Crop establishment of cereals; the role of biostimulants

The use of biostimulants in crop establishment is now standard practise to many arable farmers. However, the extent and variety of biostimulants and soil conditioning products used during establishment has increased in the UK over the last decade. From speaking to our customers, this is down to the rapid uptake of direct drilling and other regenerative agriculture practises. In such situations biostimulants are seen as an essential tool to get the crop up and growing as quickly as possible, rather than just a ‘nice to have’ as seen in most conventional ‘plough, till, and sow’ situations.

Before sowing

Pre-planting is the perfect time to apply soil conditioners, or any biostimulant in a form that would interfere with the development of the crop if applied post-germination. This includes granular products, such as standard fertilisers and potassium humate granules. Many liquid fertilisers and biostimulants that would cause scorch on young foliage should also be applied now. Sometimes you may wish to apply a very high dose of a product to get a base level in the soil. Humic Acid, Liquid Gypsum, Lime Sulphur, Phosphorus Liberator and UAN nitrogen are all good examples of this. Yes they can be applied foliar at low doses, but for high doses you will want them to go on before sowing.

As an example, a typical application of potassium humate granules before sowing is 5kg / hectare.

Whilst Lime Sulphur is often applied as a foliar in very low doses, a high dose before sowing  is very useful if a field is suffering with a pernicious pest and pathogen year after year. This includes both nematodes and Fusarium. Doing so can act like a soil fumigant due to the powerful action of Lime Sulphur. However, use Lime Sulphur with caution, and not in high doses on a healthy soil as it will also kill many beneficial microbes and soil fauna.

Weed control

The co-application of fulvic acid alongside glyphosate is now routine for many regenerative farmers. The ability of fulvic acid to improve the foliar penetration of glyphosate (RoundUP) is found repeatedly on farms.

In organic systems the emphasis is on working with the crops (and cover crops) to out-compete weeds. Ensuring the crop has a good mycorrhizal network is also essential as a number of studies have shown that plants can perform better against weeds when they are connected to fungi. This is because weeds are in essence pioneer species, which colonise bare earth. Once the climax communities start to establish the fungi associated with those species exert their dominance over the soil.

Seed coating

The main biostimulant we advocate using at seed coating is chitosan.

Chitosan makes a good choice as a seed coating not just because of its biostimulant and has fungicidal activity. Chitosan is also a great choice because it dries to form a bio-plastic adding a layer of protection and providing a ‘vehicle for adding other active ingredients around the seed. This includes bacterial consortia, mycorrhizal spores, chelated micronutrients or extra conventional pesticides.

Many seed coating companies will coat your seeds with chitosan for you. Alternatively you can use the basic, but effective, method of putting the seeds in a clean cement mixer and applying a fine mist of diluted chitosan at ml / litre until the seed is lightly covered, but not sodden. If the seed does start to clump, simply leave the mixer running for an hour or two to dry the seeds out quickly. This technique is a bit of an art-form, but most people quickly get the hang of it. Plus it represents a very cost-effective method of applying a biostimulant to a crop!

Seaweed extract can also be used as a seed coating in cereals. However, the active ingredients are anionic (negatively charged) and thus not as good at adhering to the seed coat and for loading other actives on the seed. Plus you have to check that you are not using one of the extremely alkaline seaweed extracts that dominate in the market. Please contact us if you would like to know more on the best way to choose and use a seaweed extract on cereal crops.

Post-germination

Short-circuiting photosynthesis 

During spring in the UK there is a disconnect between light intensities received by the plant and the temperatures they are growing in. Therefore, if you are able get a healthy established crop during this period the light levels can be exploited. It is just under normal conditions the plants are being held back by the prevailing air and soil temperature. It is my belief that this challenge is the reason farmers see such advantage from using biostimulants during spring. Compounds such as amino acids require energy intensive metabolic pathways. So if you can provide plants with these they can use them directly without having to consume valuable assimilates at this key point of development.¹

The other great feature of an amino acid biostimulant during establishment is their ability to promote root growth. This is true of all amino acids, but especially glutamic acid (glutamate). Glutamic acid is found in high levels in meat, or more bluntly, dead animals. Therefore plants have evolved to detect glutamic acid as a sign of zones that will soon be high in nutrients as the dead body decomposes and hence roots proliferate in these areas. This could be a microscopic animal  like a nematode or a dead elephant. This is not surprising when we think of the powerful effect  glutamic acid containing compounds have on us humans, our taste buds respond to very low doses of mono-sodium glutamate and its ‘meaty umami’ flavour it imbues in food! So applying a biostimulant high in glutamic acid will be good for creating a strong root system that is essential for crop health and fulfilling yield potential. Potato farmers know this too well, with establishing a strong root system seen as essential for ‘tolerating’ the build up of pathogenic nematodes later in the season. The same will be true of cereal crops. 

Another advantage of amino acids is that they combine well with many other biostimulants, and can usually be tank mixed with seaweed extracts. Amino acids can also be linked to micronutrients to chelate them. However, the concentrations that can be reached with synthetic chelates is not as high, and the chelation power is not as extreme. 

Disease control

Farmers are well aware that successful control of summer diseases, such as rust, involve getting things right in the spring. At Eutrema our most successful customers routinely use chitosan to control of rust from seed coating through to the flag leaf opening.

If you need further convincing of the effects of chitosan for the control of fungal diseases in cereals simply do a search for studies on ‘wheat rust chitosan’ on google scholar.

When to transition out of an establishment program?

As we move into late spring and early summer, root establishment becomes less of an issue, but canopy growth and disease prevention remain prioritises. At this time other considerations such as disease control, flower development, and loading the grain with protein and starch will also become priorities. If you want to know more about the biostimulants and bio-pesticides that assist in these areas, feel free to contact us. 

Planning the purchase of your biostimulants

At Eutrema we have good stock of all the raw materials required to manufacture our unique  biostimulants and soil conditioners. However, lead times can stretch during March and April. This is because we always manufacture our biostimulants to order to ensure farmers obtain product with the longest shelf-life and with the highest bioactive concentration possible. So please do consider how you will integrate any biostimulant into your growing program in the winter months. Obviously, if you are located outside the UK, planning purchases in advance is a necessity to get them on farm in time for spring.

If you want to further information or clarification on any of the topics covered in this post, please do not hesitate to contact us.

¹ It was actually only relatively recently that scientists discovered that plants can absorb and utilise amino acids directly. Before the 1990s it was assumed that amino acids had to be broken down into amine nitrogen to be absorbed. This viewpoint was debunked by ecologists working on arctic flora in Alaska where it was found that amino acids found in the peaty soils where one of the main sources of nitrogen for these plants. For more info see: Kielland, Knut. “Amino Acid Absorption by Arctic Plants: Implications for Plant Nutrition and Nitrogen Cycling.” Ecology, vol. 75, no. 8, 1994, pp. 2373–83