Florida Agricultural Experiment Station


be modified to avoid, as much as possible, any plowing. In most
cases the grass and weeds and legumes should be removed as hay
or left to rot without being turned under. Where necessary to
break up the sod in order to use the Acme harrow, the cut-away
harrow will be better than a plow.
 In the early years of the citrus industry clean cultivation was
practiced extensively. By this method the soil was cultivated
thruout the year. No growth of grass or legumes was allowed
to be made. This was found by experience to be a bad practice.
After a time the humus content of the soil was so reduced that
the soil was put into a condition not conducive to growth. The
excessive stirring of soil was found to be favorable to develop-
ment of dieback. This system is seldom used at the present time.
 Mulching the trees with a heavy covering of grass, weeds or
legumes is a good substitute for cultivation and should be used
during the dry season to hold the moisture in the soil if a dust
mulch is not maintained. The chief objection to this mulch is
that it is difficult to obtain mulching material in some localities
and the danger during dry periods of fire spreading thru the
grove. Pine straw is not a good material to use as a mulch; it
sometimes causes young trees to turn yellow. When worked into
the soil it does not decay readily and substances in the leaves
put the soil into a poor physical condition.
 It sometimes happens that Bermuda grass gets started in the
grove and the grower tries to eliminate it by cultivation. The
deep and continued cultivation necessary to do this will often
throw the trees into a dieback condition. It was formerly thought
that a Bermuda sod was very harmful to the grove. It has been
found by experience that such is not the case.
 The repeated growth of corn and other crops that require
deep cultivation may bring on a dieback condition of the trees.
The occasional growth of such crops is probably not harmful.
Care should be taken to use a fertilizer for such crops that is
adapted to the trees.
 It is a common practice along the lower East Coast of Florida
to raise pineapples between the rows of grapefruit trees. A
regular organic fertilizer is given the pineapples but no fertilizer
at all is given the trees. The trees make a thrifty growth and
dieback is much less prevalent than might be expected. It is
probably explained by the particular type of soil, the small
amount of cultivation given, and the heavier feeding ability of
the grapefruit trees.