Feb, 2000

FC 26.7

Pea and Small Grain Mixtures

Dan Undersander

Extension and Research Forage Agronomist

 

            Many farmers have considered including peas with small grains used as a cover crop for establishing alfalfa or as an emergency silage crop.  The resulting silage is more palatable and higher in quality than small grain silage.    The following information summarizes research regarding the influence of variety selection, seeding rate and mixture proportion. 

 

Influence of small grain varieties

 

            Studies were conducted at the University of Wisconsin Arlington Research farm comparing different oat and barley mixtures with peas during 1986 to 1988.  The small grain was planted at 20 seeds/sq ft (about 2 bu/a) both in pure stands and when mixed with peas.  Peas (Trapper) were included at 10 seeds/sq ft (about 1.5 bu/a).  Fertilizer applications were sufficient to ensure that N, P, and K levels were at least medium high.  Alfalfa was seeded with 16 lb/a.  The mixtures were harvested when three to five kernel of heads had emerged from the boot.  Cutting height was 2.5 inches.  

 

            The data (in tables 1 and 2) clearly show that adding peas to oats improved forage quality by increasing protein content 3 to 5 points and reducing NDF by 4 to 8 points.  Adding peas to barley increased protein 2 to 4 points and reduced NDF by 5 to 9 points.  The addition of peas increased yield in only one of three years.  Generally, it is expected that, unless nitrogen is limiting, adding peas to small grains will have minimal effect on total forage yield.  Therefore the only reasons for adding peas are to improve small grain silage forage quality and palatability. 

 

Peas do not dry as fast after cutting as small grain forage, so small/pea mixtures will dry slower than  pure small grain forage.

 

            Barley and oat varieties had the same average yields, both alone and in mixture with peas.  Shorter, earlier heading varieties have lower forage yields and higher forage quality.   Thus, varietal selection, not species selection, has the greatest effect on yield.  Triticale (data not reported) also has about the same average yield with taller, later maturing varieties yielding more than early, shorter varieties. 

 

On the other hand, alfalfa harvested following shorter, earlier small grains yielded more.  The recommendation is to harvest small grain silage when at the boot stage for dairy cows and soft dough (slightly lower forage quality but greater tonnage) for other categories of animals.  Small grain/pea mixes should be harvested by the stage of maturity of the small grain.

 

 Influence of small grain and pea seeding rates.

 

            Studies were conducted at the University of Wisconsin Arlington Research farm comparing different oat and barley mixtures with peas during 1986 to 1988.  Fertilizer applications were sufficient to ensure that N, P, and K levels were at least medium high.  Alfalfa was seeded with 16 lb/a.  The mixtures were harvested when three to five kernel of heads had emerged from the boot.  Cutting height was 2.5 inches.  

 

Addition of peas increased yield moderately when adequate moisture was present.  This was especially at lower seeding rates.  It appears that increasing oat seeding rate above 45 to 60 lbs did not result in further yield increases (Fig1).  Similarly, increasing pea seeding rates above 100 lb/a (8 seeds/sq ft) did not result in further yield increases, though forage NDF continued to increase with increases in pea seeding rate (Fig 2).  Pea seeding rates not resulting in both yield and quality increases (above 100 lb) are not economical.  In fact, as peas prices increase above 12¢ per pound, it may not be economic to seed more than 50 lb peas/acre.  In addition to cost, higher pea seeding rates mean slower drydown during harvesting. 

 

Under dry conditions oat seeding rates above  15 seeds/ sq ft (45 lbs) may decrease the alfalfa stand.  Thus the recommended seeding rate for optimum yield and quality are for 10-15 oat seeds /ft2 (60 lb) and 8 pea seeds/sq ft (100lb) of trapper peas.  The final seeding rates selected should be adjusted down if moisture may be limiting and seed cost is higher.

 

Peas vary widely in seed size.  While the studies above were conducted with Trapper peas and seed rates are expressed for this variety, the actual seeding rate should be adjusted for the pea variety used as shown in fig 3.

 

In summary, small grain/pea mixtures produe forage higher in protein and lower in fiber than pure small grain silage with minimal yield changes.  Further, the pea component does not change in quality as fast as oats, so the mixture has a longer harvest window than small grains by themselves.  The silage is also more palatable.   Disadvantages of the mixtures are greater seed cost, slower drying rate, and great lodging potential.

 

                                                                                               
Table 1.  Characteristics of oats and oat-pea mixtures harvested as forage at Arlington, Wisconsin in 1986-88.

 

 

Oat or

 oat-pea

mixture

 

 

Cut

date

 

Height  at cut

date

 

 

Forage

yield

 

Forage crude

protein

 

 

 

ADF

 

 

 

NDF

Alfalfa yield

during

establishment

year 1/

Total

1st year

forage

yield 2/

1st cut alfalfa

yield during

year after establishment3/

 

June

in

1b/a

%

%

%

1b/a

1b/a

1b/a

 

 

 

 

 

 

 

 

 

 

Webster

5

21

2197

15.4

27.5

48.5

2294

4491

5433

Webster/peas4/

5

21

2402

20.0

28.0

43.3

2092

4494

5612

 

 

 

 

 

 

 

 

 

 

Stout

7

21

2769

14.3

29.7

52.1

1955

4724

5658

Stout/peas

7

22

3035

18.1

29.3

45.9

1848

4883

5423

 

 

 

 

 

 

 

 

 

 

Ogle

9

24

2860

13.2

31.6

53.3

2156

5215

5951

Ogle/peas

9

25

3217

18.0

30.1

44.8

1998

5016

5778

 

 

 

 

 

 

 

 

 

 

Hazel

10

23

3154

12.9

31.3

54.6

1905

5059

5426

Hazel/peas

10

24

3450

16.7

31.0

48.3

1734

5184

5779

 

 

 

 

 

 

 

 

 

 

Centennial

11

25

3024

13.4

29.6

51.8

2061

5085

5925

Centennial /peas

11

25

3331

17.8

29.6

46.1

1980

5311

5446

 

 

 

 

 

 

 

 

 

 

Lyon

13

28

3359

12.9

29.4

51.0

1805

5164

5604

Lyon/peas

13

28

3581

17.1

29.5

46.6

1729

5309

5702

 

 

 

 

 

 

 

 

 

 

Porter

14

24

3519

13.1

31.3

55.2

1884

5403

5345

Porter/peas

14

25

3728

16.9

30.6

48.5

1771

5499

5416

 

 

 

 

 

 

 

 

 

 

Dal

15

26

3347

13.5

31.0

53.2

1739

5086

5467

Dal/peas

15

26

3719

16.6

30.9

46.7

1520

5238

5462

 

 

 

 

 

 

 

 

 

 

Lodi

15

30

3798

12.7

31.5

55.4

1523

5320

5769

Lodi/peas

15

30

3849

16.4

31.0

47.1

1346

5195

5599

 

 

 

 

 

 

 

 

 

 

SN404

16

28

3978

13.7

32.7

54.0

1824

5802

5504

SN404/peas

16

28

4096

17.8

31.1

45.7

1685

5781

5840

 

 

 

 

 

 

 

 

 

 

Oat average

12

25

3201

13.5

30.6

52.9

1915

5135

5608

Oat/pea ave.

12

25

3441

17.6

30.1

46.3

1770

5191

5591

 

 

1/  Alfalfa was harvested in mid to late August.  To increase the probability of good winter survival, fall      regrowth of alfalfa was not harvested in October in any year

2/  Total first year forage yield = forage yield from oats or oat – pea mixture harvested in June plus alfalfa yield harvested in August.

3/  Two year results

4/  Trapper field peas

Data from L.B. Chapko, M.A. Brinkman, E.T. Gritten, and K.A. Albrecht, 1989

 

 

 

 

 

 

 

Table 2.  Characteristics of barley and barley-pea mixtures harvested as forage at Arlington, Wisconsin in 1986-88.

 

 

 

Barley or barley-pea mixture

 

 

Cut date

 

Height at cut 

date

 

 

Forage yield

 

Forage crude protein

 

 

 

ADF

 

 

 

NDF

Alfalfa yield during establishment

year 1/

Total

1st year forage yield 2/

1st cut alfalfa yield during year after establishment 3/

 

June

in

1b/a

%

%

%

1b/a

1b/a

1b/a

 

 

 

 

 

 

 

 

 

 

Morex

7

28

2932

14.0

31.0

56.9

1800

4733

5730

Morex/peas4/

7

28

3149

17.2

30.2

50.7

1639

4788

5786

 

 

 

 

 

 

 

 

 

 

Hazen

8

27

3467

13.4

32.4

58.2

1776

5244

5572

Hazen/peas

8

27

3587

16.4

31.3

52.1

1536

5054

5410

 

 

 

 

 

 

 

 

 

 

Robust

8

28

3023

13.7

32.2

57.7

1897

4919

5825

Robust/peas

8

28

3201

16.5

31.3

51.0

1600

4801

5820

 

 

 

 

 

 

 

 

 

 

Chopper

10

28

3848

13.3

33.7

59.6

1642

5491

5815

Chopper/peas

10

28

3940

15.6

32.1

53.0

1531

5471

5600

 

 

 

 

 

 

 

 

 

 

Barley average

8

28

3318

13.6

32.3

58.1

1779

5097

5736

Barley/pea ave.

8

28

3469

16.4

31.2

51.7

1577

5029

5654

 

 

1/  Alfalfa was harvested in mid to late August each year.  To increase the probability of good winter survival, fall regrowth was not harvested in mid-October in any year.

2/  Total first year forage yield = forage yield from barley or barley-pea mixture harvested in June plus alfalfa yield harvested in August.

3/  Two year results.

4/  Trapper field peas.

Data from L.B. Chapko, M.A. Brinkman, E.T. Gritten, and K.A. Albrecht, 1989

 


 

 

Undersander©2001