tock as they
mature and form seed. If grass be allowed to go to seed, most of the
nutrition in the stalk is used to form the seed.

[Illustration: FIG. 229. HARVESTING ALFALFA]

Hence a good deal of food is lost by waiting to cut hay until the seeds
are formed.

Pasture lands and meadow lands are often greatly improved by replowing
and harrowing in order to break up the turf that forms and to admit air
more freely into the soil. The plant-roots that are destroyed by the
plowing or harrowing make quickly available plant food by their decay,
and the physical improvement of the soil leads to a thicker and better
stand. In the older sections of the country commercial fertilizer can be
used to advantage in producing hay and pasturage. If, however, clover
has just been grown on grass land or if it is growing well with the
grass, there is no need to add nitrogen. If the grass seems to lack
sufficient nourishment, add phosphoric acid and potash. However, grass
not grown in company with clover often needs dried blood, nitrate of
soda, or some other nitrogen-supplying agent. Of course it is understood
that no better fertilizer can be applied to grass than barnyard manure.

SECTION LII. LEGUMES

Often land which was once thought excellent is left to grow up in weeds.
The owner says that the land is worn out, and that it will not pay to
plant it. What does "worn out" mean? Simply that constant cropping has
used up the plant food in the land. Therefore, plants on worn-out land
are too nearly starved to yield bountifully. Such wearing out is so
easily prevented that no owner ought ever to allow his land to become
poverty-stricken. But in case this misfortune has happened, how can the
land be again made fertile?

On page 24 you learned that phosphoric acid, potash, and nitrogen are
the foods most needed by plants. "Worn out," then, to put it in
another way, usually means that a soil has been robbed of one of these
plant necessities, or of two or of all three. To make the land once more
fruitful it is necessary to restore the missing food or foods. How can
this be done? Two of these plant foods, namely, phosphoric acid and
potash, are minerals. If either of these is lacking, it can be supplied
only by putting on the land some fertilizer containing the missing food.
Fortunately, however, nitrogen, the most costly of the plant foods, can
be readily and cheaply returned to poor land.

[Illustration: FIG. 230. ALFALFA READY FOR T