Macon beacon., 1917-04-20

ment OF AgricultureJ
From the earliest days OF agricul-
ture farmers have observed that the
clovers, alfalfa, beans and peas en-
riched the soil so that wheat, corn,
cotton and similar crops gave better
yields following them than when plant
cd after the grains or grasses. The
reason for this benefit to the soil, how
ever, Is OF recent discovery and the
broader practical application Of the
knowledge Is just beginning to be ef-
fectlve.
Leguminous plants arc readily dis
tIngulshed, In most instances, by the
characteristic form OF their flowers, OF
which the garden pea is typical. and
by the secd-bearlng pods which split
upon ripenlng, at both edges or SUI
lures. The most important difference,
however, between legumlnous and non
legumlnous crop plants as they affect
the fertility of soil Is the formation Of
nodulcs or tubercles, normally at
tnChcd to the roots Of thriving plants
OF the legume family. These nOdules
vary greatly in size and shape. On
the roots Of red clover they are about
the size Of plnhcad and ovoid In
form; on alfalfa they are somewhat
larger and irregular in shape, fire.
quently forming In egg shaped misses,
the aggregate Of which may be the size
of very small marble, while on soy
beans the nodules resemble the seeds
Of the common pea both in size and
shape. For many years and until com
paratlvcly recent times these nodules
were thought to be form Of root gall
disease. In 1885, the scientists He'll
ricgel and Wilfnrth discovered their
real function In relation to the plants
and to the soil
Function of Root Nodules and Nodule
Bacteria.
If n nodulc on living plant be cut
open and some of the juicy substance
in 1t be spread thnly upon n glass
Slide examination under n high
power microscope will reveal an I'M
mcnse number Of living single-celled
organisms of the kind called bacteria.
These nodule-formlng bacteria, when
In the soil, pass into the minute root
hairs of legumlnous plants during
their early growth and establish them
solves In the outer layer of cells of
the true roots, where they multiply
rapidly and form the cnlargements
called nodules.
The nOdule bacteria ana the host
plant are mutually helpful. The plant
furnishes II home for the bacteria and
the bacteria in turn manufacture food
for the plant.
Plants, like animals, require food
materials for growth. Among the
most important plant foods are com
pounds of the element nitrogen, which
as m invisible gas comprises about
four-hfths of the atmosphere. Nitro
gen cannot be taken In directly by tn,
leaves of plants rs IS carbon dloxld
hut must first be'comblned with othel
elements to form soluble compounds
of nitrogen which can be readily ab
sorhcd by the roots. The nodule bac
terra of leguminous plants use nitro
gen directly from the mir as II circu
lates In the soil and convert It into
nltrogcnous compounds which are uti
lized in the growth Of the plants.
Nonleeumlnous Crops.
Nonleguminous crops, including corr
and other grains, cotton, and tn,
grasses, secure all of the nitrogen fo
their growth from the soil. All legu
mlnous crops, under normal conditions
obtain large part of their nitrogen
through bacterial action directly iron
the air. and In general they contain
larger percentage Of nitrogen and con