Ammonia in 1,000 grains of | | | | | |
soil after liming and | | | | | |
exposure to the vapor | | | | | |
of ammonia | 2.226| 2.066| 3.297| 1.076| 3.265| 1.827
Ammonia in 1,000 grains | | | | | |
of soil after exposure to | | | | | |
ammonia without liming. | 1.906| 2.557| 3.286| 1.097| 2.615| 2.028
----------------------------+------+------+------+------+------+------

No. 1. Surface soil of London clay.
No. 2. Same soil from 1-1/2 to 2 feet below the surface.
No. 3. Same soil 3-1/2 feet below the surface.
No. 4. Loam of tertiary drift 4 feet below the surface.
No. 5. Gault clay--surface soil.
No. 6. Gault clay 4 feet below the surface.

It is evident that lime neither assisted nor interfered with the
absorption of ammonia, and hence the beneficial effect of liming on such
soils must be accounted for on some other supposition. This negative
result, however, does not disprove the truth of Prof. Way's hypothesis,
for it may be that the silicate salt in the natural soils was that of
lime and not that of soda. Indeed, the extent to which the natural soils
absorbed ammonia--equal, in No. 3, to about 7,000 lbs. of ammonia per
acre, equivalent to the quantity contained in 700 tons of barn-yard
manure--shows this to have been the case.

_The lime liberated one-half the ammonia contained in the soil._

"This result," says Prof. Way, "is so nearly the same in all cases, that
we are justified in believing it to be due to some special cause, and
probably it arises from the existence of some compound silicates
containing ammonia, of which lime under the circumstances can replace
one-half--forming, for instance, a double silicate of alumina, with half
lime and half ammonia--such compounds are not unusual or new to the
chemist."

This loss of ammonia from a heavy dressing of lime is very great. A soil
five inches deep, weighs, in round numbers, 500 tons, or 1,000,000 lbs.
The soil, No. 1, contained .0293 per cent of ammonia, or in an acre,
five inches deep, 293 lbs. After liming, it contained .0169 per cent, or
in an acre, five inches deep, 169 lbs. The loss by liming is 124 lbs. of
ammonia per acre. This is equal to the quantity contained in 1200 lbs.
of good Peruvian guano, or 12-1/2 tons of barn-yard manure.

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