rmit air
to enter. The loosening is excessive when the planting must follow
soon, permitting rapid escape of water. The roller or plank-drag is
employed to compress the soil, and to crush crumbs of soil that are too
large for good soil conditions. The harrow follows to make a mulch of
fine, loose soil at the surface to assist in prevention of evaporation.

A sandy soil will retain its mulch in effective condition for a longer
time than a fine clay, if no rain falls. When the air is laden with
moisture, clay particles absorb enough water to pack together and form
an avenue for the rise of water to the surface, where the dry air has
access to it.

Mulches of Foreign Material.--The truth that moisture is a leading
factor in soil productiveness is evidenced by the value of straw and
similar material as a mulch. A covering of straw around trees in an
orchard, or bush fruits, or such plants as the potato, may give better
results than an application of fertilizer when no effort is made to
prevent the escape of water. People so situated that little attention
can well be given to the fruit and vegetable garden obtain good results
by replacing tillage with a substantial mulch that keeps the soil
mellow, prevents weed growth, and retains an abundant supply of water.

In grain-producing districts where all the straw is not needed as an
absorbent in the stables its use as a mulch on thin grass lands, or
wheat-fields seeded to grass, is more profitable than conversion into
manure by rotting in a barnyard. The straw affords protection from the
sun, and aids in the conservation of soil water, when scattered evenly
in no larger amount than two tons per acre, and a less amount per acre
has value. The sod is helped, and as the straw rots, its plant-food
goes into the soil.

Plowing Straw Down.--The practice of plowing straw under as a manure is
unsafe, when used in any large quantity per acre. It rots slowly, and
while lying in the bottom of the furrow it cuts off the rise of water
from the subsoil which is a reservoir of moisture for use during
drouth.

The Summer-fallow.--Bare land loses in total plant-food, but may make a
temporary gain in available fertility. The practice of leaving a field
uncropped for an entire season has been abandoned in good farming
regions. Where moisture is in scant supply, and a soil is thin, there
continue instances of the summer-fallow. In a crop-rotation containing
corn and wheat, the corn-stubble la