AGRICULTURAL UTILIZATION OF, ACID LANDS 9 
indication of its resistance to acidity, for such lands are usually acid. 
Tf, however, the mineral food is actually insufficient and there is no 
humus from which nitrogen can be extracted, one can not reasonably 
expect a heavy yield, even from buckwheat. The plant can with- 
stand acidity, but not starvation besides. A reasonable amount of 
humus, such as is easily provided by plowing under a good legumi- 
nous crop, will ordinarily result in heavy yields of buckwheat. 
REDTOP. 
The principal grasses of ordinary agriculture, notably bluegrass 
and timothy, do poorly in acid land. To this general rule, however, 
there is one notable exception, redtop. This grass often reaches a 
luxuriant development in markedly acid lands. The stem growth of 
redtop, however, is so light compared with that of timothy that it is 
not recommended as a substitute so far as the production of hay is 
concerned, but, lke bluegrass, its bottom growth is heavy and it 
makes an excellent pasture. 
> 
CORN. 
Corn yields well under acid conditions if the soil is well provided 
with humus and the usual mineral nutrients. It may be regarded. 
as a plant having a fair degree of acid tolerance. 
CARROT. 
The carrot, as might readily be inferred from its common occur- 
rence as a weed in old and worn-out fields, is decidedly tolerant of 
acidity. It grows almost equally well in either type of soil. 
TURNIP. 
The common turnip produces good though probably not maximum 
yields on acid land, differing in this respect from the rutabaga, or 
Swedish turnip, which yields wel! only in neutral or alkaline soils. 
LEGUMINOUS PLANTS FOR ACID SOILS. 
While the crop plants thus far enumerated furnish material for 
such agricultural necessities as grain, grain hay, fodder, root crops, 
cover crops, pasturage, and small fruits, they do not supply the 
nitrogenous green manures which are necessary to the maintenance 
of soil fertility under most agricultural conditions and which are 
satisfactorily derived only from leguminous plants. It is admitted 
that in acid-land agriculture red clover, the ordinary green-manure 
crop, 1s not available for this purpose. What, then, are the legumi- 
nous plants which will produce in an acid soil a heavy growth of 
tops equal in value to red clover for plowing under as green manure ? 
The answer is, cowpea and hairy vetch. Crimson clover, soy bean, 
lupine, and serradella are also useful under certain conditions. 
