Oats: seeding and establishment

Page last updated: Tuesday, 1 May 2018 - 1:41pm

Please note: This content may be out of date and is currently under review.

Plant population

Establishment of an optimum plant population is essential to achieve the maximum possible yield. The desired number of plants per square metre is mainly dependent on yield potential but also can improve crop competitiveness against herbicide resistance ryegrass.

  • The recommended plant density for oat grain production in the higher rainfall regions is 240 plants per square metre (m2), while in the lower rainfall region it is 160 plants/m2.
  • The recommended plant density for oat hay production is between 240-320 plants/m2, with higher density helping to compete better with weeds and to reduce stem thickness, which is desirable in quality export hay.

Reasons to increase plant density include:

  • Hay production - to help plants compete against weeds and to produce finer stems as required for the export market. Target 320 plants/m2.
  • Dwarf varieties - plump-grained varieties can be sown at higher density.
  • Seedling emergence and establishment are likely to be reduced.
  • Plant tillering is expected to be low because of variety or soil fertility effects.
  • Delays to sowing.
  • Good rains expected during the season.
  • Soil fertility and moisture levels are high.
  • A dry finish is expected.
  • Likely infestation of insects which may cause seedling mortality.
  • A high risk of waterlogging (mid season) - to compensate for a lack of tillering.
  • Moderate to high grass weed densities are likely - increase competitiveness.

Avoid higher plant densities where:

  • Plump grain is required for milling quality.
  • Lodging could be a problem - slightly lower densities can encourage thicker stem growth.
  • Crops are growing on stored soil moisture and may risk deplete most of the moisture before the crop matures.

Seeding rate

Calculate seeding based on seed size, target plant population and calculated germination percent. Work in terms of plants per square metre rather than kilograms per hectare (kg/ha) because grain size and weight varies between crops, varieties and seasons.

To determine the average grain weight, count and weigh 1000 seeds of the graded sample. The seed rate calculation is:

Seed rate (kg/ha) = [Target plant density (plants/m2) * Average grain weight (mg)] / Expected establishment per cent (%)

For example, if the desired plant population is 240 plants/m2, the average grain weight is 40 milligrams (mg) and expected establishment is 80% the calculation is: 240 * 40 / 80 = 120 kg/ha

Table 1 shows examples of seed rates calculated on the basis of target plant population, seed weight and establishment percentage of 80%.
Average seed weight (mg) 160 plants/m2 240 plants/m2 320 plants/m2
33 66 99 132
35 70 105 140
37 74 111 148
39 78 117 156

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