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S7q9-/ Agricultural Research & Education Center
IFAS, University of Florida
Bradenton AREC Res. Rept. GC1979-14 August 1979
COMPARISON OF YIELD AND WATER USE OF BROCCOLI, SWEET CORN, AND ZUCCHINI
SQUASH WITH SEEP AND DRIP IRRIGATION METHODS
Alexander A. Csizinszky
Production of several vegetable crops in southwest (SW) Florida is based
upon the use of full bed plastic much, large amounts of high analysis fertilizers
and irrigation water.
In recent years, regulatory agencies increased pressure on the agricultural
industry to reduce the amount of water used in the production of various crops
in order to prevent the excessive depletion of underground water which, at present
is used as the main source of irrigation.
To reduce the water consumption by the agricultural industry, drip or trickle
irrigation, instead of the traditional seep irrigation, was tried by researchers
and growers. However, there are no references available to compare the efficiency
of the seep and drip irrigation systems under SW Florida conditions for the produc-
tion of various vegetable crops. Investigations were started, therefore, at the
AREC-Bradenton to compare the yield and the amount of water used to produce
vegetables with the seep and drip irrigation methods. In this report the results
of the experiments conducted in the spring of 1978 are summarized.
Materials and Methods
In February 1978, five-week old seedlings of broccoli (Green Comet Hybrid)
and two-week old seedlings of zucchini squash (Fordhook) were transplanted, and
seeds of sweet corn (Silver Queen) were sown in a field of Myakka fine sandy soil
with a hardpan at approximately 32 in. Beds were formed with 4.5 ft centers.
8 in. high, and 2.5 ft. across the top. In both the seep and drip irrigated
lands, lateral ditches were formed after every 7th row; thus a total of 7,350
row ft. per acre (A) were used for production and the area under plastic mulch
.was 18,369-sq. ft./A. In this report the nutrients applied are expressed on a
100 row ft., instead of the per acre basis, since it more precisely describes
the amount of fertilizer used. Both lands were fumigated with MC-33, at a rate
of 3.6 Ibs per 100 row ft., applied with 3 chisels 14 days before transplanting.
At the same time mole cricket and cutworm bait (Difonate) at a rate of 2 lbs/1000
sq. ft. and fertilizers were applied. Superphosphate (20%) with fritted micro-
nutrients at a rate of 3.9 lbs/100 row ft. was broadcast and 18-0-25 + 2 at a
rate of 10.3 lbs/100 row ft. was applied in 2 bands. In the seep irrigated land
the fertilizer bands were applied 12 in., and in the drip irrigated land 8 in.,
from the bed.center. Water in the drip irrigated land was applied through a
duPont Viaflo, Typ- 2(R) single seam tape and was placed 2 in. from the center
and 2 in. below the soil surface. Black polyethylene film, 1.25 mil thickness,
was laid over the entire bed in both lands. Hater in the seep irrigated land
was applied at a rate of 0.524 acre inches (A in.) per day (14,231 gal/A)
throughout the season and irrigation started 2 days before planting the crop.
In the drip irrigated land, the flow rate was 9.6 gallons per minute (gpm) per
tube for a 300 ft. long row at 3.5 Ib/sq. in. pressure, regulated by a Dole flow
control valve. Amount of water applied was adjusted at 10 day intervals to
provide adequate soil moisture as plant size, air temperature, day length and
daily evaporation changed, according to the recommendations of G. A. Marlowe,
Jr. and J. S. Rogers (1). Water was turned off in both fields when daily
precipitation exceeded 0.75 in. Within row planting distances in the 25 ft
long replicated plots were 18 in. for broccoli and 30 in. for zucchini.
Sweet corn was seeded 8 in. apart in double rows. Plants were sprayed weekly
with approved pesticides. At harvest, weight of marketable yield was taken.
Results and Discussion
Irrigation water applied and rainfall received during the season for seep
and drip irrigated lands are presented in Table 1 and Table 2.
With seep irrigation, the rate of water application was uniform throughout
the season (Table 1) affected only by the number of rainy days during which the
irrigation water was turned off. With drip irrigation, the quantity of water
applied was increased gradually as the season progressed, then reduced as plant
growth decreased for the sweet corn and zucchini. Under weather conditions in
the spring season in SW Florida, such a reduction of irrigation water may not
always be feasible for certain vegetables.
S The amount of water applied by irrigation for the crops in the seep method
was much higher than in the drip system (Table 3). Broccoli received 3.48,
sweet corn 2.75, and zucchini 3.13 times more irrigation water with the seep
than with the drip method.
Yield of broccoli per plant and per acre was higher with seep irrigation
(Table 4). Weight of individual broccoli sprouts in the seep irrigated plots
was 11 oz and in the drip irrigated plots 7 oz. Sweet corn in the drip irrigated
plots did not germinate uniformly. Plant stand was only 88% compared to seep
irrigated plots. However, there were no differences in yield per plant between
the two irrigation systems. Zucchini yields per plant and per acre were almost
identical in both irrigation systems.
Water used per lb. of marketable yield declined as yield of vegetable crops
increased (Table 5). Broccoli used the highest amount of water per lb. of yield,
followed by sweet corn and zucchini. If water supply in Florida in the future
becomes critically short in some areas, we may have to select vegetable crops
on the basis of the nutritional value produced per acre relative to water used.
In the experiments the flow of water in the seep irrigated plots was not
regulated. Large amounts of water ran off at the end of the lateral irrigation
ditches. At the AREC-Bradenton, experiments are under way to regulate the
amount of water applied by seep irrigation in the production of vegetable crops,
without reducing the quality and quantity of their yield.
Drip irrigation systems have a higher equipment and installation cost than
the seep system. Also, the yields of certain vegetable crops are lower with
the drip system under the experimental conditions described in this report.
These disadvantages of the drip system have to be taken into consideration when
comparing costs with 1he amount of water saved when selecting an irrigation
mehtod for vegetable crop production.
1. Marlowe, G. A., Jr., and J. S. Rogers. 1976. Water use by Florida vegetable
crops. Vegetable Crop Extension Report No. 16-1976. IFAS, University of
schedule for broccoli, sweet corn, and zucchini. Spring 1978.
No. of irri-
gation days 8
Rain (in.) 1.13
Table 2. Drip irrigation
ir. Mar. 25- Apr. Apr.
i-25 Apr. 3 4-13 14-23
0 10 10 10
524 0.524 0.524 0.524
241 5.241 5.241 5.241
0 0.12 0.04
rainfall received for broccoli,
and zucchini. Spring
No. of irri-
Table 1. Seep irrigation
Table 3. Water applied for broccoli, sweet corn, and zucchini with seep and
drip irrigation. Spring 1978.
Growing season, days
The ratios of the quantity of water received in seep vs. drip irrigation are
Table 4. Yield of broccoli, sweet corn, and zucchini with seep and drip
irrigation, Spring 1978.
Broccoli Sweet corn Zucchini
Seep Drip Seep Drip Seep Drip
Number of plants I
per acre 4,900 4,900 22,050 19,404 2,940 2,940
Yield per plant
lb2 0.68 0.44 0.42 0.42 13.50 13.92
Yield per acre,
ton2 1.67 1.08 4.63 4.07 19.85 20.46
88% of seeds germinated
2Average of 4 replications for seep and 3 replications for drip irrigated plots.
Table 5. Water applied per plant with seep and drip irrigation and to
produce 1 lb of marketable yield. Spring 1978.
Broccoli Sweet Corn Zucchini
Seep Drip Seep Drip Seep Drip
gal per plant 164 47 47 20 409 131
Rain, gal per plant 18 18 15 17 116 116
gal per plant 182 65 62 37 525 247
gal per lb of yield 241 107 112 48 30 9
Total water, gal268 148 148 88 39 18
per lb of yield 268 148 148