Controlling cleavers early boosts wheat yields

UK - May 07, 2010



Taking early and effective action against cleavers in the spring, before they begin to compete seriously with the crop, has significantly increased winter wheat yields on the Gemmill family's heavy-land farm in Essex.

"There's no doubt that as a result of switching to an earlier timing to control cleavers our winter wheat has not suffered from nearly as much competition and is generating greater financial returns," observes Jamie Gemmill who after gaining a Degree in Agronomy at Newcastle University took over the day-to-day management of J. Gemmill & Son's Highgates Farm at Little Sampford. On the 245 hectares of heavy Hanslope-Series chalky boulder clay, Viscount, Einstein and Cordiale winter wheats now occupy 150ha. Vision winter oilseed rape and Wizard winter beans complete the arable rotation.

"Cleavers are three times more competitive than wild oats and seven times more so than black-grass, so crop losses can be very high if they are not controlled effectively. They thrive on our heavy land and are the biggest broad-leaved weed problem. Although they tend to be patchy, in areas that are affected crop yields can be depressed by well over two tonnes per hectare," explains Jamie, who is BASIS / FACTS qualified and makes all the farm's agronomy decisions.

"Previously we relied on agronomy advice and used Starane 2 as part of a T2 tank mix. But by the time it went on, the cleavers were quite large and had reached the top of the crop, so were competing directly for light and nutrients.

"Four years ago I changed the strategy and switched to Boxer (florasulam) because it also takes out Shepherd's needle (Scandix pectin-veneris) which was starting to become a problem in certain fields. If we didn't do that we'd need to use a combination of Starane 2 and Ally, which would be significantly more expensive.

"Normally we apply Crystal pre-emergence on winter wheat and although it does a fantastic job on black-grass and most broad-leaved weeds we found that some cleavers would get through, particularly in first wheats after beans, because they are difficult to control in the preceding break crop. We usually apply Atlantis to part of our winter wheat acreage during the autumn, but this season everything has gone on in the spring and timings are 10 - 14 days later due to the cold weather. Using a 24m/3000-litre Knight trailed sprayer we applied Atlantis just after Easter and the Boxer went on at the same time, at a reduced rate of 75 ml/ha, which is possible because Atlantis has some effect on cleavers. Although we have applied Boxer later in the season at T1, at that stage you have to use a higher rate of 100ml or 150ml/ha, particularly if the cleavers are quite large by then.

"Taking steps to achieve better control of cleavers has not only allowed us to boost yields but is also reducing seed returns for the future, which means that we've been able to achieve almost complete control in more heavily-infested areas over a four or five-year period. As part of this process we will try using Boxer this autumn in some of our first wheat after beans.  We've not done this before even though there is a label recommendation for it. The benefit would be to take cleavers out even earlier using a lower application rate, with the additional benefit of controlling volunteer beans, which is important because now that we no longer have CMPP the opportunities to do so are becoming increasingly restricted.

"Doing our own agronomy has big benefits in terms of timeliness, attention to detail and reducing variable costs. It also means that we can source products at the best prices through the AtlasFram Group, of which we have been a Member for four years and through which we now purchase most of our farm inputs.

WARM WEATHER THREAT
"With the weather warming up, growers must be on their guard against a late flush of broad-leaved weeds and cleavers," emphasises agronomist Stuart Jackson of Dow AgroSciences. "Cleavers' prolonged emergence pattern makes it difficult to determine the best control strategy. The precise timing of emergence and balance between the autumn and spring flushes does vary, while the timing and abundance of the spring flush is difficult to predict because of differences between individual sites and year-to-year variations. If you attempt to control cleavers too early in the spring you run the risk of missing later-emerging plants, but leave it too late and the risk is of crop damage from early weed-crop competition, potentially poorer control and significant yield loss.

"After GS32, speed of control becomes essential to get on top of fast-growing cleavers, preventing them from smothering the crop and competing for light. They can be controlled successfully by later applications, but the longer that they are left after that time the greater will be the yield penalty. Products based on fluroxypyr provide the best solution under fast-growing conditions because they deliver rapid control."