At the Sigma Team's first meeting on Wednesday the over-riding point was that oilseed rape's potential yield of 6t/ha (48.5cwt/acre) is nowhere near being met by UK growers. The national average is only 3.2t/ha (26cwt/acre). Why is that? What are we doing wrong?

Andrew Blake - Senior Arable Writer, FWG

I think there are 2 main reasons:

The first is technical, and that is that we have only relatively recently come to understand yield formation in oilseed rape, seed number per unit area is of paramount importance, you would expect that this would be achieved by having large numbers of pods, but in fact it is best achieved from relatively few pods (c. 7,000 per m2), so what we thought was a good looking crop with high pod numbers has actually been restricting yield potential.

The second is structural, since the early 1990's when oilseeds moved from tonnage support to area support, the importance of yield to the returns from the crop has been reduced.  We have therefore been growing the crop with a mindset to controlling input costs which has limited output.  With increased seed value a much lower yield response to any input is needed to give a return on investment, we therefore need to revaluate how we grow the crop to maximise output.

Lack of attention to detail. This is aided by bad articles like this one http://www.fwi.co.uk/Articles/2008/07/17/111219/oilseed-rape-seeding-advice.html

No self respecting German grower would a) use FSS, b) not grow a hybrid, or c)be so lazy with pest control to let slugs etc decimate the crop. Other nations also realise that rape is the most profitable crop to grow and spend time getting it right. Forget preening your wheat - spend more time on your rape as it is the big payer for the next few years.

Low seed rates of vigorous hybrid crops, established in a way that lets root growth be unhindered, and nurished to ensure no element is lacking will always perform better than the average. This year we will be drilling our main regime rape at under 30 seeds a meter. A trial plot will be drilled with a modified beet drill to drill 20 and apply N&P in a band. I will be upset if we dont do better than last years hybrids at 4.75t/ha.

If you just slap on 5kg out of your shed, sadly you will be disapointed. You cannot grow a high yielding rape crop by skimping, although I would say you can and should slash N rates using more targeted N, and slap on fungicide like there was no tomorrow.  

TC

So why is it a "bad" article? Surely it's sensible advice, interestingly from a breeder acknowledging that some home-saving is inevitable (for whatever reasons), stressing the importance of getting seed tested professionally? At least that's a step toward the "attention to detail" many growers (like yourself  now realise is required to get the best from this crop.

Incidentally, as a farm manager in the 1970s I was, I believe, among the first to have a stab at growing it. Faced with sowing its tiny seeds via my ancient MF29 combination drill, from which the seeds would have disappeared like water, I decided instead to mix it with 1cwt/acre of Nitram and to spin it onto ploughed and cultivated land with a Vicon spreader, rolling it in. Needless to say the crop grew like mad so that by the time we shot over it in November it was knee high, and my shooting colleagues were praising me for clearly knowing how to grow this novelty. Inevitably, with hindsight, it went as flat as the proverbial Shrove Tuesday offering and was a nightmare to combine, yielding as far as I can recall about 8cwt/acre.

The next year I followed the same establishment route but cut the seeding N to 0.5cwt/acre. The crop took well, but being on an exposed bank and plagued by pigeons it had, apparently, all gone by the end of January and I considered ploughing it up. But closer inspection revealed that most of the growing points were intact. So I left it. It recovered and gave nearly 1t/acre which was pretty good in those days.

 Re "attention to detail" my neighbour, who always considered himself one step ahead technically, scoffed at my initial sowing attempts, pointing out that a special "fine seed" kit was available for the Vicon which avoided the need to bulk up with fertiliser. It consisted of some plates which were simply laid to block off all but one of the holes in the bottom of the hopper. He duly bought these and his operator set off, only to find that before the headland had even been finished the seed for a 30 acre field was all gone. It's weight was apparently insufficient to keep the plates in position on the bumpy land!