Field Selection and Crop Rotation

Field Selection

Oat yield the best in the black and grey wooded soil zones due to the higher moisture content of the soil. Select fields with good drainage, sandy loam to heavy clay soil textures. Oat is well adapted to no-till fields where retention of non-cereal stubble and snow and improved soil water infiltration provide increased soil moisture.

Avoid fields with:

  • Cereal stubble
  • Heavy wild oat populations
  • Herbicide residues that may affect oat

Crop Rotation

There is considerable evidence that diversification of crops leads to higher yields, reduces disease pressure and improves nutrient utilization. Repeated planting of oat in the same field will lead to a build-up of diseases and weeds, both are difficult to control in oat.

Avoid fields with a history of heavy wild oat pressure. Wild oat is a significant source of downgrading. Avoid fields with a history of residual herbicides that may affect the growth of oat. Some herbicide affect oat crops two years after application (Table 3.1).

Additionally, many wild oat herbicides affect oat in the year of application and should be considered if oat is replanted after a crop seeding failure.

Table 3.1. Herbicides with residual effects on oat two years after application (2020 Saskatchewan Guide to Crop Protection). Avoid fields where these products have been applied.

  • Avadex
  • Command
  • Edge
  • Fortress MicroActive
  • Imazamethabenz*
  • Metribuzin
  • Metsulfuron *, **
  • Pulsar
  • Trifuluralin

*Brown and Dark Brown soils
** Soil pH 7 to 7.9

Avoid fields planted in cereal crops the previous year to reduce disease pressure, reduce volunteer cereals that cannot be controlled in oat crops and optimize yields.

Back to back rotation with other cereal grains increases the risk of plant disease and weed pressure. As well, an oat sample may be downgraded because volunteer cereal grain that cannot be controlled in oat crops.

More desirable rotational crops include: canola, hayfields, peas, lentils, soybeans, and/or other legumes. Pulses give the oat crop a strong yield potential by providing nutrients and reducing disease risk. Because of the wild oat control achieved in canola crops, they may be preferable to pulses as a rotational crop, if wild oat are present. Corn falls between the desirable rotational crops listed above and cereal grains. Corn can increase the risk of some plant diseases and crop residues tie up nitrogen early in the season.

Cereal crops benefit from being in rotation with other cereals, compared to back-to-back rotations (Table 3.2).

Table 3.2 Relative yield of major crops sown on selected stubble types in rotation in Manitoba 1994-1998 (from Manitoba Crop Insurance Corporation)
Wheat 100 109 110 118 114 120
Barley 115 100 110 119 122 122
Oat 114 103 100 124 123 115
Brassica napus canola 114 115 117 100 118 128
Flax 148 148 146 133 100 *
* insufficient data

Planting crops in a yearly rotation, such as oat/soybeans/wheat/corn, helps to prevent the buildup of many destructive organisms. Keeping disease organisms and insects at low levels reduce the risk of unexpected yield loss and the need for pesticide applications.