Manage residue now for winter wheat seeding

Farmers are focused right now on getting this year’s crop in the bin, but it is important to remember that the success of next year’s winter wheat crop begins with this year’s harvest.

How you deal with residue from the previous crop will affect seedling establishment and winter survival, which is critical for a good stand of winter wheat.

Winter wheat must be sown into stubble to reduce the risk of winterkill. Standing stubble traps snow, keeping soil temperatures warm enough to allow the crop to overwinter. The stubble must be tall enough and uniform across the field to trap a loose, insulating blanket of snow during winter. Water can also be a limiting factor in crop production and the trapped snow will melt and become available for crop use in the spring.

Residue should be evenly distributed to allow good stand establishment and uniformity of crop development. Care must also be taken to avoid excessive traffic on the field during harvesting to avoid trampling down stubble. Canola stubble is an ideal choice but you can seed into other crop residue as long as there are enough stems of decent height to trap snow.

Producers should be aware of Manitoba Agricultural Services Corp. (MASC) insurance coverage on winter wheat in relationship to seeding into “eligible stubble.” Contact your local MASC agent for full details.

Seed shallow

Winter wheat must be seeded shallow as deep seeding results in weak, spindly plants, leading to winterkill, poor weed competition, later maturity and lower yield. Soils are cooler in the fall and with less evaporation off the surface light rains can soak into that top inch of soil and be accessed by the seed. As little as one-third inch of rain is often enough to successfully establish winter wheat. Ideally, the crown will develop three-quarters to one inch below the surface. Deep seeding forces the plant to expend extra energy to move that crown up.

Seeding rate should be 1.5 to 2.5 bu./acre to achieve a target plant population of 20 to 30 plants/ square foot. Information is available on the MAFRI website to calculate seeding rates by plant population.

Timing is critical

The best window for seeding winter wheat is between August 25 and September 5. Crop insurance deadlines are Aug. 20 to Sept. 15, with reduced coverage to Sept. 20. Seeding too early results in a larger crown that is more susceptible to freezing injury. Seeding too late usually results in poorly established plants with lower winter survival potential. Plants need to have a well-developed crown and about three leaves going into the winter. This year’s leaves and roots will die off but the crown survives to initiate new growth early next spring.

Always use starter fertilizer with winter wheat. Phosphorus is important for root growth, winter survival and recovery from winter injury. Generally 30 to 40 lbs. P2O5 is sufficient. Seed-placed nitrogen increases the risk of winter injury. Nitrogen can be side banded or mid-row banded, or applied after seeding in fall or spring.

Potash can be applied as KCl, potassium assists with stem strength and chloride helps with disease resistance. Apply sulphur according to soil test recommendations as it aids in production of amino acids, the building blocks of protein. If your winter wheat protein is low despite adequate N fertilization, or if you have high S-using crops in rotation, then adding five to seven lbs. S/acre can help.

Weed management

Controlling biennial and perennial weeds, either in the previous crop or prior to seeding, is important as they can be very competitive during establishment. To eliminate the risk of wheat streak mosaic virus, it is imperative that any volunteer spring or winter cereal plants be completely controlled prior to seeding winter wheat. Fall-germinating winter annuals such as stinkweed and shepherd’s purse can be controlled through the proper use of post-emergent herbicides in late fall. By removing early weed competition, the result will be a well-established winter wheat crop that can better survive the winter.

— Kim Brown-Livingston is a farm production advisor and Pam de Rocquigny is a business development specialist for feed grains with Manitoba Agriculture, Food and Rural Initiatives at Carman, Man. This article includes information from the MAFRI website and provincial Winter Wheat Production manual.

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