Agronomy BLog - MArch

Crop Condition Overview

Winter cereals that emerged by November are coping well with current conditions. Wheat drilled in December, especially after roots, remains mixed in performance and highly dependent on how each field has handled the rainfall. Many late-planted areas will need assessing for redrilling as land begins to dry.

Redrilling Options and Seed Considerations

The legacy of 2020 has left many growers with spring wheat or Skyfall seed suitable for patching up thin areas. Spring barley remains an option, although it continues to suffer from a significant discount relative to new-crop wheat.
If using home-saved, undressed seed, seed testing for seedling disease is recommended before drilling.

Large patches, headlands, or whole fields may need redrilling. If possible, avoid an airing cultivation pass beforehand. Seedbed conditions can change rapidly, often drying faster than expected, so proceed cautiously to avoid overly dry seedbeds.

Managing Volunteer Cereals

Volunteer oats in wheat and barley remain under control, but barley volunteers in wheat continue to be problematic. Wheat volunteers also continue emerging in winter barley. Unfortunately, no practical in-crop solutions exist for managing wheat volunteers in barley. Growing a vigorous barley crop helps, but ultimately glyphosate at harvest and separate storage may be required if contamination becomes significant.

Assessing barley volunteers in wheat is still difficult while the plants remain yellow from wet conditions. Where pressure was high in autumn, it remains high now, and many fields will need a spring follow-up to reduce volunteer numbers. Success will depend on catching volunteers as growth restarts (as fields drain and temperatures rise) but before they become too large. Control will vary and may even be poor, so prepare for harvest contamination if needed.
Monitor or blackgrass rates of Topik remain the least-worst herbicide options, with decisions influenced by other grassweed pressures present.

Prioritising Nitrogen Applications

Nitrogen applications will be restricted to land that can carry machinery. For many, oilseed rape will receive nitrogen first; if not, winter barley should take priority, followed by wheat. Winter barley needs biomass early to secure yield, as barley sets yield potential sooner than wheat. Retaining tillers and driving early growth is therefore critical.

While backward wheat crops may tempt early prioritisation, the reality is simple: whichever fields travel first will receive nitrogen first. If forward wheat travels earlier than backward wheat, growers should take that opportunity and apply nitrogen—reducing the rate if the crop is already large or has received organic nitrogen.
Delaying nitrogen by three weeks risks hitting a dry March or April, which could limit uptake. Late-planted wheat needs nitrogen but carries lower yield potential, so prioritise the stronger, “banker” wheat crops first.

Opening nitrogen doses have steadily increased in recent years to ensure nitrogen is available while moisture supports uptake. Doses of 70–80 kg/ha from mid-February onwards are now common, adjusted for any organic N already applied.

Oilseed Rape: The February Effect

Canopy Decline and Crop Stress

Crop appearance is shifting as the full, green canopies of early January disappear. Waterlogging, cold weather and frost have accelerated leaf senescence, opening the canopy and pushing crops into a critical period of canopy retreat.

Last February was particularly hard on OSR, especially on smaller crops with higher larval pressure. A crop can only lose so much canopy before larvae activity overwhelms new growth, eventually killing the plant later in spring.
Maintaining top growth is one of the few levers growers can influence: keeping pigeons off, applying nitrogen, and avoiding unnecessary growth regulation all help. Ultimately, the field must drain quickly, and a kinder start to March is desperately needed.

Herbicide Windows and Blackgrass Performance

The window for propyzamide application has now closed. Crawler remains an option until the end of February, but growers must weigh potential crop effects and the implications for following-crop choices if OSR fails.

Blackgrass control appears average due to prolonged wet conditions, but mid-month frosts may improve results where roots have taken up herbicide.

Disease and Weed Management in OSR

Phoma is present on leaves, but decisions on phoma, light leaf spot and PGR fungicides will wait until conditions warm and crop recovery is assessed.

Persistent charlock continues to survive frost. Fox may be required before month-end if charlock threatens crop growth or grain sample quality.

Nitrogen Timing and Frost Considerations

Applying nitrogen to frosted ground is poor practice. However, when land freezes hard enough to prevent tramline damage, many crops will receive a minimum of 60 kg/ha of nitrogen this month. Decisions on higher rates depend on forecast conditions, workload, and how easily the land travels. Fields with easier travel allow more flexibility; tougher land may justify slightly higher early rates to buy time before the next pass.

Where crops retain canopy with low larval pressure, GAI-based canopy models remain valid.

Liquid nitrogen requires caution in frosty conditions. Yellow tramlines from dribble bars are common when applied over frost. These marks usually have minimal impact on yield, but given waterlogging and larval activity, growers should avoid avoidable crop stress wherever possible.

Direct Drilled Cereals

Crop Performance and Soil Conditions

September-drilled crops established directly into standing cover look strong and often walk drier than those planted into conventional seedbeds at the same time. Most crops drilled into dry seedbeds are now draining better and travelling more easily than October/November plantings on wetter soils.

October/November cereals and winter beans drilled into green cover are holding up well where drainage is adequate.

Field Drainage: A Continuing Priority

This season again highlights the value of keeping drainage maps updated as land changes hands. Consistent ditch cleaning and timely moling remain essential when conditions permit.