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How To Avoid Manganese Deficiency In Your Crop

19 April 2023

The cold, wet spring and general slow start to the growing season this year has seen Manganese deficiency much more evident than normal in winter barleys. While some crops have responded to applications of a Manganese product, others have continued to struggle, with at best a loss of tillers to be expected and in the worst cases, patches where plants have died off and rotted out.

While the weather has undoubtedly been the biggest factor at play in winter crops this spring, it does provide us with a timely reminder about the importance of Manganese in cereal crops and why it is important to be on the front foot when considering crop establishment and spray programs for spring sown cereals.

severe manganese deficiency in barley.

Why Manganese Is So Important

Manganese plays a key role within the plant, particularly in the processes associated with photosynthesis. In addition, it helps improve crop establishment and makes the plant more robust, both in terms of resistance to disease and general hardiness. Deficiency is widespread across the country and if left untreated, yield losses of between 30-60% can occur. Symptoms are easily recognised and will be well known to most farmers, namely-

  • New leaves will begin to pale and become limp initially followed by the development of chlorotic or grey streaks and spots on the leaves of individual plants
  • Irregular light green or yellow patches across the wider field, with tramlines / wheel marks remaining green although other reasons for yellowing e.g. waterlogging should also be considered.

It is also more common in the following scenarios

  • Fields with a higher pH
  • Fields with poor or unconsolidated seedbeds
  • Cold and dry weather
  • Cold and wet weather
  • Sandy soils

As with other deficiencies, prevention is better than cure and growers shouldn’t wait until it becomes visible in the field – by then it may be too late. As has been seen this spring, poor uptake or availability is the normal cause for deficiency to occur as opposed to an actual shortage of the nutrients in the soil. With this in mind, what can growers do to mitigate the effects in spring barley crops and how can they assess the likelihood of deficiency and the need to take action?

  • Despite the time pressures this spring and the later start to sowing, take the time to create as good seedbeds as possible. Achieving good seed to soil contact is the first step in ensuring seedlings will develop the best root system possible.
  • The rolling of seedbeds after sowing helps consolidate the seedbed, further improving contact between plant and soil. Consolidating the seedbed also helps retain moisture within the soil, helping sustain the young plant, aiding its establishment.
  • Identify and address underlying areas of compaction- if left alone, these areas will see poorer root development and ultimately reduced uptake.
  • Don’t over lime- apply lime as needed based on soil analysis results. Blanket applications may be simpler or easier, but in fields with a range of pH levels, taking levels above 6.2 will start to see nutrient lock up including Manganese.
  • Cereals grown in higher organic matter soils e.g. peat can be more susceptible along with fields following grass leys. Crops gown on light and sandy soils are also prone to Mn deficiency.
  • Does your farm have a history of Manganese deficiency? In many cases an application of Manganese will be applied routinely, however as margins are squeezed due to falling grain prices, its important to resist the temptation to cut out what is in most cases a very cheap and most likely, necessary treatment.
  • Using a combine drill with compound fertilisers containing Ammonium-N is believed to reduce the likelihood of deficiency, with the acidifying effects of the fertiliser helping increase the availability of Manganese in the early rooting zone.
  • How has the weather been and how is it affecting crop establishment? Cold periods after sowing can slow the development of the crop and its roots, again leading to reduced uptake.
  • As the crop develops it can also be worth taking tissues samples to show Manganese levels within the plant. Your agronomist will be able to interpret the results and while two years are never the same, helps build a picture for future reference.
Manganese 2

Treatment Options

Growers have a range of products to choose from, whether it is for treating a deficiency or applying for maintenance.

Seed treatments or coatings can be used and while these provide Manganese near the seed, they need to be followed up by a foliar application.

More commonly foliar applications of Manganese will be used. These can be in the form of powders or solutions and indeed there are many products available that allow other potential nutrient deficiencies to be addressed e.g. copper. Cereal crops can be very responsive to an application of manganese and it’s also important to remember that because you cannot see it, it doesn’t mean there isn’t a deficiency. Manganese products are on the whole fairly cheap usually and can be applied along with herbicides or fungicides although care should be taken to ensure products are able to be tank mixed. As always, take the time to read labels for suitable rates, timings and periods between follow up applications.

It can be very easy to adopt a “wait and see” approach however if there is a history of manganese deficiency on your farm or there is high risk of it developing, getting on early with a precautionary application can act as an insurance and provide piece of mind. It can also help give your crop the best possible start and best chance of success.




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