By Janet Kanters
For those players in the industry, biostimulants have a place, and many studies have shown their benefits. Indeed, the advantages of plant biostimulants have been reported numerous times. Yet, there has been a general lack of quantitiative assessment of the overall impact of biostimulants on crop production, hence, the doubt in some circles.
The study, ‘A Meta-Analysis of Biostimulant Yield Effectiveness in Field Trials’, was undertaken by Jing Li, doctorate student/research assistant, Thijs Van Gerrewey, post doctoral researcher, and Danny Geelen, all of Ghent University. In it, they summarized over one thousand pairs of open-field datasets to compare the yield gains of different crops (cereals, legumes, vegetables, fruits, root/tuber crops, and others) upon certain biostimulant application. Yield gains in open-field cultivation upon biostimulant application were compared across different parameters, including biostimulant category, application method, crop species, climate condition and soil property.
The overall results showed that the add-on yield benefit among all biostimulant categories is on average 17.9 percent and reached the highest potential via soil treatment; biostimulant applied in arid climates and vegetable cultivation had the highest impact on crop yield; and, biostimulants were more efficient in low soil organic matter content, non-neutral, saline, nutrient-insufficient and sandy soils.
“I'm (pleasantly) surprised that the benefit is so high on average given their broad range in scientific sophistication,” noted Matthew Wallenstein, chief soil scientist at Syngenta Group, on his LinkedIn feed. “No wonder the industry and growers are still enthusiastic about biologicals. If the average yield improvement is 18 percent, just imagine the potential of biostimulants driven by strong and sophisticated science, applied with data-driven precision.”
Biostimulant effectivenessCrop yield enhancement is a popular claim listed in the product description of many biostimulants. As various environmental factors and management practices influence yield performance, empirical knowledge that depends on different experimental conditions is of critical value for the farmer. Because of the variability in agronomic management and environmental conditions, studies with similar or identical biostimulants have resulted in different effectiveness data, noted the study authors.
“As crop yield is a multi-trait property, meta-analysis has been conducted to gain insight into the impact of soil property (Oldfield et al., 2019), climate change (Challinor et al., 2014) and microbial biostimulants application (Schütz et al., 2018),” they stated. “Hence, effectiveness remains poorly understood to what extent these variables affect non-microbial biostimulants.”
Variation in biostimulant effectiveness is expected as different crops respond differently to biostimulants, and the environmental conditions are likely also influencing the effects. “In this study, we looked at the bigger picture and queried the literature for data published on the effectiveness of biostimulants. The study focused on biostimulants derived from natural resources categorized according to their origin and chemical properties, and restricted to crop yield experiments in open fields that are closer to an application and commercialization target,” stated the authors. “The main result from the meta-analysis was that it revealed correlations between biostimulant effectiveness and impactors that have, insofar as we are aware, not previously been completely recognized.”
For the study, six subcategories of non-microbial biostimulants were categorized: chitosan (Chi), humic and fulvic acids (HFA), animal and vegetal protein hydrolysates (PHs), phosphites (Phi), seaweed extracts (SWE) and silicon (Si). The authors also reference plant extract-based biostimulants (PE) (excluding SWE). Products with a single active compound were not included in the review. Moringa leaf extract (MLE) was separated as a subgroup of interest, and the rest were other PE under the PE group.
With the high yield gain found, one would expect widespread use of biostimulants in many crop production systems. But this isn’t the case. The authors suggest the average yield increase they reported is an overestimation of what can be expected in a commercial context.
“Noteworthy here is that the efficiency of non-commercial products was seven percent higher than commercial ones (see Figure 1). Indeed, a more conservative estimation of the yield increase is warranted, and there is a need for a more systematic collection of yield data to conclude the effectiveness of commercial crop production systems.”
Figure 1. Percentage yield response to biostimulant application affected by the biostimulant category and the commercial status of biostimulant products. The point size correlates to the estimate's precision, and the error bars represent 95 percent confidence intervals (CI) of mean estimated effect sizes. The number of comparisons and studies is indicated in each line. The combined effect estimates and the heterogeneity test on the random-effect model (RE) are summarized at the bottom, where the heterogeneity test is significant (p< 0.001) and/2 ≥ 75 percent implies substantial heterogeneity. Chi, Chitosan; HFA, humic and fulvic acids; PHs, protein hydrolysates; Si, silicons; Phi, phosphite; SWE, seaweed extracts; PE, plant extracts; MLE, moringa leaf extract.
Previously, a meta-analysis focusing on humic substances under controlled environment and field studies reported an estimate just above 20 percent of the increase in
dry weight of shoot and root (Rose et al., 2014), which is close to the yield gain the study authors found (+17.9 percent) (Figure 1). In the case of microbial biostimulants, Schütz et al. (2018) found that the yield benefit in field trials was between +8.5 and +20.0 percent.
“Taken together, the published data show some level of consistency across the different biostimulants analyzed. Chemical fertilizers also contribute to a yield gain, and here the average contribution was estimated to be around 40-60 percent (Stewart et al., 2005),” noted the authors. “Considering that biostimulants are commonly applied as supplements under conventional fertilization schemes and in many cases usually contain NPK fertilizers, the net positive effect of the bioactive ingredients is expected to be a considerable fraction of the total yield gain. Nevertheless, biostimulants sustainably improve the yield and provide a solution to reducing the dependency on synthetic fertilizer.”
The meta-analysis illustrated that the extent of yield improvement varied across categories, with PE biostimulants and MLE as the best performing biostimulants (Figure 1). “MLE has been historically tested on many different crops displaying beneficial effects on seed germination, plant growth and yield, nutrient use efficiency, quality traits, and tolerance to abiotic stresses,” noted the authors. “The significant profitability and variability in MLE and other PE efficacy might be due to their complex composition of plant metabolites, containing many macro and mineral nutrients, osmoprotectants and antioxidants. PE also likely contains plant hormones, which, in small quantities, are known to harbour the capacity to stimulate crop production (Harms and Oplinger, 1988).”
The scientists estimated the effect of SWE products with more confidence, they said, compared to the other biostimulant categories, adding the consistency in yield benefits linked with SWE application is likely a result of the standardization of SWE extraction and formulation methods. The use of SWE as a plant growth regulator can be traced back as far as the Roman Empire (Henderson, 2004), with the first commercial product marketed in 1952 (Milton, 1952).
The meta-analysis also found that biostimulants consisting of complex mixtures were more effective, although it remains to be demonstrated whether the complex biostimulants exert stronger bioactivity because of synergistic interactions between bioactive ingredients.
Impact of applicationThe meta-analysis showed that biostimulants applied via soil resulted in about 10 percent higher yield benefits than foliar and seed applications “This outcome is surprising as foliar and seed applications deliver the biostimulants directly to the plant, allowing faster uptake of the bioactive ingredients,” noted the study. “For instance, surface spraying acts more directly and results in rapid responses to ripen fruits. Soil application of biostimulants likely has a different mode of action related to nutrient uptake efficiency or enhancing microbial activity on and around the crop.”
Yet foliar application is the favoured method – the authors posit that is because it can be merged with conventional spraying practices. “Remarkably, single biostimulant sprays were nearly as effective as multiple applications. This suggests that the yield benefit is likely due to nutrient supply and other rapid-growth stimulation induced upon spraying the crop once or twice. Also noteworthy is that applications above four times resulted in a negative trend with lower efficiency. The diminishing returns of higher biostimulant application frequencies may be caused by changes in the uptake and assimilation rate of effective agents throughout the germination, vegetative and reproductive plant developmental stages. In general, the efficiency of biostimulants depends on the plant's nutrient uptake rate, which is highest prior to maximum growth rates depending onthe crop type.”
Crop responseVegetable and legume crops showed the highest gain in yield upon biostimulant application
(see Figure 2). A previous meta-analysis study on the crop yield improvement via biofertilization with microbial biostimulants argued that vegetables require higher fertilizer concentrations for optimal growth, and legumes engage in symbiotic nitrogen fixation, which is stimulated upon the addition of microbial biostimulants (Schütz et al., 2018).
“As our analysis included only non-microbial biostimulants, the stronger legume response is not likely attributed to the stimulation of symbiotic interactions with nitrogen-fixing bacteria. It is currently unclear why vegetable and legume crops are more responsive to biostimulant application.”
Figure 2. Percentage yield response to biostimulant application affected by the crop categories. The point size correlates to the estimate's precision, and the error bars represent 95 percent confidence intervals (CI) of mean estimated effect sizes. The number of comparisons and studies is indicated in each line. The combined effect estimates and the heterogeneity test on the random-effect model (RE) were summarized at the bottom, where the heterogeneity test is significant (p< 0.001) and/2 ≥ 75 percent implies substantial heterogeneity.
Growing conditionsOverall, the meta-analysis illustrated that biostimulants showed the strongest crop yield effects in soils of low quality (acid and alkaline soils, saline soils, barren soils with low SOM, and P- or K-deficient soils. “Therefore, we suggest combining biostimulant applications with ‘integrated fertility management’ to maximize yield potential and reduce crop loss risk under climate change scenarios,” the authors advised.
The effectiveness of biostimulant application was the highest under suboptimal growing conditions of arid climates with low precipitation conditions. A similar conclusion was made from a meta-analysis on the yield improvement using microbial biostimulants (Schütz et al., 2018), noted the study authors. In addition, exogenously applied compounds may elicit a stress response that prepares the plant for subsequent stresses caused by limitations in water, soil fertility, or unfavourable temperature conditions.
“Phytohormones are also commonly present in biostimulants, and their interactions with plants are known to enhance osmolyte accumulation and tolerance to stress (Sharma et al., 2019),” stated the study. “In addition, plant-derived biostimulants contain antioxidants and improve the adaptation to unfavourable growing conditions by eliminating reactive oxygen species (ROS) (Drobek et al., 2019). Therefore, the bioactive compounds in biostimulants may evoke either stress alleviation (e.g., suppression of ROS) or induce stress response factors that trigger the immunity against abiotic stresses (Brown and Saa, 2015), validating the hypothesis that biostimulants are more effective under suboptimal growth conditions.”
ConclusionsThe authors state the meta-analysis underscores the importance of evaluating biostimulant application methodology and the crop cultivation conditions, and stressed that the impact of biostimulant application on crop yield depends on the type of products and application management.
“Our results also provide various environment-specific assessments of biostimulant performance in open-field conditions, which can be used to set up more effective farming practices for future biostimulant application strategies. In conclusion, biostimulants improve crop yield by reducing yield reductions under stress conditions. This approach can help improve food security for the growing world population under increasing climate change threats.” ●
…there is a need for a more systematic collection of yield data…
Researchers have found inthe campos rupestres – mountaintop grasslands that are a biodiversity hotspot in Brazil- – an unprecedented diversity of microorganisms that are highly specialized in capturing and recycling the phosphorus available in the soil. The discovery paves the way for the development of new agricultural biotechnologies aimed at increasing agricultural cultivars' phosphorus absorption.
Campos rupestres are located in the central region of Brazil. They are considered a biodiversity hotspot because they concentrate many single-occurring species in this region that are currently threatened by mining and animal farming activities.
The research was published on The ISME Journal by researchers from the Genomics for Climate Change Research Center (GCCRC) – an Engineering Research Center (ERC) constituted by Embrapa and the State University of Campinas (Unicamp), funded by the São Paulo State Research Support Foundation (FAPESP).
“The soil of this ecosystem is extremely poor in phosphorus and very acidic due to geological conditions. In spite of that, this ecosystem harbors almost 15 percent of the Brazilian plant diversity, and this intrigued us a lot, since it is an apparently hostile environment for plant development,” explains Isabel Gerhardt, a researcher at Embrapa Digital Agriculture and GCCRC and one of the authors of the study.
“There have been a lot of studies about the physiology of these plants in order to understand how they grow in this ecosystem, but from the perspective of nutrition associated with microorganisms, it is a first,” says Antônio Camargo, first author of the study developed during his PhD at the GCCRC with a FAPESP scholarship.
Soil nutrients are not always in a form that plants can absorb, but microorganisms can make such nutrients soluble for the plants to absorb. An example is mycorrhiza, a group of fungi that colonizes roots and helps plants absorb nutrients from the soil, and Bradyrizobia, bacteria that helps plants absorb nitrogen.
In the case of phosphorus, its absorption is known to be intermediated by microorganisms. The differential of the GCCRC study was to find a large diversity and abundance of bacteria that are highly efficient in making phosphorus available to plants in an environment where this element is poorly available. “We found many families of phosphorus-associated bacteria with about 25 percent more genes involved in the solubilization of the nutrient than those previously catalogued,” Camargo states.
To reach those conclusions, the researchers studied two plants of the Velloziacea family that are typical of campos rupestres. One grows in the soil and the other on rocks. They then collected samples from the plants, soil and rocks to analyze the microorganisms present there. All genetic material was sequenced and compared to public microbial gene banks.
A total of 522 genomes were identified, half of which were new to science. The study added 21 new families of bacteria. Some understudied phyla have been significantly expanded, as are the cases of the phyla Eremiobacterota and Acidobacteria. By comparing the genomes of bacteria from plants that grew on local soil and rocks, the researchers found that those were very different communities, but with overlapping species. “The most interesting thing is that the bacteria associated with phosphorus tend to be shared by the two plants and are very abundant,” Camargo adds.
Another aspect the group analyzed was whether the high number of genes related to phosphorus solubilization by the bacteria from campos rupestres was a general trait of the families described therein. To do this, the scientists compared the frequency of these genes with evolutionarily related bacteria found elsewhere. “We found that bacteria from campos rupestres tend to have more phosphorus solubilization genes indeed,” Camargo explained.
In the search for this rare nutrient in the environment, plants also do their part. The researchers have shown that they secrete solutions that attract bacteria through their roots. “Plants recruit microorganisms that solubilize phosphorus by having their roots secrete organic compounds such as amino acids and organic acids that recruit such microorganisms,” the authors explain.
“These findings show that campos rupestres harbour an enormous genetic repertoire that is still little known to science. All this information can generate valuable technological assets in a bioeconomy model,” Gerhardt adds. “This is another reason to seek the sustainable use of those areas and the preservation of the biodiversity that exists there.”
One of the expected developments from the published study is to help to select phosphorus-solubilizing bacteria to support new agricultural biofertilizer technologies. ●
Located in the central Brazil, the biome campos rupestres(rupestrian grasslands) are considered a biodiversity hotspot because they concentrate many endemic species. Photo: Rafael Souza (GCCRC)
Rovensa Group has launched Rovensa Next, a new global business unit dedicated to biosolutions for agriculture.
Rovensa Next aggregates 10 Rovensa Group companies, creating a platform of biosolutions to shape a sustainable future for agriculture and drive its bio-transformation. With this announcement, Agrichembio, Agrotecnología, Idai Nature, Microquimica, MIP Agro, OGT, Oro Agri, Rodel, SDP, and Tradecorp will become part of the new business unit, combining local technical knowledge, innovation and teams that work alongside farmers and distributors in the field.
“Farmers and distributors do not need a singular product or a multi-card generalist; they need specialized advisers to help them create a potent strategy that considers their local environment and challenges,” said Eric van Innis, Rovensa Group CEO. “Rovensa Next is our answer to our partners’ needs for sustainable crop management that leads to safe and healthy products with better quality and increased yield.”
Rovensa Next unites a global network of 30 R&D laboratories, excellence centres, fields and greenhouses; 14 production plants; more than 84 partnerships with research centres and universities; 100 R&D and innovation specialists; and a dedicated team of more than 850 field experts.
According to Carlos Ledó, co-chief operating officer of Rovensa Next, with a rising population and a changing climate, there is a need to transform the agricultural sector. “The formation of Rovensa Next, consisting of 10 brands with entrepreneurship in their DNA, gives us the right talent, know-how, expertise and innovation to drive the necessary change in agriculture. The time is now for sustainable transformation.”
José Alfredo García, co-chief operating officer of Rovensa Next, added: “We want to be a trusted partner that helps our customers drive sustainable transformation without compromising on performance and yield output. Our unique value add is our team of field experts that work on the ground with growers to understand their needs and solve their challenges. By uniting all of our local and specialized expertise in various crops and geographical areas into one global portfolio of solutions, we aim to help facilitate, or even kickstart, the bio-transformation for customers, ultimately helping to shape an overall more sustainable future.”
With the new business unit, Rovensa Group anticipates a turnover of more than EUR 1 billion by 2025. The global transition to Rovensa Next will be followed by local implementation across all countries from July 2023. ●
José Alfredo García, Co-COO Rovensa Next, Javier Calleja, incoming CEO Rovensa Group, Eric van Innis, CEO Rovensa Group and Carlos Ledó, Co-COO Rovensa Next.
Acadian Plant Health has revealed ‘Sea Beyond’ as its new branding and vision for innovative biostimulant solutions.
“Our ‘Sea Beyond’ launch is our new vision, leadership and commitment to providing innovative and sustainable solutions for global agriculture,” says Nelson Gibson, president, Acadian Plant Health. “We are challenging conventional thinking to ‘Sea Beyond’ the way the biostimulant industry delivers agricultural solutions that respond to the growing global demand for food and climate stress.”
The announcement builds on the company’s leadership position in the global biostimulant sector, to become the leading crop abiotic stress management company with patented seaweed core technology. Acadian Plant Health research and development delivers sea-to-land, science-based solutions, proven to alleviate crop stress from factors like drought, heat, chill, salinity and nutrient deficiencies, while still maintaining and improving the productivity of the crop. Acadian Plant Health products are designed and created as unique active ingredient solutions that will both stand-alone and fit into other technologies to solve key agricultural challenges.
“The more we spoke with our customers, the more we realized that there is a misconception of ‘either/or’ when it comes to performance and sustainability,” says Gibson. “There is a perception that you couldn’t get the yield you needed with ‘eco-friendly’ products. But we’re challenging this conventional thinking. Working together with our industry partners, our biostimulants promise stronger yielding crops in a sustainable manner, which we have been proving with science for the past 40 years.”
Acadian Plant Health opened its second Formulation Centre of Excellence in Malvern, U.K, in December 2021. The facility is designed to tailor proprietary formulations for the company’s partners. The company’s first Centre of Excellence is in Cornwallis, Nova Scotia, Canada.
Acadian Plant Health is a division of Acadian Seaplants Ltd, which is the largest independent marine plant harvesting, cultivation and extraction company in the world. ●
Indigo Ag, Inc. and ISAOSA, a fertilizer distributor in Mexico, announced plans to bring Indigo's microbial technology to Mexican corn growers for the first time.
Indigo 30, which is part of Indigo's biotrinsic portfolio of microbial products, has shown to increase crop yields of corn. The formulation will enable Indigo 30 to be directly mixed with fertilizer, which expands the window of application of the product for farmers.
According to Georg Goeres, global commercial biologicals licensing lead for Indigo Ag, the results of multiple trials “have demonstrated significant yield improvements for corn growers. This novel formulation, which is incredibly hard to achieve, enables Indigo 30 to be directly mixed with fertilizer for the first time. This significantly broadens the window of application for the farmers as well as creating new market opportunities for Indigo to work with fertilizer producers.”
Commercial launch is planned for the first half of 2024 following completion of the registration process.
Under the proposed agreement, ISAOSA would be the exclusive distributor for Indigo 30 in Mexico and will add the product to its fertilizer portfolio. ●
Verdesian Life Sciences announced a new biological growth enhancement liquid for all crops. Accolade, which contains Azospirillum brasilense – a free-living, nitrogen-fixing bacteria – can increase root development and secondary lateral root systems.
According to Kurt Seevers, technology development manager with Verdesian, the rhizobacteria doesn’t inhabit a nodule so it can be used with all crops. “In furrow or on the seed, it grows alongside the roots as they expand. The plant provides nutrition for the bacteria and, in exchange, the rhizobacteria in Accolade produce nitrogen.”
The company states that in trials, the product worked well on corn, as well as pulses, cereals and soybeans, bolstering plant
performance in stressed conditions. Especially with corn, Accolade supports young root systems with early access to nitrogen, giving them time to grow into nitrogen that is applied later in the season or incorporated into the soil. ●
Ferm O Feed and Plant Health Cure (PHC) have merged into Den Ouden GrowSolutions.
The Netherlands-based businesses both specialize in soil improvement and fertility, and offer solutions to stimulate plant growth (GrowSolutions).
Ferm O Feed develops organic fertilizers and biostimulants and distributes them to 75 countries worldwide. PHC is an expert and leader in the field of mycorrhizal technology and soil biology.
While business units Ferm O Feed and PHC will jointly continue under the name Den Ouden GrowSolutions, the former trade names will continue to exist as they are, and product portfolio will also remain the same.
PHC’s head office will stay in Schijndel, The Netherlands, while the production location of Den Ouden GrowSolutions is located at the current production location of Ferm O Feed in Helmond, The Netherlands. ●
Olmix Group has acquired French biotech company Bois Valor, expert in foliar biostimulants and seed treatment solutions, using substances extracted from wood and plants.
With this acquisition, Olmix intends to accelerate its growth by consolidating its portfolio of bio-sourced solutions for soil and plant health and seed protection.
Both companies have developed a complementary industrial know-how focused on the extraction of active ingredients and the design of technical solutions for the whole agricultural sector based on natural resources: algae for Olmix, wood byproducts and plants for Bois Valor.
Bois Valor was created in 2004 after 15 years of research in collaboration with the National Superior School of Agronomy of Toulouse (ENSAT) on substances extracted from wood and plants. The company set up its headquarters, research laboratory and industrial site in Saint-Juéry, near Albi in southwest France, to exploit the patent that resulted from the research work on a unique extraction process. The company’s product portfolio consists of registered biostimulants, seed coatings and solvent-free extracted plant molecules. ●
