Tillage Newsletter - April 2024

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In this month's edition:

• Spring crops
  The poor weather in March delayed field work in most of the country. Prioritise the sowing of beans, wheat and oats, and aim to have them sown as early as possible in April.
  • Fertiliser for spring cereals:
    • select a suitable fertiliser to deliver sufficient seedbed nitrogen (N) for early establishment and sufficient phosphorus (P) and potassium (K) to match crop offtakes;
    • P trials in spring barley indicate the benefits of placing P fertiliser on P index 1 soils in terms of rapid root and tiller development;
    • recent work in spring barley has also shown that higher rates of K (80-100kg/ha) can help to reduce brackling;
    • reduce the chemical fertiliser rates where organic manures have been applied;
    • apply remaining N at mid tillering – for malting, apply all the top dressing as soon as tramlines are visible; and,
    • watch crops for signs of manganese deficiency and treat as soon as symptoms appear.
  • Aphids
    The few early March-sown crops will not need an aphicide; however, crops sown in late March, which emerge in April, and April-drilled crops, are at higher risk, especially in areas with a history of barley yellow dwarf virus (BYDV) or near coasts.
  • Weed control:
    • early application (4-5 leaf stage of crop) using reduced rates will save money;
    • best results will be achieved when the weed and crop are growing actively;
    • weather before spraying will influence how well the weed takes up the chemical – ideally wait for two to three warm days before spraying; and,
    • options include: sulfonylurea, e.g., Ally Max or Cameo Max, etc., half to two-thirds rate plus fluroxypyr 0.75L/ha or Galaxy 0.75L/ha or Pixxaro 0.375L/ha, or Zypar 0.75-1.0L/ha, depending on the weed spectrum of the field.
  • Wild oats
    Pinoxaden (Axial Pro 0.6L/ha) or fenoxaprop (Foxtrot) can be applied with certain herbicides on different crops, so check each label for restrictions. Where wild oat herbicides are applied separately, obey intervals to maximise the efficacy.
• Winter wheat
  • Nitrogen
    Complete the main N application now (before GS32). This generally equates to half the total amount of N for the crop in a three-split programme and is typically in the range of 100-125kg/ha (80-100 units/ac). Apply the final split at flag leaf.
  • Weed control
    There are still some crops that haven’t received a herbicide, especially if sown late. Where there are grass weeds (e.g., bromes) Pacifica Plus or Broadway Star are options.
  • PGR
    Apply a plant growth regulator (PGR) by first node (GS31). Options include CCC 75% 2.0L/ha plus or minus an adjuvant – K2 1.8L/ha, CCC 1.0L/ha plus Moddus 0.2L/ha or Meddax Max 0.2kg/ha. Temperatures need to be above 8ºC for best effect.
  • Fungicide
    • Leaf 4 spray (T0): long-term Teagasc trials have shown little or no yield response to the T0, so this is definitely an area where savings can be achieved, especially in first wheats that were late sown.
    • Leaf 3 spray (T1): Apply when the third last leaf is fully emerged. Growth stage may not be an accurate indicator of the actual leaves present in the crop, so dissecting plants and identifying the correct leaf to apply the first fungicide is critical for optimum septoria control.
• Winter barley
  April is key for growth in winter barley and all the vital jobs need to be done, i.e., complete fertiliser application, growth regulation and disease control.
  • Nutrition
    Complete N applications before GS32 as barley does not use late N efficiently and needs its N working before you see the flag leaf.
  • Fungicide
    Most crops are probably on a two-spray strategy, with the possible exception of those in the south. Crops in the northern half of the country on clean varieties will receive two applications at GS31-33 followed by GS39-49.
  • PGR
    Aim to apply a PGR on two-row varieties between GS32 and 37 for effective shortening, e.g., Terpal 1.2-1.5L/ha, Cerone 0.5-0.7L/ha, Meddax Max 0.3-0.5kg/ha. For six-row varieties or two-row varieties on very fertile sites, two applications are generally required.
• Fertiliser safety
  Spreading fertiliser can be high risk. Consider if a contractor can help. Keep fertiliser spreading equipment in good condition. Bulk or big bag options minimise the need for manual lifting but you need the appropriate equipment.