Successful spring barley

Establishing optimum plant population

Quickly establishing the optimum plant population is key to spring barley success in most seasons, Scottish Agronomy’s Eric Anderson says.  

Years of research shows the optimum final ear count for spring barley is about 775 /m2 and adjusting seed rate to drilling date and field conditions improves the chances of achieving this target. 

Early drilling into cold, wet soils, reduces establishment rates, while in later-sown crops, establishment rates cab be higher, but increasing day length reduces tillering potential. In either scenario, seed rates should be increased to achieve a plant population that will provide 775 ears/ m2 for top yield. 

“We typically look to drill from mid-March at about 375 seeds /m2, increasing the seed should you go earlier or later,” explains Mr Anderson. 

“In any situation, patience before drilling is key. Waiting for conditions conducive to rapid and even establishment will pay dividends at harvest.” 

Establishment method

Establishment method is another important consideration for getting spring barley away quickly, with the right plant population. 

Duncan Wilson, manager at Strathmore Farming Company, harvests about 930 ha of combinable crops in Angus, including 180-200 ha of spring malting barley. 

Ploughing before drilling has delivered the highest establishment rates, but he has experimented with direct drilling into cover crops in recent seasons. 

The aim is to improve soil structure and conserve moisture – useful in dry years like 2022 – but correct cover crop destruction and getting crops away quickly are challenges he is still to overcome. 

“We’re getting there, but more work is needed before it’s a success. It’s about having the right tools for the job, including varieties best suited to the system.” 

Variety choice

As with many growers, end-market appeal drives variety choice with Laureate his preferred variety. Data from the Maltsters Association of Great Britain (MAGB) show this variety made up 55% of the GB spring barley market.  

Mr Wilson has experimented with LG Diablo in recent seasons, but it is late maturing, and performance did not beat Laureate, so his 2023 area will be almost 100% Laureate, grown for malt distilling. 

Mr Anderson says Laureate is a good dual use option, as its yield of 102% competes with any feed variety, and it offers a potential quality premium. 

“Normally more than 2-3% yield differences in Recommended List trials are required to translate into significant differences in the field.” 

Use glyphosate wisely

Glyphosate is central to integrated weed control and growers are urged to use this herbicide wisely to minimise the risk of resistance developing.

In dose response studies, ADAS found less sensitive sterile brome populations, and work by NIAB, sponsored by Bayer, revealed a small number of Italian ryegrass populations exhibiting reduced sensitivity to glyphosate.

Product stewardship ahead of spring crops is particularly important, as multiple applications are sometimes used, increasing selection pressure, and weeds are often bigger and tougher to kill.

Limiting use intensity is key, with a maximum of two applications deemed an acceptable risk, provided there is an intervening cultivation, as advised in WRAG guidelines. Avoid repeat doses to surviving weeds.

Good application practice should be the norm, with a steady forward speed, 50 cm boom height and appropriate nozzle choice maximising coverage and minimising under-dosing.

“Appropriate dose for the weeds present is essential,” says Mr Bradbury. “Small grass-weeds in the autumn are well controlled with 720 g of active substance/ha, but in spring stubbles increase that to 900-1080 g AS/ha.

“Higher rates are needed for tough broad-leaved weeds like cranesbill, volunteer oilseed rape and polygonums, too.”

Growers must think carefully about glyphosate use and what it might mean if resistance develops on their land, he adds.

“Many businesses are turning the corner with black-grass, and that could be compromised without glyphosate, so there is no room for complacency.”

Early nutrition

Balanced soil pH above 5.9 is critical for spring barley, along with early nutrition to aid rapid and even establishment. Mr Wilson typically uses a 10-18-28 blended fertiliser alongside seed at drilling.

This is followed by liquid nitrogen, with 120 kg/ha total N applied depending on soil type and site. This compares to about 150 kg/ha for a feed crop.

Mr Anderson says matching timing to target market is critical: “The whole nitrogen balance must be applied to a malting crop by the three-leaf stage to avoid high grain N concentrations.

“Feed crops typically receive 100- 120 kg/ha in the seedbed, with the remaining 30-50 kg at early tillering.”

Weed control

Pre-drilling weed control (see panel above) is important, particularly where grass-weeds are problematic, but in-crop control is necessary to protect quality and ease of harvest.

Mr Anderson says 0.3 L/ha Liberator (flufenacet + diflufenican), plus additional diflufenican in more challenging situations, applied pre-emergence, controls grass and broad-leaved weeds.

In fields with specific issues like fumitory and/or groundsel, he suggests a mixture of containing pendimethalin + picolinafen, plus diflufenican. At mid- to late-tillering, a an application of florasulam + halauxifen- ethyl or florasulam + fluroxypyr,  will tidy-up remaining broad-leaved weeds, while for wild oats, he recommends applying pinoxaden once oats have germinated. 

“If the mix is getting too complex, split it out to avoid unnecessarily stressing the crop.”

T2 focus

Scottish Agronomy trials in the absence of active Rhynchosporium or Brown rust have shown little response from T1 fungicides, except on high fertility sites, so fungicides are generally applied at T2 only, as awns start peeping.

Mr Anderson says benzovindiflupyr + prothioconazole has a place if Rhynchosporium is rife, but otherwise he favours fluxapyroxad + mefentrifluconazole plus folpet at T2.

“It provides better protection against Ramularia, which is now our greatest concern in spring barley.”

This article is an extract from CropFocus magazine.