Winter Oilseed Rape (WOSR) Experiences on the Dunne Farm East Cork

I farm in East Cork with my brother Alan, and since moving away from a spring barley monoculture in 2007, we have become firm believers in rotation. This rotation includes Winter Oilseed Rape, Beans, Winter Wheat, Winter Barley and Spring Barley.
The reasons we use rotation can be summarised as follows:

• Break crops in the rotation lead to higher cereal yields.
• Rotation spreads the workload and weather-related risk.
• Break Crops provide an opportunity to control grass weeds.
• Rotation improves soil health through N fixation (legumes) and the incorporation of crop haulm.

Winter Oilseed Rape has had a place in our rotation ever since we first grew it in 2007. We immediately saw a lift in our spring barley yields and now have moved to grow more winter wheat to capture the yield benefit of the preceding break crop fully.

We try to grow WOSR every 6th year, using cereals and beans in the intervening years. I am a firm believer in the phrase,

“The less often you grow any crop, the better it will perform”.

Over these 17 years, we have learnt a lot about growing the WOSR crop and have seen great improvements in the genetics available in the varieties; more on this later.

The 2023 Crop

This year’s crop (LG Auckland) was sown on Sept 1st, following spring barley. The land in question had grown an excellent crop of spring barley in 2022 (4tn/ac), and it would have been tempting to go with spring barley again for 2023, but I wanted to stick with the planned rotation and something in my gut reminded me that it might be good to not be completely exposed to August as our sole harvest month in 2023. For the same reason, we planted a couple of fields of Winter Barley (not a crop that we commonly grow); little did I know how this would transpire…..

Establishment

The LG Auckland was planted using strip tillage (Sumo DTS planter); the stubble had received a run of a disc harrow prior to planting to increase the level of tilth on the surface and to lessen any slug pressure. I like strip tillage for WOSR as the leading shank of the planter creates a compaction-free channel under the seedling which allows the root to grow vertically unimpeded by compaction. In addition, the strip tillage loses less soil moisture which was important in the summer of 2022.

The target plant population was 40 plants/m2. 52 seeds/m2 were planted, assuming an establishment rate of approx. 75%. In a plough-based system, the establishment rate would be expected to be higher through better seed placement when compared to strip tillage.
The crop’s P&K requirements, along with a small amount of N was applied at planting.

The crop was established well, and weed control consisted of an early application of a graminicide followed by a post-emergence application of Legion.
No fungicide was applied in the autumn as the land became untrafficable.

The Growing Season

Thankfully, disease levels (Light Leaf Spot and Phoma) appeared to be negligible in the spring (LG Auckland has very good disease ratings). Our climate can lend itself to high levels of Light Leaf Spot, which can be very difficult to control chemically if it becomes established. A fungicide (0.6L/Ha Proline) was applied at stem extension along with Epso Bortop (Mg, S & Boron). A second fungicide (0.8L/Ha Prosaro) was applied at mid-flowering with a second application of Epso Bortop. Caryx was also applied at early stem extension as a PGR.

The Nitrogen input for the crop was curtailed as it had, for the most part, developed a high Green Area Index by spring. However, I had another reason to cut back on N: Parts of the field had sat very wet over winter and into the spring, so much so that I felt that the rooting in these areas was heavily compromised. With concerns over the rooting in these areas and consequent lodging in my mind, I applied a total of 120 units/ac (150kg/Ha) of N to the crop; 30 units of this were left until just before the crop was too tall to spread fertiliser (late N can benefit the yield of WOSR by increasing seed size).

The crop of LG Auckland was harvested on the 25th of July. The yield of the crop came in at 2.1tn/ac (5.2tn/Ha) in a moisture range of 9-10% and it was sold to Dairygold. I was delighted with the yield considering how waterlogged some of the fields had been over winter and also considering the relatively low nitrogen input. A crop of KWS Dawsum winter wheat is the next crop planned for this land.

Improved Genetics

Since we first started growing WOSR, we have seen great advances in the yield potential and specific traits available in the modern WOSR varieties. Pod Shatter is something that, for us as growers, is non-negotiable; I will not grow a variety without it, and Goldcrop will only sell varieties that have this trait. (varieties with Pod Shatter Resistance include DK Expansion, DK Expose, LG Ambassador, LG Auckland and LG Armada).

Because of our mild climate, TuYV (Turnip Yellows Virus) is a common disease of WOSR in Ireland, varieties are available from Goldcrop with TuYV resistance, and this trait brings an extra level of consistent performance to WOSR in Ireland (varieties with TuYV resistance include LG Auckland, LG Ambassador, LG Armada and DK Expose).

 

 

 

Article by John Dunne, Goldcrop Ltd.