Agronomy Advice

Barley needs more micronutrients than just manganese

Most barley growers will be familiar with manganese deficiency and will recognise deficiency symptoms and understand the causes. However, other micronutrients, particularly copper and zinc are just as important yet tend to be overlooked.

Farmer in a barley field
Farmer in a barley field
A deficiency of any single nutrient is enough to limit barley yield

Micronutrients have key roles to play in the growth of barley and oats and have an impact upon crop efficiency and, ultimately, yield. Manganese, copper and zinc are important micronutrients for all cereals and can increase the grain size and weight and also influence the number of grains per ear.

Manganese deficiency is commonly seen in all cereals with oats and barley being the most sensitive. Manganese is often referred to as the element of life as it triggers the water-splitting process which is the first step in the chain of reactions of photosynthesis.  It is also involved with chlorophyll production and has a key role in protein synthesis helping to improve N-utilisation in the plant.

Zinc, like manganese, is a component of many enzymes and is involved in protein synthesis, chloroplast development and carbohydrate metabolism.  Zinc is also responsible for auxin metabolism and regulating key growth processes.

Copper is important as a catalyst of photosynthesis and respiration and is also a constituent of several enzymes involved in carbohydrate and protein metabolism.

Manganese and copper are both immobile in the plant which means these nutrients cannot be moved within the plant from old leaves into newer ones as needed, so the timing of application becomes important.

Research has also demonstrated that manganese, copper and zinc have all increased the thousand grain weight in barley. When applying these nutrients at the T1 fungicide timing, we see increases in the thousand-grain weight and the number of grains per ear can be positively influenced with copper and zinc in particular. These three micronutrients have also been shown in the literature to improve disease resistance in crops, a healthier plant has improved defence mechanisms against fungal infection and therefore is better able to deal with them.

Manganese, zinc and copper influence both grain size and grain weight

Manganese, zinc and copper with their roles in nitrogen metabolism within the plant will improve wheat grain size and grain weight.

Research has demonstrated that manganese, copper and zinc have all consistently increased thousand grain weight in barley.

Effect of copper, zinc and manganese on barley grain numbers per ear

Effect of copper, zinc and manganese on barley thousand grain weight

Instead of applying just manganese consider including copper and zinc too.

Grain size in barley can be reduced by late nitrogen applications. Secondary tillers form ears with small grains, therefore affecting the overall quality of the harvest. Nitrogen applied early will ensure a canopy that is large, containing high levels of stem carbohydrate that is translocated to the developing grain during maturation. If we go back to micronutrients then both manganese and zinc have roles in nitrogen metabolism by the plant and therefore sufficient supply will improve grain weight.

It should be noted that for yield attainment, grain number is more important than grain weight so care should be taken not to reduce it too much by focusing on grain weight. Small grains can also be caused by delayed or late applications of nitrogen that causes secondary tiller growth to form ears and grains. These late ears will reduce the quality of the sample, being small and high in moisture content.

Since results confirm that all three micronutrients have an influence on barley yield it makes sense to include them together rather than just a straight manganese product, particularly when data from tissue analysis confirms that all three nutrients are often deficient together.

YaraVita Mancozin contains all three key nutrients and is, therefore, an ideal product to apply with the T1 fungicide timing on barley.  Where magnesium deficiency is also suspected YaraVita Magflo 300 should be applied at T2 to ensure sufficient Mg is present as the main canopy leaves develop and emerge.

Micronutrients are not just for high yield potential crops

Are micronutrients only worth investing in on high yielding crops? Is another question we often get. Whether a barley crop is 6 t/ha or 10 t/ha, any additional yield is the same value irrespective of total yield. There is an argument that every extra bit of yield that can be achieved on a low yielding crop helps to spread the fixed costs that are higher per tonne on a poor crop!

It is also worth thinking about the return on investment in micronutrients.  Based on current crop and product prices, if applying Mancozin at 2.0 l/ha, only an additional 18kg per ha are required to cover the cost of application.

Key actions

  • Apply YaraVita Mancozin at T1 fungicide timing, between the second node detectable stage and flag leaf emergence (GS 32- 37).
  • Where magnesium deficiency is an issue, apply YaraVita Magflo 300  at T2 timing.

How much will it cost?

See how much extra yield is needed to justify the cost of a YaraVita application.

YaraVita cost calculator

Extra yield needed to cover cost of application

23 kg/ha
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