The Ordway new era., 1912-01-26
DRY FARMING SOILS
Addition of Humus Does Not In
crease Availability of Water.
To Secure Greatest Benefit earnyard
Manure Should Be Applied In
Small Amounts and at Rath-
or Frequent Intervals.

That the addition of humus to the
soil In the dry-farming regions does
not increase the availability OF water
In the ground and that humus-beartng
material-ba manure. straw.
leaves. or other vegetable matter
should be added to the soil frequently
IN small amounts. are conclusions
drawn from experiments recently con-
Quoted at the experiment station OF
the state OF Washington. says the
Country Gentleman.
The basis OF the experiments was
soil taken from the dry-farming zones.
one cubic foot OF which. without
humus. weighed eighty pounds and
was capable OF absorbing and retain
Ing. without drainage. rs per cent. OF
Its weight OF water. or the water. only
16.S pounds could be taken up by
plants. willing occurring when cubic
foot OF the soil held but 3.2 pounds OF
water. Seventy-six pounds OF this
soil was mixed with four pounds OF
humus. the soil being capable OF hold
ing 10 pounds OF water. and the humus
four-that Is. 100 per cent. OF its
weight. A cubic foot OF the humus-
bearing soil retained % pounds OF wa
ter. while a similar amount OF soil
without humus held but 20 pounds.
Forty per cent. OF the water held by
the humus -1.6 pounds-and 3O4
pounds held by the soil were unavaii-
able to plants.
Since in one cubic foot OF soil with.
out humus. containing 20 pounds OF
water. but 1853 pounds we're available
for the growth OF plants. in tier OF
three cubic feet Of soil 5O.4 pounds OF
water were available for plants. 10
make this amount OF water available
In three cubic feet OF soil without hu-
mus a volume OF water a foot square
and IL inches deep was required. the
amount available-5O4 pounds-being
equal to 81 inches OF the depth indi.
Gated.
With these facts in mind the next
problem was to find how many inches
of water would be available to plant
growth when five per cent. OF humus
was put into a cubic foot OF soil. In
the humus- bearing soil. as stated. from
% pounds OF moisture retained 1885
pounds were available for the use OF
plants. 1t was found that the soil
containing humus absorbed a greater
amount OF water than did the soil
| without humus. two and three-fourths
cubic feet OF the former holding as
much water as had been retained by
three cubic feet OF the silt. Since
Aa ~ 0vQfla htn
for the growth OF plants in a cubic
foot Of the humus.iaden soil. two and
three-fourths cubic feet held 6O.4y
pounds OF available water-or vol
ume foot square by 9.7l inches deep
Hence, with no humus in tho soil. ~
inches OF the given volume had been
available for plants. and with humuf
added in the amount indicated. 9.71
inches OF the same volume were avail
able.
Said Prof. Clark c. Thorn. in dis
cussing these results: In all cases
where humus Is added to the soil wa
ter Is held nearer the surface and Is
therefore more easily evaporated
Five per cent. OF humus-which Is as
much as is likely to be added-does
not Increase the availability OF mois
ture and Is OF no direct benefit in this
respect: indeed. It may even be detri
mental In that It holds the moisture
nearer the surface. where It Is more
quickly evaporated.
The beneficial results OF frumus ar.
IN creating a new supply OF plant food
and It is always advisable. even i'm
perative. that humus be present In
the soil. Clays are opened up by It,