BENEFITS OF TAILORING N APPLICATIONS TO SPRING BARLEY

New high performance spring barley varieties often grown on heavier soils, mean existing fertiliser recommendations are coming under the spotlight.

“Spring barley is a complex crop, traditionally grown on lighter soils by farmers who specialise in producing malting barley. But as more farms turn to spring cropping to help spread the workload and combat grassweed issues there is a need for good, modern advice on a range of management issues, including Nitrogen rates, application timing and Sulphur to help meet quality specifications”, explains Dr Sarah Kendall, Crop Physiologist at ADAS Gleadthorpe, Nottinghamshire.

CF Fertilisers arable agronomist Allison Grundy, highlights the lack of recent evidence for spring barley stating “this knowledge gap was particularly evident with a lack of N management data for heavier land and application rates to reliably achieve higher grain N contents from new high-yielding spring barley varieties”

ADAS has been working with CF Fertilisers since 2016, and 2018 marked the start of a three-year project involving multiple partners with trial sites in Norfolk, Nottinghamshire, North Yorkshire and Scotland. Each site is testing several varieties to assess the optimum rates of Nitrogen (N), different rates of Sulphur (S), varietal impact and the effect of different timings on grain yield and N.

CF Fertilisers commissioned ADAS to review, update and improve the data for use in the CF N-Calc programme, which now includes N recommendations, so crops meet high, medium and low levels of grain N. Using this in conjunction with the CF N-Min service, the only Nitrogen test to measure both Soil Mineral Nitrogen (SMN) and Additionally Available Nitrogen (AAN), enables the Total Nitrogen available to crops during the growing season to be accurately quantified.

FINE TUNING APPLICATIONS ON C.W. RICHARDSON & SONS' 400ha FARM AT SWATON NEAR SLEAFORD

Fine-tuning N applications last year enabled owner Chris Richardson to achieve spring barley yields of 7t/ha despite the incredibly dry season, which was not much less than the farm’s five-year average.

Chris explains “During the last four years we have increased spring crops from 10% of the farm to 45%-50% to help combat grassweeds, particularly blackgrass. It’s an increasing issue in this area, so we want to prevent it from becoming a major problem. Chemicals are becoming less effective and increasingly costly, which has reduced significantly the difference in margin between winter and spring crops. All of the original fields that were spring cropped three years ago have now been returned to winter cropping, proving the effectiveness of this approach.”

Heavy land at Grove Farm is well suited to producing spring barley with a higher grain N and the £35/t premium more than compensates for Explorer’s slightly lower yield compared with other varieties .Anheuser Busch, the brewer of Budweiser beer, are keen to expand production and offer an enhanced premium for 1.8%-1.9% Nitrogen barley. Budweiser is brewed using water, barley, malt, rice, yeast and hops, the 1.8%-1.9% Nitrogen barley being required to counteract the low N content of the rice.

Arthur Baldwin, Area Manager, ACT Ltd, produces the farms’ fertiliser recommendations and paperwork recording good practice and regulatory compliance. Chris has been a committed user of the CF N-Min system for the last ten years and states “The CF N-Min recommendations have always been spot-on and crop yields have been equal to, or better than those we would have achieved by using our previous fertiliser rates”

2018 - A CHALLENGING WEATHER YEAR

Initial fertiliser recommendations calculated following the N-Min tests were based on the farm’s 8.5t/ha five-year average for spring barley grown in a trial situation, however, as the crop had unavoidably been drilled three weeks late and the forecast was for continued dry weather throughout the shortened growing period. Therefore Chris and Arthur Baldwin reasoned that it could not achieve its full potential and reduced the target yield to 7.5t/ha. Fertiliser applications were based on that figure and as the season progressed it became evident that was a good call. The crop got off to a flying start and its roots had penetrated the heavy land quickly where they were able to tap into what little moisture was available. Following the N-Min / N-Calc recommendations Chris applied the second dose of Nitrogen as Nitram (34.5%N) during the first week of May and a third during the third week of May (see tables 1 and 2).

Chris explains, “It was amazing despite the incredibly dry season the average yield for spring barley was 7t/ha. Reducing the yield target from 8.5t/ha to 7.5t/ha saved approximately £12/ha in fertiliser that would not have been utilised during this exceptionally dry season. That reduces our costs, avoids wasting a valuable input and eliminates any potential environmental impact from over-application giving us the confidence to tailor our applications precisely to soil and crop requirements.”

NEW GUIDELINES

According to Sarah Kendall from ADAS, it is hoped the ongoing project will help growers optimise their spring barley Nitrogen applications. The new guidelines reflect no one-size-fits-all recommendation, so farmers must adapt to changing conditions and the results from the first year’s trials must be treated with a certain amount of caution because of the exceptional weather, but they show clearly the benefits of tailoring Nitrogen applications to crop conditions and potential. 

Growers who do not normally test for soil Nitrogen may wish to consider this a useful tool for the future

*Based on a crop value of £120/t, an N price of 0.51p/kg and an NS price of 0.69p/kg