While usage of biological fertilisers and soil inoculants in other parts of the world is growing rapidly, it is possibly not something you have even heard a lot about in the UK. Over the last 15 years, research and development of bacterial soil inoculation, combined with the invention of state-of-the-art microbiological and biotechnological methods have yielded ranges of soil specific inoculants. These bacterial soil inoculations offer a way to improve soil health and promote plant efficiency.

Biotechnological and microbiological methods can help cut back on the use of nitrogen and phosphorus fertilizers once the correct soil levels have been balanced. Microbiological soil enrichment methods have been trialled for the past 20-30 years in Europe and the USA. These microbiological products have since progressed from experimental plots and spread to commercial plant production, in both field and greenhouse cultivations. Today, in Europe hundreds of thousands of hectares are treated with soil inoculants. So why have they not been adopted in the UK?

What we have seen in other countries

Trials in Hungary have isolated beneficial soil microbes including nitrogen-fixing bacteria that are capable of fixing and transforming atmospheric nitrogen into a plant available. Phosphate and silicate mobilizing soil bacteria can provide available mineral available phosphates and potassium to plants by solubilizing them. Phytostimulating strains should also be mentioned, they produce plant hormones and hormonelike substances, directly enhancing plant growth and development and improving abiotic stress tolerance. Research companies have spent years isolating and selecting these bacterial strains to create complexes of plant growth promoting, nitrogen-fixing, phosphate and potassium mobilizing soil inoculants commercially available, but relatively unknown in the UK.

Taking into account not only the beneficial properties but the rate of growth and metabolic activity of the strains in acidic or alkaline pH and at low temperatures reaserchers have had to develop specific inoculant products for specific soils. Field studies in have shown that inoculation with the right products reduces nitrogen and phosphate fertilizer use and enhances crop yield in corn, wheat, barley, sunflower, soybean, rape, rice, sugar beet, cucumber, pea, sweet pepper and tomato cultivations.

Exact numbers, of course, depend on the variety and the quality of the soil. Regulated studies for some products have confirmed – an 18% increase in corn yields and 39% increase in soybean yields. Results and efficiency of field inoculation is greatly subject to weather conditions, like virtually all agricultural procedures, so expected yields can only roughly be estimated. According to the official studies, the success of inoculation is marked by an increase in root length, stem height, number and surface area of leaves, total protein content, shoot mass and crop yield. Besides the increase in profitability, improving yields and possible savings on fertilizer costs, the reduced environmental load is also significant.

What now?

In the UK, it is certainly possible that these products have the potential to increase yields and reduce the usage of traditional fertilisers. However, in developing countries, where overpopulation and a rapidly increasing need for arable land exists, having biologically sustainable soils is critical to feed the population.

In China and India, the increased requirement for food production has driven the use of chemical fertilisers up by 60%. In nitrogen and phosphate deficient African soils, the increasing but unsustainable agricultural production is promoted by subsidiary fertilizers and seeds. If the developing world continues to rely on chemicals and keeps increasing usage, they will soon face the severe issue of soil degradation that has been seen in parts or Europe and the USA. Transportation, storage and application of live biological products brings new challenges to farmers.

Products have a shelf life that can be extended through refrigeration, but how many farmers could currently store an 800-litre pallet of inoculants at refrigerated temperatures? While the wife may be happy for 10 litres to sit in your fridge, 800 litres just won’t fit. Therefore, these products would need to be supplied on a just-in-time basis where products arrive on farm and are used within days ideally Factors like exposure to UV light will degrade the products rapidly so they need to be incorporated to soils quickly after application or ideally placed in the slot with seed under a no-tillage regime. There is still a lot for us to learn about soil inoculants. As more scientific and farm trials take place in the UK we will understand how effective these products can be and whether the margin over input cost when using them is returned. It is yet another interesting technology for farmers to understand and investigate over the coming years.

Trials in the UK

Trials are already underway in the UK, we will report on them as they are completed in future issues. If you are able to conduct a trial with such a product and want to test it this Spring then please do get in contact.