Vermont watchman and State journal. [volume] (Montpelier, Vt.) 1836-1883, 1879-08-27

ply Of them in a soluble condition, since
having once become soluble in becoming a
part Of plant, they afterwards, to great
extent, remain so. The same effect is pro-
duced by the application Of stable manure,
since this manure is composed Of digested
and decayed plants, and contains the min
eral matter which they absorbed during
their growth.
Question--Wbat is the cause Of the de-
creasing crop of any cultivated plant grown
year after year on the same soil, without
manure
Answer-The principal cause is the ex-
haustion Of mineral plant food in soluble
condition.
Question-Ts there ever an absolute ex-
haustion of any one kind of plant food, or
only reduction Of the supply in soluble
state ?
Answer--No soil, originally fertile, is ever
entirely exhausted of any element of plant
food.
Question-How can the supply of such
food be economical SO as to last as long as
possible under cropping when no manure is
added
Answer-By thorough tillage, by rotation
of crops, by following and by rest.
Question-How by tillageP
Anscer-Because tillage continually sep
arates the particles of the soil and exposes
them to the influence of the weather, by
which new portions Of plantfood are rem
dered soluble in the soil water 1t has been
proved by experiment that tillage alone, if
deep, constant aud thorough, is capable Of
keeping up naturally good soil to the
point of profitable productiveness for very
long period of years.
Question-IIow by rotation Of crops2
Answer-Because different crops draw on
the soil for plantfood in different proper
tions. Some require much potash, but lit
tie phosphoric acid; some require little iron,
and so on. Now if you can follow crop
that requires much potash with one that re-
quires but little of that mineral you may
get good crop, and at the same time allow
soluble potash to accumulate in the soil by
the effects of climate, tillage and the chem
ical changes that take place there. A judi
cious rotation, following grain crops by root
crops, and these by grass, will preserve the
fertility Of the soil for a long time.
Queshon--How by following and rest ?
Answer-Strictly speaking, following and
resting soil is the same thing. But in prac-
tice they differ. By allowing land to rest,
absolutely, we mean abandoning it to itself,
which usually means allowing it to grow up
to weeds, bushes and trees. II this is done,
after longer or shorter period the land
may be cleared off and brought under tillage
again, when it will be found to have regained
its fertility in proportion to the time during
which it has lain uncropped. But by fall
lowing is understood either bare fallow,'
where the field is titled repeatedly, but no
no crop grown upon it, or a"green fallow y
where crop, such as buckwheat, rye, or
clover, is grown, not to be harvested, but To
be plowed under for the enrichment of the
land. A bare fallow is often very useful on
heavy soils; it is, in fact, simply tillage
without a crop. Light soils sometimes suf-
fer more by the loss of their volatile plant
food (see next chapter) than they gain by
the increase Of mineral plant food in bare
fallow, so that for these soils green fallow
is preferable,