture In the soil than wa had be-
fore. the percentage liz the same. but
Il has gon down further. We are OBJ
tanning q greater depth Of moist
ground.
Some farmers pillow shallow. owing
20 q misconception OF this action of
moisture. They expect the moisture
to rise by capillarity 10 moisten their
crust and hold the drouth ut bay,
when capiilarity Ia already exhausted
by the downward pun Of gravity.
After making several hundred tests
in all varieties OF soil during the last
80 years. I have been unwillIngly
forced TO the Inevitable conclusion
that capillarity as a help to the dry
farmer Ia bringing up moisture from
the subsoii to the roots Of his crops
Is a negligible quantity on true dry
farm land that is not sub-irrigated.
We all allow. however. that capillar.
ity works very strongly sometimes for
a few days on the top three or four
inches after wet weather, before the
moisture has diffused downward, and
we a make use of this knowledge
for seed termination, by using the
press drill, which will draw the mois.
ture to the packed seed rows. with
out packing and baking the whole
neld.
Since the moisture does not rise to
moisten our crust except very slight
ly by distillation. 1t Is clear that the
best thing we can do Ia to go down
after the moisture. Tho only way to
do this Is to pillow deeply. not any six
or seven inches. but eight. nine. ten
or twelve.