Crop Watch: Cautious start to spring drilling on light land
Most oilseed rape is at the green bud stage and in wheat, septoria is being found on lower leaves as a pool of infection. If we see warm, wet weather in the coming weeks, the disease pressure will rise significantly.
Some spring drilling has started on the drier land in the east, but in the main, it’s still too wet to travel.
Plenty of patience is going to be needed in the coming weeks to achieve reasonable seed-beds, as forcing them in will reduce yield potential before they have even emerged.
West: Neil Potts
Matford Arable (Devon)
Since last contributing, very little has changed in the deep South West. We have suffered storms Ciara and Dennis and further subsequent wet weather which has left the ground as wet as it has been all winter.
See also: How to manage ramularia without chlorothalonil
The past week has continued to be wet, but possibly not as much as it has been, and at the time of writing the forecast for the coming week looks more promising.
Some growers have managed to get nitrogen on to some crops, but most are awaiting their first application of the season.
There is plenty of catching up to do as well, in terms of herbicides and barley yellow dwarf virus control, but this cannot really be done until crops are recovered or recovering from the winter’s water stress.
Priority, therefore, needs to be given to getting nitrogen underneath these crops without any further delay. My advice to growers is to go so long as you are not going to get stuck in the field doing it. Making a mess of the tramlines is a price worth paying.
Many oilseed rape crops are at the green bud stage and have yet to receive any input whatsoever, since they received their pre-emergence herbicide back in August or September.
These crops are now desperate for their nitrogen and should also receive a fungicide as a matter of urgency.
With poor rooting and wet soils, they will almost certainly benefit from a trace element cocktail designed to meet the needs of a brassica.
Wheat and barley crops are quite variable, with some crops looking pretty much as you might expect at this time of year, while others are looking underdeveloped and waterlogged.
Most wheat crops have significant levels of septoria on the lower leaves so there is a pool of infection within most crops.
For this reason, a T0 is going to be necessary and with that time rapidly approaching it is high time the weather started to play its part and dried up.
Early plant growth regulators are likely to be a useful tool to encourage rooting and tiller survival, and at the same time adding in minor nutrients to relieve the stress on the plant of having a root system that is not big enough yet to support rapid spring growth.
With no spring planting having yet taken place, there is going to be a lot of demands put on labour and machinery on farm in the next few weeks.
My advice would be to prioritise the care of crops that are in the ground and then concentrate on spring plantings, but with the proviso that patience is exercised, as planting spring crops into poor, wet seed-beds is a recipe for poor performance.
Hopefully, by the time of my next contribution we will have seen a welcome turnaround in the weather.
North: David Martindale
Arable Alliance (Yorkshire)
Land has finally dried up enough to allow most autumn-sown crops to receive their first dose of nitrogen fertiliser.
Slurry is also being applied to crops, which has provided some welcome relief as some stores were getting close to capacity.
There has been sufficient rainfall since application to wash the fertiliser and slurry into the soil profile, and crops have been quick to respond.
Some crops of spring barley and beans have also been drilled on the more free-draining soil types, which has added to the feelgood factor.
For some though there has been plenty of frustration on heavier soils as some land has been close to drilling, only for more rain showers to cause further delays.
There still remains a large area of planned spring crops to sow.
Winter wheat crops sown in September look particularly well. Those sown during October and November are improving although for many a mediocre yield will be regarded as quite an achievement this year.
Septoria tritici levels are high on susceptible varieties, even those that were sown relatively late. The excessive winter rainfall has allowed plenty of infection opportunities to provide a potentially high background of disease inoculum.
The weather over the next two months will drive septoria pressure, with a warm wet spring favourable for its development and spread.
Yellow rust is also starting to become more obvious in coastal areas. With so few wheat varieties resistant to this disease it will need monitoring prior to any T0 fungicides being applied.
Yellow bud stage
The earliest oilseed rape crops are now at yellow bud with the first flowers beginning to open. Most crops, however, are at the green bud stage.
High winds and regular rainfall during the first half of March has made it difficult to apply herbicides, such as clopyralid, for the control of mayweeds and thistles.
With some crops racing through their growth stages, it means the cut off timing for these herbicides has already passed.
Light leaf spot levels remain low mainly due to a combination of varieties with better genetic resistance and many planned autumn fungicides only recently being applied.
Despite the obvious presence of cabbage stem flea beetle larvae in plants, most crops appear to be growing away without too much hindrance.
The decision to apply any growth regulators to oilseed rape crops during stem extension has been limited to all but a few crops this season.
Deciding on when to start drilling is proving much more of a challenge this spring. Land cultivated in the autumn which did not then get sown has gone quite solid due to the high rainfall.
As the seed zone layer is drying, the soil below still remains very wet.
On heavier soils, this is providing the dilemma of deciding whether to drill direct into the soil in its current state or wait and then rip the soil open to let it dry out and start again.
For those understandably anxious about drilling this spring the main advice is to be patient.
There is still time to establish crops with a good yield potential and forcing seed-beds by sowing too early will reduce this potential before the crop has even had chance to emerge.
South: Tod Hunnisett
AICC (Sussex)
“What are we going to do with these late drilled and water-stressed crops” asked the farmer in January. “Well,” said the agronomist, “for a start we’ll get a bit of nitrogen on as soon as we can travel in February”.
So here we are, way past the middle of March, and all the ground that needs the help most is still too wet to travel (at the time of writing).
However, the forecast is showing signs of being not quite so dire as it has been, so by the time this gets to press the situation may have changed somewhat.
And when it does change, things will get manic. There will be spreading, spraying and drilling all trying to take place at once.
To that end, where I have growers who are essentially one-man-bands, I am encouraging the use of contractors to do the spraying if possible to avoid clashes of workload.
Where the ground is drying out, even on undisturbed soils, weeds are beginning to germinate so a good eye is needed to spot any emerging grassweeds.
For spring cereals I’m not too worried about seedling broad-leaved weeds, but blackgrass and ryegrass are worth doing something about.
Some of the OSR crops that I thought looked OK are now not looking too special. Last spring, even with significant larval numbers, crops with a strong rooting system and canopy framework managed to compensate and still yielded surprisingly well.
This year, we don’t have the roots and crops are going backwards. On some of these crops all they’re getting for the time being is a bit of N+S and we’ll make a decision later as to whether they’re worth spending much more money on.
What we need is a long, dry warm (not hot) flowering period.
East: Ben Pledger
Farmacy (Bedfordshire/Hertfordshire)
Spring crop drilling is slowly getting under way on lighter land with peas going into well-structured soils.
Pendimethalin and clomazone will be used as a pre-emergence herbicide here.
With the recent weather and soil conditions still sitting very fresh in our minds, it is important to be patient when drilling spring crops.
The temptation to grab the next dry spell and rush out with the drill may be strong, but growers will need to make sure seed-beds are in good order before drilling.
Walk fields to check for weed pressure, in places there are emerging populations of small weeds which cannot be seen from the gateway which will benefit from an application of glyphosate prior to moving any soil.
Previously worked soils may have slumped, and require a cultivation to open the soil up and allow it to dry.
Select the correct machine for this, and pay attention to working depth to minimise further soil damage by smearing from the implement.
Pay attention to tyre pressures to allow yourself to tread as lightly as possible.
Second N dose
Winter crops are now taking up applied nitrogen fertilisers, with some showing signs of needing a second application where growers were able to get on with a light dose in January or early February.
Some crops of oilseed rape have begun stem extension, and really are motoring upward, with noticeable increases in height visible between field visits.
This has left virtually no time for application of clopyralid-based herbicides, again showing that the choice of aminopyralid + propyzamide as an autumn herbicide was the correct call.
First spring fungicides for light leaf spot will be based on prothioconazole or metconazole, depending on the amount of growth regulation needed to reduce apical dominance. If further growth regulation is needed, trinexapac-ethyl will be employed.