Iron deficiency – Nitrogen is the real problem, not pH

Farmers growing crops on high pH calcareous soils often have issues with iron deficiency that can be hard to correct. The answer traditionally has been to use chelates such as EDDHA to keep iron available – but is there a better way? Lets look at how plants use iron.

When we look in the hedge or the side of the road we can observe that most wild plants have no iron deficiency even when growing on calcareous soils with high pH. Despite this most cultivated plants on the same soils have iron deficiency, this should make us ask a few questions:

  1. Why do cultivated plants have more iron deficiency?
  2. Can we grow plants in a way that prevents iron deficiency?

There is a strong link between nitrogen inputs and Iron deficiency

The more nitrogen plants receive the more Fe they require, however this is not due to a direct link between nitrogen uptake and iron use, rather it is a link between nitrate processing and iron use.

Plants need to use Fe as an enzyme co-factor for nitrate reductase enzyme systems, so when plants process nitrate into the proteins they are made from there is a requirement for Fe.

Indeed cultivated plants use as much as 70% of their available Fe for processing nitrates.

Nitrate uptake reduces iron uptake

When we look closer we can see that not only does nitrate (NO3) increase need for iron, it also reduces uptake when compared to other nitrogen forms. Plants use other forms of nitrogen such as ammonium (NH4) and amine (NH2) to take in non-mobile nutrients from CEC in the soil via local root zone acidification.

When plants take up ammonium or amine molecules, roots exude protons (H+), which help the root to dislodge and absorb bound nutrients like Iron. In nature plants have relatively low access to nitrogen and do not grow quickly, but the nitrogen they do receive is in a balanced mixture of nitrate, ammonium and amine. This way the plants iron supply keeps pace with growth.

In agriculture to make crops grow faster we increase Nitrogen supply via a variety of synthetic and organic N sources, but due to bacterial activity in the soil the quantity and form applied bears little resemblance to what the plant takes up.

With the vast majority of nitrogen picked up by the plant as nitrate – the form that uses lots of iron to process, and the form that does not trigger root absorption of iron. So we feed plants is a way that increases need and decreases supply.

To prevent iron deficiency we need to reduce demand and improve supply.

The priorities for reducing iron deficiency should be as follows:

  1. Reduce need for Fe
  2. Improve harvesting of locked up Fe
  3. Supply any additional requirement

The traditional approach over the last 40 years has been to ignore points 1 and 2 and focus purely on point 3. by supplying additional Fe in the form of synthetic chelates that stay soil available.

Use of amine N provides a better way to deal with Fe deficiency.

Elona-Fe

Levity’s scientists have developed Elona-Fe, a product that provides stabilised amine Nitrogen alongside Iron. This approach addresses, both access (better roots), demand (reduces plants requirement for Fe) and supply (provides iron in a highly available manner).

Supplying stabilised amine improves iron levels in crops in several ways:

  1. Promotes better root development providing better access to nutrients.
  2. Better harvesting of Fe from CEC sites via proton expulsion from root hairs.
  3. Reduces need for iron, as no need for iron intensive nitrate reductase enzymes.
  4. In Elona-Fe, the iron is linked to the stabilised amine. The plant pulls in iron alongside the nitrogen.

Additionally Elona-Fe uses Levity’s proprietary nutrient uptake stimulant ‘Catalyst’ which increase the speed of uptake and utilisation of Fe by the crop – so deficiencies disappear rapidly after application.

Elona-Fe provides farmers with an easy to use way of preventing and correcting iron deficiency, whilst also improving growth habit and photosynthesis to improve yield.

Contact us for more information about purchasing Elona.

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Award winning scientist and experienced agronomist. With multiple patents, and proven track record of product development in biostimulants, pesticides and fertilisers.

David Marks

Managing Director, Linkedin Profile