IRRIGATION IN FLORIDA. 25 
terns in Florida, but in such cases it is possible that the water plane 
stood above the tiling for long periods, thus preventing the entrance 
of tree roots, as the roots of most cultivated trees will not penetrate 
below the level of the usual water plane. 
There are several groves near Terra Ceia that are subirrigated 
and at least one grove near Palatka. At the present time these sys- 
tems are working well, and are especially valuable from a drainage 
standpoint. As these installations are new it can not be determined 
how long they will withstand clogging by the tree roots. The sub- 
soil surrounding the tile may be of such character as to keep roots 
away from the tile or the ground water may be high enough to dis- 
courage deep rooting. Still there is considerable danger of clogging 
if the ground water should be lowered by protracted drought or by 
artificial drainage on a large scale. 
A common rotation of crops in the Sanford trucking district is as 
follows: first, lettuce is planted about September 1 and harvested 
about the middle of October. This is followed by celery, which 
should be harvested by February. Cucumbers may follow immedi- 
ately and should be off the ground by the first week in May. Corn 
then can be planted and harvested in August. There still remains 
enough time to grow a crop of native hay before the time to plant 
lettuce again. 
Many of the farmers follow an entirely different schedule, al- 
though most of them plant celery. Some plant celery in October and 
get two crops, the last crop being harvested in July. Others, plant 
beans, cabbage, cauliflower, and various other vegetable crops, while 
still others plant a considerable acreage of potatoes. The winter 
truck crops are shipped to the northern markets, while the corn and 
hay crops usually are consumed at home. 
It has been stated that the cost of tiling averages $100 to $125 per 
acre. This would be a heavy outlay for many crops, but when the 
total cost of equipping land and the annual expense of growing a 
celery crop is considered, the cost of irrigation does not seem ex- 
orbitant since the cost of equipment, outside of irrigation, is about 
$450 per acre. 
It should be emphasized that the Sanford subirrigation method 
serves also for drainage — entirely, in fact, for some crops. This is 
true especially for the summer cropping during the rainy season and 
frequently during heavy. rains in the winter season. There are some 
disadvantages in having subirrigation and drainage systems com- 
bined, one being the large loss resulting from the draining away of 
expensive fertilizers; and another, the need of saturating the soil in 
order to get enough moisture at the surface. Even if other methods 
of irrigation were used, however, it would be necessary to have 
drainage systems installed to take care of excess water, and when it 
61867°— Bull. 462—17 4 
