Please find some new linksconcerning the use of silicon in agriculture.

The IPNC (International Plant Nutrition Colloquium) Copenhagen, August 2017. It is necessary to consider the action of silicon on plant growth and development in connection with the availability and uptake of ‘other’ essential mineral elements from the soil. In this sense, silicon is not an ‘independent’ operator and at very least, it is now described as a quasi-essential element. See IPNC See IPNC or Proceedings direct.

The second link is to the proceedings of the 7th International Conference on Silicon in Agriculture that took place at Bangalore, India, October 2017.  Congress proceedings pdf

Thirdly and not least, ‘The effects of Foliar Sprays with Different Silicon compounds’ is the title of a scientific review by Dr. Henk-Maarten Laane, CEO of Rexil-Agro BV, published in Plants (2018) DOI: 10.3390/plants7020045. This fully documented paper strongly suggests the need for further pure research on just how silicic acid is ‘absorbed’ by the leaf and translocated or more likely how it triggers a long distance signalling mechanism that stimulates root growth, to support of the obvious and positive effects of foliar application promoted by silicon supply companies, grower trials and grower utilization. Paper pdf

There is also a rapid increase in the conference market worldwide, on the subject of biostimulants in agriculture, stimulated by greater control or ban on a wide range of traditional plant chemicals and the upsurge in biological or at least integrated production systems. Silicon sits uncomfortably, on its own or as a component, within the category ‘Biostimulant’ because it quite clearly has a positive (indirect) effect on plant resistance also to various biotic stresses.

The use of silicon still suffers from a lack of recognition by agricultural ministries in various countries as a substance with an active and positive role in plant growth and development. I can only recommend my book ‘Silicon Solutions’ (Sestante Edizioni 2014) in English or a digital Flipbook (see HORTCOM Blog) as a primer. While not peer reviewed, it is useful and valid introduction to the argument. See Below.

Lastly, through the foundation of the ISSAG (International Society for the use of Silicon in Agriculture), the scientific community is consolidating its presence and networking in this field throughout the world. ISSAG 

July 2018

There are a number of learned books on the effects of Silicon in agriculture but few are addressed to the grower and agronomist in a practical, technical sense. If agriculture (all sectors) are to benefit from the application of silicon-based formulations, the KEY is education. Education to the point where teachers, students and extension services present SILICON alongside Calcium and NPK because of its very wide ranging effects for sustainable agriculture, food quality and security. The book ‘Silicon Solutions’ could be used as a ‘primer’ for course work in agricultural universities and colleges.

Silicon is an important mineral for the growth and development of plants and for human and animal nutrition. The plant available bioactive molecule is mono-silicic acid (above diagram shows the attachment of individual molecules). It’s action is that of a biostimulant.

Putting silicon on the shelf.


Edward’s book entitled ‘SILICON SOLUTIONS was published August 2014 by Sestante Edizioni, Italy, English language, ISBN: 978-88-6642-151-1. Paperback 17 x 24cm, 184 pages, cover price €29,00. INTRODUCTION EN pdf. See leaflet for details on purchasing and methods of payment. Leaflet May 2015 or go to: Amazon Italia or Sestante Edizioni. The book was launched during the VI International Silicon in Agriculture Conference that takes place at Stockholm, Sweden, 26-30 August 2014.

“A remarkable account of research, experimental trials, scientific conferences and illuminating ideas. The book addresses a real need. With strong conviction it brings together evidence, experience and scientific insight, also highlighting aspects that have not yet been adequately explored”

Bioactive, plant available SILICON acts as a biostimulant. The global interest in this category of products is rapidly increasing, mirrored by the growing number of international conferences.  This category of product is the subject of discussion on new legislation and new applied research. In contrast to agrochemical products that eliminate problems, biostimulants tend to work directly or indirectly in more subtle and less obvious ways in the reinforcement of plant resistance to pests and diseases. For this reason, more applied research is necessary to better understand the processes involved and to convince growers to use biostimulants in place of agrochemicals that have been banned or in following the trend toward biological production and more sustainable agriculture. Some international conferences on biostimulants 2016/2017.

 The book ‘Silicon Solutions’ is a digest of information intent on providing an HOLISTIC review of the importance of the mineral element silicon to plant growth and development in the context of plant stress dynamics and soil fertility. It attempts to bring the subject to the attention of farmers, growers, students and the food industry in a way that they will appreciate the potential of silicon to help plants against stress thereby improving yields and the internal quality of agricultural produce.

Holistic view of nature. Nature should not be considered as the sum of the individual parts, because no organisms exist in themselves for themselves, but only as part of a multiplicity of beings without which they would not be what they are. To understand the world it is not enough to sum up the knowledge we have of each of its individual parts, because the whole is greater than the sum of its single parts, just as each of us is not the sum of our individual organs. Nature can be viewed as a whole that has further, perhaps more important properties that cannot be deduced from the study of its individual parts, but captured only from a vision of the more complex whole. Scientists are today seeking the big picture, perhaps after having laboured all their lives on aspects of detail. We have been thinking that actions on small parts of the ecosystem would be absorbed without trauma because we could not see the effects in the immediate future – but there are no sealed compartments in the ecosystem (Germano Federici, Bergamo, Italy). The importance of silicon on plant growth and development, on the soil and on the environment, can only be appreciated from a more holistic viewpoint. See also:

DESCRIPTION: The use of silicon has the potential to become a fundamental tool in support of sustainable agriculture, biological/organic production and in safeguarding the environment. It can also render intensive agriculture more sustainable.

There is a large body of scientific research and knowledge on the benefits to plants of an adequate supply of silicon, yet few books (if any) have attempted to transform the resulting academic information into a form more accessible to the practical interests and needs of growers and agronomists. As such it is the first of its type. Of particular note, it also emphasizes the important contributions that silicon can make to improving the internal quality of produce and its post-harvest characteristics in terms of nutritional value, packing, transport, storage and distribution. How ‘pure’ is your science’?

The effects of silicon on plants cannot be considered separately from its influence on soil structure, soil microorganisms and in the context of plant stress dynamics – because silicon has beneficial effects in ALL of these areas. The work is divided into sections addressed to agricultural, horticultural and floricultural crops together with a series of tables showing positive results obtained from the use of silicon. It is written in a straighforward style and is amply illustrated. THE BIG PICTURE

Plant available, bioactive silicon is not classified as a fertilizer or an essenial element. In most modern legislation, it is being described as a Biostimulant that has a positive effect against abiotic stress but not biotic stress since it does not have a DIRECT effect on the eradication of insect pests and fungal diseases.

Instead, the indirect but nonetheless important effects of Silicon to biotic stress in strenghtening the plant and improving responses to infection and feeding insects. In this context note the following video presentations : Dr. Lawrence Datnoff, Dept. of Plant Pathology and Crop Physiology, Lousiana State University Agriculture Centre. See also the presentation by Michael Gauthier, R&D Manager at Les Fraise de L’ille d’Orlien on the effects of silicon on fungal diseases of strawberries.

Experiments made br  Dr. Margit Olle at the Estonian Crop Research Institute 2016 on foliar application of Silicic acid on Field Peas, Tomato transplants and Cucumber transplants can be found here. Mineral concentrations of N,P,K,Ca, Mg in field peas  field-peas-minerals; Effect of growth and chemical composition in tomato transplants tomato-transplants; Growth and Quality with cucumber transplants cucumber-transplants.

Innovation takes time. It implies a change in thinking and a change towards more natural ways of growing plants to obtain better results and a more sustainable agriculture. Above all it requires applied research and education. Vested interests and old legislation also have to be reviewed.

Modern agriculture is focused on the re-generation of soil fertility based on  thriving populations of microorganisms. Conditioners and bio-stimulants that contain strains of bacteria, mycorrhizal fungi and nutrients are highly beneficial  when added to the soil. The effect is positive for soil fertility, plant growth and development and depuration of the soil.

Recent research with Soyabean has demonstrated that soluble aluminium in the soil binds onto and enters the walls of a group of cells in the root caps, preventing root elongation. This stunting effect is very rapid after the roots are exppsed to soluble aluminium, thereby preventinmg the root system to obtain water and minerals required for normal growth. P M Kopittke, K L Moore et al: “Identification of the primary lesion of toxic aluminium in plant roots”. Plant Physiology, April 2015 Vol 167 no.4 1402-1411. UQ:354053. Doi: Kopittke & Moore 2015

It is well known that bioactive silicon binds strongly to soluble aluminium suggesting an important effect to improve acid soils that tend to contain high levels of soluble aluminium.

Bioactive silicon inserts itself perfectly in this dynamic, adding important benefits to soil structure, growth of microorganisms and of the plants themselves (above and below ground level) and in soil depuration especially from heavy metals.

Soils habitually used for intensive production loose their microbial life and fertilility and require greater quantities of fertilizer and plant chemicals to obtain similar crop yields. Internal produce quality declines (sugars, vitamins, anti-oxidants, minerals and other vital substances), made worse by the accumulation of chemical residues.

The application of bioactive silicon and a soil conditioner-stimulant provides  basis for sustainable agriculture with significant reductions in the need for fertilizers, plant chemicals and irrigation water. When applied together, one can expect a significant boost through potential synergic effects. See Introduction video by Dr. Wendy Zellner, Research Plant Physiologist at the USDA ARS. The Blog’s theme focuses on bioactive silicon. See: General introduction to Bioactive Silicon LD pdf ; Silicon Review Rutgers pdf

See: Five practical research reports in Italian from Siliforce day 2009, Bologna, Italy, on the application of stabilized ortho (monomeric) silicic acid, sponsored by Agro-Solutions BV / Ilsa Agrotecnologia. Siliforce Dossier Italian pdf. Article in Italian. In English see: Agro-Solution 08316

A. Utilizzo del prodotto: come, dove e quando, Eugenio Babini;  B. Esperienza su uva e ortaggi da frutto, Antonio Melillo; C. Verifiche di campo su fragola, albicocco e patata, Gianluca Molinari; D. Esperienza triennale su melo e vite, Duilio Porro; E. Panorama delle richerche internazionali, Alessandra Trinchera; F. RMI Innovazione per l’agricoltura, Massimiliano Valentini; G. Programma convegno

Files from Agro-Solutions in English pdf: Siliforce Potato; Siliforce Table Grapes; Siliforce Strawberry; Siliforce Apricot;  In Spanish: An early summary. More recently a presentation from Las Palmerillas Experimental Station, Almeria, supported by Fundazione Cajamar, see: Las Palmerillas Experimental Station

Q1. From where can growers obtain stabilized Silicic acid and in what form?

Today, stabilized silicic acid (SSA) is available in four formulations. The first is SSA in combination with molybdenum and zinc, the second, with molybdenum, zinc, boron, and copper, stabilized with PEG (polyethylene glycol). There is an imperfect geographical division in terms of distribution. The above two formulations are marketed as Siliforce (R*) by Agro-Solutions BV in Europe, North and South America. The third formulation consists of SSA combined with boron, also PEG stabilized, marketed as OSAB3 by SiLife BV (now ReXil Agro BV) in Asia, Australia and Africa.  The fourth is SSA stabilized by choline rather than PEG and marketed by Yara (YaraVita) ActiSil.   ActiSil for Poinsettia_Yara  A fifth formulation called Optysil – is described by Intermag Sp. z o.o. (Poland) as stabilized monosilicic acid containing 2% chelated Fe

These above forms of SSA have been marketed in competition with each other, taking on individually the on-going costs of experimental trials, international patents, marketing, promotion, education, distribution and sales. One would have thought that a combined marketing project would already have created a stronger international market position. It is claimed that part of the reason for this is due to the relative simplicity of the molecule in question. SSA has also suffered from difficulties in being registered as a fertilizer or micro-nutrient fertilizer.

Q2. What are the best informations sources for bioactive silicon products?

Slowly but surely more growers are using OSA/OSAB and more distributors are listing the product. One example is Ilsa Agrotechnologia in Italy Because of crop specificity, further trials are necessary and lots more education.  The following site in the French language is very informative and see website in English

Q3. What other silicon fertilizers are available?

New research work on the application of Sirius and Rigel G (2 silicon-based formulations) by Orion Future Technology on strawberry plants is revealing. In Strawberry plants treatment with Sirius (silicon biphosphite) there was not only an increase in the thickness of the cuticle but also in the density and length of leaf hairs. The number of leaf hairs correlated with a lower level of powdery mildew (Podosphaera aphanis). Dr. Avice Hall, University of Hertford, England 2011. OrionFT_Strawberry  See also News page 11, The Fruit Grower, April 2015  Impressive results against fungal diseases have also been obtained using Orion’s product Trident (a zinc, copper, silicon micronutrient complex with a malic/citric acid polymer chelate).

See also article in New Ag International/June 2016 English edition/Plant protection section, referring to work by Dr. G Percival at Bartlett Tree Research Laboratory, Reading University, UK on the successul use of Silicon phosphite (Sirius from Orion FT) to reduce apple scab (Venturia inequalis) and the incidence of pear blister mite.

Many silicate salts and mineral earths are available in formulations for agricultural use, obtained mainly from pyrophyllite clays and diatomaceous soils that can be applied as fine dust or foliar sprays.

The Australian company Advanced Plant Nutrition produces Maxsil™, a calcium silicate derivative from waste glass, ground to a fine poweder made up of spherical granules after other additives have been added. Application rates of about 100kg/ha are being tested on sugarcane. There is also a liquid suspension available. It is claimed that MaxSil can replace up to 50% of normal application of phosphate in traditional fertilizer treatments.

Advantages for silicate fertilizers is that they also provide the soil with mineral elements other than silicon (e.g. calcium from calcium silicate or potassium from potassium silicate), some of which become plant available.

Another advanatge of silicates over SSA is the potential slow-release of silicon to the soil; slow-release has been demonstrated with diatomaceous earth and zeolites. Another example of slow-release fertilizer consists of coated calcium amonium nitrate fertilizer containing silicon.

Potassium silicate formulations include: ZacSil (Zaclon LLC – Sil_Matrix (Certis USA –, Pro-TeKt (Dyna-Gro, AgSil (PQ Corporation –, SiKal (Yara Industries – Calcium silicate fertilizers (sometimes also + Mg) are available as: AgrowSil, Agrosilicio and Excellerator from Harsco – ) and others:

Foliar application of Carbon Silpower and Carbon Defence in the cultivation of cucumbers resulted in significant reduction of mildew (Podosphaera xhantii, Sphaerotheca fuliginea) in susceptible varieties. The most effective treatment with Carbon Silpower reduced disease severity by as much as 87% compared to the control. Experimental results WFL Carbon Silpower is described as low salt, noncarbonated, liquid potassium and silicon concentrate, while Carbon Defence as: low salt, noncarbonated, liquid phosphorous and potassium concentrate containing silicon.

See also various pdf files: AgSil_PQ Corporation / Si for Turf Grass_Rutgers / AgrowSil_Harsco  / Diatomaceous earth AgriPower pdf  / Silicon Presentation Agripower pdf  / Sil-Matrix PQ Corp pdf  MontanaGrow provide an amorphous volanic tuff (ignimbrite) for various sectors, including all segments of agriculture

Cosmocel SA, Mexico, supplies the product Barrier, described as a liquid suspension containing 10% calcium and 24% silicon for foliar application or to the root substrate. Espanola de Productos Humicos SA commercializes a product called Silik-Humico where potassium and silicon are combined with humic acids.

Q4. What about using clay itself? 

Silicon containing diatomaceous earth can be applied as fine dust that kills insects by dessication and reduces soil borne fungal pathogens such as Pythium and Fusarium. Liquid suspensions can be made for spraying. / Nutrifert Role of silicon pdf   /  /  /

On the basis of human health, take a look at the benefits claimed by the Austrian company Fangocur GmbH. for its fine clay formulation. I have no doubt that an immediate application of the solution obtained after adding water and stirring releases significant amounts of silicic acid. This is of course not an economic proposition for agricultural application.

Clay soils are largely composed of Aluminium silicates.  In a fertile soil containing clay, a small quantity of  Silicic acid is usually released by hydrolysis and acidification of Silicate salts. The respiration of plant roots, soil organisms and microorganisms releases C02 that combines with water to form weak carbonic acid. Organic acids are also released by plant roots and soil organisms.

Q5. So why not just ensure that the soil contains enough clay minerals to form a good fertile structure, home to a large and varied population of micro-organisms?

Silicic acid is the only bioactive Silicon molecule, therefore it is Silicic acid that is taken up by the plant roots. The problem is that Silicic acid is very unstable and rapidly polymerizes to inactive colloidal silica, silica gel and hydrated silica (silicon dioxide). Furthermore, in the complex soil-water relationships, some of the Silicic acid released is quickly sequestered by heavy metals such as Al and Mn, Phosphoric acid and organic substances. Another part is lost inside the plant during its uptake in the transpiration stream and successive deposition in the leaf cuticle and around the stomata. This implies that a plant, even growing in fertile soil or substrate will often benefit by supplementary Silicic acid applied to the leaves.

Q6. How can plants benefit fron Silicon fertilizers, if Silicic acid is so unstable?

About 12 years ago at the University of Antwerp, Prof. Dirk Vanden Berghe succeeded to exploit the synthesis of ortho or monomeric Silicic acid (OSA) stabilized with Choline. See  Interview VDB pdf   Stabilized silicic acid provides growers for the first time with the possibility of applying concentrated Silicic acid directly to the leaves as a foliar spray.  This opens important new horizons in plant production, from agricultural crops, fruit and vegetables to grass, horticultural and ornamental plants.

Q7. Other information sources?

See future posts for further information and questions on stabilized silicic acid and
Proceedings from the VI Silicon in Agriculture Conference 2014 Also Proceedings from V Silicon in Agriculture Conference, Beijing 2011. See also the Rutgers University pdf file on this conference and Si in Agriculture. Conference South Africa 2008: Proceedings of the IV Silicon in Agriculture Conference pdf. Conference Brasil 2005: Proceedings of the III Silicon in Agriculture Conference

Bioactive silicon is beneficial to animal and human health and has been made available as a food supplement, but that’s another story!

Silicon Review Prof Datnoff NewAg pdf

Silicon and plants james Locke pdf

Silicon and crop productivity Agripower pdf

Interview VDB pdf

Can silicon based life exist pdf

See also:

Plant Nutrition, other beneficial elements, silicon.

For more information on the author’s books go to: Books for Sale

Edward Bent ©2012 | HORTCOM



  1. David Archer says:

    Hi Edward
    A colleague of mine passed this on to me. Fascinating stuff, the constantly increasing amount of knowledge that we accumulate on the benefits of silicon in agriculture. I will be purchasing your publication.

    My company is a relatively newcomer (6 years in R&D stage) to the agricultural arena and now has patents for a new silicate material in Australia, New Zealand and South Africa with more applications in National stage in many other countries. We have developed a cost effective, slow release granule that has around 7 times the effective soluble Si fraction of diatomaceous earth products. If you get the opportunity I would direct you to our website at which has a wealth of information including trial results across a range of crops.

    The product goes into commercial phase this year, initially in sugar cane where we have seen results of up to 10 tonnes a hectare increase off dose rates of around 100 kg per hectare.

    Great to see the good work!

  2. Pingback: Combatting stress-related spread of Xylella | hortcom

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