The daily sentinel., 1912-04-11
SHADE CROP
IS NECESSITY
Prof. R. S. Herriok Tells Why Soil
Needs Decayed Matter to Com
plete Its Essential Elements.
Gives Directions.

There are 3S different chemical
elements which are used to make up
the growth of a plant. The follow
ing Inc are very essential for the
proper development of the orchard
plant; Carbon, hydrogen, oxygen
nitrogen, sulphur, phorphorus, potas-
SUM. calcium and iron. The three
most important of these. and which
are sometimes absent in available
form, are nitrogen, phosphorus and
potassium. A certain amount of
nitrogen is required for the vigor-
Gus growth of the plant and is used
principally in the formation of the
woody part of the plant. Phosphorus
is not as essential in fruit growing
as 1t is in the growing of grains. as
1t Is used to make up large per
cent of the seed, but is, however, es-
sential to aid the proper ripening of
the fruit. Potassium aids in the
proper coloring of the fruit and goes
to make up large per cent of the
ash of both the fruit and of the
fruit wood
Many of our orchard soils are rich
chemically in nitrogen. phosphorus
and potassium, but oftentimes these
elements are not available for the
plant on account of the poor physi-
cal condition of the soil: we mean
that II lacks humus BY humus we
mean the complete decay of organic
matter which can be obtained by the
plowing under of some green manure
crops, such as alfalfa, clover. vetch.
oats, rye, etc.
In the east where experiments
have been run with clean cultivation
versus sod for orchard soils. the re-
suits were found to be in favor of
the clean cultivation. Clean cult
vation versus a rotational shade crop
has been tried in Colorado and the
results We're in favor of the shade
crop rotation. In the East, cover
crops are used. which means the SOW
ing of the sebG in late summer and
the plowing under of the green ma
nure crop the next spring or in the
early summer. Our conditions are
such that this method does not work
well. the greatest trouble being that
me spring plowing under of a great
mass of green material interferes
greatly with the first summer iriga-
tion, as it sometimes causes the soil
to puddle and thereby causing the
leaves to turn yellow BY shade
crops is meant the sowing of the seed
in the spring of the year, thus shad-
ing the soil during the summer from
the sun, and the plowing under of
the green crop either the following
fall or the next fall depending on
whether an annual. biennial or per-
ennial crop is grown.
Nearly all the Colorado orchard
soils are very poor in humus content
and this is the principal reason why
they are so poor physically that is,
they are hard to work when it comes
to irrigation and cultivation. Such
soils do not take water readily nor
CO they hold it after they have been
irrigated Humus in the soil will do
away to large extent with these
troubles and can be obtained by the
plowing under of barnyard manure,
but on account of the scarcity of it
the orchardists will have to rely to a
great extent on the growing and the
plowing under of shade crop.
Shade crops are divided into two
classes, viz: leguminous or non
leguminous. The legumes are plants
like the alfalfa, clovers, etc; the
non-legumes are the grains, like oats,