Yellow Mustard and Canola for Direct Seeding Systems 


Jack Brown

University of Idaho, PSES, Moscow, ID 83844-2339


Future farming practices likely will be less dependant on agricultural chemicals and greater profits will be realized by reducing input costs. Two vital elements of sustainable farming are crop rotation and growing crops which require minimum chemical inputs. Several years ago, sustainable agricultural research began at the University of Idaho to identify potential crops to include in rotation with small grain crops that predominate in the dry-land regions of the Pacific Northwest and other US states.

Small-grain cereal crops dominate Pacific Northwest dry-land agriculture and very few alternative crops have shown adaptability to be included in rotation with wheat and barley. Winter canola and yellow mustard produces excellent rotational advantages when included in a crop rotation with small grain cereals, corn, alfalfa or potato (Holmes, 1980; Finnigan, 1994; Wilson et al., 1994). In some European countries, for example the United Kingdom, canola and mustard has been valued as a break crop between cereals (Holmes, 1980). By including Brassicacae crops as part of a rotation scheme, pathogens in both soil and straw residue can be dramatically reduced. In the US, wheat following canola had significantly less sub-crown internode damage and crown blackening, caused by take-all disease, than either wheat planted after plowed or burned stubble (Finnigan, 1994). Wilson et al. (1994) reported that when canola was incorporated in rotation with small grains such as wheat and barley, the disease incidence on the cereals decreased and the quality increased. In Europe, mustard and canola crops long have been recognized for their value in crop rotations with small grain cereals (Ward et al., 1985; Almond, et al., 1986). Compared to continuous cereal production, 17% to 20% yield increases have been found when these crops are included in rotation (Grodzinsky, 1992).

The reasons for the advantageous rotational benefits of canola and yellow mustard crops are not fully understood. However, all parts of Brassicacae plants contain glucosinolates (Davis, 1988). Glucosinolates break down in the soil into toxic sulfur compounds that have been proven to have insecticidal (Lichtenstein et al. 1964, Brown et al. 1991), nematicidal (Mojtahedi et al. 1991) and fungicidal (Papavizas and Lewis 1971) properties. In addition, growing Brassicacae crops improves the physical soil structure and increases soil fertility (Guy, 1994). These crops have a long tap root that can improve soil structure (Angus et al. 1991) and utilize nitrates deep in the soil.

Soil erosion is a major problem in many Pacific Northwest agricultural regions. Crop residue is a critical resource for protecting soil from erosion. An average canola or yellow mustard crop will provide as much residue as a normal cereal crop. For example, a yellow mustard crop yielding 2,000 kg per hectare of seed should produce 4,000 to 6,000 kg of dry plant residue per hectare that is useful for soil erosion protection and becomes soil organic matter (Guy, 1995). Other crops that are grown in rotation with small grains (i.e. pea and lentil) commonly produce considerably less (450 to 900 kg/ha) crop residue (Gareau and Guy, 1995). In addition, canola and yellow mustard residue easily breaks apart and is spread well by combine harvesters (Brown, et al., 1995).

Greater attention has been given to sustainable agricultural systems in the Pacific Northwest. No-tillage and minimum-tillage is seen as having advantages under our climatic situations. These tillage practices have potential to conserve soil moisture, reduce multiple machinery operations, and reduce soil erosion. However, suitable crop rotation will be a necessary component in successful no-tillage systems.

In summary, canola and yellow mustard have shown high adaptability to the Pacific Northwest region and both offer alternatives rotation crops for use in no-tillage and minimum-tillage systems.

Yellow mustard

Yellow mustard is predominantly grown for condiment use. Canada, the major producer in North America, produces approximately 350,000 hectares, yielding 160 million metric tons of seed (Anon., 1989). In 1994, the US imported 63,936 metric tons of yellow mustard seeds, 6,194 metric tons of yellow mustard flour and 5,066 metric tons of processed yellow mustard products at a total estimated cost of $28,488,000. At present little yellow mustard is grown in the US, only 6,300 ha were planted in 1995 and an estimated 10,000 ha planted in 1997.

The breeding group at the University of Idaho have been developing condiment yellow mustard cultivars for over five years and recently released the first cultivar, `IdaGold' (Brown et al., 1997) developed specifically for the Pacific Northwest agricultural conditions, and the first yellow mustard cultivar release in the US. Compared to Canadian cultivars, IdaGold showed a 10-20% yield advantage under Pacific Northwest dry land conditions and already has created tremendous interest from the farming community.

US domestic consumption of yellow condiment mustard could be produced on 40,500 to 60,000 ha (assuming an average of 1,600 kg/ha). There has been increasing demand for yellow mustard in other countries (particularly Pacific Rim countries) and US yellow mustard crops could become a valuable export commodity, which could increase production.

Yellow mustard has been evaluated throughout the Pacific Northwest (and other US regions) and shows adaptability and high yield potential in dry-land situations with lower rainfall than suitable for spring canola production. Between 1993 and 1995, yield trials comparing the performance of yellow mustard and spring-planted canola were grown in Oregon, Washington, Idaho and Montana. All test sites were non-irrigated, and locations used in these studies were classified into high and low rainfall areas. With higher rainfall, yellow mustard yield averaged 2,220 kg/ha while rapeseed or canola produced 1,605 kg/ha (Table 1). Yellow mustard yield under lower rainfall was 1,396 kg/ha, and spring canola was only 624 kg/ha. It should be noted that the 1994 growing season was extremely dry and a more accurate assessment of yield potential would be from the other two years. Ignoring the 1994 data, average yellow mustard yield in high rainfall was 33% higher (2,517 kg/ha) compared to spring canola (1,896 kg/ha). Under more arid condition yellow mustard yield was almost double (1,630 kg/ha) that of spring rapeseed/canola (834 kg/ha).

Table 1. Average seed yield of yellow mustard and spring canola (B. napus) cultivars in three years on non-irrigated land. Locations were divided into low rainfall, less than 35-cm annual average and high rainfall, greater than 35-cm annual average.

Species 1993 1994 1995 Average
  ------- kg/ha --------
Low rainfall locations  
Yellow mustard 1116 928 2146 1396
Spring canola 139 206 1530 624
High rainfall locations        
Yellow mustard 2498 1627 2538 2220
Spring canola 2035 1023 1756 1605


Insect damage is a major limiting factor in canola/rapeseed production in the US. Insects cause yield loss and require regular insecticide application for acceptable crop production. Little genetic variation for insect resistance exists among genotypes within B. napus or B. rapa. Work in Canada found that yellow mustard is resistant to flea beetle (Phyllotreta cruciferae (Goeze)) (Lamb, 1980; Bondaryk and Lamb 1991), a major early season pest of Brassica and related crops. Research at the University of Idaho confirmed this resistance (Brown et al., 1997a) and found that yellow mustard is highly tolerant to late season pest damage caused by diamondback moth (Plutella xzlostello (Linnaeus)) larvae and aphids (Myzus persicae, Brevicoryne brassicae, etc.). Furthermore, yellow mustard is highly resistant to cabbage seedpod weevil (Ceutorhynchus assimilis Payk.) (Brown et al., 1997b), an important pest of rapeseed and canola. Some results from these studies are presented in Table 2. In this study, two species of rapeseed/canola (B. napus and B. rapa) and yellow mustard were compared for yield response under complete insect control (using multiple insecticide applications), and no insect control. Both studies (involving 10 cv's per species) show that yellow mustard produces desirable yields even when no insecticides were applied and usually out-yielded either spring canola species that had several insecticide applications.

Effective weed control often is difficult to attain in fields planted to spring canola. For example, Canadian estimates show canola yield is reduced about 10% each year by weeds resulting in an annual economic loss of over $306 million (Chandler et al. 1984). Brassicacae weeds can decrease rapeseed and canola oil and meal quality, causing additional losses (Thomas 1994, Brennan 1995.)

Table 2. Yield of two spring-planted canola species and yellow mustard when early and late season insects were chemically controlled (Chem) and when no chemical control was applied (None).

    1992 1993
Crop Species Chem None Chem None
    ------- kg/ha -------
Early season pests
Yellow mustard S. alba 2190 1883 1717 1600
Canola B. napus 1746 1501 1671 1331
Canola B. rapa 1344 1067 1453 1342
Late season pests
Yellow mustard S. alba 2204 2149 1659 1554
Canola B. napus 1669 1261 1599 797
Canola B. rapa 1595 1101 1529 1029


Preliminary studies conducted by University of Idaho plant scientists in 1996 compared competitiveness of the spring planted crops, canola (Brassica napus L.), pea (Pisum sativum L.), lentil (Lens culinaris M.), and yellow mustard with weeds (mainly common lambsquarters, redroot pigweed, shepherd’s purse, and volunteer winter wheat (Triticum aestivum L.). Each crop was subdivided into four weed control treatments; trifluralin plus sethoxydim, trifluralin, sethoxydim, and an untreated control. In the untreated control plots, there were 52, 96, 137, and 102 total weeds/m2 when the competing crop was yellow mustard, canola, pea, or lentil, respectively (Table 3). In herbicide treated plots, average weed number was 10 plants/m2 in the yellow mustard crop and 31 plants/m2 in canola, pea, and lentil. Averaged over all four weed control treatments, plots seeded to yellow mustard had 49 to 73% less weed biomass than the plots seed to the other crops.

Table 3. Weed biomass and crop yield with broadleaf and grass herbicide and with no herbicide application.

    Herbicide No Herbicide
Cultivar Crop Weed biomass Yield Weed biomass Yield
  -- g/m2 -- -- kg/ha --- -- g/m2 -- -- kg/ha --
IdaGold Mustard 9 753 71 878
Springfield Canola 13 894 228 468
Columbia Pea 49 246 246 235
Brewer Lentil 115 44 220 98


Yellow mustard clearly competed more aggressively with the weeds in these studies than the more traditional crops grown in rotation with winter wheat. Smaller, less competitive weeds will produce fewer seeds that potentially can be returned to the soil seed bank and few weeds in following crops. Ultimately, the ability of yellow mustard to better compete with weeds compared to canola, pea, and lentil should reduce herbicide use within the overall cropping system (e.g., winter wheat, spring barley, yellow mustard), resulting in a more integrated approach to weed control

A survey conducted by the University of Idaho in 1996 showed that growers were growing yellow mustard with conventional-, minimum- and no-tillage practices. Averaged over all growers surveyed, highest yield was obtained using no-tillage and direct seeding, while lowest yield obtained from conventional tillage. It also should be noted that the method of tillage used was greatly dependent on normal precipitation and a high proportion of the no-tillage and minimum-tillage was in lower rainfall regions. Yellow mustard therefore has obvious potential as a direct seeded crop.

Table 4. Yellow mustard cultural practice survey.

Tillage method Number of Growers Seed Yield
    -- kg/ha --
Conventional tillage 16 942
Minimum-tillage 27 1004
No-tillage 11 1172

Winter Canola

Population growth and improved living standards throughout the world have resulted in an increased demand for fats and vegetable oils (Downey, 1976). FAS, Oilseeds and Production Division reported that 11,161,000 metric tons of rapeseed (including canola) was produced worldwide in 1995, making rapeseed/canola the second largest source of edible vegetable oil (USDA, 1995a).

Since "Generally Regarded as Safe" (GRAS) status was granted to canola (Brassica oil with less than 2% erucic acid content) in 1985, there has been a rapid acceptance of canola products in the US. Canola oil continues to increase in popularity among US consumers because it fills a health niche, having the lowest level of saturated fat of all edible oils and the second-highest level of monounsaturated fat (PGAL, 1987).

High demand for canola products has resulted in a rapid increase in imports into the US. In 1988, consumption of canola in the US was just under 12,000 metric tons while in 1995, 409,500 metric tons of canola seed and 425,466 metric tons of canola oil was imported to the US (mainly from Canada) at an estimated cost of $94,500,000 for seed and $222,120,000 for oil imports (USDA, 1995b). By the end of this decade, the estimated demand for canola oil in the US will exceed one million metric tons (Powell, 1994).

In contrast to demand and use, canola production in the US has been very low. In 1993 the total US canola/rapeseed production was from less than 185,000 ha (Powell, 1994) and in 1995, production was only slightly greater, at an estimated 200,000 ha. The gap between production and demand is an enormous incentive to increase canola and industrial rapeseed oil production in the US.

Seed yield of winter canola has exceeded 6,000 kg/ha in small plot trials grown in the Palouse region of Northern Idaho (Mahler et al., 1988). Insects do not damage winter canola as much as spring canola. Neither do high temperatures at flowering influence winter canola and seed fill. As a result, yield of winter canola often exceeds 3,000 kg/ha from farmer’s crops when planted on summer fallow. Winter canola is traditionally planted on summer fallow, in early August, into moisture conserved by the fallow operation. However, current trends in agricultural practice have reduced the acreage of summer fallow in the region, which has greatly reduced the potential winter canola planted.

Greater attention has been given to identifying new cultivars that could be planted later in the fall (mid-September to early October). This would allow winter canola to be grown after a cereal crop in regions with higher rainfall, and would offer growers in low rainfall regions to plant canola later, when fall soil temperatures are not too high.

In 1995, 1996 and 1997, an experiment was conducted to examine the potential of late planted winter canola. Four cultivars (`Cascade', `Ceres', `Ericka', and `Selkirk') were planted at two locations in each of three years. At each location, each cultivar was planted in early August and late September, with 5 kg/ha and 10 kg/ha seeding rates.

Table 5. Plant establishment (1-9 scale of increasing establishment) and plant density (plants m-1) averaged over four cultivars and all sites of early and late planted canola at two seeding rates.

  Early Planting Late Planting
  5 kg/ha 10 kg/ha 5 kg/ha 10 kg/ha
Plant establish 6.0 7.1 2.3 4.6
Plant stand 14.1 21.1 8.5 12.1


Obtaining good crop establishment is critical in direct seeding systems. Plants sown early had good establishment, irrespective of seeding rate (Table 5). However, later planted crops shown a significant reduction in plant establishment at the lower seeding rate. In both plantings, lower seeding rates produced a 66% to 70% reduction on plant stand compared to double the seeding rate. However, there was less than 50% plant stand at the late planting compared to early planting. Poor establishment and low plant stand could both contribute to lack of competitiveness with weeds and indeed considerably greater weed populations were observed on the late planted plots with lower seeding rates.

All four cultivars showed good to excellent yield potential under early-planted conditions (Table 6). The effect of seeding rate on the early seeding was low. Averaged over the four cultivars, Yield of 5 kg/ha seeding rate was only 1% less than the higher seeding rate. In contrast, lower seeding rate at the late planting reduced yield, on average, over 14%. Ericka and Ceres showed better late-planting potential than Selkirk and Cascade was not suitable for late planting.

Table 6. Seed yield of four cultivars planted at two seeding rates and two planting dates.

  Early Planting Late Planting
  5 kg/ha 10 kg/ha 5 kg/ha 10 kg/ha
  ------------ kg/ha ------------
Cascade 4830 4930 1845 2305
Ceres 6092 6214 3741 4494
Ericka 6071 6001 4075 4667
Selkirk 5635 5685 3651 3957
Mean 5650 5707 3328 3855

In conclusion, there is good opportunity to include winter canola in re-crop or late planting systems. If canola is to be planted later in the fall, then higher seeding rates will be required to ensure sufficient crop establishment and plant stand to allow reduced weeds and greater yield.

A study of no-tillage Ericka is being conducted at the University, starting fall 1997. Crop establishment and yield will be determined under full-tillage, minimum-tillage, no-tillage into straw stubble (loose straw removed), no-tillage into straw stubble (loose straw intact), and no-tillage after straw burning. Initial crop establishment showed that significantly better establishment in the no-tillage plots and minimum-tillage plots compared to the full-tillage plots.


Including broad-leaf crops in rotation with small-grain cereals will have a major contribution to the success of sustainable to-tillage farm practices. Both winter canola and yellow mustard have good potential to be included in rotations with small-grain cereals. Both crops have no-tillage and minimum tillage possibilities. Further studies on the advantages and disadvantages of including Brassicacae crops in minimum cultivation practice system is merited.


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