Using a foliar feed of urea and humic acid on pasture, a UK study set out to see if a foliar feed could replace soil-applied nitrogen while still producing the same level of grass, or dry matter yield. New AG International spoke to the project leader to find out the answer.
A three-year trial from2019-2021 was conducted in Wales on four farms in Pembrokeshire and Ceredigion. A foliar feed based on urea and humic acid was used alongside the conventional farm fertilizer protocol of solid nitrogen applied to the soil.
Nigel Howells was the leader for this European Innovation Partnership (EIP) Wales project.
“When I set the project up six years ago, nobody was interested,” Howells told New AG International. But things changed during the fertilizer price spike in 2021. This prompted interest in how nutrient efficiency could be maximised. Howells said they held a meeting where 95 local farmers came along to find out more about the project.
Howells points out that the idea of foliar application has been around for a while in the arable sector. The difference here was using humic acid combined with a liquid nitrogen formulation on pasture.
The conventional way to apply nitrogen is in granule or prilled form to the soil. The nutrients are washed into the topsoil by rain and are then taken up by the roots of the plant.As the report says, a host of factors such as soil compaction, drainage, bioactivity, soil temperature, and dry or wet weather can affect the nutrient release and uptake by the grass with this method. A more direct method of getting nitrogen into the grass is through the poresin the leaves.
Project method Based in Aberystwyth, Howells has 25 years of experience managing dairy farms, as well as 10 years
running his grass and soil management consultancy business. As well as coordinating the project, he was responsible for the gathering of 42 data points from every field, every week.
On each of the four farms, one large field was split into three equally sized sections.
The following treatmentswere made:
One section received standard prilled urea at a rate of 125 kg/ha of product.
Another section received foliar feed based on urea and humic acid, applied at three-week intervals during grazing season at rate of 20 kg/ha of product.
There was a control section that received no fertilizer application.
“We actually started off with another [humic] product, but it didn’t dissolve properly. Only 85 percent dissolved, leaving 15 percent organic matter, which created issues while using a conventional sprayer,” said Howells.
We actually started off with another [humic] product, but it didn’t dissolve properly.
That’s when a product from German producer Humintech was brought in. Susan Wilson, Humintech’s agent in the UK, told New AG International that although she already supplied arable farmers in various parts of the country, the dairy farmers she supplied added it to their slurry, where it proved highly effective.
While foliar feeding as a technique has been used for many years in the arable sector, this was the first study of the technique on pasture-based agriculture.
“The first objective was nutrient-use efficiency (NUE), and we ticked that box by the end, so we adapted the project,” said Howells.
In the second year of the project, a silage plot was added to one of the sites. The NUE was being exceeded with the foliar application after the first year, explains Howells, but “at low levels we weren't growing the same amount of dry matter as the conventional protocol.”
Forage from the silage plots was analysed for quality including dry matter, digestibility, crude protein, sugars and metabolizable energy.
In the third year, in the light of previous years data, the project leaders decided to look at the effect of increasing nitrogen (N) concentration in the foliar feed mix on nitrogen use efficiency.
Heart of the - dry - matter Two key metrics in the study were the dry matter yield and the N content of the fresh grass. They measured using a plate meter and nitrate meter during the year, respectively, between January to December.
Dry matter is a measure of what is left from the grass once the moisture is removed. This is a mixture of proteins, vitamins, minerals, fibre and carbohydrates. Dry matter matters because it is necessary to grow sufficient forage to feed the livestock over the winter period.
The amount of dry matter required depends on the ‘stocking rate’, said
Howells. If there are more cows grazing a plot, then more dry matter will be required. The dry matter will vary, but a typical range is 1.5-2.5 tonnes/hectare. The project had access to three paddocks in total with one being a control, which was the base for dry matter yield and with which a comparison could be made with the other plots.
“It took about three years to getthe funding to run the project,” explained Howells. “We made sure all paddocks had some clover in,<5 percent, as the control plot would go cold turkey on no fertilizer, and it did take 18 months to adjust to the protocol before growing an acceptable amount of dry matter. Sugars were higher using thefoliar than conventional. Higher sugar levels provide more energyto make better quality dry matter,” expanded Howells.
Better dry matter leads to better quality food for the livestock. One of the other observations from the trials was an improvement in animal health. Howells stresses this was not formally measured and was based on comments from the farmers involved.
Key results Absolute yields varied across the sites, depending on differences in growing conditions and elevation. The elevation from site 2, which was south facing at 30 metres (m) above sea level, to site 3, which was north facing and at 300 m.
Yield was highest in conventional plots (soil-applied urea), lowest in the control plots and approximately midway between the two in the foliar feed plots.
Yields were between 1 and 3 tonnes/hectare higher in conventional plots compared to foliar feed plots. This was not unexpected since the conventional plots received significantly more N.
However, the report notes there were exceptions.
In 2019, the foliar feed plots grew 0.5-1 tonnes dry matter (t DM/ha) more than the conventional plots up to the end of April, indicating faster
early growth. “This could bebecause of more rapid uptake ofN through the leaves compared to absorption through the roots at lower soil temperatures.”
In 2020, the foliar feed plots had higher yields at site 2 and 3 (2.5 and 0.8 t DM/ha respectively). One reason could be due to soil moisture conditions: the spring of 2020 was exceptionally dry, and the uptake from conventional fertilizer through the roots may have been reduced.
One conclusion given in the paperis the results suggest that foliar feeding may lead to increasedyield in cold and/or dry conditions, compared to conventional, dueto improved N uptake.
Chart 1: Dry matter yields 2020
Nitrogen use efficiencyOne of the findings of the study was that at the lower N concentrations,
the foliar feed increases NUE compared to conventional fertilizer.
NUE is defined as the increase in DM yield per additional kg of N applied.
On average, NUE was between 2 and 4 times higher on foliar fed plots compared to conventional plots [tables 1 and 2].
When explaining how NUE is improved, Howells said that the humic acid helps to stabilize the urea to reduce volatilisation and helps to the urea enter the plant. “This work is known,” said Howells.
In the report, the authors suggested the following reasons for the improved NUE:
The humate in the home mix, stabilises the urea in solution and helps carry it onto the grass leaf.
Reducing environmental losses when being sprayed, as well as helping to break grass cell wall down to allow the urea solution to be taken in by the leaf. “This process is more efficient than absorption through the roots.”
Humic acid is also a source of carbon which means the energy required for absorption is more readily available and does not draw on soil’s energy reserves.
When foliar feed enters the soil, humic acid is known to aid soil activity and make mineral and trace elements more availableto plants.
Final year – high rates of foliar fed N In the third and final year of the project (2021), the project tested the hypothesis of whether increasing the N concentration in the foliar feed would proportionately increase the yield. The N applied by foliar feeding
was increased from average of 70 kg N/Ha to 100 kg N/Ha.
The increase in N in foliar feed resulted in similar yields on conventional and foliar fed plots, in grazed and silage systems.
There was one exception – site 1 – which the commentary in the report puts down to field conditions. The authors suggest there were possibly low levels of magnesium on this site, which might lock up nutrients and reduce benefit of N and a light soil on the foliar fed plots, which may have had an impact during the drought in spring 2021.
In the final year – 2021 – the foliar fed plots continued to show increased NUE. These plots achieved similar DM yields to conventional plots by applying 40-50 percent of N, depending on the specific site. “The variation in sites and years makes it difficult to draw firm conclusions about the relationship between the concentration of N in the foliar feed and NUE,” said the study.
Looking at the table [table 4 from report], produced here with permission from Nigel Howells, it is possible to see that exception in site 1 where the conventional plot has 275 kg/ha applied in 2021, producing additional 5700 DM / kg N while the foliar fed had 110 kg /ha of N applied, with additional yield of 3200 kg/ha.
However, looking at the rest of the plots it can been seen that the additional yield in DM is equivalent for the conventional and foliar plots. As mentioned above, the foliar plots are showing greater NUE since the increase in N in foliar plots is bringing about a greater increase in DM. Taking site 3 as an example – the NUE (additional kg DM for each kg of N) is 8.4 percent while that for foliar feed is 26.4 percent. ●
Four farms took part in the trial – 3 in Pembrokeshire, UK and one in Ceredigion, ranging from 100-300 ha in area. All were dairy farms with 180-550 cows, either Holstein Friesian herd or Friesian cross bred.
The farm at the highest altitude was at 300 metres above sea level, with south and north facing land. Three farms where grass-based rotational grazing with one being a housed higher input herd.
The fertilizer application was after grazing, approximately every 21 days March through to October, through a sprayer. At the low rate: 20 kg of urea and 1.5 litres of humic acid diluted in 20 litres of water applied at 200 litres/ha.
At the high rate: 40kg urea with 1.5 litres of humic acid diluted in 20 litres of water and applied at 200 litres/ha. Solution prepared 24 hours before application.
Costs and benefits The report showed a detailed table comparing the cost of N per litre of additional milk (i.e. over and above the produced on ‘no fertiliser plots’) for conventional and foliar fed systems.
An energy balance was used to estimate the volume of milk produced in each system. It was assumed that 5.5 MJ of energy is needed to produce a litre of milk, and that forage contains approximately 11.5 MJ/kg DM (using analysis of forage at the plots).
The cost of the foliar feed ingredients was about 25 percent higher compared to conventional fertiliser. “This is partly because foliar feed requires unprotected urea to be used which is more expensive (£360 £/t) and partly because of the cost of humic acid (approximately £2.25/ ha),” said the report. “The application costs for foliar feed are also much higher than for conventional fertiliser (about £7.5/ ha for applying granular fertiliser compared to about £15/ ha for spraying foliar feed).”
The authors of the report said these additional costs were compensated for by increased NUE in the foliar plots. “With two exceptions (Site 4 grazed in 2020, and Site 1 in 2021) the cost of N per additional litre of milk was lower in foliar fed compared to conventional plots.The difference varied (range 18-89 percent across all sites in all years) but on average the cost of N per litre of additional milk produced was 39 percent lower in foliar fed systems.”
A notable feature of when this study was conducted was the high fertilizer and energy prices in 2021 and the beginning of 2022. The calculations presented in the report were based on prices at the time of data collection – prior to these price increases. “As N costs increase, the higher NUE in foliar feeds becomes even more important in reducing costs,” the authors wrote.
Conclusions from project This project set out to see if a foliar feed combined with humic acid could replace soil-applied nitrogen while still producing the same level of grass, or dry matter yield.
When summarising their conclusions, the authors said that at higher rates of N, foliar feeds achieved comparable yields to conventional application systems.
At lower rates of N application, yields were lower in foliar fed systems. However, NUE was greater in foliar fed systems.
Foliar fed systems achieved higher yields in adverse conditions for example in cool/dry conditions. “This could be because absorption through the leaves was less affected by adverse soil conditions compared to uptake through the roots,” saidthe report.
The conclusions stated that the data was unable to show any relationship between the method of N application and nitrate levels in leaf tissue. Peaks were observed in the plots with no fertilizer, which are linked to higher clover levels inthese plots.
“The higher NUE results of this project means that, at lower rates of N, foliar feed systems can potentially deliver significant benefits interms of reducing the N costsper litre milk.”
All about the soilAlthough the results of the project show that the same amount of pasture could be grown using less nitrogen, Howells adds a note of pragmatism: “You can’t expect to half usage overnight,” he said. “There is huge potential, but it all comes down to soil health. ●
Farming is a long game, and soil is a long game.
*The project ended in September 2021. In order to obtain a measure of the NUE, grass growth from October - December 2021 was estimated from figures for the two previous years of the project.
Table 4: Nitrogen Use Efficiency at higher concentrations of Nin foliar feed - 2020
BioConsortia has reached its 10-year anniversaryin 2024 and is looking to build on results in Brazil to acceleratethe launch of its bionematicide.
BioConsortia has released data from its trials in Brazil for its bionematicide product Solvarix.
The results for Solvarix echo those seen in North America, says the biotech company, headquartered in Davis, California, with laboratories in Davis and in New Zealand.
Dr. Debora Wilk, BioConsortia’s director of plant pathology, said: “Solvarix, in both USA and Brazil, has demonstrated direct control of important nematode pests and increased corn yields 578 kilograms per hectare (8.6 bushels per acre)on average.”
Wilk said the product was highly consistent, delivering increased yields in 91 percent of all trials and “outperforms leading chemical nematicides in both yield contribution and consistency.”
“BioConsortia’s microbial seed treatment products are an excellent fit for nematode challenges impacting key crops in Brazil like corn, soybean, sugarcane, cotton and vegetables,” said CEO Marcus Meadows-Smith. “Based on a patented strain of spore-forming microbes isolated using our powerful AMS [Advanced Microbial Selection] strain discovery system, Solvarix is shelf stable for two years and on-seed stable for an additional two years. This eases grower handling and storage of the product and opens a new addressable market among Brazil’s seed companies.”
BioConsortia says it is going through the registration process and anticipates launching Solvarix bionematicide through seed and crop protection partners, initially in Brazil and U.S. beginning in 2026, with global commercialization to follow.
This year marks BioConsortia’s10-year anniversary.
Talking to New AG International about the early days, Meadows-Smith said they had a microbe from New Zealand that they were trying to make work in the Midwest. “We tried to get a New Zealand microbe to love the Midwest soil,” he recalls. Starting again with a U.S. microbe for U.S. soils reset the discovery clock, he said.
With new products about to launch, BioConsortia is looking to sell to seed companies so they can sell pretreated or treated on-farm. ●
We tried to get aNew Zealand microbeto love the Midwest soil.
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Microbials in agriculture Biocontrol agents and biostimulants improve the resilience of plants against biotic and abiotic stressors, and are thus important sustainable crop inputs in agriculture. In particular, microbial agents offer a variety of beneficial interactions with plants. Commercially significant microbials include the Gram-positive rhizobacterium Bacillus velezensis, which produces antimicrobial compounds that are active against plant pathogens and can trigger induced systemic resistance, thus providing both biocontrol and biostimulant action.[1] The same applies to the fungus Trichoderma harzianum, which mobilises nutrients and protects against soil-borne diseases such as Rhizoctonia spp., Fusarium spp. and Sclerotinia spp.[2] The entomopathogenic fungus Beauveria bassiana is a widely used fungal biocontrol agent with efficacy against pests such as whitefly, the European corn borer and the Colorado potato beetle.[3]
However, maintaining cell viability is a persistent challenge, even for currently marketed microbial products. In many cases, products have short shelf lives and require cooling, and as a consequence, application may be inefficient. Formulation is a key factor for tackling this challenge. Many products come as wettable powders, but liquids are often preferred as they are dust-free, easier to dose, rapidly dispersible in water and compatible with filters. Carrier fluids for microbials need to provide a low-water activity environment to ensure cell viability. Because of this, aqueous carriers are often unsuitable and non-aqueous fluids are preferred.
The goal of the present study was to evaluate the potential of CITROFOL® AI to function as a carrier fluid for three commercially significant microbials (Bacillus velezensis, Trichoderma harzianum and Beauveria bassiana), focusing on its impact on cell viability. We also aimed to develop a protocol for adjusting the rheology of CITROFOL® AI to ensure stable suspensions. Finally, a greenhouse study was conducted to confirm that CITROFOL® AI is compatible with plants.
Benefits of CITROFOL® AI as a carrier fluid for microbials CITROFOL® is Jungbunzlauer’s globally recognised brand of citrate esters. The CITROFOL® range comprises clear, colourless and odourless oily liquids. One of these citrate esters is triethyl citrate, sold as CITROFOL® AI, which is produced by esterification of raw materials derived from fermentation and is thus 100% bio-based and biodegradable.
The physicochemical properties of CITROFOL® AI give it distinct benefits as regards handling and formulation (table 1). Firstly, it is non-flammable, non-volatile* and non-toxic, and therefore safe to store and handle. It offers water solubility of up to 58 g/L, allowing it to homogeneously dilute into water at relevant use rates, thus obviating the need for emulsifiers and allowing simpler formulations. It is stable at cold temperatures and well pourable over a wide temperature range, with a viscosity of 27 mPa·s at 25°C and 400 mPa·s at –10°C across shear rates.
*As defined by Directive 2004/42/EC
Table 1: Overview of relevant physicochemical characteristics of CITROFOL® AI
CITROFOL® AI is listed in international chemical inventories and is registered under the EU REACH Regulation. In the USA, triethyl citrate is approved as an inert ingredient for use in pesticide products applied to food and non-food, respecting the limitations set by 40 CFR Part 180. CITROFOL® AI is also USDA Certified Biobased under the USDA BioPreferred® Program, and is suitable for use in bio-based applications in designated categories.
Materials and methods Viability tests To assess the impact of CITROFOL® AI on microbial viability, commercially significant microbials were obtained from the market as formulated products. These comprised the Gram-positive bacterium Bacillus velezensis (wettable powder and aqueous suspension concentrate) and the fungi Trichoderma harzianum and Beauveria bassiana (both formulated as wettable powder). The powder products were suspended in distilled water amended with 0.2 wt% Tween® 80, and the samples were thoroughly vortexed to ensure cell dispersion. A tenfold serial dilution was performed, with the suspensions being streaked onto Luria-Bertani agar plates (B. velezensis) or potato dextrose agar plates (T. harzianum and B. bassiana) in duplicate. Plates were incubated at room temperature and colony-forming units (CFUs) were counted to determine the products’ starting viability.
To test storage stability, cell suspensions were prepared in CITROFOL® AI by suspending the wettable powder products at a use rate of 10 wt%. All of the formulations and commercial products were stored at 40°C and/or room temperature for up to six months, and cell viability was periodically measured by plate counting as described previously.
Rheology modification To facilitate development of formulations, rheology modifiers were screened regarding their suitability for thickening CITROFOL® AI. This was achieved by dispersing hydrophobic fumed silicas in CITROFOL® AI at a use rate of 3.0 or 4.5 wt% by homogenisation for ten minutes. The flow curve was measured by rotational viscometry (Haake Rheostress, plate-cone geometry C35/2° Ti L). Because of the samples’ shear thinning behaviour, they were allowed to rest for a period of 10 min after application onto the rheometer platform before measurement was started. The apparent viscosity was determined at continuously increasing shear rates from 0.01to 1000 s-1.
Greenhouse study To prove that CITROFOL® AI is compatible with plants and does not interfere with the efficacy of microorganisms, a greenhouse study was conducted using maize (two plants per pot, six replicate pots per treatment, three plots in a randomised design). Seeds were placed into pots containing a 1:1 blend of sand and soil collected from non-fertilised grassland, with a pH of 8.3 and a low level of plant-available P. The substrate was supplemented with non-plant- available P (calcium phosphate) to 25–35 ppm. The N and K content was adjusted to 80 mg/kg and 150 mg/kg respectively (setup based on Eltlbany et al.[4]). T. harzianum, which is known to mobilise P and thus promote plant growth under low-P conditions, was applied to the maize upon sowing and after germination by diluting a test formulation of T. harzianum in CITROFOL® AI or a reference wettable powder product in water according to the manufacturer’s instructions and applying these formulations at a rate of 1.5 x 107 CFU/plant. Plants were cultivated in a growth chamber (17–24°C, 16 h light/8 h darkness) for two weeks, then transferred to an open greenhouse. The plants were irrigated from the bottom to prevent the applied microbials from draining away. Germination rate and agronomic parameters (plant height, above-ground biomass, root length and biomass) were measured four and eight weeks after germination. A statistical analysis was performed using the SPSS 28 software package (ANOVA with post-hoc Tukey test).
ResultsValidation of cell viability method The starting viabilities of the original microbial products, determined as colony-forming units (CFUs), were in line with the respective manufacturers’ specifications. This was an important underlying observation for the shelf-life study, confirming the suitability of the protocol used for microbial cultivation and plate counting. Additionally, the cell counts in the original products were the same as in the CITROFOL® AI formulations when measured directly after blending. This underlined the good dispersibility of the cells in CITROFOL® AI even in the absence of a dispersing agent, resulting in a high validity of cell counts. The partial water solubility of CITROFOL® AI simplifies the procedure, since the cell suspension can be directly transferred to an aqueous serial dilution. This is a
benefit compared to viability measurements in common oily carriers, which require the addition of surfactants and centrifugation to transfer cells from oil to an aqueous medium.[5]
Cell viability of B. velezensis The viability of the spore-forming bacterium B. velezensis was monitored at a challenging storage temperature of 40°C. Despite these harsh conditions, the B. velezensis wettable powder product proved robust and fully maintained its viability throughout the six-month test period. However, this was not the case with the commercial B. velezensis liquid product – an aqueous suspension concentrate – in which cell viability dropped from 1.5 x 1010 CFU/g to
4.3 x 108 CFU/g over six months at 40°C. Although not as robust as the wettable powder formulation, suspension in CITROFOL® AI did deliver an improved shelf life for liquid product formats: The viability of B. velezensis declined slightly from 1.5 x 109 CFU/g to 4.8 x 108 CFU/g, less than one order of magnitude, during six months at high temperatures (figure 1).
Figure 1:Cell viability of B. velezensis stored at elevated temperatures for an accelerated storage test, comparing a commercial wettable powder with a commercial aqueous suspension concentrate and a non-aqueous suspension in CITROFOL® AI. Differences in starting viability are due to different cell concentrations in the products.
Cell viability of T. harzianumT. harzianum proved more susceptible to high storage temperatures, but shelf-life monitoring at 40°C for six months was nonetheless feasible. There was a pronounced drop in cell viability in the wettable powder product over this period, from 1.8 x 109 CFU/g to 5.1 x 104 CFU/g. Suspension in CITROFOL® AI attenuated this loss: the CITROFOL® AI suspension had a viability of 2.7 x 106 CFU/g at the end of the measurement period, almost two orders of magnitude higher than the reference powder product.
Figure 2:Cell viability of T. harzianum stored at elevated temperatures for an accelerated storage test, comparing a commercial wettable powder product with a suspension in CITROFOL® AI. Data point at 12 weeks for the wettable powder was below the detection limit.
Cell viability of B. bassianaAmong the microorganisms tested in the present study, B. bassiana was the most sensitive to elevated storage temperatures. To provide better resolution, shelf life was monitored both at room temperature and 40°C. After just two weeks at 40°C, cell viability in the wettable powder product had dropped from 5.3 x 108 CFU/g to below the detection threshold of approx. 1.0 x 103 CFU/g. Under the same conditions, the suspension in CITROFOL® AI had only decreased slightly to 1.1 x 108 CFU/g after two weeks, and was still as high as 1.0 x 106 CFU/g after twelve weeks (figure 3). As expected, viability declined more slowly when B. bassiana formulations were stored at room temperature. Under these conditions, cell counts in the wettable powder product dropped from 5.3 x 108 CFU/g to 4.1 x 107 CFU/g after 24 weeks. Shelf life was better still in CITROFOL® AI, where cell counts were 2.5 x 108 CFU/g at the start and 1.6 x 108 CFU/g at the end of the test period (figure 4). Our observations are in line with published results showing an increased tolerance of B. bassiana to elevated temperatures when formulated in an oily carrier.
Optimising rheology The formulation-relevant physical characteristics of a carrier fluid are an important consideration. Adding hydrophobic fumed silica at a low use rate of 3.0 wt% was sufficient to modify the rheological characteristics of CITROFOL® AI in the desired way. The apparent viscosity of the thickened fluid was around 100,000 mPa·s at a low shear rate of 0.01 s-1, indicating that dispersed cells could be very well stabilised against sedimentation. At the same time, the thickened fluid displayed strong shear thinning
properties, which was apparent when the shear rate was increased to 10 s-1, resulting in a 100-fold reduction of viscosity to around 1,000 mPa·s (figure 5). These values show that formulations based on thickened CITROFOL® AI have good pourability and dosability.
The stabilisation capacity of the formulation was tested using talcum powder as a model particulate substance. The samples were stored at 40°C for seven months. After this time, only slight separation had occurred at the top of the sample thickened with 3.0 wt% hydrophobic fumed silica. Stirring or shaking was sufficient to reverse this slight phase separation. The sample thickened with 4.5 wt% hydrophobic fumed silica was stable at 40°C for over seven months (figure 5).
Greenhouse studyFinally, it is important that co-formulants are plant-compatible and do not interfere with the efficacy of the microbial application in question. This was assessed by comparing the development of maize plants treated with water (negative control), T. harzianum wettable powder product (positive control) and T. harzianum dispersed in CITROFOL® AI. No significant difference was found in any of the agronomic performance parameters tested (germination, root and shoot growth). Since the positive control did not exhibit the expected beneficial effect on plant development, the results do not allow for drawing definite conclusions regarding the non-interference of CITROFOL® AI with microbial efficacy.
However, since the agronomic parameters did not differ significantly between the negative control and the treatment with CITROFOL® AI either, it can be concluded that CITROFOL® AI is a plant-compatible carrier fluid.
Conclusion Our results prove the suitability of the citrate ester CITROFOL® AI in the novel function as a carrier fluid for microbials. CITROFOL® AI is a sustainable co-formulant, is very safe and boasts favourable physicochemical characteristics. In particular, it combines the low water activity of an oily carrier with partial water solubility, thus making emulsifiers and preservatives obsolete and ultimately simplifying formulations. CITROFOL® AI is fully plant-compatible and has significant potential to improve the shelf life of liquid microbial formulations, as shown with all organisms tested in this study (B. velezensis, T. harzianum, B. bassiana). It helps to maintain high cell viability even at elevated temperatures, which is important for farmers working in warm climates or where continuous cooling of the product during transport and storage
is not feasible. Ensuring high cell viability and long shelf life is a major step in overcoming constraints in the commercial- isation of microbials. Viable microbial cells are indispensable for obtaining satisfying results in the field and thus boosting confidence in the benefits and economic feasibility of these sustainable crop inputs.
M.F. Rabbee, M.S. Ali, J. Choi, B.S. Hwang, S.C. Jeong, K.H. Baek, Bacillus velezensis: a valuable member of bioactive molecules within plant microbiomes, Molecules, 2019, 24(6):1046.
S.L. Woo, M. Ruocco, F. Vinale, M. Nigro, R. Marra, N. Lombardi, A. Pascale, S. Lanziuse, G. Manganiello, M. Lorito, Trichoderma-based products and their widespread use in agriculture, Open Mycol. J., 2014, 8(1):71–126.
G.M. Mascarin, S.T. Jaronski, The production and uses of Beauveria bassiana as a microbial insecticide, World J. Microb. Biot. Journal, 2016, 32:1–26.
N. Eltlbany, M. Baklawa, G.C. Ding, D. Nassal, N. Weber, E. Kandeler, G. Neumann, U. Ludewig, L. Van Overbeek, K. Smalla, Enhanced tomato plant growth in soil under reduced P supply through microbial inoculants and microbiome shifts, FEMS Microbiol. Ecol., 2019, 95(9):fiz124.
D.G.P. Oliveira, G. Pauli, G.M. Mascarin, I. Delalibera, A protocol for determination of conidial viability of the fungal entomopathogens Beauveria bassiana and Metarhizium anisopliae from commercial products, J. Microbiol. Methods., 2015, 119:44–52.
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The Authors
Dr Teresa Berninger – Application Technology, Jungbunzlauer Ladenburg GmbH
Teresa.berninger@jungbunzlauer.com
Amirah Bajawi – Application Technology, Jungbunzlauer Ladenburg GmbH
Amirah.bajawi@jungbunzlauer.com
Carolin Stern – Technical Service, Jungbunzlauer Ladenburg GmbH
carolin.stern@jungbunzlauer.com
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Figure 3:Cell viability of B. bassiana stored at elevated temperatures for an accelerated storage test, comparing a commercial wettable powder product with a suspension in CITROFOL® AI
Figure 4:Cell viability of B. bassiana stored at room temperature, comparing a commercial wettable powder product with a suspension in CITROFOL® AI
Figure 5:Flow curves of CITROFOL® AI thickened with different amounts of hydrophobic fumed silicas.
The images show the condition of the suspensions after being stored at 40°C for seven months, with talcum powder used as a modelparticulate substance.
SugaROx Ltd and Fera Science Limited will explore the feasibility of using biostimulant technology to improve tomato resilience to climate change, whilst also reducing the carbon footprint of production inthe UK.
In tomato production, plant growth, fruit set and yield are optimal at day/night temperatures of 21C to 29.5C and 18.5C to 21C, respectively. An increase of just a few degrees above these ranges can damage reproductive organs, leading to drastic decreases offruit setting.
Studies show that temperatures of 32C during the day and 26C at night 10 days before anthesis can significantly decrease the number and viability of pollen grains. This impact on pollen is associated with changes in carbohydrate concentration in developing anthers, and affects fruit set.
SugaROx is set to disrupt this space with formulations based on active ingredients (AIs) inspired by plant molecules. “While traditional biostimulants offer yield gains of 2-5 percent for farmers, our approach has the potential to boost yields by up to 22 percent on arable crops,” says Dr. Cara Griffiths, SugaROx’s CTO. “In this new 24-month project, our main objective is to explore the viability of adapting our technology to boost the ability of tomato plants to cope with heat stress. The new high-throughput phenotyping capabilities available at Fera allow us to test this in a very effective and efficient way.”
According to Dr. Aoife Dillon, principal scientist for crop protection at Fera, digital phenotyping tools, such as hyperspectral imagery, “allows us to detect changes in plant status in response to environmental stress much earlier than using traditional methods. In addition, digitalisation reduces the need to destructively sample plants, so is more efficient in terms of time, space and energy usage”.
Using the Phenospex PlantEye Technology, Fera will produce 3-D scans of miniature tomato plants under abiotic stress (heat and drought) with and without the SugaROx biostimulant and compare the development of these plants to unstressed (control) plants. “The model system that we will develop in this study can be used by other biostimulant manufacturers to test their products”, explains Dillon.
Bianca Forte, SugaROx’s business development director explains that to “evaluate the potential of our technology to reduce the carbon footprint of tomato production, experts from ADAS will be involved in our study.”
Sarah Wynn, managing director of the ADAS climate & sustainability team adds: “Through understanding the carbon footprint of the biostimulant itself, and then assessing the carbon benefit of using the biostimulant, versus non-use, we can model the potential carbon gains and the added benefit from its application.”
The British Tomato Growers’ Association (BTGA), which represents the majority of commercial tomato growers in Great Britain, will act as Knowledge Exchange Champion in the consortium. Forte adds: “Through their input, we will ensure our strategy to explore the strengths and weaknesses of our approach takes into account end-users’ practices and needs.” ●
ICL and Lavie Bio announced they have made a significant advancement in the development of biostimulants.
Leveraging artificial intelligence(AI), more than a dozen novel microbe candidates, which met the product requirements for efficacy, stability, shelf life and fertilizer compatibility, were computationally identified and verified in multiple greenhouse trials.
The microbes were discovered and validated using Lavie Bio’s Biology Driven Design (BDD) technology platform, powered by Evogene’s MicroBoost AI tech-engine.
In a joint news release, ICL and Lavie Bio state this success paves the way for field trials in both the U.S. and Brazil in the second half of 2024, with results available by year-end.
According to Amit Noam, CEO of Lavie Bio, using ICL's agricultural expertise was essential in focusing Lavie Bio's discovery efforts “and has enabled us to advance to field trials in multiple target geographies quickly."
Lavie Bio said it will continue to leverage AI to drive product development and optimization, while ICL will guide the development and lead the way to product commercialization. The parties aim to start the regulatory process in 2026.
"We are pleased to collaborate with Lavie Bio in the search for a novel solution to address a significant and proven market need in regions strategic to ICL," said Dr. Elinor Erez, vice president of R&D for ICL Growing Solutions. "We are excited to move forward to field trials and are confident any future novel product will revolutionize how the agricultural community approaches plant resilience and productivity." ●
Agchem formulation specialist PI Industries is acquiring AIM UK-listed biologicals company Plant Health Care (PHC).
PHC produces peptide- and protein-based products used for biocontrol and biostimulants.
The company’s commercial business has been driven by sales of Harpinαβ, a recombinant protein which acts as a biostimulant to promote yield and crop quality, and PHC279, a harpin-derived peptide that boosts a plant’s natural defence against a range of diseases.
PHC products are in key agriculture markets, such as the U.S., Brazil, Europe, and Mexico. The company reported revenues of $US 11.2 million for FY 2023 with a gross profit margin of 60 percent.
Under the terms of the agreement, PHC shareholders will receive 9 pence in cash for each share. The acquisition values PHC at approximately £32.8 million, according to a statement by PI Industries.
In the PI Industries statement, the company said the acquisition would be done through a wholly owned international subsidiary of PI, with the offered purchase consideration of approximately £32.8 million paid in cash and funded from the earlier Qualified Institutional Placement (QIP) proceeds. A QIP is a common way for listed companies to raise capital in India and Southeast Asia.
Headquartered in the northern state of Haryana and founded in 1946, PI Industries has two manufacturing units in Gujarat, an R&D site in Rajasthan and overseas officein Germany.
“PHC’s acquisition aligns with PI’s long-term strategic objective to build a differentiated portfolio of integrated solutions for sustainable agriculture,” the company said. Through the acquisition of PHC, PI Industries gains access to peptide technology in the “Plant Immunity Inducers” space.
“PI’s growth in biologicals has been consistent. PI already has a portfolio of eight products and many more in the development and registration pipeline. Revenue from biological products increased by ~29 percent in FY24 [sic],” the company said.
PI Industries formed a joint venture with Mitsui Chemicals Agro (MCAG) in 2016 called Solinnos Agros, with the purpose of providing registration services for MCAG in India.
PI Industries lists biostimulant products on its website, which are based on Ascophyllum nodosum seaweed and humic and fulvic acid. ●
