Pulse crops discussed in this review include soybean (Glycine max L.), dry pea (Pisum sativum L.), lentil (Lens culinaris Medik.), dry bean (Phaseolus vulgaris L.) and chickpea (Cicer arietinum L.). Basic maturity requirements, yield relationships with rainfall and temperature, relative yield comparisons, water relationships, water use efficiency (WUE), crop management, tillage systems, and the rotational impact of these crops on productivity were considered. With the exception of soybean, maturity requirements for pulse crops are met in most locations within the northern Great Plains. Yield was more closely related to growing season precipitation than maximum temperature for all pulse crops except dry bean and lentil. The inability to effectively relate weather parameters to dry pea and lentil yield may indicate broad adaptation of these two pulse crops within the northern Great Plains. Correlation analyses showed the productivity of chickpea, dry pea, and lentil to be most closely associated with each other and for dry bean productivity to be most closely associated with that of soybean, effectively grouping pulse crops into their respective cool‐ and warm‐season classifications. Dry pea and chickpea had high WUE values, similar to spring wheat (Triticum aestivum L.). Examination of plant water relations of these crops revealed an ability for chickpea and dry pea to grow at lower relative water contents than spring wheat. Increased wheat grain yield and/or protein following pulse crops under widely different N‐limiting growth conditions indicated a consistent N benefit provided by pulse crops to wheat. Four general research needs were identified. First, comparative adaptation among pulse crops remains poorly understood. Second, best management practices and key production risks remain incompletely characterized. Thirdly, the knowledge of rotational effects of pulse crops in the northern Great Plains remains imprecise and inadequate. Fourth, genetic improvement for early maturity, increased yield, improved harvestability, and disease resistance requires attention. Pulse crops are poised to play a much greater role in diversifying cropping systems in the northern Great Plains but require that these key research areas be addressed so that their production potential can be realized.

1960; Walton, 1975; Carr et al., 1998; Chapko et al., 1991). Robinson (1960) reported that pea improved oat (Avena Intercropping barley (Hordeum vulgare L.) with Austrian winter sativa L.) forage yield. In a 2-yr pea-barley and pea-oat pea (Pisum sativum ssp. arvense L. Poir) may increase the use efficienintercropping study, Carr et al. (1998) found that total cies of growth resources and reduce fertilizer N requirements. The forage yield was unaffected by intercropping when the objectives of this study were to determine (i) row configuration and (ii) fertilizer N effects on yield, protein content, and the land equiva-cereal crop was sown at a rate equal to or greater than lent ratio (LER) of barley-pea intercropping systems. A 3-yr barleythe sole crop seeding rate. However, less forage was pea intercropping study was conducted at the Western and Central produced when the cereal component was sown at half Agricultural Research Centers (WARC and CARC) of Montana State the sole crop seeding rate. They also found that the University from 2000 to 2002 with three row configurations (4 rows intercropping forage yield was unaffected by the pea barley ϫ 4 rows pea, 2 rows barley ϫ 2 rows pea, and barley-pea mixed seeding rate. In other studies, forage and grain yield of within rows) and three N application treatments (0, 67, and 134 kg legumes were suppressed by cereal components (Ofori N ha Ϫ1 ). Barley biomass production increased 41% at WARC and and Stern, 1987; Hauggaard-Nielsen and Jensen, 2001; CARC, whereas pea biomass production decreased 34% at WARC Hauggaard-Nielsen et al., 2001). Seeding rates for comand 46% at CARC with the row configuration changing from the 4 ϫ 4 ponent crops in cereal-pea mixtures are commonly less to the mixed configuration. The LER ranged from 1.05 to 1.24 on a biomass basis and from 1.05 to 1.26 on a protein basis, indicating a than when either the cereal crop or pea is sown alone production advantage of intercropping. Barley is a more competitive (Carter and Larson, 1964; Droushiotis, 1989). component than pea. Separated row arrangements are advantageous The efficiency of an intercropping system can be evalwhere the desired outcome is a greater pea component in the harvested uated by the land equivalent ratio (LER), defined as forage, but the mixed arrangement has a greater total biomass yield the total area required under sole cropping to produce and LER. Fertilizer N increased total biomass yield and protein level the equivalent yields obtained under intercropping (De in barley-pea intercrops, but high N rates could decrease the LER Wit and Van Den Bergh, 1965; Willey, 1979; Mohta and and result in toxic levels of nitrate in the forage. De, 1980). It is expressed as:

Row spacing, plant density, and N application timing can be manipulated to optimize plant growth and spatial distribution, therefore maximizing sunlight, nutrients, soil water use effi ciency and grain yield. A 2-yr fi eld study to evaluate the eff ects of four seeding rates (108, 215, 323, and 430 seeds m -2 ), two row spacings (15 and 30 cm), and three N treatments (FA1, 100% at seeding; FA2, 50% at seeding and 50% at tiller formation; and FA3, 50% at seeding and 50% at shoot elongation) on grain yield of McNeal hard red spring wheat (Triticum aestivum L.) was conducted in central Montana. Spring wheat accumulated greater biomass at a faster rate under the 15-cm row spacing than the 30-cm row spacing. Grain yield was 410 and 412 kg ha -1 greater at 15-cm than at 30-cm row spacings in 2004 and 2005, and the yield increase was primarily attributed to 44 and 40 more spikes m -2 at 15-cm than at 30-cm row spacing in 2004 and 2005, respectively. Grain yield was not signifi cantly aff ected by the N treatments, thus all N should be applied at seeding. Th e optimum seeding rate was 215 seeds m -2 . Tillers at higher seeding rates had larger phyllochrons and greater mortalities. Low protein content was found in FA3 and high seeding rate treatments in 2005. Narrow row spacing is recommended for high spring wheat yield in the northern Great Plains. Th is yield increase cannot be achieved by increasing seeding rate at wide row spacing.

Winter pea (Pisum sativum L.) and lentil (Lens culinaris Medik.) have potential agronomic advantages over spring types in the Pacific Northwest (PNW) and northern Great Plains (NGP). The objectives of this study were to: (i) determine suitable seeding date and cereal stubble height in no‐till systems for winter pea and lentil; (ii) quantify and compare biomass and seed yield of winter pea and lentil with spring types; and (iii) compare adaptation of winter pea and lentil between the PNW and the NGP. Two breeding lines each of winter pea (PS9430706 and PS9530726) and winter lentil [LC9979010 (‘Morton’) and LC9976079] and two commercial cultivars each of spring pea (CDC Mozart and Delta) and spring lentil (Brewer and CDC Richlea) were sown on different dates (early and late fall dates for winter lines and spring date only for spring cultivars) and into different stubble heights (0.1 and 0.3 m) and compared for yield and agronomic adaptation in no‐till systems at four locations: Moccasin and Amsterdam, MT; Genesee, ID; and Rosalia, WA. Stubble height did not influence winter or spring pea biomass production or seed yield. Tall stubble increased lentil biomass by 220 to 530 kg ha−1 and seed yield by 100 to 260 kg ha−1 in five out of nine site–years. Fall‐seeded winter pea lines produced as much as 1830 kg ha−1 more seed yield than spring cultivars at the PNW sites, but not at the NGP sites. Early fall‐seeded lentil yielded as much as 480 and 590 kg ha−1 greater than spring types in the NGP and PNW, respectively. Delayed fall seeding and reduced stubble height decreased yields more frequently in the NGP than in the PNW.

found a regression relationship between canola seed yield and precipitation from 21 June to 20 August and Canola (Brassica napus L.) yield is often limited by heat and water mean daily temperature from 15 June to 15 August. The stress. Early seeding may avoid the heat and water stress at critical regression equations indicated that for each millimeter growth stages but will encounter low soil temperatures and frequent increase in precipitation, the yield of canola increased frosts. Three experiments were performed at two locations in Montana by 5.9 kg ha Ϫ1 . Also, for each degree rise in mean daily from 2002 to 2004 to determine (i) early spring seeding effect on seed temperature, there was a corresponding yield reduction yield and oil content and optimum seeding rates for early seeding, (ii) base temperature (T b ) for germination and heat requirement for of 188 kg ha Ϫ1 . In dryland cropping systems, water is emergence, and (iii) suitable cultivars for early spring seeding. Late-the most limiting factor for crop production. In a review March-seeded canola yielded 0 to 5% greater than mid-April seeding. paper, Johnston et al. (2002) suggested that a minimumDelaying seeding from mid-April to mid-May resulted in 43 to 63% of 127 mm of water is required for canola seed producyield reduction. Oil content was 12 to 22 g kg Ϫ1 greater for mid-May tion in the northern Great Plains. After the minimum seeding than mid-April seeding in 3 out of 5 site-year combinations.water requirement is met, canola produces 6.9 to 7.2 A seeding rate of 32 to 65 seeds m Ϫ2 was found sufficient to produce kg ha Ϫ1 of seed for every millimeter of precipitation optimum yields. Oil content tended to decrease 10 to 20 g kg Ϫ1 when consumed. Canola has a tap root system that can extract seeding rate increased from 11 to 97 seeds m Ϫ2 . The T b for germination water from a soil depth of 1.1 to 1.7 m (Nielsen, 1997). In was less than 4؇C, and the growing degree days for 50% emergence shallow soils that have a limited water-holding capacity, (GDD 50 ) were 42 to 81. Yield was negatively correlated (r ϭ Ϫ0.46 such as the Judith clay loam (fine-loamy, carbonatic to Ϫ0.65) to the days to 50% flowering, and biomass measured at Typic Calciborolls) in central Montana, canola may have 60 d after planting was negatively correlated to the chlorophyll fluores-to rely on frequent rainfall to sustain growth and procence ratio (F v /F m ) after cold stress (r ϭ Ϫ0.58). The optimal seeding duce seed during the latter part of the growing season.period for the region is between late March and mid-April. Several genotypes were found to have favorable characteristics for early Precipitation timing and amount vary greatly year to seeding.year and location to location in Montana. Consequently, growers in the region encounter highly unstable canola yields.