Spring barley seed treatments for 2025

Spring barley has traditionally been a key crop for many areas of the UK, but over the last 10 years, it is grown more extensively due to black-grass issues or as a consequence of poor autumn drilling conditions.

Malting end-uses continue to attract premiums for brewing and distilling while some farmers grow it for feed and straw. Seed treatments provide a valuable tool to cope with disease and either cool or dry conditions that often pose a challenge for the crop, especially on heavier soils.

Here is an overview of the seed treatment options available to spring barley growers.

Base fungicides

Almost all certified seed receives a base fungicide to control seed-borne diseases, including loose smut, which is endemic but maintained at low levels using seed certification and routine seed treatment. Rancona iMix is Agrii’s preferred treatment as it combines the best loose smut activity while conferring good control of leaf stripe and seed-borne net blotch.

Where seed is to be sown without a base treatment, as is sometimes the case with farm-saved seed, it should first be tested to establish its status. Seed found to be carrying disease above threshold levels should not be drilled without a base treatment.

Nutritional seed treatments

Manganese deficiency and low soil availability are significant constraints on early growth. Soil pH, poor drainage, unconsolidated seedbeds, high phosphate concentrations and generally poor growing conditions can all negatively impact performance. Manganese uptake can also be compromised by limited root growth, wet soils, low temperatures and nitrogen deficiency.

Agrii offers iMan, a high-load formulation delivering 450 g Mn/tonne. Unlike other formulations, it is taken up through both the seed coat and the roots and is co-formulated with a chelating agent to prevent the manganese from being locked up by cations in the soil.

The use of iMan has delivered consistent yield benefits across all soils over the past nine years, to the extent that the data indicates iMan should be applied as standard as it routinely delivers a positive return on spend.

Seed treatments are not the only means of supplying manganese to the young crop. Starter fertilisers, such as Micro-Match Mn, help to bridge the four- to six-week ‘Hunger-gap’ between the emergence and later application of foliar nutrients. Evidence from Agrii trials shows that iMan and Micro-Match Mn perform similarly and are a worthwhile complement to foliar applications (Figure 1).

For the past eight years, Agrii has sold other nutritional seed treatments, including Zax (high-load zinc) and Fielder Copper (high-load copper), and while beneficial, these are less widely applied to spring barley than iMan. When used in combination, the benefits are amplified (Figure 2). Copper tends to be more responsive in Scottish soils.

Biostimulants

Agrii has sold Take Off PGA ST since 2011. The combination of stabilised phosphite and pyro-glutamic acid boosts germination and early crop establishment. Responses have been particularly good on drought-prone soils.

Vibrance Duo can be used instead of Rancona iMix to control seed-borne diseases with the benefit that it is a biostimulant that improves establishment, root and shoot biomass, and tillering. It is helpful in delayed drilling situations or on lighter, more drought-prone soils.

In summary

The case remains strong for the routine use of fungicide and nutrient seed treatments in spring-sown crops, especially manganese.

Only 20% of spring barley seed supplied by Agrii is treated with manganese, which suggests a missed opportunity for many growers to improve yield at minimal cost. Spring barley is routinely treated with a two-spray foliar manganese programme, but the overwhelming evidence suggests that early manganese applied is complementary and either as a seed treatment or starter fertiliser more than covers its costs.