sified as follows:

{ Barn or stable manures,
Farm manures. { Green-crop manures,
{ Composts.

Commercial { Materials furnishing nitrogen,
fertilizers { " " phosphoric acid,
or artificial { " " potash,
manures. { " " lime.

IMPORTANCE OF FARM MANURES

Of these two classes of manures the farmer should rely chiefly on the
farm manures letting the commercial fertilizers take a secondary place
because:

Farm manures are complete manures; that is they contain all the
necessary elements of plant food.

Farm manures add to the soil large amounts of organic matter or humus.

The decay of organic matter produces carbonic acid which hastens the
decay of mineral matter in the soil and so increases the amount of
available plant food.

The organic matter changes the texture of the soil.

It makes sandy soils more compact and therefore more powerful to hold
water and plant food.

It makes heavy clay soils more open and porous, giving them greater
power to absorb moisture and plant food. This admits also of better
circulation of the air in the soil, and prevents baking in dry
weather.

Farm manures influence all of the conditions necessary for root growth
while the commercial fertilizers influence mainly the plant food
conditions.

The farm manures are good for all soils and crops.

They are lasting in their effects on the soil.

BARN OR STABLE MANURE

Barn or stable manure consists of the solid and liquid excrement of
any of the farm animals mixed with the straw or other materials used
as bedding for the comfort of the animals and to absorb the liquid
parts.

The liquid parts should be saved, as they contain more than half of
the nitrogen and potash in the manure.

The value of barn manure for improving the soil conditions necessary
for root growth depends in a measure upon the plant food in it, but
chiefly upon the very large proportion of organic matter which it
contains when it is applied to the soil.

These factors are influenced somewhat: by the kind of animal that
produces the manure; by the kind of food the animal receives; by the
kind and amount of litter or bedding used; but they depend
particularly on the way the manure is cared for after it is produced.

LOSS OF VALUE

Improper care of the manure may cause it to diminish in value very
much.

_Loss by leaching._

If the manure