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Arable

AGRONOMY UPDATE – EAST Yields in Agrovista’s Norfolk maize trial were down 20 per cent on last season, but good early nutrition improved results, says Agrovista agronomist Craig Green. Delayed drilling and a lack of sunlight is limiting maize yields this season across many parts of the country, as reflected in Agrovista’s Great Ellingham biogas maize trials. Bulk yields and, more importantly, cob and resulting starch yields, are well below last year’s levels, says Craig. “Delayed drilling and a lack of sunlight in June reduced growth potential and there were fewer, smaller cobs as a result,” he says. A clutch of varieties did stand out, he adds. KWS Amagrano, a specialist biogas newcomer with an FAO score of 230 performed well on the medium soils, providing plenty of bulk and cob. So too did Hobbit from Grainseed, a variety with similar maturity, the third of three very different seasons that the variety

has delivered, he points out. Early maturing Nordic Star did well in its group and will suit more marginal conditions well, says Craig. Topping the yield table was P8200, an intermediate maturity variety from Pioneer, while Elsoms’ new energy maize hybrids gave it a run for its money. “Sumatra, an intermediate variety (FAO 190-200) and the later maturing Susetta (FAO 220-230) look to be very high-yielding, albeit after a one-year snapshot.” The value of early nutrition was clearly demonstrated across the trial, Craig adds. Plots treated with N-Lock, a nitrogen stabiliser applied to the seedbed that slows the bacterial conversion of ammonium (bagged N) to nitrite for up to six weeks, performed better. Yields rose 10–15 per cent

depending on variety, covering the cost of the 2.5-litres/ha application several times over, he points out.

OSR fungicides Light leaf spot (LLS) will be a key focus of Craig’s this season. “Both Bayer and DuPont have provided data that shows crop yield is affected once spores geminate on the leaves. “More potential than we thought can be lost before the disease becomes visible in the spring. I will be advising clients to ensure their phoma spray, many of which are due in the next two or three weeks, has a good level of curative activity against light leaf spot.” Frelizon (penthiopyrad + picoxystrobin) at 0.5-litres/ha will be his favoured option. “If you are growing a variety with high phoma resistance and/or a decent LLS score – 6 or above is very good – I would still spray sometime in the next few weeks. “Light leaf spot is the biggest

robber of yield in OSR. You can’t afford to be on the back foot in the spring, but you can always hold off at that time if crops are clean.” If temperatures cool sufficiently, the fungicide spray could be combined with a propyzamide application, to control grass weeds, saving a pass. “Last year people who sprayed even when it was theoretically too warm achieved a good result.” Some early drilled wheats are already infested with black-grass. Craig is advising growers to spray off badly affected areas with glyphosate. “If black-grass looks like hairs on a cat’s back now, it is not worth spending more money. “It has broken through the preem application and a post-em spray will have very little effect, so it is better to burn off and re-drill, or better still, sow a spring crop.” ■ Craig Green is an agronomist with Agrovista, based at Great Ellingham, Norfolk (Craig.Green@ agrovista.co.uk).

AGRONOMY UPDATE – WEST Unlike their counterparts in the east, maize growers in the far south west are generally pleased with their maize crops, says Agrovista agronomist Martin Stuart. Most maize in Devon and Cornwall has been harvested in good conditions, with early ripening coinciding with a dry first half of October. “The first two weeks of the month were a gift,” says Martin. “After some catchy weather in September, the weather came good again. “Some maize might have been taken a little early, a legacy from last year’s late season which saw some people miss the boat. But generally the crop has been two to three weeks ahead of last year and most has been fully fit. “It’s early days, but judging by cob maturity we should see some good starch figures.” Despite a cold initial drilling period and a dull June, which capped cereal yields, most growers say this year was better than 2015, with yield, starch and maturity, the three main drivers, all improved, says Martin. “July and August temperatures were higher, allowing maize to gain the required heat units. In the far south west temperatures are usually 3–5ºC cooler than Exeter eastwards,

which has quite a significant effect on maize production – we are more akin to the north-west than Somerset. But this year we got enough warmth to finish the crop well.” The early harvest has left soil in good condition, good news for the rotation and providing a welcome window to sow grass catch crops. These have gone into good warm seedbeds and will help optimise soil stabilisation and nutrient retention.

Grass establishment Establishing grass post-maize is usually more of a lottery in more typical October weather. Martin is keeping a close eye on work that Agrovista is undertaking in Lancashire, with Reaseheath College and machinery manufacturer Pottinger. The trials involve sowing grass and leguminous species within the maize crop, either at or several weeks after drilling. The hope is that these species will mitigate run-off, and provide established grazing post-harvest, or further AD feedstock, while alleviating the pressure and costs associated with

Nordic Star’s cobs have a very small stova and long, deep grains.

establishing grass leys after maize harvesting, often in poor conditions. “There is certainly potential from companion cropping – we used to spin on ryegrass when maize was at the 4-leaf stage, but if it was dry it didn’t work. We also lost atrazine, so weed control became a problem. “But technology has moved on, and we can now drill between rows with ease and have access to much better post-emergence chemistry. It could be a useful tool for at-risk fields.” Given the more typical south west climate, early varieties are par for the course in the region, says Martin. A new variety from Syngenta Seeds, Nordic Star, that has been trialled by Agrovista for two years, appears to have lived up to its early promise in its first commercial year. “The variety has been bred for

northern latitudes, and is rated FAO 180, the old Group 9 equivalent, the same as Ambition. It looks very promising and has good disease resistance, especially to eyespot. Crops remained greener for longer and produced better quality bulk at harvest. “It ripened at the same time as some ultra-earlies this season, yet produced significantly higher grain and starch yields,” says Martin. “If it carries on performing as it has done, it will be another step forward in getting more yield for the same earliness.” ■ Martin Stuart is an agronomist advising for Agrovista in Cornwall (Martin.Stuart@agrovista.co.uk).

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