Arable News

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Agronomy update – Maize drilling must be spot on

Maize drilling must be spot on – Maize establishment, cereal fungicide sprays and grass management all need tackling in the next couple of weeks.
Ideally maize drilling shouldnt begin until soil temperatures reach a minimum of 8C, advises Agrovista agronomist Craig Green. Maize is set to get off to a flying start this season across the eastern counties. Most fields were pulled down and ready to go several weeks ago, reports Norfolk-based Agrovista agronomist Craig Green, who will be looking after about 1,850ha (4,500 acres) of the crop this season. Seedbeds should be warm and relatively moist. Ideally drilling shouldnt begin until soil temperatures reach a minimum of 8C and are rising to ensure rapid emergence and strong early growth up to four or five leaves. Heavy land growers should wait until soils reach 12C. That wont pose too much of a problem this season on most soils; even if growers did have to wait, todays modern, early-maturing and high-yielding hybrids will buy extra time with little if any yield penalty. To help growers get the timing spot on, KWS has just launched a free live maize soil temperature service which allows growers and advisers to access readings based on their postcode, says Craig (see Farmers Guide April edition, p17).
Maize is very sensitive to soil compaction, but most growers in the region will have had plenty of time to sort out problems, he notes. Seedbeds should be deep and loose with a reasonable proportion of smaller clods on top to avoid capping. Soils should not be overworked. You only want enough tilth to cover the seed.
Small maize plants are very sensitive to competition, so good early weed control is vital, says Craig. Where annual meadowgrass and broad-leaved weeds predominate, pendimethalin applied pre-emergence will form a strong base.
If no pre-emergence spray was used, an early post-emergence spray is vital to prevent early competition, he says. A low rate of Templar (bromoxynil + terbuthylazine) at 1 litre/ha applied at the 23 leaf stage of the crop will take out small flushes of broad-leaved weeds.
Callisto (mesotrione) can be applied at the main timing of 4 true leaves for the remaining broad-leaved weeds, or Elumis (mesotrione + nicosulfuron) which broadens the spectrum to include grass weed control. There are, however, restrictions for following crops including sugar beet and beans, Craig notes.
Grassland is now growing away quickly. Farmers need to think about ragwort control. Forefront T (aminopyralid + triclopyr) is a good choice for grazed pastures, otherwise Thrust (2,4-D + dicamba) could be used.
For dock control use products based around fluroxypyr such as Doxstar Pro (fluroxypyr + triclopyr). Watch harvest intervals though this may mean having to take the first silage cut and treating regrowth.

Planning for T2Wheat growers must include a mix of SDHI and triazole chemistry in their T2 plans, Craig believes. Crops are full of potential this year being lush, thick and green and we need to keep the pressure on disease. Ill recommend Librax partnered by Ennobe (epoxiconazole + prochloraz) at varying rates depending on disease and variety. Librax contains fluxapyroxad, plus metconazole to help broaden the spectrum.
The SDHI and mixed triazoles form a broad and robust treatment with added formulation benefits. I may also consider adding a multisite fungicide such as chlorothalonil or folpet to boost protectant activity and to help resistance stewardship.
Craig also recommends a leaf analysis to ensure crops have the nutrients they need. This will be more important than usual this season given the lush state of crops.
The nutrient to watch at this stage is magnesium, which is important for chlorophyll production in the flag leaf, which drives yield. A test costs about 20. Some thick crops could remain prone to lodging, despite having had a two-stage PGR programme. Risk will depend on variety, how thick the crop is, the presence of stem-based disease and the fertility of the site. If there is a doubt I will include Strate (2-chloroethylphosphonic acid + chlormequat) at T2. T2s will be going on to winter barleys in the next few days. Jaunt (fluoxastrobin + prothioconazole + trifloxystrobin) is favoured, though Craig will also try Librax following its approval on the crop. T2 is critical in barley to keep the awns green for as long as possible to drive yield. At 0.75 litres/ha Librax is a new SDHI offering to the barley crop, whereas Jaunt or Siltra Xpro are well established, and so it will be interesting to see how it fares. *Craig Green is an agronomist with Agrovista and is based at Great Ellingham, Norfolk ([email protected])  Other crops: Spring barley 
– Mild winter and late stubbles means there is plenty of disease inoculum.
– Apply robust T1 to ensure clean start and to keep crops disease-free to T2 (Jaunt plus Fielder (chlorothalonil + proquinazid) if mildew is present). OSR
– Flowering could be protracted this season.
– Plan for a late-flowering sclerotinia spray Recital contains fluopyram, an SDHI which optimises greening, helping seed set and pod fill. Other choices include Filan (boscalid).

  • Written by: Farmers Guide
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