This is quite as indispensable to good farming and gardening as any
other tool. It serves a great variety of useful purposes. The first is
to pulverize soils. No man can get a full crop on a soil not made fine
on the surface, however rich that soil may be. It is often the case that
land needs rolling two or three times before the last harrowing and
sowing the seed. Another purpose is, on all light soils, to place the
soil close around the seeds after they have been covered. When this is
not done, seeds will vegetate very unevenly, and, in dry weather, some
of them not at all. Another advantage of rolling a field-crop is the
greater facility and economy with which it can be harvested. It makes a
level, smooth surface, sinking small stones out of the way of the scythe
or reaper. Rolling makes grass-seed catch, when sown with a spring-crop.
All beds of small seeds--as onions, beets, carrots, parsnips,
&c.--should be rolled after planting. It will so smooth the surface,
that hoeing and cultivating can be done without injury to the plants.
The rows are also much more easily seen while the plants are young. Any
crop will grow better and larger by not being too much exposed to the
action of the atmosphere on its roots. When the soil is coarse, part of
the seeds and roots are greatly exposed to the action of the atmosphere,
and this exposure is very irregular. The roller so crushes the lumps and
fills up the openings in the soil as to cause the atmosphere to act
regularly on the whole crop. Few farmers stop to think that the pressure
of the atmosphere on their soils is fifteen pounds' weight on every
square inch, and that, hence, the air must penetrate to a considerable
depth into the soil; and where the soil is coarse, the air enters too
freely, and acts too powerfully for the good of the plants. Rollers are
made of wood, iron, or freestone. For most purposes, wood is best. A log
made true and even, or, better, narrow plank nailed on cylindrical ends,
are the usual forms. From eighteen inches to three feet in diameter is
the better size. Iron or stone rollers, in sections, are best for
pulverizing soil disposed to cake from being annually overflowed with
water, or from other causes.