G. P. Lafond

Oilseed crops for semiarid cropping systems in the Northern Great Plains

oilseed crop produced in the USA, canola is the dominant oil crop in Canada. The cool climatic conditions Oilseed crops are grown throughout the semiarid region of the characteristic of the Canadian prairies provide an ideal northern Great Plains of North America for use as vegetable and industrial oils, spices, and birdfeed. In a region dominated by winter environment for Brassica spp. oilseeds and flax (Table and spring wheat (Triticum aestivum L. emend. Thell.), the accep2) while the climate found in the USA is better suited tance and production of another crop requires that it both has an to the warm season crops like soybean and sunflower. agronomic benefit to the cropping system and improve the farmers’ In the northern Great Plains, soybean is a relatively economic position. In this review, we compare the adaptation and new crop finding a place in semiarid cropping systems rotational effects of oilseed crops in the northern Great Plains. Canola with the development of early maturing, low heat–unit (Brassica sp.), mustard (B. juncea and Sinapis alba L.), and flax cultivars (Miller et al., 2002). As a result, the vast major(Linum usitatissimum L.) are well adapted to cool, short-season conity of soybean production in both the USA and Canada ditions found on the Canadian prairies and northern Great Plains occurs in wetter regions east of the Great Plains. Howborder states of the USA. Sunflower (Helianthus annuus L.) and safflower (Carthamus tinctorius L.) are better adapted to the longer ever, for the other oilseed crops listed in Table 1, the growing season and warmer temperatures found in the northern and majority of production occurs within the northern Great central Great Plains states. Examples are presented of how agronomic Plains. practices have been used to manipulate a crop’s fit into a local environDiversification within cereal-based cropping systems ment, as demonstrated with the early spring and dormant seeding can be critical to breaking pest infestations that are management of canola, and of the role of no-till seeding systems in common with monoculture (Bailey et al., 1992, 2000; allowing the establishment of small-seeded oilseed crops in semiarid Elliot and Lynch, 1995; Holtzer et al., 1996; Krupinsky regions. Continued evaluation of oilseed crops in rotation with cereals et al., 2002). Results of crop rotation studies in the Great will further expand our understanding of how they can be used to Plains revealed that where oilseeds are adapted, their strengthen the biological, economic, and environmental role of the region’s cropping systems. Specific research needs for each oilseed inclusion in rotation with cereals could increase net recrop have been recommended. turns and reduce risk through improved production stability (Lafond et al., 1993; Dhuyvetter et al., 1996; Zentner et al., 2002). In addition, the yield of wheat was increased when following oilseeds in rotation, confirmO crops are grown throughout the semiarid region of the northern Great Plains of North ing that monoculture systems are the least effective America for use as vegetable and industrial oils, spices, means of optimizing wheat production (Lafond et al., and birdfeed. In a region dominated by winter and 1992; Brandt and Zentner, 1995; Anderson et al., 1999). spring wheat (Triticum aestivum L.), the acceptance and The use of minimum and no-till seeding systems has production of another crop requires that it both has an been found to provide an effective means of controlling agronomic benefit to the cropping system and improves soil erosion in various regions of the Great Plains (Black the farmers’ economic position. Given that most oilseed and Power, 1965; Lindwall and Anderson, 1981). Imcrops have an indeterminate growth habit, adaptation provements in seed yield with conservation tillage have is influenced by tolerance to high temperature and been reported as a result of increased levels of plantdrought stress and by crop management to take advanavailable water throughout the soil profile in the spring tage of optimum environmental conditions for flowering (Aase and Reitz, 1989; Brandt, 1992; Lafond et al., 1992) and seed fill. The increasing area of oilseed crop producand increased water use efficiency due to favorable mition is an indication of the success of plant breeders croclimate conditions created by standing stubble (Cutand agronomists in developing suitable cultivars and forth and McConkey, 1997). Some oilseed crops are production methods in this semiarid region (Table 1). small seeded, requiring good surface soil moisture for While soybean [Glycine max (L.) Merr.] is the major seed germination and crop establishment, as is effectively provided in direct-seeding systems in the northern A.M. Johnston, Potash and Phosphate Inst. of Canada, 12-425 PineGreat Plains. As a result, adoption of conservation tillhouse Dr., Saskatoon, SK, Canada S7K 5K2; D.L. Tanaka, USDAage management not only reduces soil loss by erosion, ARS, Northern Great Plains Res. Lab., Box 459, Mandan, ND 58554; but also can facilitate extending the crop rotation and P.R. Miller, Montana State Univ., Dep. of Land Resour. and Environ. Sci., P.O. Box 173120, Bozeman, MT 59717-3120; S.A. Brandt, Agric. allowing for diversification of the crops grown. Ecoand Agri-Food Can., Box 10, Scott, SK, Canada S0K 4A0; D.C. Nielnomic success with a diversified crop rotation has been sen, USDA-ARS, Cent. Great Plains Res. Stn., 40335 Country Rd. reported to be improved with the implementation of GG, Akron, CO 80720; G.P. Lafond, Agric. and Agri-Food Can., Box conservation tillage practices, such as minimum and zero760, Indian Head, SK, Canada S0G 2K0; and N.R. Riveland, North Dakota State Univ., Williston Res. Ext. Cent., 14120 Hwy. 2, Williston, tillage (Lafond et al., 1993; Rossetti et al., 1999; Zentner ND 58101-8629. Saskatoon Res. Cent. Publ. 1421. Received 1 Dec. et al., 2002). 2000. *Corresponding author (ajohnston@ppi-ppic.org). The objective of this review is to summarize information on the adaptation and production potential of some Published in Agron. J. 94:231–240 (2002).

Effect of tillage and crop rotation on root and foliar diseases of wheat and pea in Saskatchewan from 1991 to 1998: Univariate and multivariate analyses

Disease severity and incidence of fungal species on wheat and pea were evaluated under zero, minimum, and conventional tillage in three rotations with increasing broad-leaved crop diversity from 1991 to 1998 at Indian Head, SK. The objective was to determine whether differences in crop rotation and crop residue at the soil surface would increase crop disease problems. Rotation and tillage had little impact on disease relative to the environment. Reduced tillage did not substantially increase disease severity from leaf spot diseases of wheat or on diseases of field pea. However, the relative importance of root pathogens of wheat was affected; under reduced tillage Bipolaris sorokiniana and Gaeumannomyces graminis decreased, but Fusarium spp. increased on wheat roots. These changes did not affect overall root severity or yield. Rotations had limited impact on wheat disease severity and the prevalence of fungal species, but wheat grown in diversified crop rotations using cereal, pea and flax had consistently...

Seeding rate, fertilizer level and disease management effects on hybrid versus open pollinated canola (Brassica napus L.)

New canola cultivars have much higher yield potential than conventional canola cultivars and changes in production practices may be needed to achieve optimum yield from these cultivars. Studies were conducted to investigate the influence of seeding rates (2.8, 5.6 and 8.4 kg ha-1), fertilizer level (67% – low, 100% – medium, 133% – high of the commercial recommendation) and fungicide application on growth, dry matter accumulation, seed yield and seed quality using two high-yielding canola cultivars [cv. Quantum, open pollinated (OP), and cv. Invigor™, hybrid (HYB)]. The studies were conducted from 1999 to 2001 at three sites in the Parkland region of the Canadian prairies. The two cultivars did not differ in their responses to seeding and fertilizer rates, or fungicide application. Plant density was lower for the HYB than the OP because the HYB had larger seeds, with fewer seeds per kilogram. Emergence declined slightly at high fertilizer levels in some site-years due to fertilizer induced seedling damage...

Inoculant formulation and fertilizer nitrogen effects on field pea: Nodulation, N2 fixation and nitrogen partitioning

Field pea (Pisum sativum L.) acreage has expanded rapidly in the past 10 yr in the Peace River Region of Alberta as well as western Canada. Understanding nitrogen dynamics of Rhizobium inoculants and applied N will provide farmers opportunities to improve N nutrition of field pea. Field experiments were conducted (a) to compare the effects of soil inoculation using granular inoculant, and seed inoculation using peat powder and liquid inoculants with an uninoculated check, on field pea nodulation and N2 fixation, and (b) to determine whether starter N is required by field pea to enhance N2 fixation. The effects of inoculant formulation on nodule number, N accumulation and N2 fixation were in the order: granular > peat powder > liquid = uninoculated. Field pea, from soil-applied inoculant, accumulated more N prior to and during podfilling than field pea with seed-applied inoculant. Fertilizer N application rates < 40 kg N ha-1 had no significant effects on biomass N at flatpod, indicating that starter N was...

Survival of leaf spot pathogens on crop residues of wheat and barley in Saskatchewan.

Pycnidia of Stagonospora nodorum, and pseudothecia of Phaeosphaeria nodorum and Pyrenophora triticirepentis occurred in greater numbers after one overwintering period on residues of wheat and barley stored on the surface of the soil than on residues from the previous fall. Conidial numbers of Bipolaris sorokiniana and Drechslera teres on residues of wheat and barley, and pseudothecia of Pyrenophora teres on residues of barley decreased over one winter but these pathogens continued to sporulate at low levels after two winters. With residue from the soil surface, Drechslera teres and B. sorokiniana conidia occurred in greater numbers on lower parts of the plants. Drechslera teres occurred primarily on leaf and sheath areas and B. sorokiniana, on sheath and stem areas, while P. teres sporulated mainly on stems. Numbers of conidia of D. teres may have declined because the pathogen occurred mainly on leaves, which disintegrated after one winter. The wheat pathogen Stagonospora nodorum was able to sporulate on ...

Inoculant Formulation and Fertilizer Nitrogen Effects on Field Pea: Crop yield and Seed Quality

Appropriate rhizobial inoculation and fertility management can increase field pea (Pisum sativa) seed yield and improve yield stability in western Canada. The objective of this study was to determine the effect of inoculation method and N fertilizer application on pea seed yield and quality. The effects of soil inoculant (granular) and seed-applied inoculant (peat powder or liquid) used with and without urea-N application on field pea were investigated in the Peace River region of Western Canada. At low applied N rates, field pea biomass was significantly higher for soil-applied inoculant as compared to seed-applied inoculant. Soil-applied inoculant resulted in 15, 18, 9 and 0% higher pea biomass yield at the flatpod stage than seed-applied inoculant at 0, 20, 40 and 80 kg N ha-1, respectively. Averaged over all N rates, soil-applied inoculant resulted in 17, 50, and 56% higher pea seed yield than peat inoculant, liquid inoculant, or the uninoculated check, respectively. Soil-applied inoculant increased t...

Field pea seeding management

The impact of seed placement and seeding rate on crop yield is not clearly understood for field pea (Pisum sativum L.). A field experiment was conducted at Melfort, SK, and Lacombe, AB, in 1998 and 1999, to evaluate the effect of three seed placements (distinct row: 23 cm and 30 cm with a hoe opener; and spread band: a 20-cm spread using a 28-cm sweep on a 23-cm row spacing) and three seeding rates (50, 100, and, 150 seeds m-2) on pea seedling density, seed yield and seed weight of a leafy prostrate and semi-leafless upright cultivar. A follow-up experiment was conducted at seven sites across Saskatchewan in 2001 to further examine the influence of a wider range of seeding rates (20, 30, 40, 50, 60, 70, 80, 90, 100, and 120 target plants m-2). Pea productivity for both cultivars was not affected by the different seed placements, despite a 4 mg greater seed weight for distinct row seed placements compared with spread band placement across all 1998–1999 sites. Moreover, the absence of a seed placement by se...

Foliar fungicides to manage ascochyta blight [Ascochyta rabiei] of chickpea in Canada

Ascochyta blight, caused by Ascochyta rabiei, is a major constraint to chickpea production in Saskatchewan. Foliar fungicides were evaluated at various rates and timings for managing blight epidemics over 18 station years from 1998 to 2000. Dry weather in 1998 resulted in low disease pressure, and fungicide application had no effect on blight severity and yield. In 1999 and 2000, wet conditions favored the development of epidemics. Under high disease pressure, a single fungicide application often reduced disease severity, but had no effect on yield. Two applications (early + mid flowering) of chlorothalonil (Bravo® 500) at 1 kg active ingredients (a.i.)/ha, two applications of azoxystrobin (Quadris®) at 125 g a.i./ha, or chlorothalonil + azoxystrobin reduced ascochyta blight and increased yield. An alternative formulation of chlorothalonil, Bravo Ultrex®, was less effective than Bravo 500, but more effective than mancozeb (Dithane®). Fungicide application had a substantial impact on seed yield; at one site, yield in the untreated control was less than 5% of the best fungicide treatment. Regression analysis showed a strong relationship between disease severity and seed yield. With high disease pressure in 2000, the incidence of seed-borne A. rabiei was 30–;48%. Applying azoxystrobin at early + mid flowering reduced it to 7–9%. Fungicide application had no impact on other seed-borne pathogens such as Botrytis cinerea, Sclerotinia sclerotiorum, and Fusarium spp. These results indicate that fungicide application can complement partial resistance to reduce blight severity and increase seed yield and quality in chickpea.

Comparative nitrogen response and economic evaluation for optimum yield of hybrid and open-pollinated canola

Plant breeders have dramatically improved the yield potential of new canola cultivars. To achieve optimum yield with such cultivars, particularly hybrids, may require changes to fertilizer management practices that were established prior to development of these cultivars. We investigated the influence of N fertilizer rate (0, 30, 60, 90, 120, and 150 kg N ha-1) on plant density, days to flowering, length of flowering stage, days to maturity, biomass, seed yield and quality, and economic returns of two canola cultivars (Quantum, a high-yielding open-pollinated; and InVigor® 2663, a high-yielding hybrid) on a Dark Brown (Scott), a Thick Black (Melfort), and a Thin Black (Indian Head) Chernozem soil in Saskatchewan in 2000 and 2001. Plant density was slightly lower for InVigor 2663 than Quantum due to larger seed size of the former. InVigor 2663 tended to take more days to flowering and had shorter flowering stage duration compared with Quantum, but the two cultivars showed no consistent difference for the n...

Adaptation of oilseed crops across Saskatchewan.

Differences in response to nitrogen (N) fertilizer will affect the production economics of field crops. Currently, there is limited information comparing the agronomic and economic performance of juncea canola (Brassica juncea L.) and sunflower (Helianthus annuus L.) to napus canola (Brassica napus L.) and flax (Linum ustitatissimum L.) in Saskatchewan under no-till practices. A study of these species was carried out at five Saskatchewan locations over 3 yr and included eight nitrogen rates. All four species had a curvilinear increase in grain yield as N rate increased with the largest yield response observed in napus canola to as much as 200 kg N ha-1. The majority of the increase in flax grain yield occurred as the N rate increased from 10 to 90 kg ha-1, while most of the increase in grain yield of juncea canola and sunflower occurred as N increased from 10 to 70 kg ha-1. Biplot analysis indicated that grain yield variation was reduced at and above 50 kg N ha-1 in flax, napus canola and juncea canola, b...