he sorrel out. There is constant
competition among plants for food and water and space, and some of our
worst weeds are not strong competitors of clover and grass where soil
conditions are not unfavorable to the latter.

Blue grass, the clovers and timothy give a good account of themselves in
a contest with sorrel and plantain where lime is abundant. This does not
mean that the seeds of these weeds may not be so numerous that an
application of lime cannot cause the clover and grasses immediately to
take the ground to the exclusion of other plants, but it is true that
the crowding process will continue until the time comes in the crop
rotation that these weeds cease to be feared, and clean sods can be
made. It is the absence of lime that permits such weeds to maintain
their reputation for good fighting qualities.

[Illustration: Limed and Unlimed Ends of a Plot at the Ohio Experiment
Station]

[Illustration: Effect of Finely Pulverised Limestone on Clover in a Soil
Having a Lime Requirement of 5200 Pounds of Limestone per Acre at the
Pennsylvania Experiment Station]

_The Clovers._ Red clover can make growth in some soils that have a lime
deficiency. If all other conditions are favorable, the lime requirement
may exceed one-half a ton per acre of fresh burned lime and not affect
the clover adversely, but farm experience throughout the country has
demonstrated that when soil acidity is only slight and clover grows with
difficulty, an application rarely fails to favor the clover in a marked
degree. Experience has taught the land owners to fear soil acidity when
red clover does not thrive where formerly it made good growth.

The prevalence of alsike clover in a farming region is indicative of
lack of lime. This clover thrives in a calcareous soil, but is more
indifferent to a small lime supply than is the red clover. As red clover
seedings begin to fail, the alsike gains in popularity, and where a soil
is decidedly sour the alsike is most in evidence. The latter has less
value to the farmer, rooting nearer the surface of the soil, and making
less growth of top, but it has gained in favor with farmers as soil
acidity has increased.

_The Grasses._ Timothy is more resistant to acidity than red clover,
but often fails to make a heavy sod where the deficiency in lime is
marked. Rhode Island Bent, known as redtop, is less exacting, and where
it thrives to the exclusion of timothy, or is in evidence in grass
lands, the i