The midland journal. (Rising Sun, Md.) 1885-1947, 1905-03-31
ABOUT SOIL.

kADOO1 kJO14s
The investigation of the physical
characteristics of soils deals chiefly
with the classification of soils accord
ing to the amounts of particles OF va
rious sizes which constitute the soil.
In order to secure uniformity of clas-
sification and description conven-
tional table of sizes has been adopted
by the Bureau of Soils, United States
Department of Agriculture. and the
soils are described in the terms OF
this table. Thus all material above
two millemetres (about liz OF an
inch) are classed as gravel and stone;
from one millimetre to one-half mill
metre, or about the size OF clover
seed, the grains are called coarse
sand; from one half to one-quarter
millimetre the grains are classed as
medium sand; from one-quarter TO
one-tenth millimetre as fine sanu'
from one-tenth to five one-hundredtn
millimetre as very fine sand. so 1ar
all. grains are readily distingulshaDle
by the eye as separate fragments OF
various minerals, and little knoWi-
edge of the appearance OF dlHerent
minerals enables one to identity the
grains as belonging to one or more
of a half dozen common rock ana soii
forming minerals The next Two
grades. silt (5-1O0 to $4,000 and clay
(smaller than $1,000 millimetre) are
impalpable powders when dry, anu
their mineral composition can De
made out only under high power
microscope by a person skilled IN Inc
recognition Of minerals in small rag
ments.
Pure silt when moist is not gritty
like the different grades OF sand, OF
plastic and coherent, like the eA-
tremely minute particles OF clay.
The various grades of sand usually
make up the skeleton or framework
of the majority of soils. They render
a soil more or less open or porous
depending both on the size OF the
sand grains and their relative proper
tions in the total mass. The silt rem
ders a soil solid and somewhat COM
pact making it particularly adhesive
even when wet. The clay, If present
in proportions above 10 to 10 per cent
renders a soil waxy and adhesive
when wet and either granular and
cioddy when dry or else solid ana
impervious.
The graduation of soils according 10
the size of the component grains IS
a classification according to the SOIL
texture. 1t is the common classlnca-
ton of the practical farmer, and the
mechanical analysis, and standard
sizes of grains are merely USED IN
order that the terms used in one 10
cality may be more widely intelllgl-
BILE. Thus soil made up OF large
grains, possessing an open, porous
structure, draining freely and WORK
ing easily, is, by common acceptatioh'
a sand. But one locality might con-
slider a given sand as coarse, wnlle IN
a different locality it would be estl-
mated as only medium. similarly
soils locally known as clays frequent-
ly find their place in a wider ciassi-
fication as clay loans or heavy loans.
A county Astounding in clay soil might
give rise to local classification OF
lighter lands as sands, when they &C
tually deserve to be called SANDY
loans.
The physical properties OF soils de-
pend not only on the texture Oh tne
soil. the size of the component grams
but also upon the structure OF the
soil-that is, the arrangement OF the
soil particles in space, the title, as II
is frequently called. Thus clay SOIL
NAV be granulated and loamy, easy
to till, we'll drained and well airea,
or it may be SO puddled and mlxeu
that it forms Shiny, plastic mass
when wet and dries to consistency
of concrete. In both cases the me-
chanical analysis might show almost
Identical texture, but mere inspec-
ton would show a vast difference In
the arrangement of soil grains, the
structure. The first soil would be
seen to consist of lot of clay peb-
HES or grains, each made up OF thou-
sands of much more minute indivl-
dual grains. Each compound grain is
in itself infinitely porous; while be-
tween. it and its surrounding granules
large pora spaces exist. The second
soil Is made up of mass or minute
grains SO evenly distributed that no
large pore spaces intervene, and only
the most minute openings exist in the
soil. The first soil is in good condi-
ton, suited to crop production, easy
to till, productive. The second is
quite often barren and reproductive.
With the same chemical composition
and the same texture, but with such
a difference in structure, the first soil
forms a fertile, productive field; the
second forms a barren waste fit only
to support weeds or to furnish clay
for Neutrality-suspicious. Farmer.
GET THE CALF STARTED RIGHT.
To 4, worth while to GET fha calf