Nitrogen is the most essential food for plant growth. It is an
important element of plant food in manure. In ordinary manure most
of the value is due to the nitrogen, although phosphoric acid and
potash are also present. It is found in the most available form in
nitrate of soda. Nitrate of soda will benefit all crops, but it does
not follow that it will pay to use it on all crops. Its cost makes
it unprofitable to use on cheap crops; but on those that yield a
large return nitrate of soda is a very profitable investment.

"It is shown in the experiments conducted with nitrate of soda on
different crops that in the case of grain and forage crops, which
utilized the nitrate quite as completely as the market garden crops,
the increased value of crops due to nitrate does not in any case
exceed $14 per acre, or a money return at the rate of $8.50 per 100
pounds of nitrate used, while in the case of the market-garden crops
the value of the increased yield reaches, in the case of one crop,
the high figure of over $263 per acre, or at the rate of about $66
per 100 pounds of nitrate." (New Jersey Agricultural Experiment
Stations, page 8, No. 172.)

Professor Voorhees, of the same station, experimented with tomatoes,
with these results:

Manure and Fertilizer Used Cost Per Acre Value of Crop

No manure $271.88
30 tons barnyard manure $30.00 291.75
8 tons manure and 400 lb. fertilizer 15.00 317.63
160 pounds nitrate of soda alone 4.00 361.13

Such common crops as tomatoes, cabbage, turnips, beets, etc., in
order to be highly profitable, must be grown and harvested early;
any one can grow them in their regular season; their growth must be
promoted or forced as much as possible, at the time when the natural
agencies are not active in the change of soil nitrogen into
available forms, and the plants must, therefore, be supplied
artificially with the active forms of nitrogen, if a rapid and
continuous growth is to be maintained.

It is quite possible to have a return of $50 per acre from the use
of $5 worth of nitrate of soda on crops of high value, as, for
example, early tomatoes, beets, cabbage, etc. This is an
extraordinary return for the money and labor invested; still, if the
increased value of the crop were but $10, or even $8, it would be a
profitable investment, since no more land and but little additional
capital was required in order to obtain the extra $5 or $8 per acre.

The results of all the experime