and other plant-food which the soil
contains is not in an available condition. It lies dead and inert. It is
not soluble, and the roots of the plants cannot get enough of it to
enable them to thrive; and in addition to this, you will find as a
matter of fact that these poor 'exhausted' farms are infested with
weeds, which rob the growing crops of a large part of the scanty supply
of available plant-food."

"But these weeds," said the Deacon, "are not removed from the farm. They
rot on the land; nothing is lost."

"True," said I, "but they, nevertheless, rob the growing crops of
available plant-food. The annual supply of plant-food, instead of being
used to grow useful plants, is used to grow weeds."

"I understand that," said the Deacon, "but if the weeds are left on the
land, and the useful plants are sold, the farmer who keeps his land
clean would exhaust his land faster than the careless farmer who lets
his land lie until it is overrun with thistles, briars, and pig-weed.
You agricultural writers, who are constantly urging us to farm better
and grow larger crops, seem to overlook this point. As you know, I do
not take much stock in chemical theories as applied to agriculture, but
as you do, here is a little extract I cut from an agricultural paper,
that seems to prove that the better you work your land, and the larger
crops you raise, the sooner you exhaust your land."

The Deacon put on his spectacles, drew his chair nearer the lamp on the
table, and read the following:

"There is, on an average, about one-fourth of a pound of potash to every
one hundred pounds of soil, and about one-eighth of a pound of
phosphoric acid, and one-sixteenth of a pound of sulphuric acid. If the
potatoes and the tops are continually removed from the soil, it will
soon exhaust the potash. If the wheat and straw are removed, it will
soon exhaust the phosphate of lime; if corn and the stalks, it will soon
exhaust the sulphuric acid. Unless there is a rotation, or the material
the plant requires is supplied from abroad, your crops will soon run
out, though the soil will continue rich for other plants."

"That extract," said I, "carries one back twenty-five years. We used to
have article after article in this strain. We were told that 'always
taking meal out of the tub soon comes to the bottom,' and always taking
potash and phosphoric acid from the soil will soon exhaust the supply.
But, _practically_, there is really little danger of