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Healthy and productive soils: Why farmers like plant biostimulants

If you were a farmer anywhere in Europe, you would face an immediate risk of a decreasing productivity of your land. Lower productivity means directly a lower income.

The main drivers behind the reduced productivity of the soils in the EU are 2-fold:

1. Economic pressure to intensify crop production
2. Stricter regulations for mineral fertilizers and pesticides

By: Martijn Buijsse

There is a lot of pressure on the profit and loss account of farmers. This is mainly caused by constantly low- or extremely volatile prices for agricultural goods. Next to this, many measures to maintain soil fertility do not provide sufficient economic return on the short term. This makes it difficult to convince farmers to change to more extensive crop rotations or farm management practices. Actually, on the long term the trend is that farmers in general choose to farm with a smaller crop rotation. The trend of intensification of land-use already started after WorldWar 2 when the EU agricultural reforms started. It was also the period where the industrial revolution lifted off. This trend of intensification of land-use cannot be turned around in the coming decades. Further global market orientation of the EU is expected and food demands around the globe will further rise.

The intensified production has also led in some places to negative environmental effects affecting life of micro-organisms and fish in water and insects and birds in the air. Around the nineties EU member states respond to this with (strict) regulations. For example the water framework directive and the nitrate directive limits directly the use of manure. Along to this also the availability of nutrients to plants is limited. This all leads to improved situations throughout Europe, though still in many areas’ targets are still not met. The problem is that the European and also the global farming community already got used to the intensified economy of farming. It cannot turn back to practices with lower productivity. In addition to this it seems also that the willingness and capacity of citizens to pay more for their food is limited. Environmental costs cannot simply be covered by the market.

In order not to stimulate polarisation between the “economy” on the one side and “environment” on the other side this blog calls for more emphasis on healthy soils in existing regulations. And this blog calls for more recognition of biostimulants as a practical measure that farmers want- and can work with.


The future of plant nutrition

As most farmers today produce the majority of their products for the global market, the cost competitiveness is too challenging to change drastically their farm management as compared to what they are used to from 10 or 15 years ago. Cost-effective measures should be provided and promoted to make a change. Therefore, we all should focus on “ready-to-use” measures that work for healthy soils, capturing carbon, avoiding leaching- and the need for pesticides is as much as possible prevented by healthy and resilient plants.

Then, plant nutrition comes around the corner, because healthy plants need good nutrition and therefore need fertile soils (fertility in its holistic meaning: chemical, physical and biological). To achieve the equilibrium and a balanced plant nutrition, all types of fertilizing products have their importance as well as their limits. Organic fertilizers play a role in returning organic carbon to the soil, but their nutrients can be less available or too available at a moment of the crop cycle where it is less needed by the plant. Biostimulants can increase the nutrient use efficiency but are in most cases not delivering nutrients in itself. Liming materials are important to control the pH of the soil and ensure its quality. In fact, betting on the synergies between the different fertilizing products – instead of opposing them – makes a lot of sense.

Considering biostimulants more specifically, in the recent years more products find its way to the market. Biostimulants seem to become more and more to the foreground as a cost-effective measure for farmers. These products help in order to obtain a healthy soil and maintain productivity levels. This all at the background of difficult requirements from legislation. Despite the fact that  biostimulants are still associated by many people with organic farming, they now have an important role to play in conventional agriculture as a complement to crop nutrition and crop protection.


The promise of Plant biostimulants

Plant biostimulants contain substance(s) and/or micro-organisms whose function – when applied to plants or the rhizosphere – is to stimulate natural processes to enhance/benefit nutrient uptake, nutrient efficiency, tolerance to abiotic stress, and crop quality (source: EBIC).

The following three examples of biostimulants show what they are and what they do for a better soil quality.

Globally the most used biostimulant is the nodule root bacteria. A good example of this is the Rhizobia bacteria that allows plants a symbiosis between nitrogen from the air to be stored in the root system. In particular Rhizobia-bacteria are used to improve the performance of soybean and other legumes around the world. Rhizobia are strings of bacteria that are available in many forms. The bacteria are inoculated, coated, around the seeds. At the moment the seedgerms emerge, it touches the bacteria and small nodules become available on the roots that are able to capture nitrogen. When the plant comes in the stage of new seed production the nitrogen stored in the nodules is transported via the plant to the new seeds. If this has been executed successfully by the plant the seeds can be harvested.

The second example is Mycorrhiza. Mycorrhiza are better known as soil fungi. This type of product improves soil life on a micro level. The fungi absorb minerals from the soil and provide them to the root system of plants or trees where it encourages the same type of symbiosis as the nodule root bacteria. In return the mycorrhiza receive sugar from the host plant to survive. Often the fungi are mixed with a granulate or a powder in order to apply the product to the soil.

The third and last example is the plant biostimulant composed of humic substances. Humic substances are part of humus molecules which are capable to form complexes with precious nutrients like nitrogen, phosphate or potassium. It stimulates processes that take place in the soil, making nutrients and micronutrients more readily available for plants. Additionally, various physiological effects are seen in plant roots, which improves the absorption of nutrients and increases the plant’s resistance to stress. Humic substances can also be coated around mineral fertilizer in order to improve their efficiency.

Each of the three examples above shows that the use of biostimulants provide efficiency and environmental benefits.


What is required from a farming perspective?

The examples above show that plant biostimulants can deliver value to farming both environmentally and economically! However, farmers face uncertainty when it comes to products and use of the biostimulants. It is for this reason to call for more recognition on these products. This is important in a time where new technologies and synergies are developed between the seeds and the (mineral) fertilizers industry on the one side and the biostimulants industry on the other hand.

A better uptake of biostimulants is already part of the proposal for the new fertilizer regulation. This is important and the farming community supports the idea that biostimulants are not defined as pesticide as it does not directly have an effect on pests and plagues. And are not directly seen as a fertilizer as they do not add nutrients in itself to soils.

And finally, the farming sector needs an updated regulation on the use of biostimulants, classifying clearly product groups and products. A regulation for biostimulants is expected for 2022.



The farming community is facing more and more uncertainty around capturing healthy and productive soils. From a farmers’ perspective biostimulants deserve more recognition and visibility in this debate. This blog calls for more awareness on the limitations and synergies of the different fertilizer products and tools. Concerning plant biostimulants; there are good products available with clear and proven effects. And the marketsquare for the products involved is still evolving providing more and better products for the farming community. Biostimulants deserve a better position in Brussels’ regulations and implementations on member state level. Let’s collaboratively work forward on this!

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