The title is actually the punch line to a very old joke about the “Business Professional” and a Shepherd. More on that later.
Autumn 2023 appears to have resulted in two types of Oil Seed Rape (OSR) crop going into the winter, those that established and those that did not. Why such a black and white result? Of course no one really knows but when asked I would say “seedbed moisture.” Where seed was planted into some moisture and then received additional rainfall within the following 10 days the crop established successfully. What happens thereafter is another matter.
There are a few key aspects to successful OSR establishment, machinery used, seed rate, drilling date and soil nutrient status.
The construction of the oilseed rape canopy and development of green area index is greatly influenced by nutrition, starting with ensuring the availability of the key nutrients from the soil. However without sufficient water nutrient uptake is restricted.
Cabbage stem flea beetle is correctly blamed for crop loss however it is often 50:50 as to whether in fact slugs are the culprits and beetle are the scapegoats!
Because of the flea beetle issue (real or perceived) many sow their OSR crop earlier than is prudent. This then predisposes their farm business to even greater (long term) financial risk from losses caused by diseases such as Club Root or crop yield penalties as a result of other diseases infections.
A recently published article took a positive spin on the drilling date matter by stating “Grazing forward crops with sheep is part of the extra flexibility Mr Grower is building into his OSR growing strategy to cope with the increasing and variable environmental uncertainties.” This was followed with the statement “During harvest of the preceding cereal crop a long stubble is left onto which sewage sludge is spread ahead of rape drilling. This seems useful in preventing serious beetle damage.”
It has been my observation that the more you run over a stubble, baling or muck spreading, the flatter it becomes. Consequently I doubt very much the value of “long stubble” in hiding the newly emerging crop, better chop and spread the straw and chaff?
In 2011, average farm yield was 0.8 t/ha above the long-term average of 3.1 t/ha. AHDB reported that UK OSR production is estimated to be down for harvest 2023, despite an increase in area being grown. Average national yields are now considered poor being as low as 2.6 t /ha in the Eastern region of England.
Therefore is the current advice on growing OSR, its practical management or the weather the cause of this yield decline?
If you would like to hear the joke, why not message me!