Microalgae-Based Biostimulants in Agriculture: Science, Perspectives, and Challenges
Alberto J. Diaz-PCA/CCA, Dr. Pedro Cerda
12/18/2023
Agriculture is continously evolving field that is constantly seeking new technologies to feed the growing population while minimizing environmental impact sustainably. However, the traditionally slow rate of adoption in the industry poses a challenge to the fast development of new agricultural technologies. Although not new to the market, recent understanding of the benefits and mode of action of microalgae-based biostimulants provides new opportunities to expand their use in large-scale commercial agriculture.
In this article, we (Dr. Pedro Cerda and Alberto Diaz PCA/CAA) invite you into one of our “shop” conversations, by sharing two unique but related perspectives on the technical benefits to crops, and challenges to industrywide commercialization of microalgae-based biostimulants. Based on decades of combined experience, we visit some of the beneficial effects these materials can have on crops, while Alberto describes some of the limitations to widespread adoption and commercialization in US agriculture.
It is our hope you will find renewed interest in exploring the use of these biostimulants for your crops. Join us in this dialogue about the green future of agriculture!
The agriculture sector faces new and concurrent challenges in its quest to boost productivity to feed a growing global population while reducing its environmental impact and preserving natural resources for future generations. At the same time, it needs to maintain low production costs to compete in a globalized economy. Modern agriculture must, therefore, revise its practices by integrating novel approaches to producing food sustainably. One such innovative and eco-friendly approach is the use of plant biostimulants, which can reduce dependency on chemical inputs, particularly synthetic fertilizers while ensuring yield stability under unfavorable environmental and soil conditions.
According to recent European Union regulations, plant biostimulants are defined as "fertilizing products able to stimulate plant nutrition processes independently of the product's nutrient content." These biostimulants trigger natural processes in crops to improve nutrient uptake and efficiency, tolerance to abiotic stress, and modulate qualitative traits in the produce. They encompass various substances and microorganisms, including humic and fulvic acids, macroalgae and microalgae, animal or vegetal-based protein hydrolysates, silicon, plant extracts, arbuscular mycorrhiza fungi, and plant growth-promoting rhizobacteria.
Notably, algal extracts, including both macroalgae and microalgae, make up a sizable portion of the biostimulant market, accounting for up to 40% of the total. Microalgae, often referred to as 'in-house algae,' have gained increasing attention in recent years. While it is well-established that green and blue-green algae produce several bioactive and signaling molecules that are active on horticultural and agronomic crops, their targeted applications in plant science are still in their infancy.
The exploitation of microalgae-based biostimulants as a sustainable means to improve crop production under optimal and sub-optimal conditions is crucial for restoring the environmental sustainability of the agriculture sector.
How do the diverse compositions and delivery methods of microalgae-based biostimulants contribute to their effectiveness in mitigating abiotic stress and enhancing plant growth, and what are the key factors influencing their bio-stimulatory properties?
Recent research has shown that microalgal extracts have the potential to mitigate the detrimental effects of abiotic stresses, such as salinity and water stress. Some of the dominant microalgae species with bio-stimulation properties include Chlorella vulgaris, Acutodesmus dimorphus, Scenedesmus platensis, Scenedesmus quadricauda, Dunaliella salina, Chlorella ellipsoida, Chlorella infusionum, Chlorella vulgaris, Spirulina maxima, and Calothrix elenkinii.
The biostimulant activity of microalgal extracts is associated with the content of primary metabolites (carbohydrates, proteins, and lipids), key amino acids (arginine and tryptophan), vitamins, osmolytes (proline and glycine betaine), and polysaccharides (β-glucan). Additionally, various microalgae strains have been characterized by phytohormone-like activities, including auxins, cytokinins, gibberellins, abscisic acid, and brassinosteroids, which are crucial for enhancing plant growth, yield, and defense responses, especially against abiotic stressors.
The composition of biologically active molecules in microalgal extracts is primarily determined by the microalgal species, growing conditions, and extraction techniques. Different extraction methods, such as physical, enzymatic, and chemical approaches, are used to obtain various classes of metabolites from microalgae.
These microalgae-based biostimulants are typically delivered to plants and the rhizosphere through various modes, including soil drench or drip fertigation, foliar spray application, and seed treatment. While research has shed some light on the physiological and molecular mechanisms of microalgae-based biostimulants, their beneficial effects have been attributed to diverse direct and indirect mechanisms, such as biochemical and physiological changes, upregulation of key genes in plant metabolism, increased activity of microbial communities, and modulation of root system architecture to enhance nutrient uptake and efficiency.
“We’ve asked ourselves what can be done for microalgae-based products to increase their presence in the biostimulant market. Here are some thoughts.”
Obtaining data through field trialing of microalgae-based products could be expensive, but it is the only way to give consumers confidence and facilitate the entry of these products into the market. Companies considering a data collection program should be in collaboration with farmers, research centers, and researchers outside the company. This program should include the creation of experimental plots, both small and large, where trials are conducted to compare their microalgae-based products with conventional methods. It is important to collect data related to performance, quality, and profitability, concerning the farmer's standard. This data will not only help understand farmers' needs but will also build trust among consumers by demonstrating the effectiveness of products under real production conditions. Results should be reported, and the program adjusted as necessary to improve its long-term usefulness and effectiveness.
Companies must invest in the education of farmers. This involves providing detailed information about how microalgae-based products work and how they relate to biological processes in plants. This helps gain farmers' trust by demonstrating that products are backed by science.
Microalgae-based product companies play a fundamental role in promoting sustainable and environmentally friendly agriculture. To achieve this, these companies must invest in the education of farmers, providing detailed information about the science behind their products and their relationship to biological processes in plants, soil, and other organisms. This investment is not only important but also necessary for several fundamental reasons.
It is essential to highlight that it is not worth hiding information under the pretext that it is "privileged information." The opacity in the dissemination of the science behind organic products generates distrust in farmers and can lead to the spread of erroneous or dubious information. By providing detailed and accessible information, companies demonstrate their commitment to transparency and honesty, which is essential to establishing a relationship of trust with farmers.
Secondly, simply copying general information from books or other similar products is not enough. Each biological product may have unique characteristics and specific applications. Therefore, companies must explain the science behind their products in a personalized and detailed way. This involves not only describing the ingredients and processes involved but also showing how these biological processes relate to the expected effects in agriculture. Doing so provides farmers with the accurate information they need to make informed decisions about using these products on their crops.
Third, explaining how the biological processes of the product relate to the expected effects is essential for farmers to understand the efficacy and safety of these products. Farmers need to know not only what makes a product effective, but also why and how it works in their specific context. This allows them to optimize their use and maximize benefits while minimizing any negative impact on the environment.
Providing clear and detailed instructions on how to apply products is essential to ensure their effectiveness. This includes information on dosage, timing of application (by specific phenological stage or application threshold), and manner of application (e.g., foliar spray, irrigation, etc.). It is also important to highlight the specific conditions under which the best results are obtained. Furthermore, it is essential to indicate what other products they can or cannot be combined with to enhance or inhibit their action. It is crucial to take other conditions into account during application such as soil type. It is also essential to warn about conditions that reduce the efficiency of the product or when not to use it.
Companies must understand the specific needs of farmers in their target market. This includes considering climatic conditions, crop types, and regional agricultural challenges. Adapting products and marketing strategies to these needs is essential.
"3D Illustration of a microscopic view of microalgae"
In addition to these actions, companies should consider organic or green certification for their products, as this can increase market acceptance of organic products. It is also important to establish effective communication channels with farmers, such as workshops, webinars, or consultation services.
Cultural practices also present important challenges to the widespread adoption of algae-based biostimulants in agriculture.
In the US, agricultural practices are highly regulated. Land grant research institutions work tirelessly to address regulatory requirements, our farmers adhere to strict practices and record keeping, formulators adhere to registered label disclosures, and continued education is a hallmark of professionals. In such an environment, it is not surprising that new agricultural materials and methods always face strong challenges in the US.
In addition to the above, some laws recognize financial liability, which means that an entity causing financial harm to another can be held responsible for such damage. One can observe that there are two kinds of growers in the US - independently owned farms and corporate farming entities. It is important to note that independently owned farms have limited resources, which perhaps ironically, affords them a degree of freedom to explore alternatives without risking financial exposure. On the other hand, large corporate farming entities generate substantial amounts of food, which results in large financial transactions down the commercial pathway. To minimize financial risks, adhering to established practices and diligent documentation is crucial to prove that the farms, growers, workers, and advisors have performed within the industry-accepted standards. Practicing agriculture is similar to the practice of medicine, where the responsibility chain extends to the individual provider. Any PCA or CCA issuing field recommendations has legal (licensing), professional (certification), and to a smaller extent, financial exposure.
In this context, it is easy to understand why participants in large-scale agriculture are reluctant to adopt new materials, technologies, or practices that lack legally acceptable data to back up the claims of benefits. This is one of the main reasons why smaller farms embrace new materials more enthusiastically than larger ones. The primary issue, when it comes to industry-wide acceptance of biostimulants, is the lack of information, like what is available for developing fertilization rates, irrigation schedules, and pesticide recommendations. This barrier to trust triggers a precautionary response from a very conservative industry.
Improving our agricultural practices is crucial, and the use of microalgae-based biostimulants can offer significant benefits to cropping systems. However, despite these advantages, the adoption of these biostimulants in US agriculture still faces several challenges. The three main hurdles that prevent widespread adoption are risk management, biological interactions, and regulatory compliance.
Furthermore, in contrast with legal systems in other countries, recommendations issued by licensed or certified advisors in the US carry a risk of professional, legal, and financial liability. PCAs and advisors are reluctant to provide recommendations that may represent a liability risk. This potential risk of financial liability associated with adopting a novel technology can discourage even the most progressive farmer, advisor, or PCA from fully embracing the use of biostimulants.
While algae-based materials are not new, the use of biostimulants in mainline agriculture is relatively new. Early adoption is crucial for any innovative technology, but key challenges and areas of improvement need to be addressed for successful integration and widespread adoption.
Back in the early nineties, some companies refused to embrace the new Windows-based computer systems and believed the internet to be an ephemeral fad. In the end, many of those companies were overtaken by more progressive competitors. In hindsight, we can see that early adoption was not about being trendy, but critical business survival. How then, can we move forward with new materials for US agriculture, an industry that is notoriously conservative when it comes to change?
In our opinion, the primary barrier to the widespread implementation of microalgae-based biostimulants is the lack of actionable contextualized information. While we do have substantial information on the benefits of these products, much work needs to be done to develop the necessary tools for advisors to confidently issue field recommendations and document the results. Without these guidelines, growers and advisors must rely on their individual experience, which is a rare and precious commodity across the industry.
The education process starts with quality information provided by manufacturers. Growers and advisors need to understand what, how, and why of their biostimulants. Microalgae-based products can be especially complicated as they are "cropping system enhancers," meaning they can benefit many areas of crop production, such as soil structure, microbial populations and activity, plant-induced systemic resistance, nutrient mineralization, availability, and more. While any single or combination of benefits can lead to significant returns on investment, identifying the exact mode of action remains elusive.
Seeking the assistance of an experienced and educated crop advisor can be very helpful in overcoming information limitations. By applying IPM and BMP principles, a trusted advisor can maximize the value of biostimulants. Understanding the crop's limiting factors, what areas these materials can influence, and the metrics to document the effects, are key for issuing targeted recommendations, focused focus on addressing potential economic injury variables, while also tracking the benefits. However, even without tools like action thresholds and fertility guidelines, a properly targeted biostimulant can be very valuable in maximizing the crop's financial performance. Crop advisors can provide a layer of professionalism required to address the concerns of large agriculture interests that are still limiting widespread adoption.
There are numerous educational resources available through different university extension services, the Natural Resources Conservation Service (NRCS), and professional associations like the American Society of Agronomy, the Soil Science Society, and the Crop Science Society.
Algal extracts, especially those from green and blue-green algae, have gained increasing interest among the scientific community, crop producers, and agrochemical industries. They have demonstrated various biostimulant activities, such as increasing seed germination, seedling growth, crop productivity, nutrient use efficiency, and the quality of produce, as well as improving tolerance to abiotic stressors. However, several challenges must be overcome for the full realization of microalgae-based biostimulants:
In conclusion, the future of agriculture lies in sustainable solutions like microalgae-based biostimulants. With ongoing research and a focus on overcoming challenges, microalgae could play a pivotal role in making agriculture more environmentally friendly and productive.
In the coming weeks, we will explore in more detail each of the points visited above. We will dive into some of the effects of microalgae-based biostimulants and refer to actual field experiences. We aim to share insights that will motivate agriculture professionals to increase their consideration of these important materials, be that to fully integrate them into an existing cropping system or to take a serious first look.
Dr. Pedro Cerda, an esteemed agronomist and Ag Technical Manager in R&D for biorationals, biostimulants, and biopesticides, is renowned for his contributions to sustainable agriculture in Latin America.
Holding a PhD from the Universidad Autónoma Agraria "Antonio Narro", Dr. Cerda specializes in developing environmentally friendly agricultural products.
His work, pivotal in enhancing crop management and protection, reflects a deep commitment to sustainability and innovation in the agricultural sector.
