Atlanta semi-weekly journal. (Atlanta, Ga.) 1898-1920, 1909-11-19

An good farmers and scientists agree
that fertility can best be conserved
through the rotation Of crops. 1t takes
time however. to inaugurate rotation
ana one must make some investment IN
the way OF returning TO the soil certain
amount OF the crops produced thereon IN
order TO bring IL into condition 10 handle
a rotation advantageously. when TINS
end is attained. however. larger and more
uniform crops win be secured and there
Win be a resulting increase in the total
amount OF available plant food stored In
the soil. and hence We viii more nearly
approach the desideratum Of all eorrect
agricultural practice-the production OF
increased yields with the permanent main
tenance Of the fertility of the land
To show just how efficient crop rota-
ton NAV become in enriching the soil and
N conserving plant food. let US consider
that the cleared land on the farm under
discussion is divided into three equal
parts. On the first section winter oats
win be sOwn to be followed by cowpeas
to be cut for hay next year A fair yield
OF oats would be 30 bushels per acre; Of
cowpea hay. about l IL tons The next
section viii be devoted 10 corn. the yield
being based on "a bushels. On the sec
ton devoted TO cotton the yield will be
considered on the basis Of 80 pounds Of
lint with the seed In the following state
ments the amount Of plant food removed
from the soil by this rotation in three
years is shown II appears that the oats
with the straw viii removed 3 pounds OF
nitrogen. 10 pounds OF phOsphOric acid
and "a pounds OF potash The cowpea hay
VIII remove SIS pounds Of nitrogen. Is
pounds OF phosphoric acid and a pounds
OF potash. Since the cOwpeas would gath
er their nitrogen from the air II the crop
were properly inoculated and the nodules
ksA. - khsy ordinarily do. there is real
" no iosw Of nitrogen from the growth OF
this crop. but IN neknaf increase, sinos
from IS 10 20 pounds win be left IN the
roots. stubble and fallen leaves u thAs
crop. The corn and slower win re-
move from the land about "A pounds OF
nitrogen. "a pounds OF phosphoric acid
and s. pounds OF potash This crop. as
win be seen, makes by far the heaviest
draft on the soil constituents Of any in
the rotation. The 40 pounds Of lint cot
ton with the seed VIII remove about "A
pounds OF nitrogen. 5 pounds Of phosphor-
&c acid and s pounds OF potash. On add
ing Up these figures IL appears that ia
pounds OF nitrogen, IS pounds OF phos-
phorfc acid and 157 pounds Of potash have
been removed I'm the three years from an
acre OF land by this system Of cropping.
This. Of course, does not allow for any
loss BY teaching or erosion. though both
Of these agencies VIII prove destructive
OF fertility unless held I'm check by keep
ing cover crops on the land Just how
serious the loss from these two items is
most farmers do not seem to fully appre-
ciate. but 1t is not overstating the case
70 say that the loss in this direction in
aggravated cases fully equals the amount
OF plant food taken out by the crops.
Crediting the eOmpease with the nitro
gen contained in the hay, IL appears that
only ll6 pounds were removed from the
acre In a three years rotation. One crop
of cowpeas plowed under would ordinarily
supply this amount OF nitrogen. so that
the farmer can regulate the needs of his
soil so far as this high-priced element is
concerned. Three hundred and fifty
pounds OF high-grade acid phosphate
would supply the phosphoric acid re-
moved. while IA pounds OF muriate OF
potash would supply the actual potash
removed What farmer is there who
would not be able under a rational sys-
TEN Of practice to apply to his soil at
least so pounds OF high-grade acid phos-
phate and "a pounds OF muriate of potash
IN period Of three years? Since all the
plant food supplied TO the soil may not be
utilized BY a given crop and there are
losses from teaching and erosion. as al
ready pointed out. IL would probably be
the part OF wisdom on the part OF the
farmer even practicing a rotation con-
nstently to apply twice as much of these
Two mineral elements. as has been indi-
Gated. in order that there NAV be an
abundance Of them present in the soil
and thus stimulate rather than retard
the growth and yield of the various
crops. which would certainly be the case
II either element is not present I'm SUI
ncient amount to answer the demands
made upon IL by the crop.
One may not be impressed with the i'm
portance OF crop rotation from these fig
ures. yet II you consider for one moment
that three crops OF wheat with the straw
ana yielding no more than "a bushels per
acre win take out OF each acre 90 pounds