Well sown is well grown
Winter oilseed rape can only reach its potential if the crop is well established. Growers should aim to establish the crop with a strong root system that will increase its competitiveness, allow it to access nutrients and moisture at critical development stages and therefore improve its overall performance, according to BASF and independent experts.
“Recent research, conducted by independent company K-Active on behalf of BASF, has shown some encouraging trends in attitudes to rape establishment. The survey showed that fewer farmers were using a plough-based establishment method for their winter oilseed rape, just 32% last autumn compared to 47% the previous autumn. A further 30% of farmers said that they had used a tine-based minimal cultivation method as their main technique in the last two years and another 21% had used a disc-based establishment method. As before, only a small number broadcasted their crop (5%), autocasted (3%) or direct drilled (7%),” explains Diane Heath, BASF Oilseed Rape Product Manager.
“A quarter of farmers said that they had changed their method of establishment in the last two years. But what was encouraging was that 47% of them had altered this in order to improve the seedbed quality and improve establishment. Admittedly 42% had still changed for cost reasons, but it indicates that farmers are taking rape more seriously and taking positive action to ensure that the crop gets off to a better start. Good establishment of rape is the key to setting up yield potential. If this is not right, then you are always playing catch up,” says Diane.
“In my experience a well sown crop is a well grown one and it is reassuring to see that growers are considering the basics when it comes to oilseed rape establishment,” says Steve Townsend, a consultant specialising in crop establishment techniques.
According to Steve, crop establishment however should be all about root establishment. “We are always talking about what the crop should look like above ground at particular times of the year, but we should be just as interested, if not more so, in what it looks like below ground. I would like to see twice as much root mass below ground as foliar mass above ground. Crops with better, more efficient root systems can withstand pigeon damage, weather conditions and water logging as well as laying down a good foundation for high yields.”
Steve explains that there are several basic issues to consider when establishing a rape crop. “The first is “seed to soil” contact which is fundamental to rapid and even crop establishment, whatever method is adopted. Oilseed rape is a very small seed and it is not easy to achieve this. Any establishment method must aim to produce a fine, firm consolidated seed bed so that the seed can be placed in the tilth, covered adequately and have sufficient contact with the soil to germinate well.”
“Sufficient moisture is also vital for good establishment, particularly at a time of year when soil moisture is often critical. In August and September the top two inches of soil can dry out rapidly. Growers should use an establishment method that draws the moisture through the seed germination zone from depth and keeps the moisture constant, so that seed is able to germinate, even if this means drilling slightly deeper. There is always a risk of seedbeds drying out without proper consolidation. Once germinated the young plant needs to grow upwards and downwards unheeded. Consolidation is critical for successful establishment of both shoot and root systems. In plough-based systems, consolidation should be done at depth to improve stability and structure of the soil. Ploughing can bring up lumps that are difficult to breakdown and such seedbeds are in danger of drying out. Lumpy seedbeds encourage slugs and make the use of pre-emergence residual herbicides more variable. Ploughing is also time consuming when time is at a premium,” advises Steve.
Straw residues can be a problem in tight wheat/rape rotations. “It is not just the mechanical problems of straw but it can also tie up nutrients such as nitrogen and phosphate. Rape can tolerate some crop residues, but care should be taken to place seed under any straw,” concludes Mr. Townsend.
