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Forage peas could be a promising alternative to summer fallow

Pea forage could be an economic alternative to summer fallow
in no-till systems, say Montana State University researchers.

Recent research conducted by Dave Wichman of the Montana
Agricultural Experiment Station's Central Agricultural Research Center, and
Perry Miller and Rick Engel, Department of Land Resources and Environmental
Sciences (LRES), indicate pea forage management practices can affect both yield
and quality of the forage and subsequent wheat crop.

In this study, wheat yields following pea were superior to
wheat yields following hay barley at Amsterdam.

"This cropping sequence response has commonly been
observed in Montana where wheat yields on pea stubble were intermediate between
wheat yields following fallow and cereal stubble," says Miller.

At Amsterdam, wheat yields were not only affected by the
previous crop, but also by forage harvest timing and nitrogen fertilizer rate,
says Clain Jones, Extension soil fertility specialist in LRES. When forage was
fertilized with a relatively low nitrogen fertilizer rate of 45 pounds of
nitrogen per acre and harvested and terminated at first flower, wheat yields
were 15 bushels per acre greater following winter pea than when wheat was
similarly fertilized, harvested and terminated following hay barley.

On average, pea forage yield at first flower was 58% of the
yield at the plump pod stage. In addition, harvesting early at first flower
used 2.5 inches of soil water compared with 3.1 inches when forage harvest was
delayed until the plump pod stage. Compared to spring pea, winter pea utilized
about 0.8 inches less water.

In this study, wheat following winter pea forage
consistently produced higher wheat grain protein, whereas wheat following
barley forage consistently produced the lowest protein.

"Protein is higher following peas, because pea residue
contributes more available nitrogen to the soil than barley residue," says

At the Central Ag Research Center at Moccasin, wheat yields
were not affected by the previous forage treatment, and were the same as
following the chemical fallow control.

"The differences between sites are likely due to
Amsterdam's considerably deeper soil compared to the variably shallow soil at
Moccasin," Miller says. The results confirmed that often there is not much
of an advantage to fallowing shallow soils, because shallow soils cannot store
much water.

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