20 BULLETIN 462, U. S. DEPARTMENT OF AGRICULTURE. 
the hundred. The grades are uniform*in the latter case, the contours 
running about parallel to the rivers-edge. 
The surface soils of this flatwoods type generally are light and 
sandy, the percentage of sand increasing with the depth until the sub- 
soil is reached. The upper 6 or 8 inches often is rich in organic 
matter and dark in color, but a large percentage of the soil between 
the first foot and the subsoil appears to be mostly sand of a whitish 
or yellowish tinge. The small areas of muck or hammock lands have 
deeper surface soils and more organic matter throughout. The sandy 
soils offer very little resistance to the rapid percolation of water in 
times of heavy rain. 
Throughout the Sanford area there is a practically impervious sub- 
soil underlying the surface at depths varying from 1 foot to 5 feet. 
This impervious substratum is sometimes composed of a clay, but 
usually is of a sort of sandstone which appears to be cemented to- 
gether with a yellowish material apparently composed of organic 
materials containing considerable iron, and is very hard and nearly 
impervious. (See PL I, fig. 1.) 
The water supply for irrigation use is obtained entirely from 
flowing wells which vary in depth from 65 to 200 feet, the shallower 
wells being located close to the river. It is reported that there are 
at least 1,000 flowing wells in this district, most of them being 
used wholly or partly for irrigation purposes, although a number 
may water private garden patches only. The cost of the wells 
varies with the size and depth. There are few wells in use, however, 
over 4 inches in diameter, while practically every farmer adopts the 
2-inch size, which costs about $1 per foot complete. One well will 
irrigate 2 to 5 acres, depending upon the character of the soil and 
the flow of the well. A good 2-inch well will flow 30 to 100 gallons 
per minute, the better flow usually being on the lower elevations. 
It is a common practice for the farmer to have a number of 2-inch 
wells scattered over his farm rather than to attempt to get larger 
wells with greater capacity. Many farmers having 15 to 20 acres 
under cultivation will have four to seven wells, while others will 
make one well water 5 to 10 acres. The advantage of more wells 
is considerable, as rapid irrigation is especially desirable at the time 
of setting plants and depends upon the amount of water available. 
SUBIRRIGATION AS PRACTICED AT SANFORD. 
The application of water is accomplished by the so-called subirri- 
gation method. Briefly stated, this operation consists of running 
water through underground tile laid with open joints so that the 
water escapes at the joints and percolates through the ground, thus 
watering the plants in the course of time. In order to water the 
entire ground surface, the tiles are placed in parallel rows as close 
