A Rapid Test for Excesses of Copper in Sandy Soils 7

 3. Filter Paper.-A smooth surface filter paper is required.3
Cut into strips 3" x 4".
 4. Soil Sample.-The use of an adequate soil sample is just
as important for this test as for any other soil test. Volk and
Peech (12) discussed factors affecting the soil sampling pro-
cedure under citrus grove conditions. Wander (13) emphasized
the importance of using an adequate soil sample for testing
purposes and outlined the procedure for obtaining one. Samples
should be taken at the leaf drip or periphery of the tree to a
depth of 6 inches. At least 16 single samples should be taken
from the desired area and mixed as a composite to represent
the soil in this area. Usually one composite sample for an acre
or two should be sufficient. After the composite sample is air-
dried and thoroughly mixed the test can be carried out as out-
lined below.




















 Fig. 1.-A small amount of soil-approximately 2 grams-is placed on
a strip of filter paper in a cone-shaped mound. A small depression is made
in the top of the soil cone to allow the solution to penetrate the soil.

 RUNNING THE TEST
 Place about 2 grams of soil (approximately 1/2 teaspoonful)
on a strip of filter paper in a cone-shaped mound (Fig. 1). After

 SSouthern Scientific Company's filter paper No. 13061, formerly No. 7677,
was found to be suitable.