heavier applications killing from 98 to
99 per cent.

Borax has no injurious effect on the chemical composition or rotting of
the manure. However, when added in large quantities with manure to the
soil it will cause considerable injury to growing plants. A number of
experiments have been conducted to determine the effect on crops of the
use of manure treated with borax as herein recommended. When applied at
the rate of 15 tons per acre it appears that no injury as a rule will
follow. Some crops are more sensitive to borax than others, and also the
tendency to injury appears to vary on different soils. It is necessary,
therefore, to repeat the warning issued in connection with a previous
bulletin[11] on this subject, that great care be exercised, in the
application of borax, that the manure does not receive more than 1 pound
for every 16 cubic feet, and that not more than 15 tons of manure so
treated are applied to the acre.

In view of the possible injury from the borax treatment as a result of
carelessness in applying it, or from other unforeseen conditions, it is
recommended that horse manure and other farmyard manures which are to be
used as fertilizer be treated with hellebore. Borax, on the other hand,
is such a good larvicide that it call be used with advantage on the
ground of soil-floor stables, in privies, on refuse piles, and on any
accumulations of fermenting organic matter which are not to be used for
fertilizing purposes.

[Footnote 11: Department Bulletin 118, U. S. Department of Agriculture,
p. 25.]

TREATMENT WITH CALCIUM CYANAMID AND ACID PHOSPHATE.

Many experiments with mixtures of commercial fertilizers were tried to
determine whether fly larvae would be killed by any substance the
addition of which would increase the fertilizing value of the manure. A
mixture of calcium cyanamid and acid phosphate was found to possess
considerable larvicidal action. Several experiments showed that 1/2
pound of calcium cyanamid plus 1/2 pound of acid phosphate to each
bushel of manure give an apparent larvicidal action of 98 per cent. The
mixture in the form of a powder was scattered evenly over the surface
and then wet down with water. The use of this mixture adds to the manure
two important elements, nitrogen and phosphorus.

MAGGOT TRAP FOR DESTRUCTION OF FLY LARVAE FROM HORSE MANURE.

The second method of handling manure is one which does not require the
application of chemicals. It is based on the f