12th September 2022

Latest advice on spring barley agronomy

Limagrain UK’s Ron Granger offers the latest advice, based on data generated from the breeder’s extensive trials programme designed to challenge traditional approaches.

1. Choose the right variety

The key to upping spring barley yields is achieving high final head counts and choosing a variety with a greater tillering ability can help improve numbers.

First on the AHDB Recommended List in 2009, Concerto has a lower tillering ability than newer varieties such as Sienna, which was first listed in 2015. This is a trend that continues to be seen in ongoing Limagrain trials.

It is a significant contributory factor in the 10% uptick in yield seen from the top varieties added to the AHDB Recommended List over the last 10 years.

Varieties, such as Concerto, can still achieve high yields if a final target tiller count of about 775/m2 is met, but a cultivar that initially produces more tillers will compensate better for tiller loss in stressful conditions, helping crops reach their full potential in most years.

2. Drill at the right time

Drilling date is vital in getting spring barley off to the best possible start and has a major influence on final yield. Earlier drilling through late February and up to mid-March has been shown to boost yield potential compared to sowings in mid-March to early April (see Chart 1).

However, it should be stressed that waiting for the right conditions for drilling is more important than a definitive drill date to ensure rapid emergence and early growth.

3. Use the right seed rate

As newer spring barley varieties generally have stronger tillering ability, careful attention should be paid to seed rates to optimise plant populations and hit target head numbers.

Limagrain trials comparing variety seed rates over various seasons and regions suggest that with the more vigorous, higher tillering varieties, the optimum seed rate is 350 seeds/m2 when drilling in ideal conditions around mid-March.

This figure can be adjusted up or down depending on weather, drilling date, seed-bed quality, moisture availability and perhaps most importantly, the grower’s own experience on each site.

A lower rate of 300-325 seeds/m2 could suffice if drilling into an “onion bed” in March, but where forced to drill into April due to weather or agronomic reasons, pushing up to 400 seeds/m2 may be more appropriate.

4. Blackgrass control

Much of the recent jump in spring barley area can be attributed to growers trying to control blackgrass on heavy land and some experts have advocated very high seed rates in these situations to provide maximum weed suppression.

However, it is Limagrain’s view that with many of the top-yielding varieties, which inherently produce higher tiller numbers, a seed rate of 350-375 seeds/m2 provides the correct balance between maximum competitiveness and optimum plant population.

Extra care should be taken on heavy fertile sites, where excessive seed rates can result in increased lodging and disease risk, leading to increased plant growth regulator and fungicide requirements and costs.

5. Maintain tiller numbers
Balanced crop nutrition plays an important role in tiller survival and in the past, growers have been reluctant to increase nitrogen application rates in spring malting barley crops through fear of exceeding maltsters’ grain nitrogen limits.

However, the latest AHDB Recommended List varieties produce more tillers and higher yields, so in some situations additional nitrogen is required to maintain tiller numbers and maximise crop potential.

In trials, Limagrain has seen a benefit of upping nitrogen rates from a standard seed bed application of 120kg/ha to 150kg/ha, with the additional 30kg/ha applied at tillering (see Chart 2).

This was previously considered a risk to malting quality, but due to higher yields diluting the additional nitrogen taken up by the plants, this can be done without exceeding grain N percentage limits for malt distilling of 1.65% (see Chart 3).

Limagrain trials have also shown that additional nitrogen can certainly be beneficial to maximise yield potential in poorly established or lower tillering crops.

In addition to nitrogen, phosphate and phosphite will promote rooting and micronutrients such as manganese will help keep plants healthy, all reducing the risk of tiller loss through the spring.

TIP: Always refer to latest RB209 Guide.

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