If It’s Too Wet To Drive Across, It’s Too Wet To Seed

Business Development Specialist – oilseeds Manitoba Agriculture, Food and

Rural Development

Delayed seeding due to flooding or wet conditions may have you considering broadcast seeding your canola by floater or aerial application.

In general, broadcast seeding is not recommended. This includes seeding canola by aircraft onto very wet fields: if it’s too wet to drive across, it’s too wet to seed with any method.

Good soil-to-seed contact is crucial for canola to successfully germinate, emerge and produce a sufficient stand. Regardless of the broadcast equipment used, (full-width broadcaster, centrifuge spreader, or aircraft) broadcast seeding will result in substantial yield reductions when conditions are not optimum for germination.

If you are still set on this seeding option, the following may help you achieve a stand that Manitoba Agricultural Service Corporation (MASC) will cover. MASC will not cover crops broadcast seeded by ground-rig or aerial applications unless it is shown that the crop germinated and established a sufficient stand to yield at least the insured’s coverage as determined by the corporation (ballpark four to seven plants/ square foot).

Increase your seeding rate by one lb./ac. to account for increased losses due to poor seed placement and non-uniform seed depth.

Harrow packing, vibra shanking with harrows and packers, or light discing with harrows and packers to cover the seed as soon as possible after broadcasting. Harrowing alone may not pack well enough to ensure germination.

Avoid creating lumps or clods during cultivation or straw piles.

If broadcasting fertilizer as well as seed, be aware that broadcast phosphorus is only about half as efficient as banded phosphorus. There can also be greater risk of denitrification on saturated soils, reducing nitrogen fertilizer efficiency.

Adjust fertilizer rates accordingly, keeping in mind a realistic target yield based on the time of year and field conditions. For further tips on seeding under delayed conditions, refer to the following links from MAFRI:

http://www.gov.mb.ca/agriculture/news/flood/index.html#Crops_Specific_Topics.

Just a quick word on broadcast seeding of soybean and sunflower crops. These are not recommended at all by Crops Knowledge Centre staff with MAFRI.

Both sunflower and soybean need to be placed deep enough (at least a uniform half to one inch) into the soil to receive constant moisture to stimulate germination and emergence. If germination starts, but the seed dries out, it’s dead. Root development is also important in these crops – a shallower-rooted sunflower with the heavy head will fall over later in the season as it does not have the rooting support.

Added concern with soybean – on seed inoculant (liquid or peat based or liquid with extender) on soybeans are at risk of drying out and perishing if the seed is placed on the soil surface instead of in the moist soil.

About the author

Manitoba Agriculture

Anastasia Kubinec is manager of crop industry development for Manitoba Agriculture.

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