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Winter Pea: Promising New Crop for Washington's Dryland Wheat-Fallow Region



A 2-year tillage-based winter wheat (Triticum aestivum L.)-summer fallow (WW-SF) rotation has been practiced by the vast majority of farmers in the low-precipitation (<300 mm annual) rainfed cropping region of east-central Washington and north-central Oregon for 140 years. Until recently, alternative crops (i.e., those other than WW) so far tested have not been as economically viable or stable as WW-SF. A 6-year field study was conducted near Ritzville, WA (292 mm avg. annual precipitation) to determine the yield and rotation benefits of winter pea (Pisum sativum L.) (WP). Two 3-year rotations were evaluated: WP-spring wheat (SW)-SF vs. WW-SW-SF. Winter pea yields averaged 2,443 vs. 4,878 kg/ha for WW. No fertilizer was applied to WP whereas 56 kg N and 11 kg S/ha were applied to WW. Winter pea used significantly less soil water than WW. Over the winter months, a lesser percentage of precipitation was stored in the soil following WP compared to WW because: (i) very little WP residue remained on the soil surface after harvest compared to WW, and (ii) the drier the soil, the more precipitation is stored in the soil over winter. However, soil water content in the spring was still greater following WP vs. WW. Soil residual N in the spring (7 months after the harvest of WP and WW) was greater in WP plots despite not applying fertilizer to produce WP. Spring wheat grown after both WP and WW received the identical quantity of N, P, and S fertilizer each year. Average yield of SW was 2,298 and 2,011 kg/ha following WP and WW, respectively (P < 0.01). Adjusted gross economic returns for these two rotation systems were similar. Based partially on the results of this study, numerous farmers in the dry WW-SF region have shown keen interest in WP and acreage planted WP in east-central Washington has grown exponentially since 2013. This paper provides the first report of the potential for WP in the typical WW-SF region of the inland Pacific Northwest (PNW).
published: 10 May 2017
doi: 10.3389/fevo.2017.00043
Frontiers in Ecology and Evolution | 1May 2017 | Volume 5 | Article 43
Edited by:
Klaus Birkhofer,
Lund University, Sweden
Reviewed by:
José Manuel Mirás-Avalos,
Centro de Edafología y Biología
Aplicada del Segura (CSIC), Spain
Fernando José Cebola Lidon,
Faculdade de Ciências e Tecnologia
da Universidade Nova de Lisboa,
William F. Schillinger
Specialty section:
This article was submitted to
Agroecology and Land Use Systems,
a section of the journal
Frontiers in Ecology and Evolution
Received: 18 February 2017
Accepted: 21 April 2017
Published: 10 May 2017
Schillinger WF (2017) Winter Pea:
Promising New Crop for Washington’s
Dryland Wheat-Fallow Region.
Front. Ecol. Evol. 5:43.
doi: 10.3389/fevo.2017.00043
Winter Pea: Promising New Crop for
Washington’s Dryland Wheat-Fallow
William F. Schillinger *
Department of Crop and Soil Sciences, Washington State University, Dryland Research Station, Lind, WA, USA
A 2-year tillage-based winter wheat (Triticum aestivum L.)-summer fallow (WW-SF)
rotation has been practiced by the vast majority of farmers in the low-precipitation (<300
mm annual) rainfed cropping region of east-central Washington and north-central Oregon
for 140 years. Until recently, alternative crops (i.e., those other than WW) so far tested
have not been as economically viable or stable as WW-SF. A 6-year field study was
conducted near Ritzville, WA (292 mm avg. annual precipitation) to determine the yield
and rotation benefits of winter pea (Pisum sativum L.) (WP). Two 3-year rotations were
evaluated: WP-spring wheat (SW)-SF vs. WW-SW-SF. Winter pea yields averaged 2,443
vs. 4,878 kg/ha for WW. No fertilizer was applied to WP whereas 56 kg N and 11 kg
S/ha were applied to WW. Winter pea used significantly less soil water than WW. Over
the winter months, a lesser percentage of precipitation was stored in the soil following
WP compared to WW because: (i) very little WP residue remained on the soil surface
after harvest compared to WW, and (ii) the drier the soil, the more precipitation is stored
in the soil over winter. However, soil water content in the spring was still greater following
WP vs. WW. Soil residual N in the spring (7 months after the harvest of WP and WW) was
greater in WP plots despite not applying fertilizer to produce WP. Spring wheat grown
after both WP and WW received the identical quantity of N, P, and S fertilizer each year.
Average yield of SW was 2,298 and 2,011 kg/ha following WP and WW, respectively
(P<0.01). Adjusted gross economic returns for these two rotation systems were similar.
Based partially on the results of this study, numerous farmers in the dry WW-SF region
have shown keen interest in WP and acreage planted WP in east-central Washington
has grown exponentially since 2013. This paper provides the first report of the potential
for WP in the typical WW-SF region of the inland Pacific Northwest (PNW).
Keywords: winter pea, Inland Pacific Northwest USA, dryland cropping systems, winter wheat-summer fallow,
crop diversification
A monoculture WW-SF rotation is the dominant cropping system practiced by farmers on 1.5
million cropland hectares in east-central Washington and north-central Oregon. Researchers and
farmers have experimented with numerous crops and rotations over many decades, but none have
been found to be as stable, reliable, and profitable as WW-SF (Juergens et al., 2004). Grassy weeds,
mostly downy brome (Bromus tectorum L.) and jointed goatgrass (Aegilops cylindrica Host.), are a
huge problem with monoculture WW-SF. Many farmers have resorted to the “Clearfield”TM system
Schillinger Winter Pea in the Pacific Northwest Drylands
for WW production that depends on use of the long soil-residual
imazamax herbicide to control grassy weeds. A viable, stable, and
profitable broadleaf crop is much needed for crop diversity and
grassy weed control without the use of soil-residual herbicides.
Pulse crops are cool-season annual grain legumes mostly
grown in the northern tier states of North Dakota and Montana,
the high-precipitation (>450 mm average annual) Palouse region
of Washington and Idaho (NASS, 2017), and the Canadian
provinces of Alberta, Saskatchewan, and Manitoba (Statistics
Canada, 2017). During the past 20 years, pulse crops have become
an integral component of diversified and profitable dryland
cropping systems in the Canadian and US northern Great Plains
(Miller et al., 2003, 2015; Chen et al., 2006; Long et al., 2014).
In the PNW Palouse region, dry edible spring pea is
commonly grown in rotation with wheat, with 48,000 ha of
this crop harvested in 2016 (NASS, 2017). However, very little
spring pea is produced in PNW areas that receive <450 mm
annual precipitation. Experience in east-central Washington has
demonstrated that water and heat stresses during flowering and
pod fill limits yield potential of spring pea whereas WP better
avoids such abiotic stresses by reaching physiological maturity
before the onset of high air temperatures (Nelson, 2017).
Chen et al. (2006) reported that fall-planted WP in the high-
precipitation Palouse of the PNW yielded as much as 1,830
kg/ha more than spring-planted pea cultivars. This (Chen et al.,
2006) is the only published paper of such nature on WP in
the PNW. Such observations of higher yield potential with WP
compared to spring pea are not in general agreement with
the much more comprehensive data sets from the Canadian
and US northern Great Plains where winter temperatures are
considerably colder than in the PNW. Chen et al. (2006) found
that WP cultivars did not have a yield advantage over spring
pea in central and south-central Montana. Similarly Strydhorst
et al. (2015) recommended that farmers consider WP over spring
pea only in the southernmost locations in Alberta. Although
edible dry pea was harvested on 206,000 ha in Montana in 2016
(NASS, 2017) only about one percent of this was WP (P.R. Miller,
personal communication).
Essentially no edible WP was produced anywhere in the PNW,
(including the typical WW-SF region that receives <300 mm
average annual precipitation, prior to 2012. Field research (this
study) conducted since 2010 near Ritzville, WA (292 mm annual
average precipitation) has demonstrated that WP is well-suited
for the low-precipitation drylands. Winter pea plantings in the
WW-SF region have gone from basically zero to 2,730 hectares
from 2013 to 2017 (Howard Nelson, personal communication).
Although the land area planted to WP currently is still small, the
annual increase in planted hectares has been exponential during
this 5-year period. The objective of the 6-year study reported here
was to determine the yield potential and yield stability of WP
and associated rotation benefits to the subsequent crop compared
to WW in the low-precipitation WW-SF region of east-central
Abbreviations: PNW, inland Pacific Northwest; SF, summer fallow; SW, spring
wheat; WP, winter pea; WW, winter wheat.
A long-term WP cropping systems experiment was initiated
at the Ronald Jirava farm near Ritzville, WA (47.16394,-
118.473225) in August 2010. The WP cultivar “Windham”
(McPhee et al., 2007) was selected for inclusion in the
experiment based on the experience and recommendation
of Howard Nelson of Central Washington Grain Growers.
Windham is a yellow pea with mottled seed coat; with an
average 100-seed weight of 13.8 g. Windham can withstand
ambient air temperatures as low as 18C without undue
damage to plant stands (Nelson, 2017). This cultivar has an
average mature plant height of 44 cm with upright growth
habit that allows for direct combining at harvest with a
conventional header (i.e., swathing and/or a pick-up header not
Precipitation was measured on site during all years of the
study by the Washington State University (WSU) AgWeatherNet
( with a Campbell Scientific CR-1000
logger and associated hardware. The soil at the site is a Ritzville
silt loam (coarse-silty, mixed, superactive, mesic, Calcidic
Haploxerolls; Soil Survey Staff, 2010). The soil is more than 2
meters deep to underlying basalt bedrock with uniform texture
throughout the profile and with no rocks or restrictive layers.
Slope is <1%. Long-term (100-year) annual precipitation at/near
the site averages 292 mm. Annual crop-year (Sept. 1–Aug. 31)
precipitation during the study period ranged from 207 to 370 mm
and averaged 277 mm.
Treatments and Field Operations
Throughout the 6-year experiment, glyphosate herbicide was
applied at a rate of 0.48 kg acid equivalent (ae)/ha in March
to control weeds in the undisturbed residue of the WP, WW,
and SW plots that had been harvested the previous July or
August. The two 3-year crop rotations in the experiment were
(i) WP-SW-SF vs. (ii) WW-SW-SF. Experimental design was a
randomized complete block with four replicates. All phases of
both rotations were present every year for a total of 24 individual
plots. Size of individual plots was 5 ×30 m.
During the fallow year, conservation primary spring tillage
was conducted with a HaybusterTM undercutter implement in
mid-to-late May at a depth of 10 cm. For the WW-SW-
SF treatment, 56 kg/ha aqua NH3-N +11 kg/ha thiosol S
fertilizer was injected with the undercutter implement during
primary spring tillage. No fertilizer was applied to the WP-SW-
SF treatment with the undercutter during primary spring tillage.
Summer fallow in both treatments was rodweeded once in July at
a depth of 8 cm to control broadleaf weeds.
Winter pea (cv. Windham) and WW (cv. Xerpha) were
planted at the same time and depth each year in either the last
week of August or first week of September with a deep-furrow
drill with 43 cm spacing between rows. Seed was inoculated with
powdered rhizobium bacteria at time of planting to facilitate root
nodulation and fixation of atmospheric nitrogen. Seeding rate
for WP was 100 kg/ha (70 seeds/m2) and for WW 56 kg/ha
(160 seeds/m2). An average of 10 cm of soil covered the seeds.
Excellent stands of both WP and WW were achieved every year.
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Schillinger Winter Pea in the Pacific Northwest Drylands
Spring wheat (cv. Louise) was planted and fertilized in late
March in one-pass directly into the undisturbed soil and residue
left from the previous WP or WW crop. A no-till hoe-opener drill
was used to place seed in paired rows 10-cm apart with 30 cm
spacing between openers. Fertilizer was placed in a band between
and 3 cm below the paired rows. Seeding rate for SW was 78
kg/ha (225 seeds/m2) and soil covering the seed averaged 2 cm.
Prior to SW planting and fertilization, soil samples were obtained
from 2,014 to 2,106 in 30-cm increments from the middle of each
plot to a depth of 120 cm in all four replicates, then combined
to make one sample for each treatment per depth increment,
where the previous crop was WP or WW. Soil samples were then
analyzed for N, P, K, S, and other nutrients at a commercial soil-
testing laboratory (Soil Test Farm Consultants, Inc., Moses Lake,
WA). Fertilizer rate for SW was based on soil test residual soil
fertility, available soil water, and perceived grain yield potential.
Potassium fertilizer was not required as soils contain naturally
adequate quantities of this nutrient. Although soil fertility values
following WP vs. WW differed somewhat (Table 1), SW after
either WP or WW always received the same fertilizer application
rate each year. Solution 32 (NH4NO3+urea) provided the
liquid fertilizer base to supply an average of 38 kg N, 7 kg P
(aqueous solution of NH4H2PO4), and 10 kg S [aqueous solution
of (NH4)2S2O3]/ha. Excellent stands of SW were achieved every
Crop yields were determined in early-to-mid July (WP) and
early August (WW and SW) by harvesting a 1.5-m swath
through the center of each 30-m-long plot with a HegeTM 140
plot combine. After grain harvest with the plot combine, the
remaining standing crops in the experiment were harvested with
a commercial-size combine.
In-Crop and Post-Harvest Weed Control
with Herbicides
When WP reached the three-leaf (or four-node) stage of growth
in April, 1.1 kg active ingredient (ai)/ha sodium salt of bentazon
broadleaf-weed herbicide was tank mixed with 0.1 kg ai/ha
quizalofop P-ethyl grass-weed herbicide and applied. Bentazon
and MCPA Amine are currently the only non-soil-residual
broadleaf-weed herbicides labeled for use in WP. The major grass
weeds of concern in the region are downy brome and jointed
goatgrass. Both these grass weeds are winter annuals with growth
cycles similar to WW and are particularly problematic in the
2-year WW-SF rotation (Young and Thorne, 2004).
Herbicides used to control broadleaf weeds in WW were either
2,4-D ester at a rate of 0.84 kg acid equivalent (ae)/ha or 0.56 kg
ai/ha bromoxynil applied in April after WW had four tillers but
before the “jointing” stage of WW growth development. In-crop
broadleaf herbicides used for SW were 0.56 kg ai/ha bromoxynil
or 0.45 kg ai/ha bromoxynil +0.02 L ai/ha thifensulfuron applied
in May.
Glyphosate was applied at a rate of 0.90 kg ae/ha following the
harvest of SW in August of 2014 and 2015 (the two driest crop
years) to control Russian thistle (Salsola tragus L.). Post-harvest
herbicide application was not required for WP or WW in any
TABLE 1 | Soil nitrate-N, Olsen-P, sulfate-S, and soil organic matter (SOM)
in late March during 3 years after either winter pea or winter wheat and
prior to planting spring wheat.
Nitrate Phosphorus Sulfate SOM
(mg/kg/120 cm) (mg/kg/30 cm) (mg/kg/90 cm) (30 cm, %)
Winter wheat 24 53 39 1.7
Winter pea 30 52 45 1.5
Winter wheat 16 35 17 1.8
Winter pea 22 38 17 1.6
Winter wheat 17 45 16 1.4
Winter pea 24 43 13 1.6
Soil Water
Soil water was measured to a depth of 180 cm three times
each year: (i) in early August immediately after WP, WW, and
SW grain harvest (16 plots); (ii) at the end of fallow in late
August for the SF plots (8 plots); and (iii) in mid-March (all
24 plots). Volumetric soil water content in the 0–30-cm depth
was determined from two 15-cm core samples with gravimetric
procedures (Topp and Ferre, 2002) using known soil bulk density
values for these depths. Soil volumetric water content in the 30–
180-cm depth was measured in 15-cm increments by neutron
thermalization (Hignett and Evett, 2002).
Market Price, Gross Returns, and Adjusted
Gross Returns
Gross returns for WP and WW per hectare were calculated based
on the yield results for each year of the study. Edible WP grown
by farmers in eastern Washington was sold through a “market
pool” operated by Central Washington Grain Growers in Wilbur,
WA. Market streams for WP through the years included seed for
cover crops, US government food aid, export for food to Asia, and
for pet food. Winter pea marketing pool prices ranged from 160
to 339 US$/metric ton (MT).
Soft white wheat market price used was the price offered
during the first week of September for each year of the study at
Ritzville Warehouse, Ritzville, WA. Ritzville Warehouse accepts
WW and WP for storage and is the closest commercial elevator
delivery site for the study. Gross returns per hectare for both WP
and WW were calculated by multiplying yields obtained from the
study by the market prices for each year. Adjusted gross returns
were then calculated for both rotations by tabulating for each
year the cost of N and S used for WW (but not for WP) and any
differences in SW yields.
Statistical Analysis
Statistical analyses using a randomized complete block design
analysis of variance (ANOVA) were conducted for: (i) water use
of WP vs. WW as well as overwinter storage of precipitation in
the soil following these two crops averaged over 5 years, and;
(ii) within-year and 5-year average differences in SW grain yield
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Schillinger Winter Pea in the Pacific Northwest Drylands
following either WP or WW. A split-plot in time ANOVA was
used for the 5-year average soil water data and the 5-year average
SW yield data with treatment as the fixed effect factor and year
as the random effect factor. The least significant difference test
was used to detect statistical differences in treatment means. All
ANOVA tests were done at the 5% level of significance.
Soil Water
Averaged over the years, WP used an average of 30 mm less
soil water than WW (P<0.001, Table 2). The majority of this
water savings with WP occurred at soils depths below 100 cm
(Figure 1) as WP roots do not reach this depth. These data on
soil water use by WP agree closely with those reported by Miller
and Holmes (2012) in Montana and Merrill et al. (2004) in North
Dakota. However, by late March, WP plots had only 13 mm more
soil water than WW plots (Table 2) because: (i) the greater the
surface residue cover, the more water will be stored in the soil
(e.g., WP produces little residue compared to WW); and (ii) the
drier the soil, the more overwinter precipitation will be stored in
the soil (Kok et al., 2009).
The overwinter precipitation storage efficiency (PSE) in the
soil averaged 55 and 69% for WP and WW plots, respectively
(Table 2). Similar overwinter PSE-values were reported following
spring lentil (Lens culinaris L.) vs. following SW in a 21-year
study in Saskatchewan (Campbell et al., 2007). This increase in
overwinter PSE for WW over WP plots occurred within the first
100 cm of the soil profile whereas the relative difference in spatial
water distribution at the 100–180-cm depths remained about the
same for WP and WW plots (Figure 1). The end result, however,
was that when SW was planted in late March, average overwinter
soil water content was 290 and 277 mm following WP and WW,
respectively (Table 1).
Soil Nitrate-N
When measured in late March, soil nitrate-N-values trended
higher after a crop of WP compared to WW, despite the fact that
zero N was applied for WP and 56 kg of N/ha was applied for WW
(Table 1). This can be explained by the fact that WP is a legume
that fixes atmospheric nitrogen. Although statistical analysis was
not possible (soil samples were pooled from the four replicates),
nitrate-N-values were 25–41% greater following WP vs. WW.
Grain Yield
Yield of WP ranged from 1,696 to 3,158 kg/ha and averaged 2,443
kg/ha over 5 years (Table 3). Winter pea was killed by 21C air
temperatures with no snow cover in 2014 and was replaced by
spring pea (cv. Banner) which yielded 870 kg/ha. Winter wheat
grain yield ranged from 3,372 to 5,841 kg/ha for an average of
4,878 kg/ha over 6 years (Table 3).
Spring wheat grain yield was significantly greater following
WP vs. following WW in 2013 and 2015. The 5-year average
SW grain yield of 2,298 kg/ha following WP was significantly
different from 2,122 kg/ha following WW (Table 3).
TABLE 2 | (i) Soil water content to a depth of 180 cm measured after
harvest of winter pea and winter wheat and again in late March following
these two crops; (ii) overwinter gain in soil water, and; (iii) overwinter
precipitation storage efficiency in the soil (PSE).
(late Aug.)
Spring (late
PSE (%)
Soil water content (mm)
Winter pea 180 290 110 55
Winter wheat 150 277 127 69
P-value <0.001 ns 0.001
Data are averaged over 5 years. Average overwinter precipitation was 164 mm.
FIGURE 1 | Soil volumetric water content to a depth of 180 cm in early
August after harvest of winter pea and winter wheat (red lines on left)
and overwinter soil water recharge following these two crops
measured in late March (blue lines on right). Data are averaged over 5
Market Price, Gross Returns, and Adjusted
Gross Returns
Gross returns for WW exceeded that for WP in most years
(Table 4). However, cost of 56 kg/ha aqua NH3-N +11 kg/ha
thiosol S fertilizer for WW (where none was used for WP) ranged
from $66 to $97/ha and averaged $86/ha over the 6 years (actual
costs paid for the fertilizer each year). Also, SW yield after WP
vs. WW from 2012 to 2016 ranged from 143 to +589 kg/ha
and averaged +176 kg/ha (Table 3). Using the commodity market
prices shown in Table 4, SW after WP generated from $35
to +S85/ha and averaged +$39/ha more return than SW after
WW. Thus, the fertilizer savings plus the greater SW grain yield
revenue provided in the WP rotation should be considered rather
than just the gross returns shown in Table 4.
Winter wheat-summer fallow has been the dominant cropping
system practiced throughout the low-precipitation dryland
cropping region of east-central Washington and north-central
Oregon for well-over 100 years. Despite long-term and ongoing
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Schillinger Winter Pea in the Pacific Northwest Drylands
TABLE 3 | Yield of winter pea (WP) and winter wheat (WW) as well as the
subsequent yield of spring wheat (SW) following both WP and WW over a
6-year period at Ritzville, WA.
Grain yield (kg/ha)
2011 2012 2013 2014 2015 2016 Avg.
Winter pea 2,193 3,158 2,336 - - - -*1,696 2,833 2,443**
Winter wheat 5,180 5,729 5,841 3,372 4,211 4,932 4,878
SW after WP 2,010 2,992 a 1,043 2,293 a 3,151 2,298 a
SW after WW 2,153 2,700 b 965 1,704 b 3,086 2,122 b
Crop-year precipitation (mm)
330 294 254 207 208 370 277
Values at the bottom show crop-year (Sept. 1–Aug. 31) precipitation at the site.
*WP was winterkilled in 2014 and replanted to Banner edible spring pea, which yielded
870 kg/ha.
**Winter pea average yield is for 5 years (i.e., 2014 not included).
***ANOVA is for SW only. Within-column means followed by a different letter are
significantly different at P <0.05.
TABLE 4 | Ritzville soft white wheat market prices during the first week of
September and winter pea market pool price as well as gross return for
these crops based on the yield results of the experiment from 2011 to
Commodity market price (US$/MT)* Gross returns (US$/hectare)**
Soft white
Winter pea Soft white
Winter pea
2011 198 291 1,245 776
2012 242 289 1,680 1,112
2013 202 339 1,433 963
2014 172 No pool, winterkill 701 - - - -
2015 145 377 746 778
2016 123 160 731 674
*Soft white wheat price data from Ritzville Warehouse, Ritzville, WA. Winter pea market
pool price data from Howard Nelson, Central Washington Grain Growers, Wilbur, WA.
**Gross return values shown here to not account for cost of N and S used for WW (but
not used for WP) or the additional revenue from greater SW yield after WP vs. WW (see
Results section).
efforts, farmers and scientists have not yet identified any spring-
planted crop, including SW spring barley (Hordeum vulgare L.),
and numerous others, that can provide the yield stability and
economic viability of WW-SF.
A big benefit of growing WP in wheat-based cropping systems
is the opportunity for in-crop control of winter-annual grass
weeds such as downy brome and jointed goatgrass. These two
grass weeds have growth cycles similar to WW and infestations
are frequently heavy and troublesome (Appleby and Morrow,
1990), especially in the 2-year WW-SF rotation.
Another benefit of WP is its large seed size and strong
“push” by the elongating hypocotyl which enables it to emerge
from deep planting depths. For optimum grain yield potential,
farmers in east-central Washington seed WW into SF as deep
as 20 cm below the soil surface with deep-furrow drills to reach
adequate soil moisture in late August-early September, and WW
seedlings need to emerge through as much as 15 cm of dry
soil cover. Data from planting-date experiments in east-central
Washington suggest that late August-early September is also the
best planting time for optimum yield potential of WP (Rebecca
McGee, personal communication). Experience of farmers and
scientists strongly demonstrates that WP seedlings can emerge
from even deeper planting depths than WW. In addition, WP
seedlings easily emerge through surface soil that has been crusted
by rain showers whereas WW seedlings cannot do so.
A new yellow WP cultivar “Blaze” (ProGene Plant Research,
Othello, WA) is presently under seed multiplication and will
be available to farmers in 2018. Compared to Windham in
regional trials, Blaze has (i) 13% higher yield, (ii) 18 cm taller
plant height at maturity, 22% larger seed, and (iii) better cold
tolerance (Nelson, 2017). For example, during a cold event of
18C with no snow cover in 2014, Windham was winterkilled
at regional locations whereas, at these same locations, Blaze
survived (Nelson, 2017). It is estimated that Blaze has similar
cold tolerance as regionally-adopted WW cultivars. Additionally,
three advanced WP numbered lines in the USDA-Agricultural
Research Service legume breeding program in Pullman, WA
show excellent potential and are expected to be released soon.
These numbered WP lines have better cold tolerance than
Windham in addition to smooth seed coat, clear hilum, and
large seed size that are deemed highly desirable for food markets
(Rebecca McGee, personal communication).
A soil management concern about growing WP is the fact
that they produce very little durable residue. Wind erosion and
dust emission from agricultural soils is a major environmental
and air quality concern in east-central Washington (Sharratt
and Vaddella, 2012). Wind tunnel studies during the fallow year
after the oilseed crops camelina (Camelina sativa L. Crantz)
and safflower (Carthamus tinctorius L.) showed up to 250%
greater blowing dust emissions even using best management
practices for tillage-based SF compared to after WW (Sharratt
and Schillinger, 2014). Personal observation suggests that WP
residue decomposes at about the same rate as residue of camelina
and safflower. In a practical sense, this means that farmers must
be especially judicious in protecting the soil after WP by either
(i) recropping to the spring crop (as done in this study), or (ii)
conducting no tillage during the 13-month SF cycle.
There are currently few effective in-crop broadleaf herbicide
options for WP. Bentazon herbicide (used every year in
WP in the study) provides little control for tumble mustard
(Sisymbrium altissimum L.) or tansy mustard (Descurainia
pinnata L.). Although considered minor weeds that are easily
controlled with herbicides in WW, both were present in
minor to moderate levels in WP. The soil residual imazamox
herbicide can be used in WP and is used by many farmers
who practice the ClearfieldTM method for WW production.
However, many farmers are reluctant to use soil-residual
herbicides due to limitations imposed on rotation to other
crops or to WW cultivars that are not tolerant of this
herbicide. Russian thistle, by far the most troublesome broadleaf
weed in the region, was not a problem in WP in any year,
presumably due to the ability of WP to provide canopy
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Schillinger Winter Pea in the Pacific Northwest Drylands
closure relatively early in the spring before this weed can
The potential impact of increased pulse crop production on
greenhouse gas emissions deserves some discussion. Lemke et al.
(2007) and Cutforth et al. (2007) wrote review articles about
the impact of pulse crop production on climate change in the
Canadian and US northern Great Plains and the contribution of
pulse crops to the balance of greenhouse gases. Authors of these
papers agreed that rotations which include pulse crops will likely
have lower nitrous oxide emissions compared to rotations that do
not contain a pulse because legumes fix atmospheric N compared
to rotations that rely solely on fertilizer N. Lemke et al. (2007) and
Cutforth et al. (2007) further agreed that replacing a cereal with a
pulse crop will likely result in the same or slightly smaller carbon
dioxide emissions in direct relation to reduction in fertilizer N
This study showed that WP has excellent production potential in
the typical WW-SF region of east-central Washington. Although
gross returns for WW were greater than for WP during
most years, adjusted gross returns for the two rotations were
equivalent. Winter pea has unsurpassed seedling emergence from
deep planting depths, even when surface soils have been crusted
by rain showers before emergence. Excellent WP plant stands
were consistently achieved that effectively competed against
Russian thistle. New WP cultivars will be available to farmers
in 2018 that have cold tolerance similar to that of WW, greater
yield potential than cv. Windham, and better quality traits that
will fetch higher prices in regional, national, and international
Land area planted of WP in the PNW drylands is still minor,
but farmers and scientists are excited about this crop and planted
acreage has increased exponentially every year since 2013. This
paper provides the first report in the literature on WP production
in the typical WW-SF region of the PNW.
Contributions to this article were made by WS and he is
accountable for the content of the work.
The author gratefully acknowledges the cooperation and
support of Ronald Jirava on whose farm the research was
conducted. Excellent field and office support was provided by
John Jacobsen, Steve Schofstoll, and Samantha Crow located at
the WSU Lind Dryland Research Station. Much appreciation
is extended to Howard Nelson and Kurt Braunwart for
sharing their knowledge about producing and marketing
WP. Funding was provided by the WSU Agricultural
Research Center through Hatch Project 0250, the USDA-
NIFA through the REACCH Project, and by ProGene Plant
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and depletion by diverse crop species on Haplustoll soil in the northern Great
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and Engel, R. E. (2015). Pea in rotation with wheat reduced uncertainty
of economic returns in southwest Montana. Agron. J. 107, 541–550.
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crops for the Northern Great Plains: II. Cropping sequence effects on
cereal, oilseed, and pulse crops. Agron. J. 95, 980–986. doi: 10.2134/agronj20
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crops at a semiarid site in Montana. Can. J. Plant Sci. 92, 803–807.
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(Accessed Feb 17, 2017).
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oilseed cropping systems in the Pacific Northwest United States. Agron. J. 106,
1147–1152. doi: 10.2134/agronj13.0384
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Frontiers in Ecology and Evolution | 6May 2017 | Volume 5 | Article 43
Schillinger Winter Pea in the Pacific Northwest Drylands
Statistics Canada (2017). Ottawa. Available online at:
Strydhorst, S., Olson, M. A., Vasanthan, T., McPhee, K. E., McKenzie, R. H.,
Henriques, B., et al. (2015). Adaptability and quality of winter pea and lentil
in Alberta. Agron. J. 107, 2431–2448. doi: 10.2134/agronj15-0092
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USDA-Natural Resources Conservation Service.
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Analysis. Part 4—Physical Methods. SSSA Book Series: 5, eds J. H. Dane and G.
C.Topp (Madison, WI: Soil Science Society of America), 422–424.
Young, F. L., and Thorne, M. E. (2004). Weed-species dynamics and management
in no-till and reduced-till fallow cropping systems for the semi-arid
agricultural region of the Pacific Northwest, USA. Crop Prot. 23, 1097–1110.
doi: 10.1016/j.cropro.2004.03.018
Conflict of Interest Statement: The author declares that the research was
conducted in the absence of any commercial or financial relationships that could
be construed as a potential conflict of interest.
Copyright © 2017 Schillinger. This is an open-access article distributed under the
terms of the Creative Commons Attribution License(CC BY). The use, distribution or
reproduction in other forums is permitted, provided the original author(s) or licensor
are credited and that the original publication in this journal is cited, in accordance
with accepted academic practice. No use, distribution or reproduction is permitted
which does not comply with these terms.
Frontiers in Ecology and Evolution | 7May 2017 | Volume 5 | Article 43
... Current WP cultivars have an upright growth habit (i.e., they do not lay down or lodge) and can be planted and harvested with drills and combines used for wheat production. Finally, WP is a reliable crop that provides consistently decent yields in both wet and dry crop years (Schillinger, 2017). ...
... A detailed description of all field operations for the experiment are reported in Schillinger (2017) and are summarized here. For the WW-SW-F treatment, fertilizer was applied for WW. ...
... Herbicide weed control methods used in the experiment are reported in Schillinger (2017) and, therefore only briefly mentioned here. Importantly, imazamox soil-residual herbicide was recently labeled for use in WP and, beginning in 2017, 0.15 L ha -1 imazamox herbicide was tank mixed with 0.1 kg a.i. ...
This article is an overview of recent advances in dryland cropping in the region of the Inland Pacific Northwest of the United States (PNW) that receives <300 mm annual precipitation. The climate of the region is Mediterranean‐like with wet winters and dry summers. For the past 130 years, monocrop 2‐yr winter wheat (Triticum aestivum L.)‐fallow (WW‐F) has been the dominant rotation practiced on >90% of rainfed cropland throughout this region. Rapid advances in technology in the past several decades and the realities of dryland farm economics prompted most farmers to expand their acreage and adopt conservation tillage and no‐tillage practices. Three relatively new crops have gained some foothold in the past decade. These crops are winter pea (WP) (Pisum sativum L.), winter canola (WC) (Brassica napus L.), and winter triticale (WT) (X Triticosecale Wittmack). Like WW, all three of these “new” winter crops need to be planted in late August‐early September into carryover soil moisture after a 13‐ to 14‐mo fallow period to achieve optimum yield potential. Researchers and farmers have experimented with a multitude of spring‐planted crops but, to date, all have shown high year‐to‐year variability in yield and none have been economically viable in the long term. The focus of this paper is to summarize major research conducted on WP, WC, and WT, as well as farmers’ attitudes on the potential of these three winter crops for wheat‐based rotations in the PNW drylands. This article is protected by copyright. All rights reserved
... As an example, advancement of chickpea (Cicer arietinum) storage, transportation and marketing in the region has greatly expanded iPNW chickpea production, driven by high prices (Maaz et al., in press). Similarly, the varietal development of edible winter dry peas promises to expand legume acreage into the drier agroecological zones, due to their greater yield potential and ability to survive harsh winters (Schillinger, 2017). Fall-sown dry peas and lentils are well-adapted for direct seeding into standing stubble and increasing demand for cover crop pea seed provides production incentive. ...
... Replacing spring crop sequences with fall-sown winter hardy crops intensifies rotations by providing overwinter soil cover with increased yield potential (Schillinger, 2017;Stöckle et al., 2017). Fall-sown crops mature earlier than spring-sown crops, thereby avoiding heat stressors and water deficits that may occur later in the growing season. ...
... Yet, it also exhibited poor N balances (Pan et al., 2001) and it was found to be economically less viable than conventional wheat-fallow (Young et al., 2015), thus judged to be an overall lose-neutral scenario. These findings have led to evaluations of diversified crop rotations with winter canola and winter peas (Young et al., 2014;Schillinger, 2017) produced in concert with minimum or no-tillage (Figure 6). ...
Full-text available
Climate-friendly best management practices for mitigating and adapting to climate change (cfBMPs) include changes in crop rotation, soil management and resource use. Determined largely by precipitation gradients, specific agroecological systems in the inland Pacific Northwestern U.S. (iPNW) feature different practices across the region. Historically, these farming systems have been economically productive, but at the cost of high soil erosion rates and organic matter depletion, making them win-lose situations. Agronomic, sociological, political and economic drivers all influence cropping system innovations. Integrated, holistic conservation systems also need to be identified to address climate change by integrating cfBMPs that provide win-win benefits for farmer and environment. We conclude that systems featuring short-term improvements in farm economics, market diversification, resource efficiency and soil health will be most readily adopted by farmers, thereby simultaneously addressing longer term challenges including climate change. Specific ‘win-win scenarios’ are designed for different iPNW production zones delineated by water availability. The cfBMPs include reduced tillage and residue management, organic carbon (C) recycling, precision nitrogen (N) management and crop rotation diversification and intensification. Current plant breeding technologies have provided new cultivars of canola and pea that can diversify system agronomics and markets. These agronomic improvements require associated shifts in prescriptive, precision N and weed management. The integrated cfBMP systems we describe have the potential for reducing system-wide greenhouse gas (GHG) emissions by increasing soil C storage, N use efficiency (NUE) and by production of biofuels. Novel systems, even if they are economically competitive, can come with increased financial risk to producers, necessitating government support (e.g., subsidized crop insurance) to promote adoption. Other conservation- and climate change-targeted farm policies can also improve adoption. Ultimately, farmers must meet their economic and legacy goals to assure longer-term adoption of mature cfBMP for iPNW production systems.
... Oregon, Washington, and Idaho are among the top ten wheat producing states (NASS 2018). Soft wheat-the primary ingredient in pastry and cake flours-is grown almost exclusively in the iPNW, where dryland cropping systems are common (Schillinger et al. 2015;Schillinger 2017). Due to temperature and precipitation gradients, crop rotations in the region generally entail winter wheat followed by summer fallow in areas with low annual precipitation. ...
Full-text available
Climate change is expected to have heterogeneous effects on agriculture across the USA, where temperature and precipitation regimes are already changing. While the overall effect of climate change on agriculture is uncertain, farmers’ perceptions of current and future climate and weather conditions will be a key factor in how they adapt. This paper analyzes data from paired surveys (N = 817) and natural variation from baseline weather across the inland Pacific Northwest (iPNW), to determine if long-term, gradual changes in precipitation, and temperature distributions affect farmers’ weather perceptions and intentions to adapt. We note that some areas in the iPNW have experienced significant changes in weather, while others have remained relatively constant. However, we find no relationship between changes in temperature and precipitation distributions and individuals’ perceptions and intentions to adapt. Our findings provide evidence that gradual, long-term changes in weather are temporally incongruous with human perception, which can impede support for climate action policy and adaptation strategies.
... In the Pacific Northwest, where a vast majority of farmers follow a winter wheatsummer fallow rotation, introducing winter pea into crop rotation could be of interest as winter pea has been found to use significantly less soil water than winter wheat and in the following spring residual N in the soil for the next crop was higher. Consequently, the yield of spring wheat after winter pea was higher than after winter wheat (Schillinger 2017). In experiments in the Pacific Northwest, winter pea out-yielded spring pea by 1830 kg ha −1 , whereas no differences between winter and spring pea were found in the northern Great Plains (Chen et al. 2006). ...
Climate change brings increasing attention to winter sowing of traditionally spring sown crops. Crop stand height, soil coverage, grain yield and yield components of six winter pea varieties and one spring pea variety were compared in eastern Austrian growing conditions in 2014 and 2015. Crop stands of winter pea were taller up to the end of May before they declined and crop stands of spring pea were taller from early June on. Winter pea covered the soil at least partly over winter and showed faster soil coverage in spring. At the end of May, just some weeks before harvest, spring pea attained equal soil coverage. Grain yield of winter pea was almost double that of spring pea due to higher pod density whereas spring pea produced more grains pod⁻¹ than four out of six winter pea varieties and a higher thousand grain weight than all winter pea varieties. Consequently, grain density was higher for winter pea while the single pod yield was higher for spring pea. Growing winter peas in Central Europe might be a good strategy for increasing grain legume productivity and thereby European feed protein production.
... A monoculture 2-yr WW-SF rotation is practiced by most farmers on 1.5 million cropland hectares in the low-precipitation (< 300 mm annual) precipitation region of the PNW (Karimi et al., 2018). In recent years, winter pea (Pisum sativum L.) (Schillinger, 2017), winter canola (Brassica napus L.) (Pan et al., 2016), and winter triticale (X Triticosecale Wittmack) have gained popularity among farmers due to their relatively acceptable and stable yield performance; but, like WW, they require a preceding year of fallow to be agronomically and economically viable. Farmers and scientists in this dry region have experimented with many spring-planted cereal and broadleaf crops, but those so far tested are subject to water and heat stresses and have highly-variable yields that are not economically stable or attractive in the long term. ...
Camelina [Camelina sativa (L.) Crantz] is a short-season annual oilseed crop in the Brassicaceae family. Interest in camelina has increased substantially during the past 15 years because the oil is an excellent feedstock for producing low-carbon-emission biofuel and has a unique fatty acid profile as a potential edible oil. Camelina has been promoted as an alternative crop in low-precipitation dryland regions because of its low fertilizer requirement and drought tolerance. An 8-yr field experiment was conducted from 2010 to 2017 at the WSU Dryland Research Station near Lind, WA to compare a 3-yr winter wheat (WW)-spring camelina-summer fallow (SF) rotation with the traditional 2-yr WW-SF rotation. Annual crop-year (Sept. 1-Aug. 31) precipitation ranged from 193 to 375 mm and averaged 281 mm. Camelina seed yield ranged from 339 to 1175 kg/ha and averaged 643 kg/ha. Mean WW yield of 2692 kg/ha in the 3-yr rotation was significantly lower (p = 0.046) compared to 2862 kg/ha in the 2-yr rotation. Soil profile water was significantly lower (p < 0.001) after harvest of camelina compared to after WW harvest in the 2-yr rotation. This soil water reduction was consistently measured throughout the ensuing 13-month fallow cycle. There are no labeled in-crop broadleaf weed herbicides for camelina and populations of Russian thistle (Salsola tragus L.) and tumble mustard (Sisymbrium altissimum L.) were higher in camelina than in WW. This was likely a factor in the deep extraction of soil water in the camelina plots to a depth of 180 cm. Data from this study suggest that, with current cultivars and management practices, camelina is not yet agronomically or economically stable or viable in a 3-yr WW-camelina-SF rotation in the low-precipitation (< 300 mm annual) rainfed cropping region of the Inland Pacific Northwest (PNW).
Integration of field pea (Pisum sativum L.) into dryland cropping systems has increased due to ecological and economic benefits, paired with a growing market for pea‐derived products. Challenges exist in the High Plains that limit the integration of crop rotations to replace fallow periods with field pea in wheat‐based systems. This experiment compares chemical summer fallow to field pea in a fallow ‐ wheat rotation at two locations in western Nebraska. Soil water content, soil fertility, N mineralization, field pea yield, and subsequent hard red winter wheat (HWW) yields were recorded. Subsequent HWW yields were not different between crop sequences (P = 0.42). The interaction of site – year with crop sequence explained the HWW yield differences (P = 0.0005), mostly due to precipitation variability among site‐years. Most soil parameters tested only showed a main effect of date due to temporal changes in soil nutrient cycling. Replacing summer fallow with field pea resulted in reduced soil water content, however, that did not result in long‐term moisture deficiency due to crop sequence type. System annualized gross revenue was equal to or greater for two site‐years for field pea compared to fallow, with an average increase of $113.15 ha–1. Pea – wheat reduced annualized net losses in one site – year by $70 ha–1 compared to fallow – wheat in the ‘average’ pricing model. Among three site – years and three pricing models, pea‐wheat resulted in greater net profit or reduced net losses compared to fallow‐wheat in five site – year comparisons. This article is protected by copyright. All rights reserved
Full-text available
Triticale (X Triticosecale Wittmack) is a cereal feed grain grown annually worldwide on 4.2 million ha. Washington is the leading state for rainfed (i.e., non-irrigated) triticale production in the USA. A 9-year dryland cropping systems project was conducted from 2011 to 2019 near Ritzville, WA to compare winter triticale (WT) with winter wheat (Triticum aestivum L.) (WW) grown in (i) a 3-year rotation of WT-spring wheat (SW)-no-till summer fallow (NTF) (ii) a 3-year rotation of WW-SW-undercutter tillage summer fallow (UTF) and (iii) a 2-year WW-UTF rotation, We measured grain yield, grain yield components, straw production, soil water dynamics, and effect on the subsequent SW wheat crop (in the two 3-year rotations). Enterprise budgets were constructed to evaluate the production costs and profitability. Grain yields averaged over the years were 5816, 5087, and 4689 kg/ha for WT, 3-year WW, and 2-year WW, respectively (p < 0.001). Winter triticale used slightly less water than WW (p = 0.019). Contrary to numerous reports in the literature, WT never produced more straw dry biomass than WW. Winter wheat produced many more stems than WT (p < 0.001), but this was compensated by individual stem weight of WT being 60% heavier than that of WW (p < 0.001). Spring wheat yield averaged 2451 vs. 2322 kg/ha after WT and WW, respectively (p = 0.022). The market price for triticale grain was always lower than that for wheat. Winter triticale produced an average of 14 and 24% more grain than 3-year and 2-year WW, respectively, provided foliar fungal disease control, risk reduction, and other rotation benefits, but was not economically competitive with WW. A 15-21% increase in WT price or grain yield would be necessary for the WT rotation to be as profitable as the 3-year and 2-year WW rotations, respectively.
A lack of plant available water limits the ability to intensify the summer fallow-winter wheat (SF-WW) rotation in low precipitation (<350 mm) areas of the inland Pacific Northwest (PNW). The objective of this study was to compare crop yield, water use efficiency, precipitation capture, and soil water storage between conventional-tillage SF and reduced tillage fallow (RTF) and among different 2-yr and 3-yr cropping sequences. After full initiation of the experiment, eight sequences were evaluated over a 3-yr period (2016−18) including SF-WW, RTF-WW, RTF-WW-spring barley (SB), RTF-winter napus canola (WN)-spring wheat (SW), RTF-spring carinata (SC)-SW, RTF-WN-spring forage triticale (ST), and RTF-winter forage triticale (WT)-SC. Growing season precipitation was near average (269 mm) each year. Ponded infiltration rates were significantly higher (P ≤ 0.05) in 2-yr rotations managed with RTF (77.68 ± 24.56 mm h⁻¹) than SF (37.08 ± 13.03 mm h⁻¹). Water use efficiency and yields of WW were generally greater following RTF than for WW after SF. Water use and yield of winter cereals WW and WT after fallow were greater than for oilseeds WN and SC that also followed fallow. Pre-plant soil water contents were significantly lower following a primary crop than after fallow. Consequently, water use and yield of secondary crops were <50 % of primary crops. Of 3-yr cropping sequences, RTF-WW-SB and RTF-WW-SC had the highest water use efficiencies with annualized yields generally approaching that of RTF-WW and SF-WW. These results support integration of spring barley and spring carinata under low precipitation dryland conditions in the PNW to increase diversification and improve conservation of water.
Chickpea (Cicer arietinum L.) cultivar Royal (Reg. No. CV-324; PI 673002), was released by the USDA-ARS on the basis of its high yield and large seed size compared with the commercial chickpea cultivars Sierra and Nash. Royal was evaluated by the USDA-ARS across 18 location-years in Washington and Idaho receiving approximately 450 to 750 mm annual precipitation. Royal had an average yield of 1436 kg ha ⁻¹ across all trials, 5.4% less than Nash (1514 kg ha ⁻¹ ) and 7.3% greater than Sierra (1338 kg ha ⁻¹ ). Royal, similar to Sierra, has moderate resistance to Ascochyta blight. Royal was also tested by HighLine Grain Growers across 12 location-years in Washington receiving approximately 300 to 350 mm annual precipitation. In these trials, Royal had an average yield of 1366 kg ha ⁻¹ , 6.7% greater than Nash (1280 kg ha ⁻¹ ) and 23.7% greater than Sierra (1104 kg ha ⁻¹ ). In trials conducted by the USDA-ARS 100 seed weight of Royal was 55.8 g, which was less than Nash and greater than Sierra. In trials conducted by HighLine Grain Growers, 100 seed weight of Royal was 52.0 g, which was not different than Nash and was greater than Sierra. Royal produced a greater percentage of “A” seeds (>8.7 mm) than Sierra in trials conducted by both the USDA-ARS and HighLine Grain Growers. Royal is a promising alternative to Sierra as a high-yielding large-seeded chickpea cultivar, especially in regions receiving less than 450 mm annual precipitation.
Fall-sown chickpea (Cicer arietinum L.) yields are often double those of spring-sown chickpea in regions with Mediterranean climates that have mild winters. However, winter kill can limit the productivity of fall-sown chickpea. Developing cold-tolerant chickpea would allow the expansion of the current geographic range where chickpea is grown and also improve productivity. The objective of this study was to identify the quantitative trait loci (QTL) associated with cold tolerance in chickpea. An interspecific recombinant inbred line population of 129 lines derived from a cross between ICC 4958, a cold-sensitive desi type (C. arietinum), and PI 489777, a coldtolerant wild relative (C. reticulatum Ladiz), was used in this study. The population was phenotyped for cold tolerance in the field over four field seasons (September 2011-March 2015) and under controlled conditions two times. The population was genotyped using genotypingby- sequencing, and an interspecific genetic linkage map consisting of 747 single nucleotide polymorphism (SNP) markers, spanning a distance of 393.7 cM, was developed. Three significant QTL were found on linkage groups (LGs) 1B, 3, and 8. The QTL on LGs 3 and 8 were consistently detected in six environments with logarithm of odds score ranges of 5.16 to 15.11 and 5.68 to 23.96, respectively. The QTL CT Ca-3.1 explained 7.15 to 34.6% of the phenotypic variance in all environments, whereas QTL CT Ca-8.1 explained 11.5 to 48.4%. The QTLassociated SNP markers may become useful for breeding with further fine mapping for increasing cold tolerance in domestic chickpea.
Full-text available
Pea (Pisum sativum L.) is increasingly being rotated with wheat (Triticum aestivum L.) in Montana. Our objective was to compare economic net returns among wheat-only and pea–wheat systems during an established 4-yr crop rotation. The experimental design included three wheat-only (tilled fallow–wheat, no-till fallow–wheat, no-till continuous wheat) and three no-till pea– wheat (pea–wheat, pea brown manure–wheat, and pea forage–wheat) systems as main plots, and high and low available N rates as subplots. Net returns were calculated as the difference between market revenues and operation and input costs associated with machinery, seed and seed treatment, fertilizer, and pesticides. Gross returns for wheat were adjusted to reflect grain protein at “flat” and “sharp” discount/premium schedules based on historical Montana elevator schedules. Cumulative net returns were calculated for four scenarios including high and low available N rates and flat and sharp protein discount/premium schedules. Pea–wheat consistently had the greatest net returns among the six systems studied. Pea fallow–wheat systems exhibited greater economic stability across scenarios but had greater 4-yr returns (US$287 ha–1) than fallow–wheat systems only under the low N rate and sharp protein discount schedule scenario. We concluded that pea–wheat systems can reduce net return uncertainties relative to wheat-only systems under contrasting N fertility regimes, and variable wheat protein discount schedules in southwestern Montana. This implies that pea–wheat rotations, which protected wheat yield and/or protein levels under varying N fertility management, can reduce farmers’ exposure to annual economic variability. © 2015 by the American Society of Agronomy, 5585. Guilford Road, Madison, WI 53711. All rights reserved.
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To optimize cropping system benefits from pulse crops, it is important to understand their effects on subsequent crops. The objective of this study was to compare the effects of chickpea ( Cicer arietinum L.), lentil ( Lens culinaris Medik.), and pea ( Pisum sativum L.) stubbles on yield and quality of wheat ( Triticum aestivum L.), mustard ( Brassica juncea L.) or canola ( B. napus L.), and lentil or pea when grown on soils with clay and loam textures. This study was conducted between 1996 and 1999 in southwestern Saskatchewan. Rotational benefits of pulse crops (chickpea, lentil, and pea) to wheat appeared more consistent on the clay than the silt loam soil. Adjusting fertilizer N rates to account for estimated total N contribution from the previous pulse crop effectively neutralized the benefits on wheat yield and protein compared with the effects following mustard. Canola or mustard productivity was occasionally greater when grown on pea or lentil stu bbles compared with mustard and wheat stubbles. The yield increase was attributed to increased available water. Under drier-than-normal conditions, pea yields were highest when grown on wheat stubble. Wheat productivity was least when grown on its own stubble. Pea and lentil provided rotational benefits to wheat, mustard, and canola and benefitted most from being grown in wheat stubble, indicating a strong fit for diversified cropping systems on the semiarid northern Great Plains.
In a semiarid-to-subhumid region, water use by crop species can have a considerable impact on both crop production and soil landscape hydrology. Crop production following high water-using crops can be decreased while ephemeral streams and wetlands can be increased by growing lower water-using crops. Water use and soil water depletion were determined with neutron moisture meters in ten crop species (barley, canola, crambe, dry bean, dry pea, flax, safflower, spring wheat, soybean and sunflower) for two years, and measurements are presented for four of these species for one additional year. The observations were made in various species which were grown after spring wheat during crop sequence experiments. Sunflower was the greatest water user, followed by safflower and soybean. Dry pea was the lowest water user, followed in order by barley, crambe, and spring wheat. During an above average precipitation year, the depth distribution of soil water depletion among canola, dry pea, spring wheat, and sunflower was similar. In contrast, during a year of relatively low seasonal precipitation, differences were evident among the four crop species. Sunflower and canola extracted 49 percent and 45 percent of their soil water depletion, respectively, from soil depths greater than 60 cm, while spring wheat and dry pea extracted 33 percent and 27 percent of their soil water depletion from below 60 cm depth. Using a three-year dataset, it was found that water use and soil water depletion were highly correlated with seasonal precipitation, significantly correlated with median depth of water depletion and days from seeding to harvest, but not correlated with root growth parameters. As a general guide to water use by crop species, length of active growing season appears to be the most important factor.
It is unknown if winter pea (Pisum sativum L.) and winter lentil (Lens culinaris Medik.) are feasible cropping options in Alberta. Field experiments were conducted at six locations in southern and central Alberta, Canada, between 2008 and 2012, to determine the adaptability of winter pea and lentil. Two winter pea cultivars, Specter and Windham, and one winter lentil cultivar, Morton, were seeded at three fall planting dates and three seeding rates. Spring cultivars were grown for comparison. In southern Alberta, winter pea and lentil yielded up to 39% more than spring types. The highest winter pea yield was achieved when planting was completed during the first 3 wk of September. The highest winter lentil yield was achieved when planting was completed in the second and third weeks of September. Seeding rate had little or no impact on yield; therefore, winter pea should be seeded at 75 plants m–2 and winter lentil at 110 plants m–2. Seed was analyzed to compare constituent parameters. There were minor differences in the composition of winter and spring pulses. Windham had lower starch but higher resistant starch, protein, crude fat, and ash content compared with spring pea cultivars. Specter had higher resistant starch but was similar to Cutlass for all other parameters. Morton had a higher starch content than CDC Redberry; however, starch quality was similar. Winter pulses have potential to create new and profitable opportunities for growers in the Bow Island and Lethbridge areas of southern Alberta. © 2015 by the American Society of Agronomy 5585 Guilford Road, Madison, WI 53711 USA All rights reserved.
Miller, P. R. and Holmes, J. A. 2012. SHORT COMMUNICATION: Comparative soil water use by annual crops at a semiarid site in Montana. Can. J. Plant Sci. 92: 803-807. Results for soil water use in the semiarid northern Great Plains are presented in detailed tabular format for 15 crops in an ideal environment for comparative water use assessment. The effective rooting depth of winter wheat (Triticum aestivum L.) varied relative to spring wheat; it was often similar and never less. Sunflower (Helianthus annuus L.) averaged 43 mm greater soil water use below 0.9 m compared with spring wheat. Conversely, lentil (Lens culinaris Medik.) and pea (Pisum sativum L.) averaged 27 mm and 48 mm less soil water than spring wheat to a 1.2-m soil depth, respectively. Observed differences in effective rooting depth for alternative crops carry important implications for wheat-based cropping systems.
The volatility of petroleum reserves and prices coupled with concerns about greenhouse gas emissions and climate change has created worldwide interest in renewable fuels. Little is known, however, about the impact on natural resources of growing oilseed crops for biofuel. This study examined the impact of growing oilseed crops in winter wheat (Triticum aestivum L.) rotations on wind erosion and emissions of particles 10 mm in aerodynamic diameter (PM10) in eastern Washington, where atmospheric PM10 is an acute environmental concern. Wind erosion and PM10 emissions were measured immediately after sowing winter wheat in a winter wheat-summer fallow (WW-SF) rotation, a winter wheat-camelina [Camelina sativa (L.) Crantz]-summer fallow (WW-C-SF) rotation, and a winter wheat-safflower (Carthamus tinctorius L.)-summer fallow (WW-S-SF) rotation. Best management practices were implemented during the 13-mo fallow phase of the rotation, which included undercutting and fertilizing the soil in spring and rodweeding during summer to control weeds. A wind tunnel was used to assess horizontal sediment and PM10 flux after sowing wheat because this is the time when the soil is most susceptible to wind erosion. Horizontal sediment and PM10 flux were as much as 250% higher after sowing winter wheat in the WW-C-SF and WW-S-SF rotations than the WW-SF rotation. Vertical PM10 flux was higher in the WW-C-SF and WW-S-SF rotations, in part due to the aerodynamically smoother surface of these rotations compared with the WW-SF rotation. Farmers must be especially judicious in protecting the soil from wind erosion during the fallow phase of the WW-C-SF and WW-S-SF rotations.
Farmers implement an assortment of management practices to ensure the sustainability, economic viability, and resilience of their operation. Dryland farming practices dominate in the semiarid regions of the US northern Great Plains, where historical practice has been to rotate small-grain cereals with whole-year summer fallow; however, pulse crops (e.g., lentils) have become increasingly common in these regions as an alternative to fallow. The area of fallow in northeastern Montana, for example, has decreased by one-third, while the area of pulse crops has increased more than five-fold. Our objectives were: (1) to characterize the principal cropping sequences in northeast Montana during the period of regional pulse crop adoption (2001–2012); and (2) to identify changes in the relative proportions of these sequences during the same period. We identified crops at the field-level by class (cereal, pulse, fallow, or cereal–fallow strips) for 2001–2012 using multitemporal Landsat imagery in conjunction with the cropland data layer, cadastral data, ground reference data, and local producers’ records. The annual crop classifications were combined into a 12-character string for each field that represented the sequence of crop classes for 2001–2012. We then searched these strings for specific 2- and 3-year crop sequences with a string-matching algorithm. The most abundant sequences involved continuous cereal, block-managed cereal–fallow, and cereal–pulse. We also observed a steady decrease in the abundance of cereal–fallow sequences managed by strip-cropping that were coincident with increases in block-managed cereal–fallow sequences and with increases in pulse production. We conclude that, over the study's time frame, regional producers grew more cereal crops and fallowed fields less frequently, but did not appear to strongly adhere to specific sequences. Furthermore, strip-cropping as a management practice has declined substantially.
In the semiarid prairie, available water is the most limiting and nitrogen the second most limiting factor influencing crop production. Although numerous studies have been conducted on the effect of management practices on water use efficiency (WUE), most have concentrated on monoculture wheat, the major crop grown in the region. Even those studies dealing with other crop types have mostly been short-term in nature. But precipitation is so variable in amount and distribution that such an assessment is best conducted in long-term experiments. We used the results of a 21-yr experiment, conducted in the Brown soil zone at Swift Current, Saskatchewan, to determine the influence of crop type on WUE, and used the distribution of water and NO<sub>3</sub>-N in the soil, and N uptake by the crop to assist in interpreting these results. Four crop rotations were compared: summer fallow-wheat-wheat (F-W-W), F-flax-W (F-Flx-W), continuous wheat (Cont W) and wheat-lentil (W-Lent). All received N and P fertilizer based on soil test. In the following presentation, the rotation phase shown in parentheses was the phase referred to. We used water and NO<sub>3</sub>-N measured in consecutive 0.3-m depth segments to 1.2 m in the soil, taken just prior to seeding and after harvest, and precipitation, to make this assessment. About 10 mm more water was conserved in the F-W-W rotation than in the F-Flx-W system during the 21-mo summer fallow period, and most of this difference in water was located in the 0.3- to 0.9-m depth. Soil water in the profile was 14 mm greater following flax harvest than following wheat harvest (mostly located in 0.6- to 1.2-m depth), because flax produces less biomass and has shorter roots than wheat. At harvest, wheat dried the soil to near the wilting point (154 mm), but flax and lentil left about 10 mm of available water in the profile (mostly in the 0.6- to 1.2-m depth), suggesting shallower rooting depths. Over the 9-mo winter period about 58 mm of water was stored in the soil after wheat and 41 mm after flax. Wheat stubble conserved more overwinter water than flax stubble because of its taller height. Lentil, with its much shorter stubble, conserved about 7 mm less water than wheat during winter. Because flax produces much less biomass and withdraws less N from the soil than wheat, it left more NO<sub>3</sub>-N in the soil (27 kg ha<sup>-1</sup> more at seeding and 23 kg ha<sup>-1</sup> more at harvest); most of the extra NO<sub>3</sub> was in the 0.3- to 1.2-m depth reflecting flax's shallower roots. During the 9-mo overwinter period, 16 kg ha<sup>-1</sup> of NO<sub>3</sub>-N was mineralized following wheat and 33 kg ha<sup>-1</sup> following flax. In the spring, Cont W and stubble wheat in F-W-(W) had about 50% as much soil NO<sub>3</sub>-N as the W-Lent rotation, reflecting the cumulative benefits of N<sub>2</sub> fixation by the pulse crop over the years. By harvest, soil NO<sub>3</sub>-N under (W)-Lent > W-(Lent) > F-Flx-(W) > F-W-(W) > Cont W. The excess NO<sub>3</sub>-N in the (W)-Lent compared to W-(Lent) was located in the 0- to 0.6-m depth suggesting excessive fertilizer application to the wheat phase of this rotation and implying a need for agronomists to reassess the criteria used for N recommendations for rotations containing pulse crops. Lentil used as much water as wheat even though its biomass was much less. WUE for wheat grown on summer fallow aver-aged 8.11 kg ha<sup>-1</sup> mm<sup>-1</sup>, and for wheat grown on stubble 6.9 kg ha<sup>-1</sup> mm<sup>-1</sup>. WUE for wheat was also higher when it followed flax than when it followed wheat. The WUE of flax and lentil averaged 50% and 64%, respectively, of wheat following wheat. A more meaningful way of expressing the efficiency of water use is as precipitation required per unit of produce from the complete cropping system (PUE). The PUE increased with cropping intensity on a yield basis (kg ha<sup>-1</sup> mm<sup>-1</sup>): Cont W (4.6) > W-Lent (4.2) > F-W-W (4.1) > F-Flx-W (2.9) (opposite response to WUE). When PUE was calculated on a dollars produced per rotation basis ($ ha<sup>-1</sup> mm<sup>-1</sup>): W-Lent (1.0) was higher than the other three rotations (0.6 to 0.7).