Driving the use of biostimulants within production agriculture, has been the identification of bespoke bacteria (endophytes) with the ability to fix nitrogen (N) from the atmosphere.

The principles being played out are similar to those demonstrated by rhizobium bacteria in the roots of legumes, including clover, beans and peas.

What makes endophytes specifically of interest, is the fact that they can fix atmospheric N, irrespective of where they reside within a cereal plant, grass or legume.

Syngenta has reaffirmed its commitment to biostimulants during a technical briefing on the subject, held this week.

Endophytes are non-pathogenic bacteria that spend a part of their life cycle within a plant host. This is achieved through a colonisation process.

Those with the ability to fix N can do so while residing in the leaves and roots.

Also of significance in this regard, is the rhizosphere. This is the region of the soil that is directly influenced by root secretions and associated soil microorganisms.

The role of biostimulants

Endophytes have a symbiotic relationship with the host crop. They receive energy from the plant in the form of sugars while, in return, converting atmospheric N to the ammonium cation (NH4+).

It is a process that misses out the formation of ammonia gas with the inherent potential for gaseous losses to the atmosphere.

In addition, the ammonium cation can be easily converted to the nitrate anion (NO3-) – the chemical form of N that is most easily assimilated by all plants.

N has long been recognised as a key plant nutrient. It is a key driver of both overall crop yield and quality.

It was only at the beginning of the 20th century that two German scientists, Haber and Bosch, worked out how to convert atmospheric N to ammonia.

This opened up the opportunity to develop bespoke N fertilisers for use in production agriculture.

However, the key drawback with Haber-Bosch process, is the vast quantities of energy required to drive the chemical reactions taking place.

Recent years have also seen a growing awareness of the environmental challenges that can arise when N fertilisers are used to excess.

Ammonia significantly deteriorates air quality standards, while nitrate leaching can significantly impact on water quality.

Interest in N-fixing endophytes has been stimulated by their ability to fix atmospheric N in ways that make all of the resulting nutrient available to the crop.

As a consequence, there is absolutely no escape of N to the atmosphere or into surrounding watercourses.

The end result is a win-win scenario for production agriculture, in theory.