Atlanta semi-weekly journal. (Atlanta, Ga.) 1898-1920, 1916-05-26
The Relation of Water to Crop GrooOth

relating to this subject, the work must
of necessity be correlated with what we
are pleased to term, soil physics. which
is concerned with a study of the origin
of soils, their physical properties, and
the influence which these exert on their
productive capacity. Soil fertility must
also be considered. as this deals with
methods of controlling the fertility OF
the land and increasing the available
supply of plant food through the use
of commercial soil amendments. Soil
formations must be studied because the
physical and chemical surveys now in
progress in many states show that we
have many distinct series and types of
soils to deal with, and that each of
these types exerts an effect on crop
growth. Soil management must also be
Investigated for reasons which are OBJ
vious to any who will take a ride across
the country for comparatively short
distance and see what erosion and mis-
management have accomplished in what
is said to be the most civilized and pro-
gressive era in the history OF the world.
OF course, soils vary i'm their compost
tion and in their native supply OF plant
food. Therefore, the store Of the several
essential elements they contain must be
ascertained and a means sought for sup
pIementing or offsetting their natural
deficiencies. So attention must be given
TO the question OF fertilizers and ma
nures. Certainly crop rotations must be
studied. for il is known that by this
means the store of plant food can be
increased or decreased, the soil rested,
as it were. and the plant food constit-
uents maintained in equilibrium.
Thus, the subject of drainage is seen
TO be intimately related to many other
topics, all of which must be understood
if effective means of storing, utilizing
and disposing of the water which falls
as rain are to be devised and made
serviceable in improving farm practice
in Georgia. Those who have studied the
subject realize that our acre yields of
the principal farm crops are still la
mentally low, and that we can and
should increase them greatly. To this
end we should make a beginning by
studying the rainfall and devising ways
and means of conserving and utilizing il
to the best advantage. For instance, in
order to grow the largest possible crop
of corn. Widstoe found that the soil must
handle $50 pounds of water per square
foot, equivalent TO eight million pounds
per acre foot. We speak of an acre foot
of soil and in doing so regard il as
weighing from four to six million
pounds. 1t will thus be seen that the
duce the greatest crop of corn possible
may be twice that of the soil in which
lit grows. In order to raise large crops
with uniformity the soil should retain
throughout the growing season at least
so per cent of the maximum amount of
water it is capable of holding.
The amount Of water which many of
our soils are capable of holding as they
now stand is much below the amount
he nf
crops. For example, coarse sand will
hold only 40 per cent of moisture;
fine sandy loan. 6.S per cent; loan,
1873 per cent; silt loan, "a. 4 per cent;
clay loan, 32.4 per cent; and clay
3S.2 per cent. Fortunately for the
farmer, he may be largely the master
of his own destiny in dealing with his
soil. In other words. he may change
coarse sand through the use of green
crops plowed under and proper soil
amendments into a condition where it
will have two to four times the water
holding capacity it naturally possesses
When he does this he has issued a crop
insurance policy in his own favor which
cannot readily be discounted. The wide
variation in the percentage of water
which soils will hold shows to what
lengths the farmer may go in the exer-
else Of his ingenuity i'm dealing with
the problems OF crop production. In
creased yields will be determined large
" by his ability to conserve the water
supply. This will call for the exercise
on his part Of the highest intelligence.
and the establishment Of a new type of
soil so changed in characteristics by
the management accorded il as to seem
quite unrelated to the parent form.
When we reach this degree of prof.
cheney in our agricultural practice, we
will then be able TO control a sufficient
amount Of the water which falls as rain
to insure the growth OF crops far in
advance Of present day averages.
DATA ABOUT TYPES OF SII.OS
T. +. B.. Augusta. Ca. writes: I am
thinking Of building a silo, and would like
your views 10 the best kind to build and
the cost Of same.
Several types Of silos may be built