Mineral Nutrition Status of Valencia Orange 5

citrus cooperatives, caretakers and independent growers. The
names of the cooperators are listed in the Appendix (Table C.).
 All the trees were on rough lemon rootstock and were be-
 tween 14 and 47 years old. Most of the groves were situated
 on well-drained acid sandy soil. The size of the groves ranged
 from five to 20 acres. To obtain representative samples, groves
 larger than 20 acres were subdivided into smaller blocks and
 separate samples were collected from each block.

 COLLECTION AND PREPARATION OF SAMPLES

 The sampling procedure followed was similar to the one used
by Wilson et al (31). The sampling area, which consists of 20
trees in a diamond shape, covered an area of approximately two
to three acres, depending on the spacing of the trees in the block.
A diagram of a sampling area is shown below:

 (10


 (a Ia
 (7 '?
 (6 '14-

 _4 16)

 IsB)
 9)
 20)
 x
 X = Tagged tree.
 ( = Side of tree where samples are collected.

 The sampler started from the tree diagonally to the left of
the tagged tree and proceeded according to the diagram until he
finished up at the tagged tree, thus taking equal portions of the
sample from the specific side of each tree as shown in the dia-
gram. On a small number of blocks which were long and nar-
row, the sampler started from the tagged tree and proceeded
diagonally as shown in the diagram until the tenth tree was
reached. Instead of turning right at that point as shown in
the diagram, he turned 90 degrees left and proceeded for five
more trees before turning right again for the last five trees.