March Cropnotes 2010.
I have recorded 109 mm (4.4”) in February, so wetter than average. Soils are both cold and wet at the time of writing and work is starting to pile up in front of us all. Very little spraying has been done in the last three months and time is now fast running out in oilseed rape crops to get residual blackgrass control applied.
Not surprisingly snow mould has been found in some forward crops of wheat and barley. This is caused by
Fusarium nivale the same fungus that can cause stem lesions and also ear blights. Snow mould is normally seen as small patches of plants where leaves and whole plants are killed giving a bleached appearance. No action other than early nitrogen to help the crop compensate is suggested.
Frost lift has also proved a problem particularly for later sown and grazed crops on lighter land. Both the above reduce the rooting of crops and this with the frost movement of the soil has severed the roots of vulnerable crops. Early nitrogen and rolling will help weakened plants make progress this month.
Manganese deficiency is proving more widespread this season and many crops will need treatment as soon as conditions allow.
Dow has just announced they have received approval for their GF 2010 coded blackgrass herbicide. This is a co-form of their Pyroxsulam and pendimethalin, and will really compete with Atlantis in the Autumn blackgrass control slot, rather than the spring. The PDM is unlikely to add much control to established blackgrass plants. Unfortunately Pyroxsulam sits in the same resistance grouping as Atlantis and is not going to help us manage the increasing Atlantis resistance problem that is building up.
Residual soil nitrogen tests indicate similar nitrogen levels as last year, so there are few fields that should be omitted from early nitrogen applications when the weather finally warms up a bit and the soils dry up.
Where possible outstanding Atlantis and Biopower applications should go on without tank mix partners. Do not rush out on the first mild day as blackgrass needs to have started growth before Atlantis is applied. Do take care to achieve good coverage by using flat fan or hawk nozzles. You need to be achieving a medium to fine spray and many air inclusion nozzles are too coarse.
Oilseed Rape: Forward crops are just starting stem extension and so will benefit from a nitrogen application now. Crops should receive the bulk of their nitrogen and sulphur top dressing this month. There is evidence to support the practice of keeping some back until April to keep crops greener longer. This is not appropriate where liquid nitrogen is being used as some leaf scorch is inevitable and application is best kept early.
This month will provide the last chance to clear up any remaining weed problems. Galera will control sow thistles and cleavers, but has to be applied before the green buds are above the leaves.
Sugar Beet. Mice are likely to be the first pest encountered this season and they can cause damage very soon after drilling. Ensure seed are covered and put out bait points after drilling if damage has been seen in the past.
Depth of drilling early in the season should be reasonably shallow as moisture will not be limiting and it will help ensure a more rapid emergence. The soil is considerably warmer at 20mm than it is at 40mm depth. Seedlings emerging from shallow depths have larger cotyledons, and this benefit is continued throughout the life of the plant; 25 to 30mm should be enough.
Apply the first nitrogen at drilling and aim to top up as soon as emergence is complete.
Where applying Vydate granules ensure that any spills are removed or covered up and ensure the seed and granules are covered in the furrow
Peas & Beans: Drillings of peas & beans will be under way shortly. Establishment of these crops is the most critical determinant of final yield. Soil conditions, drilling depth and seed rates are the principle variables for any crop at drilling time.
I would just repeat the need to achieve a seedbed with minimum possible work in order to minimise the creation of smeared layers at the base of cultivation operations.
Ensure the pre-emergence herbicides are on the farm before drilling commences, as they remain the only robust weed control option open to us and we don’t want to miss any application opportunities to get them on.
Cross Compliance Notes
Hedge cutting closed season for cross compliance runs from 1st March until 31st July.
ELS hedge cutting options EB1 & 2 also 1st March until 31st July
Enhanced hedgerow management EB 3 cannot be cut between 28th Feb and 1st Sept.
Mike Thompson
Tel: 01760 755663
Mob: 07831 468442
Email: mgthompson@nwagronomy.co.uk