Agriculture

Winter Wheat Establishment

 Good stand establishment is critical for winter survival and early spring vigor, and the following factors need to be considered when sowing this crop.

Winter wheat must be sown into stubble to reduce the risk of winterkill.  Standing stubble traps snow, keeping the soil temperatures warm enough to allow the crop to overwinter.  How you deal with residue from the previous crop will affect seedling establishment and winter survival.  The snow-trapping ability of the stubble must be adequate, ie. tall enough and uniform across the field to trap a loose, insulating blanket of snow over the winter.  Water can be a limiting factor in crop production and the trapped snow will melt and become available for crop use in the spring.  Residues must be managed so they don’t interfere with seeding operations and need to be evenly distributed to allow good stand establishment and uniformity of crop development.
 
Shallow seeding is important as deep seeding results in weak, spindly plants, leading to winter damage, poor weed competition, later maturity and lower yield.  Soil moisture demand from the previous crop usually creates a dry seedbed, and seeding deeper does not necessarily get the seed into moisture.  Soils are cooler in the fall and there is less evaporation off the surface, so light rains that soak into that top inch of soil can be accessed by the seed.  The crown will always be ¾ to 1 inch below the surface, so seed placement at that depth is ideal.  Deep seeding means the plant has to expend extra energy to move that crown up.  Seeding rate should target a plant population of 20-30 plants/square foot.  Information is available on the Manitoba Agriculture, Food and Rural Initiatives website to calculate seeding rates by plant population.
 
Winter wheat must be seeded on time, ideally between August 25 and September 5.  AgriInsurance deadlines are August 20 to September 15, with reduced coverage to September 20.  Seeding too early lets the crown get too big and is then more susceptible to freezing injury.  Seeding too late usually results in poorly established plants with lower winter survival potential.  We want plants to have a well-developed crown and about 3 leaves gong into the winter.  Usually the leaves and roots die off but the crown will survive to initiate new growth early next spring.
 
Always use starter fertilizer with winter wheat.  Phosphorus is important for root growth, winter survival of the crown, and recovery from winter injury.  Generally 30-40 lbs P2O5 is sufficient.  Do not seed-place nitrogen with winter wheat as the risk of winter injury is increased.  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 5-7 lbs S/acre can help.
 
For further information, contact your GO representative.