LIFE STIMUL project: Yield Performance and Environmental Benefits of a Novel Biostimulant Seed Coatings

Ecological considerations, along with economic and environmental demands, are key drivers that continually challenge farmers to improve agriculture practices and techniques. Farmers must adopt the most profitable practices possible to generate higher crop yields, while using fewer chemicals and at lower toxicity levels. Ecological considerations have given rise to growing crops using new methods, such as integrated pest-management systems and precision agriculture. These new methods help strike a balance between the economic constraints prevalent in today’s market and the moderate use of plant-protection products, fertilizer and irrigation inputs.

With this in mind, over the past few years, Solvay has developed a range of bio-based, seed-applied biostimulants under the trade name AgRHO^® S-Boost™. Derived from a natural agro-polymer extracted from a legume plant, AgRHO^® S-Boost™ provides demonstrated benefits in terms of water and nutrient uptake of the plant that results in higher yields. Solvay’s bio-based biostimulant helps the plant thrive under various abiotic stress factors, such as drought, extreme temperatures and high winds, all of which can considerably reduce crop quality and yield.

Prior to the STIMUL project launch, data were still missing on how to leverage this innovation under conditions resulting from low-input cultural practices in order to reduce the environmental footprint by limiting fertilizer inputs and water consumption. Also, to grow this technology within the seed industry, it is critical to develop efficient and safe application recipes for products adapted to existing seed-plant technologies.

Funded by the European Commission (LIFE program), STIMUL (Seed Treatments to keep Inputs at Minimum Use Level) is a project led by Solvay in collaboration with Aegilops Applications, a French SME (small and medium-sized enterprise) that is  globally engaged in design and production of coating agents applied with seed treatments. The objective of the project is to generate field data to demonstrate that innovative biostimulants will give farmers the opportunity to significantly reduce fertilizer use and/or water consumption while maintaining the same level of yield.

Since 2016, in the framework of the LIFE STIMUL project, field trials have been conducted in different European countries to evaluate the agronomic performance of Solvay biostimulants. Field trials have been performed on various crops, including corn, soybean, wheat, rapeseed and sunflower. A high number of trial locations have been selected annually to assess the biostimulant performance in different conditions: climatic zones, soil type, crop variety and agricultural practices and techniques. The trials were performed using randomized complete block design in four replications for each tested product. Different notations were recorded during plant development to assess plant growth and final yield at standard moisture. For each trial, the plot was divided in two regions. One was managed with standard farming practices (e.g. standard nitrogen fertilization input), while the other corresponded to low-input farming practices (e.g. a 30% reduction in nitrogen fertilization input). This setup enabled Solvay to evaluate whether the biostimulant treatment could compensate for the yield loss triggered by low-input farming practices. Field trial results were computed and analyzed with agriculture research management (ARM) software. Statistical tests, specifically least significant difference (LSD) testing, were conducted to study the significant differences between groups. Results were considered significantly different when p < 0.05.

Together with its partner Aegilops Applications, Solvay tested different variants of the AgRho S-Boost™ range. The effects of the biostimulant treatment on grain yield are presented in Figure 1 for corn and Figure 2 for soybean. The biostimulant was applied at two dosage rates: 0.2 kg/qt and 0.3 kg/qt of active ingredient on seeds. The results presented in Figure 1 and Figure 2 correspond to consolidated results encompassing three years of field trials (2017-2019) conducted in four countries (France, Italy, Hungary and Romania) for corn and three countries (France, Italy and Serbia) for soybean. For both crops, these countries rank in the top four of European producers of grain maize and soybean (based on 2017 data). In total, 56 trials were conducted on corn and 48 trials on soybean.

For corn, the biostimulant at the lower dose rate (0.2 kg/qt) triggered a relative yield increase of +2.7%, whereas a relative increase of +2.8% was observed at 0.3 kg/qt. Both increases are statistically significant, compared to the control treatment. Hence, the biostimulant applied at 0.2 kg/qt and 0.3 kg/qt significantly increased corn yield, compared to the untreated check. The two dosage rates did not show any difference in terms of performance. Stable performances were observed from 0.2 kg/qt to 0.3 kg/qt.

Similar outcomes were observed for soybean results, as presented in Figure 2. The biostimulant treatment at 0.2 kg/qt triggered a relative gain of yield of +2.7%, while a yield increase of +3.0% was obtained at 0.3 kg/qt. As for corn, these two relative increases are statistically significant. In conclusion, the Solvay biostimulant applied at 0.2 kg/qt and 0.3 kg/qt on soybean seeds triggered a significant yield increase, ranging from +2.7% to +3.0% of relative increase.

The Solvay biostimulant modified the plant environment and metabolism, increasing root architecture by densifying secondary roots. This phenomenon was demonstrated at the laboratory scale with model experiments, as well as with field trials. Figure 3 shows observations made during the visit of a field trial on corn in Italy in 2018. The picture on the left shows a corn plant not treated with the biostimulant, while the picture on the right shows a corn plant treated with the biostimulant. Both clearly show that the biostimulant strengthens root development and maximizes plant establishment. Such a developed roots network enables an increase in nutrient and water uptake by the plant, and ultimately increases yield.

For the field trials conducted on corn, standard- and low-nitrogen input practices were compared to assess how fertilizer inputs might be able to be compensated by the use of the biostimulant seed treatment. Since 2017, 10 comparisons between full-nitrogen inputs and low-dosage rates of nitrogen (ranging from -30% to -50%) were conducted. Consolidated results are presented in Figure 4. When averaged over the different trials, nitrogen inputs were reduced by 41%, triggering a relative yield loss of -10% for the untreated check. The addition of the biostimulant seed treatment compensated for a yield loss of 31%. Hence, we could estimate that the biostimulant seed treatment could entirely compensate for a 13% reduction in nitrogen inputs.

STIMUL has demonstrated and quantified with a unique set of data that biostimulants can be used not only to optimize crop yield, but also as new levers allowing a decrease in agricultural inputs. Data consolidated in the last three years through the LIFE STIMUL project demonstrated a yield increase between +2.7% and +3.0% depending on the crop. Those data have been collected with biostimulants from the S-Boost™ range. With its partner Aegilops, Solvay demonstrated that the biostimulant offers the opportunity to significantly reduce fertilizer use while maintaining the same yield.

 
This article will be published in AgroPages '2020 Formulation & Adjuvant Technology ' magazine to be published this May. 

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