AGRONOMY UPDATE – EAST The testing harvest of 2017 has thrown up some interesting lessons, says Agrovista agronomist Craig Green. Harvest 2017 will be remembered for the awful weather that started in late July that caused many wheat crops to spoil. While we can’t change the weather, we can tweak some agronomic decisions to give wheat crops the best chance of weathering the harvest storms when they do arrive. Many of the Norfolk wheat crops have lodged to some degree, a legacy of storms that dropped up to 3in of rain in a few hours. Perhaps there has been some complacency with PGR programmes, understandable given the generally dry, cold spring and slow growth. But, with varieties scoring between 6–8 for lodging resistance without PGR on the Recommended List, how much have they been tested? That said, in most fields lodging is not widespread, but limited to overlaps and other prone areas following previous year’s muck
applications. This suggests we are, nutritionally speaking, pushing crops to the edge, without going over the top. Some serious lodging is due to over-early sowing of free-tillering varieties such as KWS Siskin. The variety has performed very well where it stood, where people followed clear advice from the breeder not to drill it before the beginning of October, preferably later.
Later slot Several new varieties are of interest to fill the later-drilling slots. There’s been a lot of interest in KWS Kerrin this year, joint highest yielding Group 4 wheat on the RL. Kerrin is flexible, can be grown on heavy or light soils as a first or second wheat. It will require a robust fungicide and PGR programme. It won’t suit early drilling due to its high tillering capacity.
Freiston, bred by Elsoms, is an early maturing, high yielding hard feed wheat, another very promising variety promoted to the 2017/18 Recommended List. It is very robust, with a high untreated yield. It looks to be an excellent later-drilled choice, especially on lighter soils after sugar beet. KWS Zyatt is still available. This Group 1 variety offers very high yields with a potential milling premium, and a good diseaseresistance package. And, in our variety trial at Long Sutton, it was the only one left standing. Established varieties offer growers the chance to farm-save seed, which can cut costs by £100–150/t even when treated with Redigo Deter (clothianidin + prothioconazole). I wouldn’t recommend homesaving seed from a crop already grown from farm-saved seed. However, seed bought in as C2 seed this time last year and kept clean from weeds makes an ideal opportunity to save some money. A Vitascope test or full germination test will reveal
viability. All samples tested before the weather delay have been around 96–97per cent. Put it over a gravity separator and ensure it is coated with a suitable seed dressing. Finally we need to be thinking of cereal pre-ems. Esme Shephard (below) has outlined our current thoughts on black-grass control. Fortunately, we don’t have too much in this area so our targets are slightly different. Herold (diflufenican + flufenacet) at 0.3-litres/ha takes out broadleaved weeds and annual meadow grass effectively. Anthem (pendimethalin) added to diflufenican boosts poppy control, which is becoming a concern on some farms. Where ryegrass is a problem, I’ll use Trooper (flufenacet + pendimethalin) and Defy (prosulfocarb) at full rate – the prosulfocarb seems to bring a good level of pre-em control to the party. *Craig Green is an agronomist with Agrovista, based at Great Ellingham, Norfolk (craig. firstname.lastname@example.org). ■
growth in the spring. I’ll be recommending Caryx at 0.5-litres/ha in leafier crops – it contains the specific growth regulator mepiquat as well as metconazole. Sunorg Pro, which contains metconazole only, but more of it, is a good option in less growy crops, applied at 100ml/ha per leaf stage, which also offers some early preventative disease control. Black-grass is now rife in this area and Avadex (tri-allate) is routine on many farms to complement the pre-emergence stack. Most growers have access to an Avadex applicator, so will use the granular form. It is worth getting the applicator tested to ensure it is spreading correctly. Forward speed should not exceed 8kph to maintain accuracy of application. The launch of a new liquid formulation of Avadex is good news for growers who don’t have access to an applicator. This is often where black-grass is less troublesome, although any black-grass present is likely to be herbicide resistant, having been
introduced from problem areas. I would recommend including Avadex as part of a zero-tolerance policy. Although the liquid formulation puts down slightly less active ingredient than the granules, to meet operator safety requirements, it will still be a very useful addition to the armoury. In all cases my pre-emergence stack will consist of Trooper (flufenacet + pendimethalin), plus Herold, which also contains flufenacet and adds diflufenican. I’ll also add Remix as routine. This is a long-chain paraffinic oil that reduces spray drift, improves spray deposition and increases adsorption to soil particles. That improves weed control and crop safety. In trials over the past few years, Remix has consistently added an extra few percentage points of control that can make the difference between reducing the seed return, or allowing it to increase. *Esme Shephard is an agronomist with Agrovista, based in Wiltshire (esme. email@example.com). ■
AGRONOMY UPDATE – WEST Extra options for weed control in oilseed rape and black-grass control in winter wheat could prove useful to some growers this autumn, says Agrovista agronomist Esme Shephard. Oilseed rape growers have a new early post-emergence weapon this season to control a range of problem broad-leaved weeds. Parish contains 320g/litre of phenmedipham, an active ingredient that until now has been restricted to sugar beet and related crops in the arable sector. It can be applied on its own at 1.1-litres/ha, or with the adjuvant Nelson, which improves efficacy, at half rate, reducing costs. Under the right conditions Parish will control chickweed, poppy, groundsel, field speedwell, cranesbill, red dead-nettle and shepherd’s purse. It must be applied when weeds are between cotyledon stage and two leaves unfolded and in bright sunny conditions when weeds are growing well. A water volume of 200-250-litres/ha applied through a medium spray is recommended to ensure good coverage.
Parish will be a useful addition where growers are reluctant to use pre-emergence protection, for example where flea beetle is a major problem, preferring to ensure adequate establishment before spending their money. It also looks a good option where seed has been broadcast and pre-ems cannot be used, or to top up poor pre-em control. It is also a useful pre-cursor to Clearfield herbicides where cranesbill is a problem.
PGR thoughts We will soon need to think about plant growth regulation in forward oilseed rape crops. As a rule of thumb, crops that exceed 25cm in height by mid to end of September should be treated, to reduce top growth and encourage root growth. This improves the crop’s overwintering capacity and helps promote strong early
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Published on Aug 31, 2017