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COG Organic Field Crop Handbook

 

3.11 Winter Wheat

Winter wheat is grown anywhere there is adequate snow cover or mild enough winters to prevent winterkill. Both hard red and soft white varieties are available. Hard red wheat is preferred for breadmaking. Soft wheat is preferred for use in cakes, cookies, batter, bulgar, pastries and breakfast cereals.

• Reasons for crop selection

Like all winter cereals, good stands of winter wheat protect the soil against wind and water erosion. It also reduces compaction in the spring because the farmer is not under pressure to go onto the field when the soil is still too wet.

Winter wheat produces lots of straw which should always be left on the field unless needed for livestock. It improves soil tilth, creates pore spaces, and generally lightens up the soil when incorporated. The stubble alone, including the roots, makes up a quality residue. The chopped straw provides a large quantity of easily broken down organic material, with a high phosphorus content. The wheat can be underseeded with clover for additional nutrient benefits to succeeding crops.

Winter cereals are stronger weed competitors that spring sown cereals. Annual and perennial weeds are controlled with tillage before wheat is planted, and once it has become established, wheat competes well with weeds.

Most of the winter wheat production is marketed domestically as a cash crop for milling or processing. It can also be used in livestock rations.

Crop requirements

A wheat crop which yields 80bu/ac removes :

N -104lb/ac, 116kg/ha; P - 40lb/ac, 45 kg/ha; K -24lb/ac, 27kg/ha

(these figures are for grain only).

Relative to other grains, winter wheat does well in heavy soils. It can be grown in a variety of soil types provided the soil is well drained. Ice or surface water will result in winter and spring kill.

Winter wheat is considered a heavy feeder, although not as demanding as corn. It is usually placed in the crop rotation after a plowdown of clover or of a hay stand. It can also follow a grain legume like soybeans. Being a heavy feeder, winter wheat should not follow any crop that also demands high fertility from the soil, like corn. It grows well after an application of from 10 to 15 tonnes/ha of medium compost or 22000 L/ha (2000gal/ac) of liquid manure.

Short straw varieties are grown to avoid lodging if the soil fertility is high. If the soil is well balanced and there is less nitrogen available, a taller variety can be grown.

• Planting methods

Planting date

The time to plant winter wheat varies considerably from place to place. Ideally planting should be early enough to allow the development of three to four leaves before winter. Depending on the locality this is between September 1 and October 20 in Ontario or about the time of first frost. Earlier seedings can develop more disease problems.

Seedbed preparation

A hay or clover stand, is usually incorporated in July or early early August (after having applied compost at 5 tons/acre if possible ?), then the field is disced at two week intervals for extra weed control before seeding the wheat. A good seedbed with good seed-to-soil contact is needed.

Winter wheat, acting as both a catch crop and a harvest crop, can follow soybeans. Overseed the winter grain when the soybean plant is at the "yellow leaf" stage or when 50 percent of its leaves have turned colour. This can vary from 20-45 days before harvest. Overseeding gives the advantage of providing continuous groundcover and holding the nitrogen (approximately 30kg/ha) which was accumulated by the soybean plant. Aerial seeding can be used on a large acreage, otherwise a broadcast seeder works well.

Winter wheat can be planted in crop residue with little tillage as long as the seed can germinate.

For optimum winter cereal survival on the Prairies, when seeding winter wheat, seed into a moist, weed free field of standing stubble or any other effective snow trap. Loose, open soils are easily dried out in hot, dry weather, so seeding in late summer can result in uneven germination and weak seedlings that are prone to winterkill.

Seeding rate

Test weight for wheat is 60lbs/bu, 75kg/hl

In Ontario and Quebec

before September 20th: 100- 112 kg/ha; 90 -100 lbs/ac.

from late September: 135-168 kg/ha; 120-150lbs/ac

If air-seeded into soybeans: 135-156 kg/ha;120 - 140 lbs/ac.

Broadcasting methods of seeding require higher rates than when seed is drilled.

 

Prairies: 56-67kg/ha; 50-60lb/ac

where moisture is more plentiful 67-78 kg/ha; 60-70lb/ac.

A 1968 Agriculture Canada publication noted that in the western Prairies north/south rows give seedlings the best protection against the wind but where moisture is limited east/west rows usually yield more. A compromise would be to seed diagonally northwest to southeast.

Seed at a depth of about 3cm. Deeper seeding delays emergence and results in weakened plants that are prone to winterkill.

• Crop management

Weeds are seldom a problem in winter wheat because of its fast growth in early spring. Harrowing in the spring will control winter annuals ?

Disease control

Use sound, clean high quality seed from disease-free fields. Winter wheat is seldom damaged by rust because it matures before the disease becomes severe. Disease problems may occur if wheat is sown too early in the fall. Where stem rust and smuts are a problem, choose resistant varieties. Also, Japanese Barberry, which is an alternative host for the rust, should be removed from hedgerows. Wheat should not follow corn in the rotation because the pink ear mold which can produce vomitoxin in wheat is common to both.

•Harvesting

Winter wheat usually outyields spring wheat. It is ready for harvest at the end of July or beginning of August. Winter wheat can be combined or it can be swathed first and then combined. Swathing before the grain becomes too ripe will reduce losses from seed shattering. Harvest wheat when the kernal is hard to the fingernail (soft wheat can be indented with the fingernail, hard wheat can not).

If the wheat has been underseeded to a forage crop, it is important to leave at least 30-60cm (1-2') of standing stubble as snow -catch for the winter.

Stored grain should not contain more than 14 percent moisture.

 

 

Suitable following crops

The early harvest allows time for a cover crop of oil radish or buckwheat to be planted. Some farmers apply manure or compost to the stubble, then seed the oil radish and incorporate both the seed and the compost with a disc. Another option is to incorporate the stubble first then seed the oil radish. This can be done by broadcasting and harrowing. A spring grain is then planted the following year. Oats do well after winter wheat.

If planting a cover crop is delayed, rye can be used instead and incorporated as a green manure in the spring. Rye should not follow as a grain crop after wheat because there is a greater risk of ergot development.

 

Winter wheat can also be underseeded with red clover early in the spring (frost seeding) at 6-8 kg/ha. (5-7lbs/ac)(sounds low to me?)

 

• Spring Wheat

Spring wheat is grown extensively on the Prairies and in areas where winter survival of winter wheat is poor.

• Spring wheat is considered a medium feeder when placed in the rotation.

• Plant spring wheat when the soil is12oC. You get higher yields if it is planted early. The cool moist conditions promote tillering and large heads.

• Spring wheat is seeded at 100-136kg/ha. ( 90-120lbs/ac.) The higher rates are used when emergence is likely to be poor due to a poor seedbed, broadcast seeding, or late planting where tillering will be reduced.

• Weed control for spring wheat is similar to other spring cereals (see barley and oats). Blind harrow after seeding and before emergence to control the first flush of weeds. If necessary, a weeder harrow can be used at the 4-leaf stage. Do not harrow if the wheat is underseeded with clover. Preferably harrow before emergence and then broadcast your clover cover crop, and harrow again.

• Spring wheat is more likely to be affected by rusts than winter wheat; so it is recommended to grow resistant varieties.

 

Copyright © 1992 Canadian Organic Growers. Inc

Reprinted with permission. All rights reserved.

 

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