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when dryland cropping systems are intensified and diversified. A study by Lenssen
et al. ( 2015 ) showed that including ecologically managed forage barley (33 %
greater seeding rate and banded N fertilizer) in dryland crop rotation produced more
forage and used water more efficiently than barley with conventional seeding rate
and broadcast N. The same study also showed greater forage yield and water use
efficiency in the ecologically managed 4-year than 3-year rotation, illustrating the
advantages of increasingly diversified cropping rotations in the NGP.
Oilseeds and pulses are important crops for diversification of dryland cropping
systems in North America, with greatest adoption in the NGP and IPNW (Fig. 3 ).
Among the oilseed crops, canola is the most widely produced dryland crop, with
lesser production of camelina, flax, mustard, safflower, and sunflower. The vegeta-
ble oils are marketed for both food and industrial uses. Further opportunity for
diversifying dryland rotations is being driven by interest in agriculturally produced
oils as feedstocks for biofuels (Lenssen et al. 2012 ; Allen et al. 2014 ; Gesch et al.
2015 ; Long et al. 2016 ). Pulse crops produced in North American dryland cropping
include chickpea, dry bean, lentil, and field pea. While adoption of dryland crop-
ping systems with oilseeds and pulses is increasing in North America, more infor-
mation is needed about the sustainability of these systems. Lenssen et al. 2012
concluded from a 4-year study in NE Montana that 2-year durum-oilseed rotations
could be used for grain production and biofuel feedstock, but that production sys-
tem sustainability would require additional research on soil quality, no-till oilseed
stand establishment, and pest management. Allen et al. (2014) reported after the
fifth year of the same experiment that durum yield following the oilseed B. juncea
was similar to that of durum following chem fallow, though yield of durum follow-
ing camelina and crambe was less than that of durum following fallow.
Fig. 3 Harvested areas of oilseed crops (camelina, canola, flax, mustard, safflower, sunflower) and
pulse crops (chickpea, dry bean, lentil, field pea) in 25 counties from NE Montana and NW North
Dakota 1990–2015. (Data from: USDA-Farm Service Agency)
N.C. Hansen et al.