Florida Agricultural Experiment Station


 Cultivation:-Groves probably should never be cultivated to
 a greater depth than three inches, since deep cultivation destroys
 a large percentage of the fibrous and smaller woody roots, which
 all too commonly deranges the growth of the trees and induces
 the development of mottle-leaf (frenching), exanthema (die-
 back), dropping of fruit, and other troubles. A generation or
 so ago it was considered good grove practice by many in Florida
 to plow deeply regardless of how many of even the larger woody
 roots were torn up. Fortunately, this detrimental practice has
 been largely abandoned of late years. Even today, however, we
 find an appallingly large amount of excessively deep and un-
 necessary cultivation practiced.
 The formerly widespread practice of excessive clean cultivation
 has been found by experience to be a bad practice, resulting in the
 depletion of the generally scanty supply of organic matter in the
 soil. Cultivation and soil building must be regarded as antag-
 onistic factors in Florida citrus groves. Under Florida con-
 ditions, the chief functions of cultivation are to destroy weed
 competition for moisture and fertilizer and to cut up and work in
 cover crops to reduce the fire hazard. It has been repeatedly
 claimed that intensive and frequent cultivation is necessary, es-
 pecially on the light, sandy soils of the ridge section, to main-
 tain a loose soil mulch and thereby conserve moisture by break-
 ing up capillary action. Recent experimental work, however,
 tends to minimize the value of this time-honored practice. It
 now seems to be pretty well established that cultivation does
 not conserve appreciable amounts of moisture in the soil, except
 to the extent to which it kills weeds which would rapidly with-
 draw moisture from the soil. At any rate, moisture losses by
 evaporation from grove soils are confined to the upper few inches
 whether the soils are cultivated or not, while moisture losses
 through use by trees extends to a depth of a few feet. These
 findings are particularly significant to Florida growers since the
 majority of our grove soils have a limited capillary action and
 by reason of their loose texture are obviously self-mulching.
 Moreover, experience seems to bear out the fact that the more
 light, sandy soils are stirred the more readily they dry out. It
 therefore appears that the cultivation of our sandy grove soils
 in excess of that required to keep down the growth of weeds
 during dry seasons and to work in cover crops sufficiently to
eliminate the fire hazard is not only a needless waste of time and