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AGRICULTURAL RESEARCH & EDUCATION CENTER
SIFAS, University of Florida
~D radenton, Florida
UBradenton AREC Research Report GC1981-13 November 1981
RESPONSE OF A FALL CROP OF GREEIl PEPPERS TO SEEPAGE AiND HIGH FREQUENCY
TRICKLE IRRIGATION A PRELIMINARY REPORT
A. A. Csizinszky
In the fall of 1979, green peppers cv. 'Early Calwonder' were grown in raised
mulched beds to investigate their yield potential with a single pre-plant application
of dry fertilizers with trickle irrigation. Green peppers grown with the conven-
tional seepage (modified furrow) irrigation served for a comparison of yield for the
IiATERIALS AND METHODS
Experiments were conducted at the AREC-Bradenton on Hyakka fine sand with a
hardpan at approximately 30 in. from the soil surface. The trickle irrigated plot
was located in a field surrounded with a rim ditch, 4 ft. wide and 4-5 ft. deep, to
exclude ground water from other sections of the farm.
Seven plant beds, 30 in. wide, 9 in. high with 54 in. centers, were formed
between tw;o lateral irrigation furrows 41 ft. apart in both seepage and trickle
irrigated land. In the trickle irrigated land, lateral furrows served as drainage
ditches after heavy rainfall. Uith both irrigation systems 7,430 ft. of plant bed
were formed per acre. In this paper, amount of fertilizers and yield per acre are
reported on this basis.
Bed fertilizer mix consisted of a 20% superphosphate at a rate of 600 Ib/A,
38-0-0 and 18-0-25 + 2 each at 75 Ib/A. Superphosphate contained fritted micro-
nutrients at 80 lb/ton.
In the seepage irrigated land, bed fertilizer mix was broadcast in the full
width of the pre bed. Then beds were formed, pressed, and a soil fumigant, 4iC-33
(66% methyl bromide) was applied with 3 chisels at a rate of 152 Ib/A. The main
fertilizer, 18-0-25 + 2 was banded on the shoulders of the plant bed at 1800 Ib/A.
The total amount of nutrients applied were 366 Ib/A N, 120 P205, and 469 K20.
In the trickle irrigated land the same types and amounts of fertilizers were
applied as in the seepage irrigated land. However, the placement of fertilizers in
the plant bed was different. The bed mix was applied in a 12 in. wide band in the
center of the bed, then mixed in the soil to a 3 in. depth. Next the soil was
pressed and fumigated, then 18-0-25 + 2 fertilizer was applied in a 2-3 in. wide
band on the bed center. Trickle tube, Chapin double wall, 4 mil thickness, 14 in.
hole spacing, was laid in the center of the bed to a depth of 2 in. so that the
banded fertilizer was above and around the tube. Plant beds were covered with a
white 1.25 mil thick polyethylene.
On Sept. 10th, 12 days after fumigation, five-week old seedlings of the cv.
'Early Calwonder', raised in Speedling trays with 1.5 in. cells, were set in 25 ft.
long plots in double rows at 12 in. between and 12 in. within row spacing (14,00
plants/A). In both seepage and trickle irrigated lands, 3 plots were planted with
In the seepage irrigated land, irrigation rate was regulated to allow the water
to flow through the full length of the furrow with a minimum or no runoff. Uater was
turned off when daily precipitation exceeded 0.4 in. In the trickle irrigated land,
a clock regulated time and length of water application through a solenoid and a
3.5 gal/min. capacity Dole valve. Water was applied 4-7 times per day for 5-14 min.
each application. The volume of water applied per day was increased by regulating
the number of daily applications and the length of flow time at each application as
the season progressed and plant size increased.
Soil moisture was determined by the oven dry method. Soil samples in the
trickle irrigated land were taken from the shoulder and tube region and from the
plant row at 3 depths: 0-2, 2-4, and 4-9 inches. In the seepage irrigated plots,
moisture samples were taken from the shoulder region and plant row at the 3 depths
Total soluble salt (TSS) content in the soil was determined by the saturated
paste extract method immediately after fertilizer application and after harvest.
Major plant nutrient levels were analyzed in young mature leaves and petioles at
the end of the harvest. Nitrogen by the modified Kjeldahl method, P colorimetri-
cally, K, Ca and Mg at atomic absorption spectrophotometry. Fruit was picked 3
times during the season. At harvest, number and weight of fruit were taken. At
the end of the season, all fruit remaining on the plants were removed and counted.
Statistical analysis was not performed on the data because on soils with a
hardpan at 2-3 ft below the soil surface, field experiments with seepage and trickle
irrigation systems cannot be set up and randomized on the same piece of land. The
high soil water table maintained with the seepage system makes impossible the separ-
ation and evaluation of the 2 irrigation systems on the same land at the same time.
RESULTS AND DISCUSSION
Amount of irrigation water applied, rainfall, open pan (OP) evaporation for the
season in 10 day intervals with the seepage and trickle irrigation methods are on
Tables' 1.and 2.
With seepage irrigation approximately 26.0 A in. and with trickle irrigation
7.8 A in. of irrigation water was applied for the green pepper crop, calculated on
a gross acre basis (2). The amount of irrigation water applied with the trickle
system is below that of the measured pan evaporation for the season.
The quantity of irrigation water applied in the two irrigation systems was not
correlated with OP evaporation, average maximum or average minimum air temperatures.
The reason for the lack of correlation of irrigation with environmental factors
during the fall season was that with seepage irrigation a constant soil water table
had to be maintained under the entire cultivated area. The soil moisture content
and the depth of the soil water table depends on the rainfall. After the rainy
season, precipitation was reduced, but average maximum and minimum temperatures
remained high and plants also grew rapidly. Therefore, large amounts of water had
to be applied to maintain a relatively even soll water table at approximately 18 in.
below the top of the mulched beds during the entire season.
In the trickle irrigation system, water was applied frequently in small amounts
at or near the plant root zone to maintain a moisture stress free atmosphere for the
plants. There is very little evaporation (except through the planting hole) from
the soil. under the plastic mulch. Irrigation water in the experiments had'to be'
applied in gradLally.increasing amounts for the pepper crop during the season regard-
less of the decreasing OP, average maximum and minimum temperature values, in order
to maintain a relatively even moisture content at the 5-9 in. soil depth (Tables 2
and 3). The largest amount of irrigation water at a constant rate of 0.103 in. per
day, was applied towards the end of the season, from Nov. 13 to Dec. 26, when average
maximum and minimum temperatures were cooler andmeasured OP evaporation was reduced
Marketable yield of green peppers were 804 bu/A with seepage and 816 bu/A with
trickle irrigation (Table 4). These yields are 50% higher than the average green
pepper yield for Florida in 1979 (1). The average fruit size was larger with trickle
than with seepage irrigation, 5.94 oz and 4.79 oz, respectively. Total number of
fruit set, including immature and cull fruit, was higher with seepage irrigation,
73,980 fruit/A vs. 67,750 with trickle irrigation. A larger percent of fruit was
marketable with seepage than with trickle irrigation, 90.2% and 80.7%, respectively.
The cumulative percent of fruit harvested at the three picking dates during the
season and the average fruit size at each picking date is listed on Table 5. Fruit
size in the trickle irrigated plots was larger at each of the three pickings than
in seepage irrigated plots.
Amount of major plant nutrients in the leaves and petioles of young mature
leaves of green peppers are shown in Table 6. The nutrient levels found in the
tissues were adequate with both irrigation systems and no deficiency symptoms were
observed on the plants durin" the rrotiing season.
Total soluble salt (TSS) contents of soil, sampled immediately after fertilizer
application and after harvest, are presented in Table 7. In seepage irrigated plots,
large amounts of residual salts remained in the soil after the harvest. In the
trickle irrigated plots, TSS level remained high at the 0-5 in. soil depth in the
shoulder region where soil moisture content was low during the growing season. Salts
were taken up by the plants and/or were leached from the soil with the irrigation
water from the tube and from the plant row region.
In the fall of 1979 with trickle irrigation and with a single pre-plant appli-
cation of dry fertilizers near the trickle tube, it was possible to produce a green
pepper crop equal in quantity and with a larger fruit size than with seepage irriga-
tion. In the trickle system, water was applied at high daily frequency, 4-7 times
per day, in the plant beds under the plastic mulch. The daily quantity of irrigation
was less than the measured open pan evaporation until one week before the first pick.
Then the amount of'irrigation water required was increased and kept at a constant
level until end of the season to maintain an approximate 11% soil moisture content
at the 5-9 in. depth in the plant row.
1. Anonymous. 1980. Florida vegetables: Acreage and indicated production winter
quarter. Florida Crop and Livestock Reporting Service, Orlando, FL
2. Csizinszky, A. A. 1979. Considerations in calculating and reporting water
application rates for drip irrigated lands. Bradenton AREC Research Report
Table 1. Seep irrigation schedule for green peppers, Fall 1979.
Sep. Sep. Sep. Oct. Oct. Oct. Nov. Nov. Nov. Dec. Dec. Dec. Total
7- 17- 27- 7- 17- 27- 6- 16- 26- 6- 16- 26- for
16 26 Oct. 6 16 26 Nov. 5 15 25 Dec. 5 15 25 27 Season
Irrigation days in
the period 2.0 0 1.3 10.0 9.0 10.0 10.J 10.0 10.0 7.0 8.0 2.0 79.3
rate, A in 0.51 0 0.37 0.33 0.33 0.36 0.31 0.33 0.28 0.38 0.29 0.21 -
for period, A in 1.02 0 0.48 3.30 2.97 3.60 3.10 3.30 2.80 2.66 2.32 0.42 25.97
Rainfall, in 6.75 5.31 2.41 0.24 0.29 0.01 0.46 0 0.12 1.52 0.97 0 18.03
Total water for
period, A in 7.77 5.31 2.89 3.54 3.26 3.61 3.56 3.30 2.92 4.18 3.29 0.42 44.05
.0vn pan evaporation
for period, in 0.95 2.15 1.25 1.55 1.63 1.55 1.35 1.17 1.05 0.61 0.93 0.27 14.49
Average r:a:;-::.: air
temperature, F0 89.1 89.2 8G.. 83.7 85.3 83.3 78.5 78.8 70.4 70.4 71.7 70.0
Average roini':tnm air
t.pc;tre, 74.0 74.0 69.3 63.6 65.3 61.9 61.3 54.2 1.2 0.2 50.7 44.1
Table 2. Trickle irrigation schedule for green peppers, Fall 1979.z
Sep. Sep. Sep. Oct. Oct. Oct. Nov. Nov. Nov. Dec. Dcc. Dec. Total
4- 14- 24- 4- 14- 24- 3- 13- 23- 3- 13., 23- for
13 23 Oct. 3 13 23 Nov. 2 12 22 Dec. 2 12 22 26 Season
Irrigation days in
the perro .
rate, A in
for period, A in
Total water for
period, A in
Open pan evaporation
for period, in
Average maximum air
Average minimum air
74.4 73.9 71.6
ZTrickle irrigation rates are
with seepage irrigation. To
multiply figures by 2.342.
63.0 67.6 61.8 62.2 53.3 55.0 57.1 53.5 49.9
expressed on a gross acre basis (43,560 sq ft) in order to have a valid comparison ;.
calculate trickle irrigation water rates for the area covered with plastic mulch,
Table 3. Average soil moisture content (%) in plant
beds for green peppers with seepage and
trickle irrigation. Fall 1979 .
Soil Location in plant bed
depth A B C
0-2 15.3 16.7
2-5 18.4 18.8
5-9 22.3 22.0
0-2 6.3 8.8 10.1
2-5 7.4 9.2 11.1
5-9 10.3 11.2 12.1
ZDetermined by the oven dry method.
YA = shoulder region; B = plant row; C = bed center.
Table 4. Yield and fruit size of green peppers with seepage and
trickle irrigation. Fall 1979.
Average fruit size, oz
Number of fruit per bu
Total number of fruit set/A (x 1000)
Number of marketable fruit/A (x 1000)
% of marketable fruit
Table 5. Cumulative percent of fruit harvested and average fruit size
(oz) of green peppers at three picking dates. Fall 1979.
Days after Amount of Average Amount of Average
transplanting the total fruit the total fruit
Date in field harvested size harvested size
% oz % oz
11.29 81 55 5.43 53 6.10
12.17 99 17 5.61 27 6.28
12.26 108 28 3.63 20 5.22
Total 100 4.79 100 5.94
ZSeedlings transplanted on 9-10-79.
Table 6. Partial mineral content of green pepper leaves and
petioles grown with seepage and high frequency trickle
irrigation. Fall 1979.
Irrigation system N P K Ca Mg
ZDry weight basis.
Table 7. Total soluble salt (TSS) content of soil solution after ferti-
lizer application and after harvest of green peppers in seepage and
trickle irrigated land. Fall 1979."
Seepage T, Trickle
Soil depth Location in plant bedJ
inches A B C A B C
After fertilizer application
zDeterminations by saturated paste extract method.
A = shoulder region; B = plant row; C = bed center.