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AGRICULTURAL RESEARCH CENTER
Hastings ARC Research Report PR-1975-9
SUBSURFACE DRAINAGE AND IRRIGATION FOR POTATOES ON LOW FLATWOOD SOILS.
D. R. Hensel, Center Director, ARC, Hastings, Florida. J. S.
Rogers, Agricultural Engineer, USDA, ARS, in cooperation with
IFAS, University of Florida. K. L. Campbell, Agricultural
Engineer, Agricultural Engineering Department, IFAS.
In 1973, three water furrows were replaced by subsurface drains (corrugated, slot-
ted, plastic tile) on the Yelvington Agricultural Research Farm at Hastings. The
drains replaced the water furrows which were normally spaced at 60 ft. intervals.
The potato beds with the tile drains increased from 16 to 18 rows.
The three 4 inch drains were placed about 24 inches below normal level of the field.
One end of the drain discharged into an open ditch and the other end was brought to
ground surface. Irrigation water could be added to the tile lines and the water
table raised to the desired depth by raising the outlet end in the open ditch dur-
ing dry periods. During wet periods the outlet pipe would be dropped and water
table lowered to desired depth. In addition excess surface water was removed by
the conventional cross cuts and tile drain placed at row alley height at lower end
of field. \..
The system was monitored by placing water table recorders mid-point between i-6
lines. The corrugated plastic drains had a nylon mesh envelope material whib
helped to keep the fine sand material from clogging the tile. Inspections of the
tile drains were made after both seasons and were found to have no apparent pro-
blems. Discharge tanks were installed in 1975 in order to monitor the system more
closely. A grower would not have to encounter this expense.
Potatoes were planted late January 1974 and harvested in late May. In 1975 pot~~t'
toes were planted in February and harvested in May. Due to inferior seed potat'ons,
some replantings were made during the last week in February.
During a typical heavy rain the water table under both systems rose quickly to the
alley surface. After the rain, the drop in the water table was noticeably more
rapid in the tile drain area than in the conventional water furrow system. The
conventional water furrow method took approximately two days longer to reduce the
water table in the center of the potato bed to the desired depth.
In Table 1, the potato yields for 1974 and 1975 are presented. The conventional
subsurface irrigation system has 11,616 linear row feet per acre and the tile sys-
tem has 13,068 feet which represents an increase of 12.5%. In 1975 none of the
rows directly over the tile drains were replanted, and their respective yields were
lower. This was taken into consideration in comparing the two systems. In 1974, a
56% increase in yield was obtained and in 1975 the yield increase ranged from 35 tc
46 percent. During growing seasons with greater rainfall than 1974 and 1975, lar-
ger increases could be expected. In seasons without heavy rains the differences
may be less.
October 30, 1975-300 copies
In 1974, no soil fumigants were used, and the potatoes were severely affected with
corky ringspot which partly accounts for a lower percentage of U.S. No. 1 potatoes.
In 1975, the soil was treated with a contact nematicide which was water soluble. As
a result the control was less effective and corky ringspot was found in the two
rows directly over all three tile drains. Corky ringspot was not found in any other
rows between tiles.
The above data was obtained on tile drains which were approximately 300 feet in
length. Growers may want to try a limited acreage using longer tile drains. At a
spacing of 60 feet, 725 linear feet of tile per acre is required. With total in-
stallation costs ranging between 50 to 75 cents a foot it becomes a management
decision whether to invest this amount of capital. Possibly a cost sharing program
at some future date may be an alternative.
Table 1. Potato Yields on Subsurface and Tile Drainage Systems at ARC,
Year Variety Irrigation Yield-/ Increase due to
US No. 1A Total tile
1/Subsurface yields are based on 11,616 feet of planted row per
treatments include actual yield of an additional 1,452 row feet
water furrow rows). In 1975 these were not replanted.