pplications, provided the nitrogen and phosphoric-acid requirements
have been met. Clay soils contain far more potash than sandy soils, and
in a farming scheme for them that permits the use of manure and clover,
it may not become necessary to buy much potash. The liberal use of
straw in the stables, and the saving of all the liquid manure, are
helps. Farms from which the hay and straw have been sold for a long
period of time develop an urgent need of potash. Much muck land is very
deficient in this constituent.

Fertilizer Tests.--Every farmer should conduct some fertilizer tests
for himself. It is only the soil itself that can make an adequate reply
to a question regarding its needs. The test should be made under
conditions furnishing evenness in the soil, and it should be continued
for years. There is pleasure to an intelligent farmer in such
questioning of his soil, and only in this way can assurance be obtained
that the investment in fertilizers is the wisest that can be planned
for the farm.

There are only three plant constituents to be tested, but they must be
used in combination as well as singly. A soil that is deficient in the
three may not give any return from potash alone, and usually does not,
although it may give a marked increase from use of phosphoric acid
alone. The plats may be eight rods long and one rod wide, containing
each one twentieth of an acre, and having strips two feet wide
separating them. The following chart suggests quantities of fertilizers
to be used on the one-twentieth acre plats, 10 in number:

+---------------------------------------+
| Nothing. |
+---------------------------------------+
| 5 pounds nitrate of soda. |
+---------------------------------------+
| 18 pounds 14 per cent acid phosphate. |
+---------------------------------------+
| 4 pounds muriate of potash. |
+---------------------------------------+
| Nothing. |
+---------------------------------------+
| 5 pounds nitrate of soda. |
| 18 pounds 14 per cent acid phosphate. |
+---------------------------------------+
| 5 pounds nitrate of soda. |
| 4 pounds muriate of potash. |
+---------------------------------------+
| 18 pounds 14 per cent acid phosphate. |
| 4 pounds muriate of potash. |
+-------------------