ghly specialized products. The operator must learn
how to work in harmony with the peculiarities of his own soil before he
can hope to get the best results.

In acquiring a tract for the growing of plants of any kind it is desirable
to get a soil type that will meet the requirements of most plants. As a
general rule, this type contains enough clay to be retentive of moisture,
enough sand to be easily worked and is generally suitable for bacterial
growth. In other words, what is commonly called a loam is the ideal type
for general agricultural and horticultural purposes. This may be a heavy
loam, in which clay predominates, or a so-called light loam, in which sand
particles predominate. An examination of a handful of soil by a person
experienced in farming will indicate its nature and its adaptability to
ordinary crop production.

_Essential Elements of Plant Food._--Countless scientific experiments in
plant growth show that potassium, lime, phosphorus, magnesium, iron,
sulphur, nitrogen, carbon, oxygen and hydrogen are essential to normal
development. The carbon, hydrogen and oxygen elements make up nearly 99
per cent of the entire composition of the plant and are derived from the
atmosphere. All of the other elements are derived from the soil except in
the case of peas, beans, clovers and other legumes which secure most of
their nitrogen from the air.

The mineral elements are not needed in large amounts but well-balanced
plant growth is strictly dependent upon their presence in available form.
Of these elements, those most likely to be deficient either in total
amount or in availability are nitrogen, phosphorus, potassium and calcium.
It is entirely feasible and economical to apply concentrated chemical
fertilizers containing the first three elements so that their lack will
not constitute a limit to size of crops harvested. In many cases it is
necessary to apply chemical fertilizers to get satisfactory yields, even
where natural manures are available and can be applied as well.

In addition to supplying essential plant food, nitrogen, phosphorus and
potassium perform specific functions in plant growth. The application of
nitrogen in one of its readily available forms (e.g., nitrate of soda and
sulphate of ammonia) will stimulate vegetative growth. If too much of this
one element is applied, leaf and branch development may occur at the
expense of the crop. Good results follow the use of nitrogen on grass sods
and on