Considerations for Delayed Seeding in 2009

General Discussion

Traditionally by mid-May farmers are well into seeding and in some years seeding is almost complete.  However, 2009 is not one of these years.  Cold weather and wet soils have delayed seeding across Manitoba from just started to 25% of the acres seeded.  As May progresses, seeding will continue but farmers may question the order of seeding.  Should crops be seeded in the conventional order that is done most years?  Should farmers think about seeding crops that still have the highest yield potential first before seeding crops that have already lost 15% of their highest yield potential?  What other agronomic factors do farmers need to think about with late-seeded crops?

Order of Crop Planting
Farmer experience and data from Manitoba Agricultural Services Corporation (MASC) suggest that as we move into the late stages of May some crops have greater yield potential and higher economic return than others.  By the 4th week of May sunflower, canola, corn, soybean and edible beans haven’t lost a lot of yield potential, while spring seeded cereals, peas and corn yields have dropped to 85% of normal yield potential.  Farmers need to think about the economics of seeding a high input crop that still has good yield potential over seeding a lower input crop that has already lost significant yield potential.  Figure 1 below illustrates relative yield (expressed as a %) of various crops as seeding is delayed from late April to mid June.

If seeding is delayed into June farmers need to consider Manitoba Agricultural Services Corporation (MASC) seeding deadlines in order to be eligible crop insurance coverage.  Depending on crop type and region, there is full coverage and extended coverage seeding deadlines.  Farmers are encouraged to contact their local MASC agent or visit MASC’s website for further information:

http://www.masc.mb.ca/masc.nsf/crop_seeding_deadlines.html

Seeding for Success
What is critical for farmers to remember is one of the first steps to maximize yield potential is the seeding operation, regardless of seeding date.  Mistakes made during the seeding operation are often irreversible so extra care should be taken, especially when facing a late-planting scenario.  Regardless of what crop is seeded, seed placement is critical. This year general soil temperatures are cold and soil moisture is close to the soil surface.  In order to have the crop emerge as quickly as possible seeding should be as shallow as possible while still ensuring optimal seed to soil contact. 

 When general seeding begins in the last half of May, farmers’ first impulse is to seed as many acres as fast as possible.  While it is important to seed as much as possible before the next 1 inch of rain comes along, having your air seeder or row crop planter trying to mimic last weekend’s NASCAR race has its disadvantages. Research has consistently shown that uniformity of seed placement (depth) is one of the first things that is lost once planting speeds exceed 5 mph. 

Planting when soils are too wet is not advised, regardless of the date. Planting when the soil is too wet will lead to soil compaction, which can decrease yield much more than planting a few days later. Yield reductions resulting from "mudding seed in" are often greater than waiting a day or two for the soil to be ready.  How much risk is associated with waiting an additional 2 days to get better seed placement anyway?  Thirty year weather data taken from the Manitoba Ag-Weather Program indicates that the 50% risk killing frost date for Dugald MB is September 18^th.  In Dugald, delaying seeding from May 25^th to May 27^th resulted in a sacrifice of 31 fewer Crop Heat Units out of 2300 total Crop Heat Units accumulated during the growing season.  Following sound agronomic practices and getting the seed placed properly in the soil probably outweighs the 31 lost Crop Heat Units. 

Plant Populations/Seed Treatments
Combination of reduced tillers/branching and fewer days for the plants to grow and flower may mean that farmers need to plant at higher seeding rates.  For the first couple of fields seeded, farmers may need to use a seed treatment when seeding into the cold soils to help ensure a high enough final plant population for maximum yield potential.  

Fertility Considerations
As seeding date gets later in the spring, crop response to applied N declines - since yield potential is lower and in-season mineralization more closely matches uptake by the crop.  As soil temperatures warm up, response to phosphorus fertilizer declines, since warm soils permit plant roots to explore and access more soil P.

Take Home Message
While we would like to have a lot more acres seeded already, with today’s seeding equipment we have the ability to plant a lot of acres in a few days once the soil is ready.  As well, many crops in our rotation maintain their yield potential until the beginning of June.  Early planting favors higher yields, but early planting does not always guarantee higher yields or seed quality at harvest.   While important, planting date is only one of many yield-influencing factors.

For further information, contact your GO representative.