What are soil ameliorants?

Soil ameliorants are inorganic and organic chemical soil conditioning products applied to enhance the quality of soil and therefore improve plant health, growth and revegetation. Soil ameliorants are used in mining, farming, erosion control, sediment control, and construction projects. There are several physico-chemical properties of soil that are improved by adding soil ameliorants. These are the soil properties improved by soil ameliorants:

  • pH
  • salinity 
  • fertility
  • heavy metals
  • micronutrients
  • macronutrients
  • electrical conductivity
  • biological and biochemical quality

In this article we evaluate the different soil ameliorants and wrap up with GRT soil amelioration solutions. 

What are the different types of soil ameliorants?

There are different types of soil ameliorants, and their uses depend on their availability, cost and ability to improve plant growth whilst supporting sustainable soil quality and health. These are the different types of soil ameliorants:

  • vermicompost 
  • gypsum
  • lime 
  • fly ash 
  • mycorrhiza 
  • soil microorganisms
  • animal manure 
  • sewage sludge
  • press mud 
  • biochar
  • fertilizer

Vermicompost: it involves the biooxidation and stabilization of organic materials depending on the combined effect of earthworms and microorganisms, where the earthworms maintain aerobic conditions, ingest solids, convert a portion of the organics to worm biomass, respiration products and expel partially stabilized matter as vermicompost. The contribution of vermicompost is as follows:

  • simple and cost effective.
  • humus addition.
  • increases phosphorus solubilization.
  • increases nitrogen availability. 
  • improves soil texture and permeability.

Gypsum: is a source of soil calcium and sulphur with the chemical formula CaSO4:2H2O. It is an ideal soil ameliorant for hard compacted soils with poor water penetration or sodicity. The role of gypsum as a soil ameliorant includes:

  • reduces erosion by increasing the ability of soil to retain water, thus reduce runoff.
  • soil aeration and water percolation. 
  • decreases Na exchange %. 
  • reduces dispersion. 
  • increases stable soil structure.

Lime: ameliorating the soil with lime is a common method of reducing soil acidity and depending on which form of lime used calcium and magnesium can be added by applying calcitic and dolomitic lime respectively. The role of lime as a soil ameliorant includes:

  • soil pH correction.
  • improves soil structure.
  • promotes growth of soil microorganisms.
  • promotes root growth. 
  • alleviates aluminium and manganese toxicities. 

Fly ash: is a byproduct of coal combustion, and it consists of tiny glass-like particles. The impact of fly ash on soil quality is primarily attributable to the changes in the texture of soil. Alteration in the soil texture is correlated with:

  • bulk density. 
  • porosity. 
  • hydraulic conductivity. 
  • void ratio. 
  • water holding capacity.

All these have a direct impact on plant growth and on the nutrient retention and biological activity of the soil. 

Mycorrhiza: there are different species of mycorrhizal fungi with examples such as Glomus intraradices. The inoculum consists of a mixture of rhizospheric soil from pot cultures containing spores, hyphae and mycorrhizal root fragments. Inoculation of fungi does the following to soil as an ameliorant:

  • improves growth of plants under salt stress.
  • mycorrhizal fungus increases sulfur uptake. 
  • increase in nutrient mineralization.
  • decrease in denitrification.

Soil microorganisms: the soil microbes are responsible for most for most of the conversion of the dead roots into humus. The living fraction of soil makes it favorable for plants to grow. The role of soil microorganisms is as follows:

  • make nutrients available to the plants. 
  • responsible for nitrogen fixation.
  • aid in aeration of the soil. 
  • release soil minerals. 
  • help in soil aggregation and granulation. 

Animal manure: it is sourced from the farmyard manure and other animal/bird wastes. It enhances soil organic matter which improves microbial stimulation. Traditionally, animal manure has been utilized for several soil ameliorants purposes:

  • soil pH buffering.
  • chelation of toxic metals.
  • microbial stimulation.
  • improves soil structure.
  • more retention of water and nutrients. 

Sewage sludge: is one of the major solid organic wastes from sewage treatment plants that is utilized to promote rapid growth of plant cover for rehabilitation as an organic soil ameliorant. The importance of sewage sludge is as follows:

  • slow release of essential nutrients, micronutrients and organic matter.
  • improves soil physical, chemical and biological properties.
  • stimulates microbial activity.
  • decreases soil bulk density. 
  • reduces metal availability.

Press mud: is a lightweight abundantly available waste product from the sugar industry. Press mud is a beneficial form of waste recycling which reclaims acid and alkaline soils. It reduces plant uptake of toxic metals and improves soil tilth. It contains crude wax, fiber, crude protein, sugar, SiO, CaO, PO4, MgO and total ash. It can be used as a rich source of:

  • organic matter.
  • organic carbon.
  • enzymes and higher microbial organisms.
  • micronutrients.
  • macronutrients.

Biochar: is a charcoal material produced as a by-product of the pyrolysis of biomass and because of its relatively stable, and inert nature, its incorporation in soil is an opportunity to increase carbon sequestration. This carbon rich material provides the following to the soil:

  • carbon addition to soil.
  • decontamination of toxic metals and organic pollutants.
  • restricts metal and nutrient leaching to ground water.
  • reclamation of acid soils.
  • indirectly stimulates soil microbial activity.

Fertilizer: there are two forms of fertilizers, inorganic and organic that can be used to promote soil quality. Fertilization using inorganic fertilizers is common. Biofertilizers contain microorganisms, providing direct or indirect positive effects on plant growth and crop yield through different mechanisms. Fertilizers offer the following to soil:

  • nitrogen fixation.
  • solubilizing phosphorus.
  • improve soil texture.
  • improve soil acidity.
  • reduces soil bulk density.

GRT soil ameliorants and their key product benefits.

Product: GRT: Enviro-Binder 

Key product benefits:

  • binds soil preventing erosion.
  • non-toxic and environmentally friendly product.
  • immediately effective once applied.
  • support seed and vegetation growth.
  • minimal soil preparation for application of product.
  • cost effective results. 
  • safe installation. 

Product: Soil-Loc

Key product benefits:

  • prevents wind erosion soil loss.
  • immediately effective upon application by binding directly to the soil.
  • accelerate germination.
  • reduces impact erosion, sheet erosion, topsoil loss and sediment.
  • cost-effective when to hydro-mulching and hydro-seeding revegetation.
  • minimizes wash away of seed.
  • aids fertiliser retention around root zone.
  • more available fertiliser for plant uptake.
  • environmentally friendly.

In conclusion

Soil ameliorants are calcium sources for short, medium and long term calcium provisions for soils that have low calcium and pH. The use of microbes improves slow release of nitrogen and remediation of soils with low carbon using soil ameliorants can boost minerals, organics and carbon. Water retention is key especially in hydrophobic conditions and soil ameliorants can be used to support revegetation. Reach out to GRT for our soil ameliorants portfolio developed and formulated by Australia’s leading soil scientists and agronomists. The well calculated key ingredients provide you with significant savings on any of your projects. 

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Qin et al. 2020. Physicochemical properties, metal availability and bacterial community structure in heavy metal-polluted soil remediated by montmorillonite-based amendments. Chemosphere. 261. 128010. 1 – 10. 

Ritsema, C.J., and Dekker, L.W. 2003. Soil Water Repellency: Occurrence, consequences and amelioration. Elsevier. New York. 

Wang et al. 2018. Soil ameliorants alter physicochemical properties and fungal communities in saline-sodic soils of Northeast China. Archives of Agronomy and Soil Science.