Agriculture

Buckwheat - Production and Management

Field Selection

Buckwheat grows well on light to medium-textured soils. Weed control options in buckwheat are limited, and therefore best yields will be obtained from clean fields. Avoid fields that contain very high levels of nitrogen fertilizer, since this can cause crop lodging.

Variety Information

Seed Manitoba Variety Selection & Growers Guide

Seeding Buckwheat

Treatments

Buckwheat is sown late, when soil temperatures are high, and seedlings will emerge quickly. Seedling diseases are not common. There are no registered seed treatments.

Dates

June 1 to June 20. Buckwheat is very susceptible to frost in late spring or early fall. To maximize yields, buckwheat should be sown early in June after the risk of frost.

Rates

36-48 lb/acre to achieve a plant stand of 13-17 plants/ft2 is ideal. New varieties tend to have larger seed size, along with increased bushel weights. These large-seeded varieties have larger leaves, and as a result do not require higher seeding rates than the smaller-seeded types.

Seeding Depth

1 to 2.5 inches. Seed should be placed only deep enough to reach moisture to obtain rapid and uniform emergence.

Fertilizer Recommendations For Buckwheat

For specific recommendations on fertilizer rates, have your soil tested. Buckwheat requires less fertilizer than cereal crops and is very efficient at removing phosphorus from the soil.

If soil analysis is not available, a general recommendation is as follows:

Nitrogen (N): Apply 0-20 lb/acre N following fallow or legume breaking, 20-40 lb/acre N following grass and grass-legume breaking and 40-60 lb/acre N following stubble. The primary nitrogen deficiency symptoms are yellow leaves and stunting.
Phosphate (P2O5): Apply phosphate at 30-40 lb/acre in a sideband or 20 lb/acre with the seed.
Potassium (K2O): On sandy textured or organic soils, apply potassium at rates of 30-60 lb/acre.
Sulphur (S): Sulphur deficiency may occur in many soils and in any area of the province. A soil test is recommended to determine the available sulphur status of fields. Apply sulphate sulphur at 15 lb/acre when required.
Special considerations: Buckwheat grown under high-nitrogen conditions is more prone to lodging. Buckwheat is also known to use phosphate from the soil and make it available for subsequent crops through stubble decay.

Weed Control

Weed control in buckwheat can be difficult and requires planning, since there are few herbicides available, particularly for broadleaf weed control. Since buckwheat is sown late, there is ample opportunity to control problem weeds with herbicides or cultivation before seeding. Do not use herbicides that may leave a residue before seeding. Weeds can reduce both yield and quality of buckwheat. Seeds that constitute foreign matter include wheat, rye, barley, oats, triticale, peas, beans and corn, as well as several weed seeds.

Insects

Grasshoppers and cutworms can damage buckwheat.

Diseases Affecting Buckwheat

Buckwheat is free from most diseases that affect other broadleaved crops. Three diseases that do affect the crop are Botrytis leaf and stem rot, downy mildew and Rhizoctonia root rot.

Also refer to Scouting for Diseases

Crop disease identification, scouting techniques, economic thresholds.

How to obtain printed copies of the Field Scouting Guide and Guide to Crop Protection.

Harvesting Buckwheat

Swathing

Much of the yield is determined by seed development in the primary seed cluster. Buckwheat should be swathed when about 75-80 per cent of the seeds have turned brown or black. The best way to determine this is to pull a few plants and turn them over and judge seed turn. Yield increases rapidly in the last two of weeks of growth, and therefore swathing should be delayed as long as possible. Usually the crop will show marginal shattering before swathing, but the amount of shattering is minimal, compared with the increases at this stage of growth.

If a light frost occurs (top third of crop canopy or less), the yields of the crop will be further improved, since all flowering will be stopped. If a hard frost occurs (more than the top third of canopy), swathing should begin immediately. Shattering losses can be minimized by swathing when the crop is damp and by matching reel speed with ground speed.

Desiccation

Desiccation weakens the stem and causes lodging. Do not desiccate buckwheat.

Timing

Standing buckwheat is difficult to manage after the crop has been exposed to frost. Where possible, try to swath the crop before a heavy frost.

Combining

To minimize shattering, ensure that the pickup speed equals ground speed. Combine adjustments are important to minimize the dehulling of seed; therefore, use a cylinder speed of 600-800 rpm, concave of 1/2 to 5/8" at front and 1/4" at rear. If seed is dehulling, increase concave size or lower cylinder speed.

Storage

A moisture content of 16 per cent or less is necessary for safe storage of buckwheat. The primary market for buckwheat is Japan, which buys only new crop seed; therefore, it is important not to mix old and new crops. These mixtures of old and new seed are easily detected, as the old seed oxidizes and the light green layer just under the hull in new seed gradually changes to reddish brown during storage.

For specific information on:

  • seed treatments, pesticides, integrated management of weeds, crop pests and diseases refer to Guides.
  • optimizing fertilizer use, refer to Soil Fertility.
  • making varietal choices based on agronomic characteristics, refer to the current Seed Manitoba.