Agronomics

Soil management and crop production.

Agronomic Information 

Crop Rotation

Flax is a broadleaved crop and does best when grown after specific crops due to reduction in weed, disease, insect pressures and accessing soil moisture from specific soil depths.  As well, research has shown flax performs poorly specifically after canola and/or mustard. The poorer performance of flax on canola stubble is  attributed to mycorrhizae fungi which do not associate as strongly with canola and decreasing during the growing season producing canola.  When flax is grown on canola stubble the following year, the mycorrhizae populations are lower, which leads to poorer early season nutrient uptake, especially phosphorus, a relatively immobile nutrient in the soil and is crucial to early flax development.

Flax does well after cereals or corn. It also does well after legume crops and alfalfa, but Rhizoctonia disease may be a problem. Flax does not do well after potatoes due to loose seedbed and potentially Rhizoctonia.

Research at the Melfort Research Farm has demonstrated that flax will perform well on spring wheat and field pea stubble relative to canola stubble (see Table 1).

Table 1: Effects of Preceding Crop on Flax Yield at Melfort, SK (1994-97)

Preceding Crop Yield Index (% of spring wheat)
Spring wheat 100
Canola 88
Field pea 103
From: A.M.Johnnston

Crop rotation of at least three years between flax crops is recommended for controlling various soil-borne or stubble-borne diseases of flax, such as pasmo.

Information from Manitoba Agricultural Services Corporation (MASC) based on “Harvested Acreage Reports” has shown that crops like spring wheat will yield well on flax stubble (see Table 2).

Table 2: Yield Response (% 1998-2007 average) of Manitoba Crops Sown of Previous Crop Stubble

Crop Planted
Previous Crop Spring Wheat Barley Oat Canola Flax Field Pea
Spring Wheat 90 101 101 103 102 102
Barley 92 88 91 100 99 97
Oat 93 91 85 95 97 93
Canola 103 105 104 83 90 93
Flax 98 104 102 98 81 79
Field Pea 100 104 105 101 111
Source: MASC Harvested Acreage
Reports 1998-2007.

Flax is adapted and fits into rotation in all the soil zones across Manitoba. With adequate weed control, the major factor influencing the yield of flax in a rotation is the availability of moisture. Because of its shallow rooting character, flax extracts 95% or more of its water from the top 71 cm (28 in.) of soil.

Flax grows well on most prairie soils, except on poorly drained soils and sandy soils because of poor water retention. Medium to heavy-textured soils are preferable. These soils may crust in spring, which can inhibit flax emergence.