Variety Mixtures for Reduced Input Barley, 2006
M. J. Ottman
Summary
Variety mixtures may lessen competition among plants and reduce effects of
stress particularly in environments where resources are limiting. Mixtures of
four barley varieties were grown under low input conditions at the Maricopa
Agricultural Center. The barley varieties seeded were Barcott, Solum, Solar,
and an experimental low input line designated Entry 9. The highest yields were
not obtained with mixtures in this experiment, but rather when the varieties
were grown alone. Barcott and Entry 9 decreased yield when part of the
mixture more than Solum or Solar. When Solum was grown in a mixture rather
than alone, test weight and lodging were improved, but yield was decreased.
Introduction
It is possible to obtain higher yields with mixtures of crops than with individual crops planted alone. Intercropping,
as this practice is called, is not practical with mechanical harvesting and is used mainly in the tropics with crops that
are harvested by hand. If a single species is planted, such as wheat or barley, varieties with differing characteristics
may be mixed and harvested mechanically. Variety mixtures can outperform solid plantings of single varieties if the
varieties in the mixtures are sufficiently different in characteristics including height, rooting pattern, or maturity.
The problem with crops where all plants are similar is that they compete more intensely with each other for
resources such as water, light, and fertilizer. An example of a successful variety mixture in Arizona is Aldente, a
mixture of WestBred 881 and Turbo that combined some of the quality of WestBred 881 with the yield potential of
Turbo. Variety mixtures may lessen competition among plants and reduce effects of stress particularly in
environments where resources are limiting.
Procedure
Mixtures of four barley varieties were grown under low input conditions at the Maricopa Agricultural Center. The
barley varieties included in the mixtures were: 1) Barcott – a high input barley, 2) Solum – a low input barley, 3)
Solar – a low input barley, and 4) Entry 9 – a low input 2-row barley (the other three varieties are 6-row barleys).
Various proportions of these barley varieties were included in 15 mixtures, and sown at rates of 1000 or 2000 seeds
per plot or 12 or 24 seeds/ft2 (assuming seeded area of 49 inches by 20 ft) corresponding to about 40 and 80 lbs seed
per acre (Table 1). The experimental design consisted of 2 simplexes (groups of 15 mixtures) and 2 initial densities.
The experiment was conducted in Field 1, Border 18 at the Maricopa Agricultural Center during the 2005-2006
growing season. The soil type was a Casa Grande sandy loam. The previous crop was bermudagrass. The surface
6 inches of soil was sampled before planting and contained 31.0 ppm NO3-N and 5.4 ppm P. The mixtures were
planted in 5 ft x 20 ft plots on November 30, 2005. Seven rows spaced 7 inches apart were planted. The irrigation
system was border flood, an irrigation to germinate the seed was applied on December 2, and an additional
irrigation was applied on February 17. Fertilizer was applied preplant as ammonium phosphate sulfate (16-20-0) at
a rate of 48 lbs N/acre and 60 lbs P2O5/acre. Nitrogen fertilizer was applied at of rate of 50 lbs N/acre as urea (46-00) on February 17 prior to the irrigation.
Stand counts were made on December 29 from four areas with dimensions of 2 ft long and 5 rows wide (23.3 ft2).
On January 16 at the 5-leaf stage, 20 plants were sampled per plot and the plant area and total dry weight were
measured. Whole plants including crowns were dug up and removed on April 19 from an area 2 rows wide by 16
Forage and Grain Report (P-154) October 2007
90
feet long. The individual varieties in each mixture were separated based on distinguishing characteristics. Barcott
is short, Solum has a rough awn, Solar has a smooth awn, and Entry 9 has 2-row head type. The following was
recorded for each variety: plant height, number of plants, stems per plant (from 10 plants), head per plant (from 10
plants), total plant weight, and grain weight. On May 11, lodging was noted and a small plot combine was used to
harvest the grain. Barley grain samples were cleaned by running through a head thresher. Test weight was
determined from these cleaned samples using a 1-pint container. Seed weight was determined from a 10 g sample
of grain.
Discussion
The barley varieties were chosen based on differences in plant characteristics. Barcott is the shortest variety, and
the others are roughly similar in height (Table 6). Solum is the earliest in maturity, and the others mature around the
same time (Table 2). Our hypothesis was that differences in these characteristics would reduce plant competition
and potentially increase grain yield. However, the highest yields were not obtained with mixtures in this
experiment, but rather when the varieties were grown alone. Three of the highest four yields were obtained when
the varieties were grown alone (Table 3). This could have occurred because Entry 9 dragged down the yield of the
others. This variety had low grain yield in this study, but also was a vigorous plant with a low grain to straw ratio
that may have competed with the other varieties without contributing a commensurate share of grain yield. Another
possibility is that the varieties had a negative impact on each other in a mixture, such as a slight allelopathic
reaction.
One of the benefits of mixtures is that negative characteristics of certain varieties can be lessened by the presence of
other varieties. For example, negative characteristics of Solum is low test weight and high lodging potential.
Solum planted alone had a test weight of 46.5 lbs/bu and lodging of 40%, but when planted with Solar
predominantly (10% Barcott, 40% Solum, 40% Solar, 10% Entry 9), the test weight was increased to 48.0 lbs/bu
and lodging decreased to 15%. However, the yield was also reduced by 14%.
Stand and initial growth was least for Barcott and greatest for Entry 9 (especially at the higher seeding rate), and
intermediate for Solum and Solar (Table 4). Thus, the composition of the mixtures refers to the amount seeded and
not necessarily the amount established. At harvest, there were fewer plants of Barcott and more plants of Entry 9 in
the mixtures than were seeded, while the percentage of Solum and Solar seeded and harvested were similar (Table
5). The same trend was measured for stem number (Table 7) and head number (Table 8). Entry 9 was also the best
competitor in the mixture in terms of total plant yield, Barcott was the worst competitor, and Solar was more
competitive than Solum (Table 9). However, since Entry 9 had a low grain to straw ratio, it did not dominate the
mixtures in terms of grain yield (Table 10). Solar contributed most to the grain yield of the mixtures, followed by
Entry 9, Solum, and Barcott.
Mixtures may have potential for increased yield compared to single varieties, but this research has not provided any
evidence for this effect. We have shown that some varieties do better than others in a mixture. Barcott, the short
variety probably did poorly because it was shaded by the taller varieties even though it was earlier in maturity.
Entry 9 was not productive when planted alone, and decreased yield of the mixtures it was part of. Perhaps the key
to increased productivity of mixtures is extensive testing and careful selection of components of the mixture.
Acknowledgments
Financial support for this project was received from the Arizona Grain Research. The technical assistance of Mary
Comeau, Mike Sheedy, and Tony Gomez is greatly appreciated.
Forage and Grain Report (P-154) October 2007
91
Table 1. Seeding rate and number of seed of each barley variety for the mixtures.
Seeding rate
seeds/plot
seeds/ft2
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
1000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
Mixture
lbs
Percentage of
seed/acre Barcott/Solum/Solar/Entry9
40
40
40
40
40
40
40
40
40
40
40
40
40
40
40
80
80
80
80
80
80
80
80
80
80
80
80
80
80
80
Mixture composition (seeds/plot)
Barcott
Solum
Solar
Entry 9
700
100
100
100
250
400
400
400
100
100
100
1000
0
0
0
1400
200
200
200
500
800
800
800
200
200
200
2000
0
0
0
100
700
100
100
250
400
100
100
400
400
100
0
1000
0
0
200
1400
200
200
500
800
200
200
800
800
200
0
2000
0
0
100
100
700
100
250
100
400
100
400
100
400
0
0
1000
0
200
200
1400
200
500
200
800
200
800
200
800
0
0
2000
0
100
100
100
700
250
100
100
400
100
400
400
0
0
0
1000
200
200
200
1400
500
200
200
800
200
800
800
0
0
0
2000
70/10/10/10
10/70/10/10
10/10/70/10
10/10/10/70
25/25/25/25
40/40/10/10
40/10/40/10
40/10/10/40
10/40/40/10
10/40/10/40
10/10/40/40
100/0/0/0
0/100/0/0
0/0/100/0
0/0/0/100
70/10/10/10
10/70/10/10
10/10/70/10
10/10/10/70
25/25/25/25
40/40/10/10
40/10/40/10
40/10/10/40
10/40/40/10
10/40/10/40
10/10/40/40
100/0/0/0
0/100/0/0
0/0/100/0
0/0/0/100
Table 2. Heading, anthesis, and maturity for the barley varieties at two seeding rates.
Seeding rate
(lbs/acre)
Barcott
Solum
Solar
Entry 9
Heading
40
3/4
3/3
3/1
3/17
Anthesis
40
3/4
3/3
3/1
3/17
Maturity
40
4/13
4/5
4/14
4/14
Heading
80
3/4
3/2
3/2
3/17
Anthesis
80
3/4
3/2
3/2
3/17
Maturity
80
4/13
4/7
4/14
4/14
Forage and Grain Report (P-154) October 2007
92
Table 3. Grain yield, test weight, seed weight, and lodging at harvest for barley mixtures.
40 lbs seed/acre
80 lbs seed/acre
Average
Percentage of
Grain Test Seed Lodg- Grain Test Seed Lodg- Grain Test Seed LodgBarcott/Solum/Solar/Entry9 yield weight weight ing yield weight weight ing yield weight weight ing
%
lbs/A lbs/bu mg
%
lbs/A lbs/bu mg
% lbs/A lbs/bu mg
%
70/10/10/10
10/70/10/10
10/10/70/10
10/10/10/70
25/25/25/25
40/40/10/10
40/10/40/10
40/10/10/40
10/40/40/10
10/40/10/40
10/10/40/40
100/0/0/0
0/100/0/0
0/0/100/0
0/0/0/100
All
3388
3415
3307
2985
3496
3254
3522
2823
3684
2904
3092
3657
3926
3791
2743
3332
45.6
46.1
49.2
50.2
49.0
46.7
47.7
47.3
48.1
47.6
49.3
44.3
45.6
51.1
49.5
47.8
34.5
34.5
33.7
34.1
35.2
33.6
33.5
31.9
35.5
33.0
33.7
32.5
37.6
37.7
31.1
34.1
10
5
40
5
10
0
10
15
15
10
2
5
20
7
0
10
3200
3576
3711
2554
3415
3469
3684
2850
3334
3307
3469
3603
4195
4114
2501
3399
46.3
46.6
48.8
49.5
47.7
47.5
49.5
47.4
47.8
48.8
48.8
43.1
47.4
49.9
48.7
47.8
31.9
34.2
33.8
32.0
33.1
34.7
34.4
30.3
31.2
34.2
31.8
29.1
36.8
34.9
28.1
32.7
50
0
25
0
10
20
15
2
15
10
5
5
60
10
10
16
3294
3496
3509
2770
3455
3361
3603
2837
3509
3106
3280
3630
4060
3953
2622
3366
46.0
46.4
49.0
49.9
48.3
47.1
48.6
47.3
48.0
48.2
49.1
43.7
46.5
50.5
49.1
47.8
33.2
34.3
33.8
33.0
34.1
34.1
34.0
31.1
33.4
33.6
32.7
30.8
37.2
36.3
29.6
33.4
30
3
33
3
10
10
13
9
15
10
4
5
40
9
5
13
Table 4. Stand on December 29, and plant weight and PAI (plant area index) on January 16 at the 5-leaf stage.
40 lbs seed/acre
80 lbs seed/acre
Average
Plant
Plant
Plant
Percentage of
Stand
Stand
Barcott/Solum/Solar/Entry Stand
weight PAI
weight PAI
weight PAI
9
%
plants/ft2 lbs/A
plants/ft2 lbs/A
plants/ft2 lbs/A
70/10/10/10
10/70/10/10
10/10/70/10
10/10/10/70
25/25/25/25
40/40/10/10
40/10/40/10
40/10/10/40
10/40/40/10
10/40/10/40
10/10/40/40
100/0/0/0
0/100/0/0
0/0/100/0
0/0/0/100
All
8.3
9.7
9.9
11.1
8.0
7.9
10.0
9.9
8.3
10.5
11.4
7.4
8.3
10.1
9.9
9.4
293
355
453
462
355
282
313
465
461
439
498
186
336
406
371
379
Forage and Grain Report (P-154) October 2007
0.63
0.79
1.07
1.06
0.79
0.64
0.74
1.13
1.17
1.07
1.20
0.44
0.83
1.07
0.99
0.91
11.5
15.0
15.4
20.4
15.9
12.7
16.9
14.2
13.7
16.0
15.5
13.3
12.6
12.3
21.2
15.1
395
582
808
682
528
533
568
423
375
468
514
231
375
507
646
509
1.10
1.49
2.26
1.85
1.42
1.42
1.54
1.22
0.99
1.31
1.48
0.68
0.95
1.47
1.85
1.40
9.9
12.3
12.6
15.8
12.0
10.3
13.5
12.0
11.0
13.3
13.4
10.4
10.4
11.2
15.6
12.2
344
469
630
572
442
408
441
444
418
453
506
209
355
457
508
444
0.86
1.14
1.66
1.45
1.10
1.03
1.14
1.17
1.08
1.19
1.34
0.56
0.89
1.27
1.42
1.15
93
Table 5. Number of plants of each variety at harvest as a percentage of the total mixture.
Plant number of each variety at harvest as a percentage of total
40 lbs seed/acre
80 lbs seed/acre
Average
Percentage seeded of
BarBarBaBarcott/Solum/Solar/Entry cott Solum Solar Entry9 cott Solum Solar Entry rcott Solum Solar Entry
9
9
9
%
%
%
%
70/10/10/10
10/70/10/10
10/10/70/10
10/10/10/70
25/25/25/25
40/40/10/10
40/10/40/10
40/10/10/40
10/40/40/10
10/40/10/40
10/10/40/40
100/0/0/0
0/100/0/0
0/0/100/0
0/0/0/100
Average
49
7
2
5
9
23
22
17
5
8
4
100
0
0
0
14
15
59
8
5
25
32
13
8
34
22
9
0
100
0
0
21
14
6
75
6
26
23
44
11
40
12
29
0
0
100
0
26
23
27
15
85
40
22
21
64
21
58
58
0
0
0
100
39
49
6
2
7
7
23
15
16
8
10
3
100
0
0
0
13
13
66
8
6
21
40
49
7
20
24
3
0
100
0
0
23
16
9
70
7
22
14
14
9
57
10
32
0
0
100
0
24
23
20
20
80
50
24
21
69
15
56
62
0
0
0
100
40
49
7
2
6
8
23
19
16
6
9
3
100
0
0
0
13
14
63
8
5
23
36
31
7
27
23
6
0
100
0
0
22
15
8
72
7
24
18
29
10
49
11
31
0
0
100
0
25
23
23
18
82
45
23
21
66
18
57
60
0
0
0
100
40
Table 6. Plant height of each variety in the various mixtures at harvest.
Plant height of each variety at harvest
40 lbs seed/acre
80 lbs seed/acre
Average
BaBarBarPercentage seeded of
Barcott/Solum/Solar/Entry cott Solum Solar Entry9 cott Solum Solar Entry rcott Solum Solar Entry
9
9
9
%
inches
inches
inches
70/10/10/10
10/70/10/10
10/10/70/10
10/10/10/70
25/25/25/25
40/40/10/10
40/10/40/10
40/10/10/40
10/40/40/10
10/40/10/40
10/10/40/40
100/0/0/0
0/100/0/0
0/0/100/0
0/0/0/100
All
24
24
24
21
23
24
24
30
30
28
23
29
------25
29
30
33
31
34
33
32
36
37
36
32
--38
----33
34
34
35
35
35
36
38
40
40
39
36
----34
--36
Forage and Grain Report (P-154) October 2007
37
34
36
36
36
36
37
40
36
39
35
------36
37
22
23
21
23
20
22
27
26
24
25
22
26
------23
30
30
32
27
33
33
37
32
31
37
34
--30
----32
33
34
35
33
33
36
40
38
34
36
36
----33
--35
32
35
37
31
31
37
39
33
34
35
37
------36
35
23
23
22
22
21
23
25
28
27
27
22
27
------24
29
30
33
29
33
33
34
34
34
37
33
--34
----33
33
34
35
34
34
36
39
39
37
37
36
----33
--36
34
34
36
34
33
37
38
36
35
37
36
------36
36
94
Table 7. Number of stems of each variety at harvest as a percentage of the total mixture.
Stem number for each variety at harvest as a percentage of the total
40 lbs seed/acre
80 lbs seed/acre
Average
Percentage seeded of
BarBarBaBarcott/Solum/Solar/Entry cott Solum Solar Entry9 cott Solum Solar Entry rcott Solum Solar Entry
9
9
9
%
%
%
%
70/10/10/10
10/70/10/10
10/10/70/10
10/10/10/70
25/25/25/25
40/40/10/10
40/10/40/10
40/10/10/40
10/40/40/10
10/40/10/40
10/10/40/40
100/0/0/0
0/100/0/0
0/0/100/0
0/0/0/100
Average
44
5
2
3
7
26
19
10
4
6
2
100
0
0
0
12
20
60
7
3
17
26
9
4
29
14
9
0
100
0
0
18
14
7
68
6
23
20
49
9
48
9
30
0
0
100
0
26
21
29
22
89
54
28
23
77
20
71
58
0
0
0
100
45
44
6
1
4
4
16
12
12
5
7
2
100
0
0
0
10
15
52
5
4
14
39
58
5
14
16
3
0
100
0
0
20
16
9
74
6
19
12
12
6
62
9
27
0
0
100
0
23
26
33
20
85
63
33
19
77
20
68
69
0
0
0
100
47
44
6
2
3
5
21
15
11
4
6
2
100
0
0
0
11
18
56
6
4
15
32
33
4
21
15
6
0
100
0
0
19
15
8
71
6
21
16
31
7
55
9
28
0
0
100
0
24
24
31
21
87
58
31
21
77
20
70
63
0
0
0
100
46
Table 8. Number of heads of each variety at harvest as a percentage of the total mixture.
Head number for each variety at harvest as a percentage of the total
40 lbs seed/acre
80 lbs seed/acre
Average
BaBarBarPercentage seeded of
Barcott/Solum/Solar/Entry cott Solum Solar Entry9 cott Solum Solar Entry rcott Solum Solar Entry
9
9
9
%
%
%
%
70/10/10/10
10/70/10/10
10/10/70/10
10/10/10/70
25/25/25/25
40/40/10/10
40/10/40/10
40/10/10/40
10/40/40/10
10/40/10/40
10/10/40/40
100/0/0/0
0/100/0/0
0/0/100/0
0/0/0/100
Average
1
2
3
4
5
6
7
8
9
10
11
100
0
0
0
12
43
6
2
3
8
30
22
11
4
5
3
0
100
0
0
18
22
60
7
4
19
24
8
4
31
13
11
0
0
100
0
27
Forage and Grain Report (P-154) October 2007
16
6
73
7
23
21
53
9
46
10
31
0
0
0
100
43
20
28
18
87
50
26
17
75
19
73
56
100
0
0
0
11
48
6
1
5
4
18
11
14
6
12
2
0
100
0
0
21
14
52
5
6
11
46
61
4
16
18
3
0
0
100
0
24
16
9
77
8
22
14
13
8
60
9
32
0
0
0
100
43
22
33
16
82
64
22
15
75
19
62
63
100
0
0
0
12
45
6
2
4
6
24
17
13
5
8
3
0
100
0
0
20
18
56
6
5
15
35
34
4
24
16
7
0
0
100
0
26
16
8
75
7
22
18
33
8
53
9
31
0
0
0
100
43
95
Table 9. Total plant yield of each variety at harvest as a percentage of the total mixture.
Total plant yield for each variety at harvest as a percentage of the total
40 lbs seed/acre
80 lbs seed/acre
Average
Percentage seeded of
BarBarBaBarcott/Solum/Solar/Entry cott Solum Solar Entry9 cott Solum Solar Entry rcott Solum Solar Entry
9
9
9
%
%
%
%
70/10/10/10
10/70/10/10
10/10/70/10
10/10/10/70
25/25/25/25
40/40/10/10
40/10/40/10
40/10/10/40
10/40/40/10
10/40/10/40
10/10/40/40
100/0/0/0
0/100/0/0
0/0/100/0
0/0/0/100
Average
38
5
1
2
4
19
13
9
2
5
2
100
0
0
0
9
18
64
4
5
25
31
14
7
33
17
11
0
100
0
0
21
21
7
74
12
30
27
57
14
47
18
36
0
0
100
0
31
23
25
21
81
41
23
17
71
18
60
51
0
0
0
100
39
39
6
1
5
5
15
9
11
5
7
2
100
0
0
0
10
17
63
5
6
18
42
14
8
21
23
4
0
100
0
0
20
21
10
76
11
28
18
59
14
60
12
42
0
0
100
0
32
23
20
18
78
50
26
19
68
14
58
52
0
0
0
100
39
39
6
1
3
5
17
11
10
4
6
2
100
0
0
0
9
18
64
5
6
21
36
14
7
27
20
8
0
100
0
0
21
21
8
75
11
29
23
58
14
53
15
39
0
0
100
0
31
23
23
19
80
45
24
18
69
16
59
52
0
0
0
100
39
Table 10. Grain yield of each variety at harvest as a percentage of the total mixture.
Grain yield for each variety at harvest as a percentage of the total
40 lbs seed/acre
80 lbs seed/acre
Average
BaBarBarPercentage seeded of
Barcott/Solum/Solar/Entry cott Solum Solar Entry9 cott Solum Solar Entry rcott Solum Solar Entry
9
9
9
%
%
%
%
70/10/10/10
10/70/10/10
10/10/70/10
10/10/10/70
25/25/25/25
40/40/10/10
40/10/40/10
40/10/10/40
10/40/40/10
10/40/10/40
10/10/40/40
100/0/0/0
0/100/0/0
0/0/100/0
0/0/0/100
Average
41
5
1
3
5
18
13
10
2
6
2
100
0
0
0
10
22
72
6
9
32
38
17
9
38
21
16
0
100
0
0
25
22
7
81
17
33
28
59
18
48
21
41
0
0
100
0
34
Forage and Grain Report (P-154) October 2007
16
16
11
72
31
17
12
63
12
52
41
0
0
0
100
31
41
6
1
5
6
14
9
12
5
10
3
100
0
0
0
10
20
70
6
10
23
49
17
10
24
29
6
0
100
0
0
24
24
10
81
16
31
19
61
20
61
13
50
0
0
100
0
35
15
14
12
69
41
18
13
58
9
48
42
0
0
0
100
31
41
6
1
4
5
16
11
11
4
8
2
100
0
0
0
10
21
71
6
9
27
44
17
9
31
25
11
0
100
0
0
25
23
8
81
17
32
24
60
19
54
17
45
0
0
100
0
35
15
15
12
70
36
17
13
61
11
50
42
0
0
0
100
31
96