Six agronomic tips for growers in the Midlands this August

Crop Progress

Harvest made good progress in July with, as this is written, winter barley finished and growers just making a start on oilseed rape. Yields of those crops seem to have been reasonable, but there is concern about how fast some of the wheats have senesced, particularly on light land.

Ben’s agronomy tips for August

1. Follow these three key things for OSR establishment

With an early barley harvest, growers will likely have itchy feet to start drilling some oilseed rape, but there are three key things to success:

• Choosing a hybrid variety with good autumn and spring vigour
• Drilling into moisture
• Getting nutrition correct at the time of drilling

All those three things complement each other to some degree – for example, if it is dry the nutrition won’t be taken up, while having all three together will maximise germination and fast establishment, which is important for cabbage stem flea beetle avoidance.

As this is written in mid-July it is difficult to know if we will have had rain to help germination, but I would be waiting to plant into moisture.

Ideally I think you need to have a plant around the 2-3 true leaf stage by 25 August to withstand flea beetle grazing. It won’t necessarily mitigate against larvae, but you should have a better developed plant in the spring to help get away from that.

That probably means drilling by the end of the first week of August, but if you’re going to drill and the seed will either not germinate or germinate and be slow then I probably wouldn’t bother as it will likely get hammered by flea beetle grazing.

There have been late drilled August and even September drilled crops, which are perhaps less likely to suffer from CSFB larvae, that have shown you can still get a good crop. So I would rather take the risk and wait for moisture than force it into a dry seedbed.

For varieties, I would be looking at some of the newer DK hybrids, such as DK Exstar or DK Exsteel, which offer good vigour in the spring as well as the autumn.

If dry conditions do push us into late August or even September drilling, then selecting a variety such as DK Exposé will give growers the confidence that the variety is suited to later drilling.

Some growers might consider Clearfield crops for three reasons:

• Looking for a simple system
• If you have problems with charlock or runch
• You’ve had problems with erucic acid levels on that land, or previously grown HEAR varieties of oilseed rape

A good proportion of your oilseed rape crop could be volunteers, and if you have grown HEAR in the past I would be very cautious about growing a non-Clearfield variety, while Clearfield will give the best control of weeds like charlock.

Don’t forget all Dekalb varieties now qualify for the Dekalb Establishment Scheme to share some of the risk of crop failure. To be eligible, seed needs to be bought from a participating supplier, the crop sown before 20 September and registered on the scheme by 30 September. Claims have to be made by the 31 October for a credit of £100/bag for failures in blocks of 6ha or more.

2. Work (most) land as soon as possible after harvest

Work land as soon as possible after harvest where there are problematic grass weed populations, but ensure those cultivations are kept to a minimum depth of no more than 5cm. Tickling the surface using some shallow discs or a stubble rake should be enough to get a chit of grass weeds.

If it works up a little cloddy because of dry conditions, then consider rolling it. A weed seed, just like a crop, wants seed to soil contact and moisture to grow. Getting land worked up as soon as possible will be beneficial in giving the longest germination period to get a good flush of grass weeds.

These should be sprayed off at an appropriate time with a good quality glyphosate brand, such as Roundup Powermax. Match the dose to the target – a flush of grass weeds will require 720-1040 g a.i./h, while bigger weeds or certain broadleaf weeds will need at least 1040 g a.i./ha.

Whether you will need one or two applications will depend on grass weed pressure. If grass weeds aren’t a massive concern, work it once, consolidate, and then spray off as close to drilling as possible.

If it is a much higher population of black-grass or Italian ryegrass, then I would take a managed approach of working it, spraying it, potentially working again before spraying again as close to drilling as possible.

3. Establish catch or overwintered cover crops in August

Similarly to oilseed rape, any catch or overwintered cover crops should be established as soon as possible. The earlier they are in, the more benefit there is likely to be, although that does depend on moisture availability.

I would try and keep the cost of establishment down by either direct drilling or spreading the seed and working in.

Where grass weeds are a concern, I’d halve the seed rate of an overwintered cover crop and use species that are more sensitive to frost. That should leave an open canopy to allow establishment of the grass weeds, and when you come to spray off in the New Year, a proportion of the canopy will have died back so you won’t need to be as worried as penetrating a thick canopy to reach those grass weeds.

4. Focus on tuber blight

As we move into the latter part of blight fungicide programmes, it is important to consider protection of tuber blight. Infinito (propamocarb + fluopicolide) is a fungicide with two unique modes of action which offers good control of tuber blight. Infinito should be positioned in the latter half of the fungicide programme.

5. Look out for new approval for sugar beet fungicide

Sugar beet crops generally looked well in mid-July, although there was some wilting in the dry conditions on lighter land. Disease levels are low, but first fungicide applications were imminent as soon as disease symptoms started to appear.

One piece of good news is that we are now hopeful of Caligula (prothioconazole + fluopyram) receiving approval in time for this season. It will fit as a third application for prolonging Cercospora and rust control in later harvested crops. Keep an eye on the Bayer website for confirmation that approval has been received.

6. Use FieldView data to help with decision making

Our digital platform, FieldView is very useful at harvest to keep track on field performance and combining progress in real-time. This information can be used to help make immediate decisions on variety choice for next season, assess results of any on-farm trials you may have carried out, or pinpoint areas for changes in management approach.

It can also, along with soil data, help with creating plans for variable rate seeding next season.

If your combine doesn’t have yield mapping in-built, FieldView also now as a retrofit yield kit available for any make, model or age of combine that can unlock real-time yield and moisture content data.