Page 295 - Area 9 - Relevant Document

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 STEP 3. Randomize the treatments in each block. Randomize the
blocks independently. The number of blocks is the number of times
you do the randomization.
 Below is the hypothetical layout of the study of 5 treatments
replicated 4 times.

I II III IV

B E A B

E C D E
A B C D

C D B A

D A E C

GUIDES IN BLOCKING
Blocking is more often used in experiment on crops. . The
experimental area is the subject of blocking. Before blocking know
first the fertility gradient or the direction to which the soil differs in
fertility. In a sloping area the fertility gradient runs from the higher
portion to LOWER Portion the lower portion as the most fertile and
the higher portion as the least fertile..

RULE NO. 1. Always Block the area across the existing fertility
gradient.
RULE NO. 2. if fertility gradient runs in only 1 direction – long and
narrow blocks perpendicular to the gradient is recommended.
RULE NO. 3. If the fertility gradient runs in two directions, make the
blocks square in shape as closely as possible.
RULE NO. 4. If the fertility gradient cannot be determined at all,
square block is recommended.