Seeding
A firm moist seedbed is required for uniform rapid emergence. The seed should be placed between 1.5 inches (4 cm) to 2.5 inches (6 cm) deep. The deeper seeding depth should only be used under drier conditions. Deep seeding delays emergence and decreases uniformity of the crop. Buckwheat will germinate at soil temperatures as cool as 7° C.
Seed size ranges from 29 to 35 grams per 1,000 kernels, and the recommended seeding rate ranges from 35 to 72 lb/ac (39 - 81 kg/ha). The heavier rate should be used in fields where weed populations are higher than desirable and where larger-seeded varieties are being grown. Lighter seeding rates may be used on cleaner fields. Too heavy a seeding rate may be detrimental, as overly thick stands produce spindly plants with short stems and few seeds. A plant population of approximately 16 plants per square foot is desirable. Buckwheat does exhibit a high degree of plasticity, branching profusely to compensate for lower plant populations.
The seeding date for buckwheat will vary slightly from region to region depending on the date when the risk of the last spring frost has passed. The range for seeding dates in western Canada varies from June 1 to June 25. In the central, north central and northern parts of Alberta, seeding dates past June 15 risk the possibility of damage to the crop caused by early fall frost. Seeding past this date is not generally recommended. Early June seeding has produced the highest buckwheat yields.
No specialized seeding equipment is required for buckwheat although some time may have to be taken for calibrating grain drills that do not have a buckwheat chart.
Rotations
Cereal grains in a buckwheat sample are undesirable from a marketing standpoint because they are hard to clean out. Barley, oat, wheat, rye and triticale are considered foreign material in buckwheat, and samples containing more than 5 per cent cereal grain by weight are graded “sample.” Unless very good control of these plants can be accomplished prior to seeding, growing buckwheat is not recommended.
Avoid growing buckwheat on canola or mustard stubble because of their volunteering habit and competitive nature. Buckwheat grows well on field pea or dry bean stubble or summer fallow. Volunteer buckwheat in a succeeding crop may be a problem. Check rotations to see if the crop following buckwheat can be sprayed to control volunteer plants.
Fertilization
Buckwheat responds well to a balanced fertilizer program, but it is not considered a high nutrient user. A soil test to determine what nutrient levels are present is critical. Early research on buckwheat fertility requirements showed that highly fertile or rich soils should be avoided. Excessively high nitrogen levels in the absence of other nutrients compound the lodging problem. Growers using animal manures have had severe lodging problems.
General recommendations for added nutrients are as follows: 20 to 40 lb/ac (22 - 45 kg/ha) nitrogen, depending on whether the crop is planted on summer fallow, pulse stubble or cereal stubble. Normal rates for phosphate range from 27 to 40 lb/ac (30 - 45 kg/ha). Potash is generally recommended if the crop is grown on sandy loam soils. The suggested rate for potash in these cases would be 31 to 62 lb/ac (35 - 70 kg/ha). When sulphur is required, apply 13 lb/ac (15 kg/ha). No more than 5 lb/ac (5.6 kg/ha) nitrogen and 20 lb/ac (22 kg/ha) phosphate should be applied with the seed.
Harvesting
Buckwheat has an indeterminate growth habit. The plant matures from the bottom upwards, flowering until cut or killed by a frost. At harvest, mature seed, immature seed and a few flowers will be present. A grower must determine when to start harvest before losses occur due to shattering.
Harvest should begin when 75 per cent of the seeds have reached physiological maturity, and the plants have lost a majority of their leaves. This stage corresponds with the time the lower seed heads begin to shatter. Buckwheat may be swathed or straight combined. Either operation must be done carefully since aggressive reel action can cause additional shattering. Adjusting the reel speed to match the forward speed of the swather or combine may help. A draper-type pickup on the combine causes less shattering than a drum type.
Cylinder concave clearance and cylinder speed must be adjusted to minimize excessive cracking and de-hulling. Cylinder speeds are generally set at 600 to 800 rpm. If seed damage is occurring, slowing the cylinder speed and/or opening the concave clearance will help. Front cylinder concave clearance of 1/2 to 3/8 of an inch and 1/4 inch at the rear is recommended. Upper sieve openings should be in and the lower 5/16 inch.
The wind setting should be set to allow the maximum amount of foreign material through without buckwheat passing through. Straight combining an indeterminate crop such as buckwheat will result in a sample containing dry mature and tough immature seed.
Storage
Grain drying or aerating may be necessary. Combining the crop at slightly higher moisture will result in less shattering. A safe temperature for grain drying, for both seed and commercial grain, is 45° C. Buckwheat can be safely stored at 16 per cent moisture. The bushel weight of buckwheat is 48 lb. Growers are not allowed the luxury of long periods of storage before marketing since buckwheat contains a high percentage of fat.
