Reward Versus Risk: Seeding Early In Manitoba

An early spring invariably results in early seeding, as we witnessed in 2010 and 2012 in Manitoba. It is not unusual for farmers to seed in April when there is an early snow melt, minimal run-off and above normal temperatures. For early seeded crops in Manitoba, what are some of the potential rewards and risks?

The Rewards: Increased Yields & Quality

Perhaps the biggest driver for early seeding is the potential for higher yields. The majority of seeding date research conducted in Western Canada reports increased yields with early seeding. Farmer data in Manitoba also illustrates the same point as Manitoba Agricultural Services Corporation (MASC) data shows earlier seeding dates normally translate into higher yields. The figure below illustrates relative yield (expressed as a %) of various crops as seeding date moves from late April to mid June.

Source: Manitoba Agricultural Services Corporation Seeded Acreage Report Records
Data represents reported seeding date and crop yields of fields >200 acres (1989-2008)

So why for most crop types do we see increased yield potential as a result of earlier seeding? Several factors can contribute to this increase:

  • Crops seeded early in the season will better utilize available soil moisture, not only early in the season but throughout the season. The chances that the crop will receive sufficient moisture during the growing season are more likely if the crop is seeded early versus a later planting date.
  • Seeding crops early may enable them to get established and give them the jump on weeds. However, the germination and growth of weeds is also regulated by temperature and soil moisture so weed competition may also be earlier than usual.
  • Date of seeding can influence the risk of damage by insect pests. One example is wheat midge. Wheat is only susceptible to attack by midge between heading and flowering. Adult wheat midge typically emerges in late June or early July. By seeding early, the crop may head and flower before peak adult midge populations occur. For more information on insects relevant to Manitoba crop production, please refer to MAFRD's website.
  • Early seeded crops may avoid certain diseases by avoiding the infection period, therefore lessening its impact on yield and quality. For cereals, stem and leaf rusts usually enter Manitoba from late June to mid-July depending on weather conditions and the extent of disease development on cereal crops in the central USA. Early seeding may allow for some grain filling before infection levels get high. For more information on diseases relevant to Manitoba crop production, please refer to MAFRD's website.
  • By seeding a crop early, the crop should flower earlier avoiding the high temperatures normally seen in July. Heat stress during flowering can have a negative impact on flowering and seed set, especially for crops such as canola. Moderate temperatures during flowering and seed development favour high yield, high oil content and high oil quality.
  • Early seeding usually translates into early maturity and harvest. In most years, weather conditions in August and into September are more favourable for harvest than later in the season. Earlier maturity can also reduce the risk of early fall frost resulting in crop damage and/or downgrading of quality.
  • Seeding date may influence lodging. Later planted crops tend to be taller (as a result of increased internode length) and therefore may be more prone to lodging. In flax, high quality straw for fibre is also more likely to be obtained when seeded early.

The Risks: Cold Soil Temperatures & Frost Damage

One potential risk with early seeding may be soil temperatures that are below the minimum needed for germination. If the soil is too cool, germination is delayed which can result in uneven or inadequate emergence. The table below shows minimum germination temperatures for several crops. These values should be regarded as approximate since germination depends on several factors.

Table 1: Minimum Germination Temperatures For Various Crops

Crop Temperature (°C)
Wheat 4
Barley 3-5
Oats 5
Corn 10
Canola 10 (Argentine)
7-10 (Polish)
Flax 9
Sunflower 6-7
Edible Beans 10-12
Peas 4
Soybeans 10

Sources: North Dakota State University Extension Service & Alberta Agriculture & Rural Development

The other potential risk with early seeding is spring frosts. Injury from freezing temperatures will depend on several factors, including air temperature, length of time the temperature is below freezing, soil moisture levels, residue levels, temperatures following the sub-zero temperatures, and the plant's growth stage. Different crops also have varying tolerance levels to freezing temperatures, usually dependent on crop stage.

Another interesting note is crops that are seeded early will often harden off which allows plants to be more tolerant to frost conditions. The hardening off process either allows plants to become accustomed to lower temperatures or individual plant cells accumulate more solutes that can lower their freezing point.

For more detailed information on the basics of frost damage, crop tolerance to freezing temperatures, the hardening off process, etc. please refer to MAFRD's Spring Frost Damage Bulletin.

Final Notes

When presented with the opportunity, farmers will seize the chance to get an early start to seeding. It is hard to argue knowing that early seeding favors higher yields; but remember, early seeding does not always guarantee higher yields or seed quality at harvest. While important, seeding date is only one of many yield-influencing factors

Critical to remember is 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, regardless of the calendar date.