21 June 2002

Seven steps towards better crop rewards

Grower levy funds invested in research are bearing fruit.

At Cereals 2002, HGCA-backed researchers profiled

seven of the latest projects. We show how they could

help growers boost crop output and cut costs

Pod shatter on way out

POD shatter is a step closer to being banished in oilseed rape thanks to targeted breeding at the John Innes Centre.

Up to 10% of the UK oilseed rape crop is lost each year due to premature pod shatter, says JICs Colin Morgan. "That creates problems with soil contamination, as the seed can lie dormant for up to 10 years, plus the obvious consequence of lost revenue."

HGCA-funded work at JIC has concentrated on introducing more genetic variability in pod shatter resistance, so that varieties with tougher pods can be bred.

"Growers can expect to have commercial varieties with pods three times stronger than those on Apex," says Mr Morgan.

Early assessment advised

MEASURING oilseed rape canopies in the spring could be the key to deciding whether or not crops need a growth regulating fungicide spray.

Yield benefits of up to 0.8t/ha can be achieved with an April application of either tebuconazole or metconazole, but crops which are too small at application suffer a yield loss, according to ADAS trials.

"If you have a Green Area Index of 0.5 or more in March, or 1 or above in April, then its worth using a growth regulator," says researcher John Spink.

Growers unsure of the crops growth in the spring should take a square metre of the crop and measure the fresh weight in kilogrammes, he advises. "You then multiply this figure by 0.8, which gives you the GAI."

"Crops are often too far forward in the spring," adds Mr Spink. "This work will help identify the situations where a growth regulator is worth using."

Larger seeds cut losses

USING larger seeds and improving mother crop management could help growers cut losses from failed oilseed rape establishment, which can top £30m in a bad year.

"Larger seed performs better in most conditions," says Gavin Lunn of the University of Nottingham. "By grading to get seed of 2mm or more, weve seen better emergence and plants with larger cotyledons. Theres also some evidence to suggest that bigger seed has improved resistance to flea beetle."

Growers saving their own seed should consider sieving or grading, he advises. "And mother crop management is important if you want to produce bigger seed.

"Denser crops give larger seed, so aim for higher plant populations than you would with a commercial crop. Populations of 80 plants/sq m are about right. And apply more nitrogen because that also seems to give bigger seed."

But putting more nitrogen on a commercial crop will depress oil content, he warns. "Its fine with a seed crop because seed with a higher protein content emerges more quickly. That can be important if its dry when drilling takes place."

Barley leaf spot warning

DONT assume barley leaf spot is only a problem in Scotland, warns Neil Havis of SAC.

"Crops as far south as East Anglia have been affected. The incidence is affected by weather and varies from year to year."

Spots can be caused by ramularia disease and/or environmental factors, causing a late season reduction in green leaf area. "In Scotland, weve recorded a 0.3t/ha yield loss in spring barley. But in other parts of Europe, they have seen as much as 20% yield loss."

Grain quality is also at risk, with increased screenings attributed to the spotting.

A well-timed strobilurin/epoxiconazole mix will protect the top two leaves and help to maintain green leaf area. "Spray between GS45-49 at a rate of 0.4 litres/ha for both products," says Mr Havis. But avoid using Corbel (fenpropimorph). "For some reason, it can make the problem worse."

Work is also underway on a PCR diagnostic test for ramularia. "It will show when levels are rising, so help with the spray timing decision."

Rhyncho spray is a must

EVEN varieties with rhynchosporium resistance ratings of 7 and 8 will need spraying against the disease, advises Simon Oxley of SAC.

"The resistance ratings dont mean much with this disease, especially as the weather has been in its favour this year."

Using the right fungicide timing and combination of products is important and is a key finding of his HGCA-sponsored project. "No one fungicide on its own will do a good job."

With winter barley, the key is to start spraying early and get on top of the disease. "That means making two applications – the first in early spring and the second at stem extension. But growers dont like the cost implications of that."

Triazoles alone should be avoided, as the disease is less sensitive to them than it was. Corbel (fenpropimorph) has eradicant activity, but is a poor protectant, so should be used where the disease is already present.

Unix (cyprodinil) works well in mixtures, so add it to either a strobilurin or Corbel, suggests Dr Oxley. "The new strobilurins – trifloxystrobin, picoxystrobin and pyraclostrobin – are all good choices, but keep up the rates of picoxystrobin."

For spring barley, its important to protect the clean crop. "That means either using a strobilurin/Unix mix early or a strobilurin/Opus mix later on. Avoid Corbel in the spring crop."

Dr Oxley adds there is a shortage of eradicant products for rhynchosporium, so it is important to protect existing chemistry. "Where disease has got established, its very difficult to get on top of it."

Wheat seed cuts in north

WINTER wheat can be grown successfully at low plant populations in northern England as well as in the south, says ADAS researcher John Spink.

"You do need a higher plant population as you go north, but its not as high as some growers think. Theres still plenty of scope for reducing seed rates."

The timing of early nitrogen can be important with low plant numbers. "If youve got low levels of residual nitrogen, then you need to get the first nitrogen application on in late February.

"Where residual levels are higher, mid-March is fine. But mid-April has shown to be too late."

An early PGR did not help at all. "If you need to promote tillering, do it with early nitrogen, not a PGR," says Mr Spink.

Seed loss from slug attack wont necessarily be higher with low seed rates, he adds. "The proportion of seed eaten at different seed rates didnt change. So growers need not worry about total crop loss with fewer seeds."

Go for seed health tests

CONSIDER using seed health tests to help target seed treatments, advises Valerie Cockerell of the Scottish Agricultural Science Agency.

"The majority of seed samples are healthy," she says. "So theres plenty of opportunity to save money by only using seed treatments where they are required."

A new rapid test will be evaluated alongside existing seed tests by both NIAB and SASA this harvest, she says. "The new test can be turned round very quickly, so growers could have the results back within 48 hours."

The key to any test is the way sampling is done on farm, she says. "Take many small samples from the seed bulk and then combine them. The sample must be representative or else the results could be misleading."

Where drilling is taking place late or seed-bed conditions are poor, growers might need to be more careful. &#42

Bridging the gap between background research and progress on arable farms, the HGCA plots had innovations aplenty on display.