Mustard is one of my favourite crops to grow on dry land in the drier regions of the Prairies. It is a great oilseed crop to include in a diverse crop rotation, which helps to disrupt pest cycles, increase moisture use efficiency and increase farm income.
Canada is a world leader in condiment mustard seed production and accounts for 70 to 80 per cent of global exports, annually. The largest markets for Canadian mustard seed is the United States, Belgium, Germany, Netherlands and Japan.
The three types of mustard commonly grown in Western Canada are:
- Yellow mustard (Sinapis alba): grown for the North American food processing and condiment industry. Yellow mustard is used as a binding agent and protein extender in prepared meats. It is also used for hot dog mustard, mayonnaise and salad dressings.
- Brown mustard (Brassica juncea): grown for European markets for condiment specialty mustards such as Dijon mustard.
- Oriental mustard (Brassica juncea): grown for the Japanese market and for condiment use. It is also used as spicy cooking oil in some Asian markets.
All of these types of mustard are broad-leaved, yellow-flowered, annual, cool-season crop that requires a relatively short growing season. Typically, yellow mustard needs about 1,520 to 1,625 growing degree days (GDD), calculated with a base of 0 C, to reach full maturity for harvest. Brown and oriental mustards need about 1,540 and 1,610 GDD to reach full maturity, respectively.
Mustard seedlings are relatively more tolerant to late spring frosts than canola. Mustard is generally considered to be more tolerant to drought and heat than canola and is well suited to production in the drier brown and dark brown soil zones of Western Canada.
To optimize production, mustard growers must plant the newest varieties with a careful focus on agronomic practices including crop rotations, seeding dates, seeding rates, fertilizer management and pest management to ensure seed production will meet industry quality standards.
Varieties and rotations
Mustard growers must consider marketing and contracting factors when selecting the mustard type and variety to be grown. Growers should select the variety to be grown based on yield potential and the agronomic characteristics most suitable for their agro-ecological area. The Saskatchewan Mustard Development Commission lists mustard types and varieties in its Mustard Growers Manual.
The first step to optimize mustard production is field selection based on previous crop and residue conditions. Using diverse crop rotations that include three or four different crops is generally the most desirable. Previous crops will affect residue conditions in fields, soil moisture conditions and weed and disease pressure.
Ideally, mustard should follow a cereal crop. A break of several years between canola and mustard is needed to minimize volunteers that would contaminate seed and lower grade. Generally, mustard is not subject to the same level of insect or disease pressures as canola.
Mustard should not follow pulse or oilseed crops. Under good production conditions, mustard is susceptible to the disease sclerotinia, which also affects most pulse and oilseed crops. To minimize sclerotinia problems, growers should interrupt the frequency of susceptible crops with cereal crops in the rotation with mustard. Fortunately, sclerotinia is usually not a serious problem in dryland mustard production areas.
Mustard yields are greatly influenced by water availability. A study we conducted with yellow mustard at 20 sites in southern Alberta (brown and dark brown soil zones), found the average water use efficiency (the amount of grain produced per inch of water) averaged over 180 pounds/acre/inch above a minimum of 3.6 inches of water.
Direct seeding mustard into standing stubble in early spring is ideal. Standing stubble helps to reduce wind velocity and reduce moisture loss from the seedbed. Uniform residue will help ensure uniform seedbed moisture and crop emergence. Poorly spread residue can result in patchy mustard emergence as a result of variable seed bed soil moisture and soil temperatures in high versus low residue areas. Emergence problems are always greater in heavy trash areas.
Our mustard research in southern Alberta generally showed that earlier seeding in spring resulted in a strong yield advantage due to capitalizing on early spring moisture, greater potential to capture more sunlight energy and often slightly cooler temperatures during flowering before the hottest part of the summer. Therefore, moisture use is optimized and temperature stress is minimized, resulting in higher mustard yields.
The highest yields of mustard are generally produced from rows spaced six to nine inches apart. Weed growth tends to be more abundant in rows spaced more than nine inches apart than in narrower rows.
When mustard is swathed, stubble to support the swath can be a problem as row width is increased. Seed openers that do not place the seed in rows, but scatter the seed in a two-, three- or four-inch wide band usually have good yield potential and have the advantage that higher safe amounts of fertilizer can be seed-placed, provided there is good on-row packing.
Seeding depth and rate
Mustard seed is very small and must be seeded shallow at 0.5 to 1.0 inch into firm, moist soil. If surface soil conditions are dry, seeding depth could be increased to 2.0 inches, but this approach will reduce crop emergence and plant stand.
Yellow mustard seed is larger than the other mustard types with approximately 100,000 seeds per pound and is normally seeded at a rate of approximately eight to 10 lbs./acre. Brown and oriental mustards have approximately 200,000 seeds/lb and are normally seeded at a rate of five to seven lbs.a/acre. Due to a larger seed size, yellow mustard has a slightly higher emergence percentage than the other types. Seeding at higher rates should be used with soils that tend to crust, land that has emergence concerns or on productive soils with a higher yield potential.
Ideally, seeding mustard at a higher rate results in a denser crop stand, which is more competitive with weeds, assists with cultural weed control and ultimately, increase potential yield.
In my next three articles, I will discuss mustard fertilizer and pest management.
Growing degree days
Agronomists use a formula to calculate Growing Degree Days (GDD).
The GDD for each day is calculated, then the results for each day over the growing season are added together.
For each day, the formula is: (Maximum Temperature + Minimum Temperature)/2 less the Base Temperature. If the answer is negative, count it as zero.
Generally, for cereals use a base temperature of 0 C; for canola use a base temperature of 5 C.
For mustard, the base temperature is 0 C. So, for example, if the maximum temperature on a July day is 28 C and the minimum temperature is 15 C, the GDD formula for that day is (29 + 15)/2 less 0. The GDD for the day is 22.