Establishment Principles – Sow Thistle

Note comments on timing of drilling and associated cultivations, and the benefits of shallow tillage during a long term fallow in severe cases. Avoid disturbing weed seeds when drilling. This is especially important where various weed species co-exist. Note comments on previous cultivations depths above. Employ the following measures to achieve this;

(i) Control speed of drilling to minimise upward soil movement;

(ii) Use disc openers or straight discs ahead of tine openers;

(iii) Use higher rake angle tine openers, preferably narrow knifes, to minimise surface disturbance and returning dormant, buried seeds to the surface;

(iv) Use low disturbance banding openers as opposed to those which can raise and disturb soil, including quick-change narrow knife options where following a cereal with a legume or OSR crop;

(v) Use individually contouring opener units with depth/press wheels to minimise excessive depths worked, and to ensure seed to soil contact is consistent and optimal;

(vi) Where soil lifting by an opener disc occurs, the use of a gauge wheel operating to the lifting side of the disc can help to control soil movement and maintain the surface soil horizons;

(vii) Make the stale seedbed preparation sufficiently consistent to avoid unnecessary tillage when drilling

(viii) Ensure the drill tractor wheel/track slip is minimised by setting tyre pressures and ballast levels optimally. This will limit additional unnecessary surface soil movement when drilling;

NOTE: in high levels of residues avoid hair-pinning (especially by multiple disc drills) by using a leading (deeper) disc, side placement of seed relative to the drill slot, or leading residue manager components to clear loose residues away from the seeding zone. Also, preferably leave a higher stubble height to reduce levels of cut residues on the surface being taken into the seeding zone by the opener action.

NOTE: when establishing with minimal disturbance, offset the low levels of mineralisation by zone placement of N with the seed and where appropriate P plus other needed trace elements. Zone fertiliser placement also reduces fertiliser availability to any germinating weed seeds;

NOTE: drill sufficiently high rates of following crops to compete effectively, Following crops should be sufficiently diverse and competitive for best overall control.