Soil Amelioration Techniques for Saline-Sodic Environments

Saline-sodic soils, characterised by high soluble salt concentrations and elevated levels of exchangeable sodium, pose severe constraints on crop productivity, soil structure and water infiltration. Amelioration strategies combine chemical, organic and biological approaches to restore soil functionality. Chemical amendments such as gypsum or elemental sulfur displace sodium ions and promote leaching, while organic inputs—vermicompost, biochar, compost and manure—enhance aggregate stability, cation exchange capacity and microbial activity. Biological measures include microbial inoculants and phytoremediation with salt-tolerant crops, which foster nutrient cycling and accelerate desalinisation. Integrated schemes leverage synergistic effects among amendments, optimise irrigation regimes and apply soil health indices to quantify recovery. Long-term field trials demonstrate that practices such as continuous rice cultivation or combined chemical–organic treatments can reduce pH, electrical conductivity and exchangeable sodium percentage, while increasing organic matter, nutrient availability and crop yields. These techniques are globally relevant for rehabilitating degraded semi-arid lands, improving food security and supporting sustainable land management under climate stress.

Research from Nature Portfolio

Recent field experiments have demonstrated that applying gypsum or elemental sulfur alongside vermicompost significantly enhances remediation of calcareous saline-sodic soils. Synergistic treatments increased soil health indices by over 100 per cent, improved wheat growth and offered a cost-effective, environmentally sound strategy for restoring degraded land. Microbial inoculation further amplified these benefits by stimulating nutrient cycling and aggregate formation.

Separate investigations into the combined use of phosphorus fertilisers and organic amendments under deficit irrigation in semi-arid regions revealed marked reductions in salinity, bulk density and toxic metal mobility. The integrated application boosted organic matter, hydraulic conductivity and available macronutrients, leading to substantial gains in wheat yield and quality. This approach underscores the value of pairing mineral nutrients with organic inputs to tackle multiple soil degradation factors simultaneously.

Soil Amelioration Techniques for Saline-Sodic Environments publication trend

The graph below shows the total number of articles in soil amelioration techniques for saline-sodic environments across all publications each year (not limited to Nature Index journals).

Technical terms

Saline-sodic soils: Soils with high levels of both soluble salts and exchangeable sodium, impairing structure and fertility.

Electrical conductivity (EC): A measure of soluble salt concentration in soil pore water, indicating salinity level.

Exchangeable sodium percentage (ESP): The proportion of sodium ions on soil exchange sites, reflecting sodicity.

Gypsum: Calcium sulphate amendment used to displace sodium and improve soil permeability.

Vermicompost: Organic amendment produced by earthworms, rich in nutrients and beneficial microbes.

Phytoremediation: Use of salt-tolerant plants to extract or sequester salts and promote soil recovery.

Soil health index: Quantitative framework integrating physical, chemical and biological indicators of soil quality.

References

1. Phosphorus-mediated succession of microbial nitrogen, carbon, and sulfur functions in rice-driven saline-alkali soil remediation. Soil Biology and Biochemistry (2023).
2. Combining chemical and organic treatments enhances remediation performance and soil health in saline-sodic soils. Communications Earth & Environment (2023).
3. Long-term rice cultivation enhances root development and yields by improving the structural properties of soil aggregates in saline–alkaline environments. Environmental Technology & Innovation (2024).
4. The integrated effect of salinity, organic amendments, phosphorus fertilizers, and deficit irrigation on soil properties, phosphorus fractionation and wheat productivity. Scientific Reports (2020).
5. Reclaiming Tropical Saline-Sodic Soils with Gypsum and Cow Manure. Water (2019).