top-dressing for grass? I will not
say that it was due solely to the decomposition of the nitrogenous
matter and other plant-food in the earth, caused by the working over and
sifting and exposure to the air, and to the action of the night-soil.
Still it would seem that, so far as the beneficial effect was due to the
supply of plant-food, we must attribute it to the earth itself rather
than to the small amount of night-soil which it contained.

It is a very common thing in England, as I have said before, for farmers
to make a compost of the sods and earth from an old hedge-row, ditch, or
fence, and mix with it some lime or barn-yard manure. Then, after
turning it once or twice, and allowing it to remain in the heap for a
few months, to spread it on meadow-land. I have seen great benefit
apparently derived from such a top-dressing. The young grass in the
spring assumed a rich, dark green color. I have observed the same effect
where coal-ashes were spread on grass-land; and I have thought that the
apparent benefit was due largely to the material acting as a kind of
mulch, rather than to its supplying plant-food to the grass.

I doubt very much whether we can afford to make such a compost of earth
with lime, ashes, or manure in this country. But I feel sure that those
of us having rich clay land containing, in an inert form, as much
nitrogen and phosphoric acid as Dr. Voelcker found in the soil to be
used in the earth-closet at Wakefield, can well afford to stir it
freely, and expose it to the disintegrating and decomposing action of
the atmosphere.

An acre of dry soil six inches deep weighs about 1,000 tons; and
consequently an acre of such soil as we are talking about would contain
6,200 lbs. of nitrogen, and 3,600 lbs. of phosphoric acid. In other
words, it contains to the depth of only six inches as much nitrogen as
would be furnished by 775 tons of common barn-yard manure, and as much
phosphoric acid as 900 tons of manure. With such facts as these before
us, am I to blame for urging farmers to cultivate their land more
thoroughly? I do not know that my land or the Deacon's is as rich as
this English soil; but, at any rate, I see no reason why such should not
be the case.

CHAPTER XXIX.

MANURES FOR BARLEY.

Messrs. Lawes and Gilbert have published the results of experiments with
different manures on barley grown annually on the same land for twenty
years in succession. The experiments commenced in 185