Manganese – Avoiding Yield Loss In Spring Sown Cereals
30 October 2024Manganese 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
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
Management
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. 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?
- 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.
Treatment and application
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 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.
Written by: Mark Bowsher-Gibbs
Posted in
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