Forest City press. (Forest City, Potter County, D.T. [S.D.]) 1883-19??, 1906-06-21
Renovation of Worn.out Soils
BY W. ). sPiLLmAN. BUREAU OF PLANT INDUSTRY.

farming was confined to a narrow strip
of land adjacent to the Atlantic: the
population was sparse, and when a field
became worn out the nearby woodland
vas cleared. AS population increased.
the younger generation crossed the AL
l%eghenies, beginning the tide of migra-
ton which has moved westward until
the present time. but which has now
occupied nearly all of the easily avail
able lands from the Alleghenies to the
Pacific. In it's westward course this
advancing host farmed virgin soils for
q century. The marvellous develop
ment which has occurred in this coun-
try during the past century was made
possible by the abundant fertility OF
the new lands brought under cultiva-
ton and the consequent abundance and
%cheapness of farm products.
So long as plenty of fertile land re-
manned unOccupied In the west the ex-
haustion of the older land in the east
vas a matter OF concern only to the
farmers OF the older settled communi-
ties. But now We are confronted by
the necessity of tilling soils whose abil-
tty to produce satisfactory crops has
been greatly impaired. There is even
a p%erceptible flow Of immigration from
the high-priced lands of the middle
west to the depleted lands Of the At
lantic seaboard. This has been made
possible by the recent remarkable de-
velopment of agricultural science.
. lGio otSa NiAS
of restoring fertility to soils.
Agricultural science is also RESPONSE
BILE for the present movement from the
city to the n The conditions of
country life have been alleviated; the
farm has been made attractive by add
ing the zest of intellectual occupation
in the splendid agricultural literature
of the day.; and farming, when intelli-
gently followed. has been made profit
able, even on lands that were formerly
unproductive.
Differences in Natural Fertility.
There is a vast difference in the nat
ural fertility of soils. Some do not pro-
duce we'll from the start unless special
attention is given to making them
productive; others produce large crops
for a short time and then rapidly d.
miniSh in fertility: while others, knOwn
as strong soils. remain productive for
many years without attention to their
fertility. But even the strongest soils
will wear III in time unless they are
in%telligently managed. Curiously
enough, as the tide Of migration went
westward in this country, the settlers
III soils of increasing natural fertil-
tty as they went, and in each new set
element the opinion prevailed that the
soil was ineXhaustible. But even the
strong soils of the western prairies
have now been cropped with grain and
abused by improper methods of till
age until they show signs of approach
ing exhaustion.
Fortunately. while the rich soils of
the west We're being depleted of their
fertility. the development of agricul-
tural science WaS going forward with
rapid strides, and. while there is much
yet to learn about the soil, we now
know, in a genera way, the steps nee
essary to build up and maintain soil
fertility. In fact. soils that We're orig
fnally only moderately productive, and
that been rendered almost sterile
by improper methods of farming, can
be made richer than they ever We're.
Nature Of the Soil.
In order to understand the methods
necessary for restoring worn-out soils,
let us consider what occurs in a fer
tile soil that is growing a large crop.
Imagine a cubic inch of ordinary field
soil magnified into a cubic mile. 1t
would then present very much the APP
pearance of a mass of rocks varying
from the size of a pea to masses several
feet in diameter. Scattered among
these rock masses would be many
pieces of decaying plant roots and 9th
er organic matter, resembling rotting
logs in a mass of stones and gravel. The
masses of organic matter would be
found to contain large quantities of
water, and to somewhat resemble wet
sponges. while every mass of rock
would have a layer of water covering
its surface. The open spaces between
the solid masses would be filled with
air.
If a crop We're growing on this soil.
its roots would be found threading
their way among the masses of rock
and decaying roots. and pushing these
aside by the pressure eXerted by the
growing root. From the surface of the
growing root, near its tip, small hol-
low threads (the root hairs) extend
into the open spaces and suck up the
water covering the rock PARTICLES. The
root hairs are not open at the end;
they absorb The water through their
walls The plant food is dissolved in
this water but is uail present in eS-
ceedingly small quantities. While the
plant is growing a constant stream of
water flows up through it and evapo-
rates at it's leaves. For every pound
of growth in dry matter made by the
plant, from 300 to 500 pounds of water
flow up through it.
The plant food substances dissolved
in the soil water nay be divided into
two classes according to their ultimate
source.
Mineral Plant Food.
Plants in their growth make use of
thirteen chemical elements. nine of
which they secure directly from the
soil. These are called the mineral
plant foods; they are phosphorus. po-
tassium. calcium, magnesium. sodium.
iron. silicon. chlorin and sulphur. We
have already seen that the soil consists
mainly of small particles of rock. The
rock particles are OF many kinds. u
nearly all kinds contain more or less
potassium, calcium. phosphoric acid,
etc. Every year the soil water dis
solves off a thin surface layer from
each particle. Plants appropriate this
water and thus secure mineral pla,lt
food.
Many generations Of plants have thus
been collecting their small toll of fool
from the soil and storing it up in their
tissues. The amount of plant food
made ready for plant use during each
growing season through the slow sol,i-