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Time running out to get Spring Barley Crops Sown

18 April 2019
Type Media Article

John Galvin, Teagasc Beef & Tillage Advisor, Mellows Centre, Athenry

In GAA terms, growers are heading into added time to get spring barley planting carried out on farms with early March – mid-April being the optimum time for sowing. Unfortunately this is becoming the norm rather than the exception with much of the 2018 Spring Barley crop sown in late April also. This is the situation and this article will highlight the challenges and suggest best practice solutions to dealing with those challenges that will help maximise the potential of the crop for 2019.

Challenges with late sowing crops:

  • Late harvesting
  • Higher seeding rates
  • Lower yield potential
  • Reduced grain quality
  • Increased BYDV risk
  • Moves quickly through growth stages (Workload & timing issues)

Variety, Seeding Rates & Sowing:

In order to make a decision on variety consult with the Department of Agriculture Recommended List along with being mindful of the past performance of varieties on your farm. It is important not to focus solely on yield and quality but also on the disease ratings as picking a variety with good disease resistance is going to be a grower’s first line of defence in reducing disease pressure on the spring barley crop.

Aim to sow 325-350 seeds/M2 at a uniform depth of 3-5cm for fast even germination and roll after sowing to ensure good soil to seed contact. Using the thousand grain weights (TGW) of seed and calibrating the seed drill correctly are vital to achieving good plant counts of >300 /M2. Late sown crops produce less leaves/tillers so must be sown to a higher seeding rate of 10-12st/acre depending on variety.

Soil fertility & Fertiliser:

Soil analysis is key to having the information required to satisfy the lime and fertiliser requirements of a barley crop. Spring barley is highly sensitive to acidic conditions; therefore soil pH must be at 6.5. Ground limestone should be spread post ploughing and cultivated in to the soil. Aim to have soil phosphorous and Potassium levels at Index 3 to maximise crop performance. Compound fertiliser should be incorporated into seedbed or ideally combined drilled with seed especially on low index soils. A typical fertiliser program for spring barley is 3 bags of 18-6-12 at sowing followed by 2 bags of CAN (27%N) at early tillering (as soon as the tramlines are visible). This programme will cost €130-140/acre for the grower. Trace element deficiencies may also need to be corrected depending on soil type and nutrient status.

Weed & Aphid Control

After establishment, the next threats to a good plant stand are nutrient robbing weeds, BYDV and wild oats. Early spray intervention at the 2-5 leaf stage (Growth stage 14) with a broad spectrum herbicide to control broad leafed weeds will have a more positive effect on yield. Applying reduced (1/2) rates of herbicides are successful where the weeds are actively grown at an early growth stage and a follow up ½ rate at late tillering should deal with most weed problems. Aphids and the resulting BYDV threat are at their highest in April sown crops. Research carried out by T.F. Kennedy and J. Connery in Oakpark has shown that the best yield benefits were attained with the application of a pyrethroid(contact) aphicide at the 4 leaf stage (GS 14). The last remaining ingredient that may be required in the sprayer is for wild oat control, this will depend on the field and crop history.

Disease Control:

The damp temperate climate in Ireland creates ideal conditions for fungal diseases to prevail in spring barley. Diseases including Rhynchosporium, Mildew, Brown Rust, Net Blotch and Ramularia are all potential threats to the yield of a crop of barley. A 2 spray fungicide programme at ½ rates has been shown to work best. At stem extension (GS 30) and flag leaf to awns visible (GS 37-49) are the key times for disease control. Trials have shown by applying fungicides at the correct time increased yields by 0.2t/ac for the same fungicide spend. With the constant threat of the loss of chemical active ingredients it is vital to use mixtures of fungicides with different modes of action to reduce the risk of resistance. Chlorothalonil which is Irish grower’s main defence against Ramularia is the latest chemical that has been refused renewal of approval for use on crops. No end date is confirmed yet so it is available for use this year.

Walking the crops regularly and checking for pests and disease and monitoring the weather conditions and growth stages carefully are key tasks when managing a spring barley crop especially with late sown crops as they will progress rapidly through the growth stages. This a very short synopsis of how to sow and manage a spring barley crop with a very short window for the grower to carry it out. Be mindful of the workload and make a plan for each task to reduce the risk of injury and levels of stress.

For further information on managing spring and winter cereals, there will be a Teagasc Crops walk at John Daly’s Farm, Hillcrest, Kilconnell, Ballinasloe, Co. Galway on 13th May 2019 at 7.00pm.