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NFREC Res. Rpt. 92-7
Canola Triticale Rotation and
Response to Nitrogen Phosphorus, and Potassium
F. M. Rhoads and R. D. Barn t Central sJce
/ 11ersity of Fl
North Forida Research and Education Center
North Florida Research and Educationz Center
Florida Agricultural Experiment Stations
Institute of Food and Agricultural Sciences
University of Florida, Gainesville
I TUCKNG RESEACH E"PAIj~~
Canola is a possible alternative crop that grows during the
cool season in North Florida. Since it is a new crop to the area
no data are available to describe the response of canola to
fertilization in North Florida. A rotation program that includes
canola once every four years is recommended in order to minimize
yield loss from diseases. This study was started in 1989 to test
canola response to nitrogen (N), phosphorus (P) and potassium (K)
and a two-year rotation between triticale and canola with soybean
as a summer crop.
Two canola varieties, and two triticale varieties have been
grown each year. Delta canola has been grown every year while the
second variety was Ceres in 1989-90, Hyola-40 in 1990-91 and
Printol in 1991-92. The two triticale varieties used each year
were Florida 201 and Sunland.
Ceres has a high cold requirement and is not suited to the
North Florida climate. Hyola-40 flowers in January and has a high
potential for yield loss due to frozen flower buds and embryos.
Delta produced higher yields than Ceres and Hyola-40 but lower
yields than Printol.
MATERIALS AND METHODS
Two canola varieties (Delta and Printol) were planted 1 Nov
1991 in NFREC fertility plots where triticale was grown in 1990-91.
Delta is a product of Allelix Crop Technologies and Printol (CC
310) is marketed by Cargill Seed Co. Row width was 8 inches and
seeding rate was 10 seed per foot of row. Soil type was Norfolk
loamy fine sand (fine-loamy, siliceous, thermic, Typic Kandiudult).
Irrigation was applied as needed to reduce plant-water stress.
Harvest dates were 14 May 1992 for Delta and 20 May 1992 for
Triticale (Florida 201 and Sunland) was planted 6 Dec 1991 in
plots adjacent to the canola where canola was grown in 1990-91.
Harvest date for both varieties was 12 June 1992. Seeding rate was
16 seed per foot of row with 8-inch row width.
Fertilizer treatments for triticale are shown in Table 1 and
those for canola in Table 2. Preplant fertilizer consisted of 46%
triple superphosphate and sulfate of potash applied broadcast to
supply P and K rates shown\for each treatment. Two applications of
K were made to the canola 1/2 preplant and 1/2 21 Jan. All N
applications were broadcast as topdressing.
Ten 1-inch by 6-inch soil cores were composite from each plot
of triticale and canola on 8 Jan 1992. Soil samples were air-dried
and ground before extracting with Mehlich-1 (double acid)
extractant. Soil analyses were carried out according to University
of Florida Extension Soil-testing Laboratory procedures (Hanlon and
Plant samples of canola were collected on 2 Mar 1992 which was
near the beginning of flowering of both varieties. Whole plants
(above ground portion) from a three foot section of row in the
center of each plot were cut at ground level and dried at 700C. Dry
plant samples were ground to pass a 20-mesh screen and nitrogen was
determined by micro-kjeldahl procedures. Samples were dry ashed at
500C and dissolved in dilute HCl for P and K determination.
Phosphorus was determined by the molybdenum blue method and K was
determined with a flame emission spectrophotometer. Nutrient
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The experimental design was a split-plot incorporated into a
randomized complete block with four replications. Whole plots were
fertilizer treatments and sub-plots were cultivars. Analysis of
variance was used to calculate least significant differences (Isd
0.05) between varieties and between fertilizer treatments (Freed,
Yield of Fla 201 triticale was 48.4 bu/acre and of Sunland was
42.1. These are overall averages and the difference between
cultivars is significant at P < 0.01. Response of triticale to N
rates between 0 and 120 lb/acre was dramatic, averaging as much as
0.45 bu of grain per pound of N. However, the response between 120
and 180 was only 0.11 bu/lb of N for Fla-201 and was not
significant (P > 0.05) for Sunland (Table 1, Fig. 1). There was no
difference in yield of either cultivar between two and three N
applications (Fig. 2).
Response to P was significant (P < 0.05) for both cultivars,
however, the response for Fla-201 occurred between 0 and 75 lb
P205/acre and between 75 and 150 for Sunland (Fig. 3). There was no
response to K for Fla-201 but Sunland yield increased 7.4 bu/acre
between 0 and 150 lb K20/acre (Fig. 4).
Canola yield was not increased by N rates above 120 lb/acre
(Table 2, Fig. 5). Yield was higher for both cultivars with two N
applications rather than four (Fig. 6). Tissue N concentration of
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canola did not vary as much in proportion as yield in response to
N rate (Fig. 7, Table 3 and 4).
Both canola cultivars produced a dramatic yield increase
between 0 and 75 lb P2O5/acre but only Printol produced a yield
increase between 75 and 150 lb/acre (Fig. 8). Tissue P
concentration gave a response to P rates similar to the yield
response (Fig. 9). Yield response of canola to K rates was not
significant but 150 lb K20/acre increased tissue K concentration
from less than 2% to more than 4% (Fig. 10 and 11).
Both canola and triticale produced 90% or more of maximum
yield with 120 lb of N/acre. Triticale produced the same yield
with three applications of N as with two applications, the N rate
was 120 lb/acre in each case. However, two applications of N
produced 19 and 36% more yield of Printol and Delta canola with 120
lb N/acre than four applications with the same N rate. The
critical N concentration of each canola cultivar appears to be
about 2.5% when plants start to flower.
Yield response to P was much more dramatic for canola than for
triticale. Yield increase for triticale ranged from 24 to 40%
while canola responded with a maximum increase of over 300%. The
critical P concentration of each canola cultivar appears to be
about 0.25% when plants start to flower.
The minimal response of triticale and canola to K fertilizer
is attributed to translocation of K from lower soil horizons to the
surface by the deep root system of canola. The basis of this
assumption is shown in soil analysis data. Triticale was grown
where canola was growing the year before. Soil samples taken from
1991-92 triticale plots had medium K levels in zero K fertilizer
plots whereas the same plots had very low K levels (Hanlon et al.,
1990) before canola was grown in 1990-91. The 1991-92 canola plots
were growing canola in 1989-90 and there was some carry over
influence on K response of canola. However, K fertilizer more than
doubled the K concentration of canola compared to unfertilized
plots. It appears that the critical K concentration of each canola
cultivar is about 2.0% when plants start to flower.
This was the first year canola was grown on the same plots
where it was grown once two years before. The yield of Delta was
near what it was in the first and second years of the test.
Maximum yields of Delta were as follows: first year 32 bu/acre,
second year 31 bu/acre, and third year 28 bu/acre. There were no
disease outbreaks observed.
This research was supported by the Florida Agricultural
Experiment Station and the Potash and Phosphate Institute.
1 Freed, R. D. 1988. MSTAT-C: A microcomputer program for the
design, management, and analysis of agronomic research
experiments. Michigan State University.
2 Hanlon, E. A. and J. M. Devore. 1989. IFAS extension soil
testing laboratory chemical procedures and training manual.
Fla. Coop. Ext. Serv. IFAS. Univ. of Fla. Cir. 812.
3 Hanlon, E. A., G. Kidder, and B. L. McNeal. 1990. Soil,
container media, and water testing interpretations. Fla.
Coop. Ext. Serv. IFAS. Univ. of Fla. Cir. 817.
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