Tackling serious weed problems improves OSR sustainability in Essex 19-Jul-2016

Ensuring the  most consistent oilseed rape performance in the face of escalating weed, not to mention market challenges, is an important element in David Lord’s drive to improve the sustainability of his family partnership’s 600 ha arable business at Earls Hall Farm, St Osyth on the Essex coast just outside Clacton-on-Sea



From a low cost cereal break in the 1990’s, winter rape has become a key element in the wheat-based rotation he and his business partner Guy Hunt run across their 350 ha of  London and marine clay land.


It continues to be the best available cereal break for their heavy ground.  Indeed, with a five year average running at almost exactly 4 t/ha as a result of their continuous improvement efforts, it’s often the best margin-earner on the farm.


Like the black-grass that’s causing such serious wheat-growing headaches for the partners and their Agrii agronomist, Vicki Brooks these days, cruciferous weeds have become an increasing challenge for oilseed rape growing.


“We grow around 80 ha of winter rape each year in an extended five year rotation with wheat and linseed on our heavy land these days,” explained David Lord. “Charlock and hedge mustard have always been about and small amounts have never been much of a problem.


“In recent years, though, the weed levels had built-up so badly we could no longer grow OSR on some fields. And on others the hedge mustard, in particular, was horrendous to deal with at harvest. It towered above even the tallest crops at more than 8ft high and its wiry stems wrapped round the combine reel so badly we had to keep stopping to clear it out.


“We just couldn’t get on top of the weeds. Bifenox sometimes worked and sometimes didn’t. And sometimes we’d get a decent frost kill and other times very little. It was hugely frustrating. Until four seasons ago, that was, when Vicki suggested we gave the Clearfield system a try.


“The combination of DK Imagine CL and Cleranda worked a treat across 20 ha of our worst-affected land. At 3.5 t/ha we were a little disappointed with the yield. But the thick carpet of charlock the system made short work of would otherwise have proved disastrous to performance.


“As well as having no hedge mustard to interfere with harvesting, the low biomass hybrid crop was lovely to combine too. And it didn’t need any plant growth regulation either.”


Since this first season, David and Vicki have employed the Clearfield system as routine across all land with more than minimal cruciferous weed problems, moving from DK Imagine CL to DK Imiron CL and then to the first standard height variety, DK Impression CL. This year they’re growing 32 ha of the latest standard height variety, DK Imperial CL. And for the 2016/17 season, given the fields coming into the rotation, they’ll be growing DK Imperial CL across their entire 80 ha.


“I know just how deceiving appearances can be with oilseed rape, but I have to say the Imperial is by far the best looking crop we have in the ground this season,” observed David. “It’s clean and beautifully uniform, in complete contrast to our Charger which is a real mess.”


As Clearfield varieties close the yield gap on mainstream ‘double lows’ they’re becoming more and more attractive to the Earl’s Hall Farm team. Last year’s records show their CL crop input costs were £470/ha against £486/ha for the Incentive they grew elsewhere. So once yields are on a par they will have no hesitation in using only Clearfield varieties.


“We’re not quite there yet,” said Vicki Brooks. “But with the breeding progress we’ve seen in the past four years it won’t be long before we are. Last year’s Impression did 3.9 t/ha, for instance, and we have even higher hopes for this year’s Imperial.


“The Clearfield system is so simple agronomically. We no longer use a pre-em, waiting to see whether we have a crop and what weeds it’s carrying before going in with a single dose of Cleranda at around eight true leaves. And if few weeds problems emerge, as in one field last year, we don’t even bother with this spray.


“As well as dealing with a wide spectrum of broad-leaved weeds and non-CL volunteers, the Cleranda has given us very valuable suppression of black-grass ahead of our main Kerb treatment,” she added.  “Now we’ve replaced a winter wheat with spring wheat ahead of rape in the rotation as part of the battle against black-grass, the SU tolerance of Clearfield varieties also gives us useful peace of mind over any herbicide residues affecting establishment.


“CL volunteers have been easy to tackle with our normal Liberator-based programme in the wheat following the rape too. Leaving almost all the seeds on the surface, the Cross-Slot drill-based no-till system currently being introduced across the farm should make this even easier.”


“In addition to overcoming the cruciferous weed problems that were threatening our OSR growing, the flexible timing of Cleranda application and its consistent activity has been  particularly useful with the almost incessant winds we suffer in our coastal fields,” pointed out David Lord. “It also takes the pressure off establishment workloads at one of our busiest times of the year.”


“Anything that makes oilseed rape easier and more consistent to grow is really good for us; especially at current market levels,” he concluded. “Luckily, so far, we’ve avoided the worst of the flea beetle problems that have been so acute for many in the Eastern counties. But we still have to put plenty of time and effort into protecting it from slugs, pigeons and a range of other significant performance threats. Not to have to worry about charlock and hedge mustard any longer is a very positive contribution to the crop’s sustainability for us.”