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Carr, P.M., E.D. Eriksmoen, G.B. Martin, and N.R. Olson. 1996. Grain yield of oat-pea intercrop. p. 240-243. In: J. Janick (ed.), Progress in new crops. ASHS Press, Alexandria, VA.

Grain Yield of Oat-Pea Intercrop

Patrick M. Carr, Eric D. Eriksmoen, Glenn B. Martin, and N. Rick Olson


  1. METHODOLOGY
  2. RESULTS
  3. CONCLUSION
  4. REFERENCES
  5. Table 1
  6. Table 2

Spring oat (Avena sativa L., Poaceae) is grown for both forage and grain in temperate regions at upper latitudes. Oat is sometimes intercropped with spring pea (Pisum sativum L.) to enhance forage quality. Oat-pea mixtures have been considered for grain and seed production, though not to the extent as for forage. Generally, total grain yield has not been increased by intercropping (Carter and Larson 1964; Cowell et al. 1988).

Oat-pea intercrops have been established by sowing both crops at rates less than those used when sole-cropping either crop. This investigation was conducted to determine how grain yield of oat-pea mixtures was affected by sowing oat and pea components at or above the sole-cropped rate in North Dakota, U.S.

METHODOLOGY

A field experiment was conducted at Dickinson (46°53' N, 102°49' W) in southwestern North Dakota under dryland management during the 1993 and 1994 growing seasons, and at Hettinger (46°00' N, 102°30' W) under dryland management during the 1993 growing season. Average daily temperature ranges from -10°C during the winter (Dec. 1 to Feb. 19) to 19°C during the summer (June 1 to Aug. 31) at Dickinson, and -9° to 20°C at Hettinger. Precipitation averages 422 mm annually at Dickinson and 407 mm at Hettinger, with slightly less than two-thirds occurring between Apr. 1 and July 31.

The experiment was established in a seedbed that had been fallowed the previous year at Dickinson in 1993 and 1994, and at Hettinger in 1993. The seedbed was prepared by disking and then firming with a field cultivator and harrow. The experiment was also established in an annually-cropped, no-tillage seedbed at Dickinson in both years.

'Dumont' oat was sown alone and mixed with 'Trapper' field pea on Apr. 29 at Dickinson and Apr. 22 at Hettinger in 1993, and May 2 at Dickinson in 1994. 'Dumont' is grown for both grain and forage and is a popular oat cultivar in the northern Great Plains region of North America. 'Trapper' is a small sized pea that is suited to intercropping with oat (Chapko et al. 1991).

Oat was sown at 185 kernels/m2 (pure live seed) in sole-crops at Dickinson in 1993, and at 93, 185, and 278 kernels/m2 in 1994. Oat was sown at 99, 198, and 297 kernels/m2 at Hettinger in 1993. Pea was sown at 80 seeds/m2 (pure live seed) in sole-crops at Dickinson and Hettinger in both years, and also at 40 and 120 seeds/m2 at Hettinger in 1993 and at Dickinson in 1994. Oat was intercropped with pea at all sole-crop rates used at each location in 1993 and 1994.

A randomized complete-block design was used at all locations. Blocks were replicated four times. Plot dimensions were 1.8 by 8 m at Dickinson and 1.6 by 8.5 m at Hettinger.

Yield was determined by collecting mixed grain and seed with a research combine. Grain and seed samples were cleaned and dried at 60°C for 48 to 72 h and weighed. Split pea seed could not be separated from oat kernels in oat-pea mixtures, so a 200 g subsample was collected from each intercropped sample and separated by hand so crop composition of the grain mixture could be estimated.

The land equivalent ratio (LER) index was used to evaluate intercrop efficiencies with respect to sole-crops. The LER defines yield as a function of area (LER = Io/So + Ip/Sp) where I and S refer to intercrop and sole-crop yields, respectively, and the subscripts o and p indicate the oat and pea component crops in the mixture.

Data were analyzed for each location but not across years or environments because some sole-cropped treatments were included in 1994 but not in 1993 at Dickinson. In addition, the recommended sole-crop rate for oat differed between Dickinson and Hettinger.

RESULTS

Yield was similar between intercrop treatments and sole-crop oat treatments where oat was sown at the recommended rate at each location (Table 1). More grain and seed generally was produced by some intercrop treatments than seed by a sole-crop of pea. These data indicate that intercropping may not reduce total yield compared with a monoculture of oat if oat is sown at the sole-crop rate or a heavier rate in the mixture. Total yield can be increased by intercropping compared with a sole-crop of pea.

More of the mixed grain and seed was oat as the oat seeding rate was increased and the pea seeding rate was decreased (Table 2). Pea composed more of the mixed grain and seed as the pea seeding rate was increased and the seeding rate for oat was reduced. No intercrop treatment in this investigation produced mixed grain that was comprised of equal proportions of oat and pea at all locations. However, roughly equal proportions of oat groats and pea was produced at Dickinson across environments and years when oat was sown at half the sole-crop rate and pea at the sole-crop rate.

The LER suggested a potential advantage for intercropping in both environments at Dickinson in 1993, and for some intercrop treatments in the fallowed environment in 1994 (Table 1). An advantage for intercropping was not suggested by LERs of intercropped treatments at Hettinger in 1993 and in the annually-cropped environment at Dickinson in 1994. The largest LER value for an intercrop treatment across locations and years occurred when both oat and pea were sown at rates heavier than those recommended for a sole-crop.

CONCLUSION

Total yield generally was maintained or enhanced when oat was intercropped at a sole-crop rate with pea compared to growing oat alone in this investigation. Previous work indicates that crude protein content is increased by intercropping oat with pea compared with growing oat alone (Robinson 1960; Johnston et al. 1978). Since total yield can be maintained when intercropping oat and pea, we suggest that oat-pea mixtures are a higher N-grain alternative to a monoculture of oat, and should be considered if the mixed grain is grown for direct consumption by livestock.

REFERENCES

Carter, J.F. and K.L. Larson. 1964. Oats, peas, and vetch for hay or silage in North Dakota. North Dakota Ag. Expt. Sta. Fargo. Bul. 14 Agr. 9-5.

  • Chapko, L.B., M.A. Brinkman, and K.A. Albrecht. 1991. Oat, oat-pea, barley, and barley-pea for forage yield, forage quality, and alfalfa establishment. J. Prod. Agr. 4:486-491.

  • Cowell, L.E., E. Bremer, and C. Van Kessel. 1988. Yield and N2 fixation of pea and lentil as affected by intercropping and N application. Can. J. Soil Sci. 69:243-251.

  • Johnston, H.W., J.B. Sanderson, and J.A. MaCleod. 1978. Cropping mixtures of field peas and cereals in Prince Edward Island. Can. J. Plant Sci. 58:421-426.

  • Robinson, R.G. 1960. Oat-pea or oat-vetch mixtures for forage or seed. Agron. J. 52:546-549.


    Table 1. Total yield of sole-cropped and intercropped 'Dumont' oat and 'Trapper' pea during 1993 in a fallowed environment located at Hettinger (1993H) and in fallowed and annually-cropped environments located at Dickinson in southwestern North Dakota in 1993 and 1994, and the Land Equivalent Ratio (LER) of intercropped treatments.
    Yield LER
    FallowAnnually-
    cropped
    FallowAnnually-
    cropped
    Seeding rate
    (seeds/m2)
    199319941993Hz19931994199319941993H19931994
    Sole-crop
    93
    (oat low)
    --17123871--1796-.--.--.--.--.-
    185
    (oat med.)
    27772272422928252386-.--.--.--.--.-
    375
    (oat high)
    --27423871--2280-.--.--.--.--.-
    40
    (pea low)
    --18161839--1814-.--.--.--.--.-
    80
    (pea med.)
    17681888186016362229-.--.--.--.--.-
    160
    (pea high)
    --18972489--2115-.--.--.--.--.-
    Intercropsy
    Oat low/
    pea low
    339917333959298220461.370.820.961.290.89
    Oat low/
    pea med.
    260119423745284221641.080.950.941.310.95
    Oat low/
    pea high
    251320173913281422171.081.021.011.330.98
    Oat med./
    pea low
    293224194041313822981.111.090.961.240.98
    Oat med./
    pea med.
    308418774264293623601.190.901.021.261.03
    Oat med./
    pea high
    292624164051292419611.141.150.991.320.86
    Oat high/
    pea low
    299126534377297523041.111.191.051.180.99
    Oat high/
    pea med.
    286825334103304321911.081.160.991.270.95
    Oat high/
    pea high
    301023593829337222161.141.100.911.420.96
    Mean28062152402128632159-.--.--.--.--.-
    CV(%)19.816.09.017.516.1-.--.--.--.--.-
    LSD
    (0.05)
    803492NSx722496-.--.--.--.--.-
    zSowing rates at Hettinger for oat were: oat low = 99, oat med. = 198, and oat high = 297 kernels/m2.
    yYield is combined yield of oat and pea.
    xNS = not significant.
    Table 2. Yield of sole-cropped and intercropped 'Dumont' oat and 'Trapper' pea during 1993 in a fallowed environment located at Hettinger (1993H) and in fallowed and annually-cropped environments located at Dickinson in southwestern North Dakota in 1993 and 1994.
    Oat grain yield (kg/ha) Pea seed yield (kg/ha)
    FallowAnnually-
    cropped
    FallowAnnually-
    cropped
    Seeding rate
    (seeds/m2)
    199319941993Hz19931994199319941993H19931994
    Sole-crop
    93
    (oat low)
    -- 17121 3871 -- 1796 -- -- -- -- --
    185
    (oat med.)
    2777 2272 4229 2825 2386 -- -- -- -- --
    375
    (oat high)
    -- 2742 3871 -- 2280 -- -- -- -- --
    40
    (pea low)
    -- -- -- -- -- -- 1816 1839 -- 1814
    80
    (pea med.)
    -- -- -- -- -- 1768 1888 1860 1636 2229
    160
    (pea high)
    -- -- -- -- -- -- 1897 2489 -- 2115
    Intercrops
    Oat low/
    pea low
    2695 1136 3871 2084 1002 704 596 88 898 1044
    Oat low/
    pea med.
    1882 833 3548 1674 563 719 1109 197 1168 1602
    Oat low/
    pea high
    1673 552 3620 1524 356 839 1464 293 1290 1861
    Oat med./
    pea low
    2642 2108 4014 2624 1540 289 310 27 514 757
    Oat med./
    pea med.
    2703 1061 4229 2070 1092 380 815 35 866 1268
    Oat med./
    pea high
    2498 1400 3942 1826 541 428 1016 109 1098 1420
    Oat high/
    pea low
    2823 2437 4337 2464 1609 169 216 40 511 695
    Oat high/
    pea med.
    2646 2057 4050 2285 1106 223 475 53 759 1085
    Oat high/
    pea high
    2723 1619 3799 2506 1192 287 741 30 866 1024
    Mean 2506 1661 3948 2188 1289 581 1029 588 961 1410
    CV(%) 18.0 21.9 9.0 21.5 28.1 36.4 11.5 54.0 14.8 19.4
    LSD
    (0.05)
    653 523 502 684 520 307 170 464 207 393
    zSowing rates at Hettinger (1993H) for oat were 99, 198, and 297 kernels/m2.
    Last update June 9, 1997 aw