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Management of Semidwarf and Conventional
Height Oat Varieties in the Klamath Basin
R.L. Dovel and G. Chilcote i
INTRODUCTION
Oats are planted on over 10,000 acres in the Klamath Basin. In 1985
the acreage planted to oats exceeded 13,000 acres. Oats are well adapted
to the organic and some lacustrine soils in the county with oat yields
exceeding that of barley or wheat in some areas. Increased interest in
the production of food quality oats has resulted in recent shortages of
this commodity.
Despite the importance of this crop to Oregon, the effects of management parameters such as fertilization, seeding rate, and planting
date on oat grain yield and quality have not been investigated. Also,
varieties currently being planted in the area are conventional height
genotypes. The advent of high yielding, semidwarf, lodging resistant
varieties provides an opportunity to more intensively manage these new
varieties than has been possible with more lodging susceptible conventional varieties. Little information is available about the value of
intensive management practices for oats because lodging has been a
yield limiting factor at both high levels of N fertilization and high
seeding rates. The development of semidwarf cultivars of wheat has lead
to the efficient use of high levels of N fertilization and other intensive management practices that contribute to increased grain yields.
Similar benefits could result from productive semidwarf oat cultivars.
Quality oats for both food and feed command a premium price. Test
weight is currently used to assess feed and milling quality. In
general, test weight declines with increasing nitrogen fertilization
rates; however, other management practices, such as early planting and
appropriate planting rate and row spacing increase both yield and test
weight. Increasing yield while lowering test weight would not be economically advantageous to the producer. Thus, a study of the effects of
N fertilization and seeding rate on oat yield and quality of both conventional and semidwarf varieties was undertaken.
PROCEDURES
The effects of N fertilization and seeding rate were examined using
a factorial design with four levels of N, three seeding rates and four
oat varieties. The experiment was arranged in a randomized complete
block design with four replications. Nitrogen as ammonium nitrate was
applied at 0, 40, 80, and 120 lbs/A. Seeding rates were 20, 30, and 40
seeds/square foot. Two conventional height oat varieties, Monida and
1/ Assistant Professor and Research Technician, respectively, Klamath
Experiment Station.
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Cayuse, and two semidwarf oat varieties, 82Ab1142 and NPB 86801 were
seeded. The semidwarf line,NPB 86801 is soon to be released as MiniMax.
Seed was planted at one-inch depth in six-inch rows. A split application of 80 lbs N as ammonium nitrate at planting and 40 lbs N at
flowering was also included.
Data collected included time to 50 percent heading, percent lodging, plant height, grain yield and test weight. Oat quality parameters
yet to be assessed include groat fraction and groat protein concentration.
RESULTS
Nitrogen fertilization affected grain yield of conventional and
semidwarf varieties differently. Grain yields of semidwarf lines
increased with increasing N fertilization (Table 1). In contrast,
grain yields of Monida and Cayuse tended to decrease as N application
rates increased, largely due to increased lodging of the two conventional varieties with increasing N fertilization (Table 1). Semidwarf
lines did not have significant lodging at any N fertilization level.
The effect of lodging was also apparent in grain test weights. Increasing nitrogen fertilization decreased test weights of the two
conventional varieties, while the semidwarf varieties were unaffected.
No difference was observed in grain yield between the split N
application and either the 80 or 120 lb N applications. Late season N
application generally does not affect yield but should result in higher
groat protein contents.
The highest yields were obtained with 82Ab11432 at N rates of 40
lbs/A or above. Resulting yields were more than 100 lbs/A greater than
in the best conventional variety/N combination.
Although both Monida and Cayuse produced higher yields than
82Ab61142 when no N was applied, there are few instances where this
practice is followed. The addition of 30-50 lbs N/A banded at seeding,
a common practice, would result in the highest yields obtained in this
study when planting 82Ab1142 and NPB86801.
Seeding rate did not significantly affect yield; however, seeding
rate affected lodging of conventional and semidwarf varieties differently (Table 2). Increasing seeding rates increased lodging in both convenonal height varieties, yet had little or no effect on lodging of the
two semidwarf varieties. Although seeding rate affected lodging of
conventional varieties, the increased lodging was not sufficient to
significantly reduce yield.
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Table 1. Effect of N Fertilization rate and
Observations of N fertilization and variety
grain yield, test weight, lodging and plant
spring oat varieties planted at the Klamath
Station in 1989.
Variety on Oats.
effects on oat
height of four
Experiment
Variety
NPB86801 Monida
N Fertilization
lbs N/acre
82Ab1142
0
40
80
120
80/40
4435
5473
5590
5626
5617
3728
4540
4777
4617
4859
4619
4016
3898
3349
3263
4401
4478
4088
3810
3585
4296
4627
4588
4351
4331
AVG.
LSD(.05)
5348
551
4504
382
3829
532
4072
NS
4439
284
0
39.2
39.9
39.7
39.4
39.7
Test weight, lbs/bu 38.2
39.5
39.9
36.6
37.7
38.6
37.0
37.7
37.6
37.6
36.6
38.2
37.4
35.9
36.8
39.2
38.2
38.0
37.9
37.5
40
80
120
80/40
AVG.
LSD(.05)
0
40
80
120
80/40
AVG.
LSD(.05)
0
40
80
120
80/40
AVG
LSD(.05)
39.6
NS
0
0
0
5
1
1
3
34
37
39
39
37
37
2.4
Cayuse
Average
Grain yield, lbs/acre
37.2
NS
37.7
1.8
38.2
1.6
38.2
0.8
16
51
72
76
90
11
30
35
40
42
Lodging, X 0
27
0
67
0
67
0
78
0
78
0
NS
63
23
61
21
32
8
Height,
39
32
33
33
32
inches 47
47
47
48
45
42
43
43
44
43
40
41
41
39
34
2
47
NS
43
NS
40
1.1
38
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Table 2. Seeding Rate and. Variety Effects on Lodging in Oats.
Observations of seeding rate and variety effects on grain
yield, test weight, lodging and plant height of spring oats
planted at the Klamath Experiment Station in 1989.
Variety
Seeding rate seed/ft'
82Ab1142 NPB86801 Monida Cayuse Average
Grain yield, lbs/acre 3979
4478
4181
4499
3725
3818
4535
3784
4217
20
30
40
LSD(.05)
5124
5531
5389
NS
NS
LSD(.05)
39.9
39.3
39.6
NS
NS
20
30
40
LSD(.05)
0
0
3
LSD(.05)
36
38
37
NS
NS
NS
38.2
38.1
38.2
NS
NS
Lodging, lbs/acre 0
44
53
0
65
64
0
82
66
24
32
38
NS
2.6
20
30
40
NS
Test weight, lbs/bu 36.8
38.1
37.8
37.0
37.6
38.6
37.6
37.2
38.3
20
30
40
NS
4440
4393
4481
17.5
Height, inches
30
47
48
32
47
32
NS
NS
16.4
6.2
44
43
43
39
40
30
NS
NS