Calcareous soils, prevalent in arid and semi-arid regions, often limit agricultural productivity due to their alkaline nature and poor nutrient availability. This study assessed the effects of mineral sulfur (312 kg ha⁻¹), nano-sulfur (12, 24, and 36 kg ha⁻¹), and compost (4.8 tons ha⁻¹) on the physical and chemical properties of saline calcareous soils and their impact on maize and wheat yields. The field experiment on new extended agriculture in Mallawy, Egypt, utilized a randomized complete block design. The results showed that nano-sulfur treatments outperformed mineral sulfur. Specifically, the combination of 36 kg ha⁻¹ nano-sulfur with 4.8 tons ha⁻¹ compost improved key soil physical properties, including bulk density, porosity, and hydraulic conductivity. This treatment also significantly reduced soil pH, electrical conductivity, and exchangeable sodium while enhancing the availability of essential nutrients such as nitrogen (N), phosphorus (P), potassium (K), and total sulfate (SO₄²⁻). These enhancements in soil health led to notable increases in both maize and wheat yields, as well as better crop nutrient uptake. The findings suggest that nano-sulfur, when used in conjunction with compost, is a highly effective amendment for improving the health of saline calcareous soils, enhancing crop productivity, and promoting sustainable agricultural practices in arid and semi-arid regions. This combination provides a promising alternative to excessive chemical fertilizers, fostering soil health and long-term agricultural sustainability.

Soil salinity poses a significant challenge to agricultural productivity, particularly in arid and semi-arid regions. This study explores the effect of compost, elemental sulfur (ES), sulfur nanoparticles (SNPs), and their combinations, i.e., compost + ES and compost + SNPs, to improve soil properties and maize productivity across a range of salinity levels (EC1 = 3.68, EC2 = 6.15, EC3 = 8.34, and EC4 = 12.18 dS/m). We hypothesized that integrating compost with ES or SNPs would enhance soil quality and maize performance more effectively than individual treatments. Results validated this hypothesis, showing that compost increased soil organic matter (SOM) by 1.33 times, reduced sodium adsorption ratio (SAR) by 33%, and boosted maize grain yield by 40% in moderately saline soils (6.15 dS/m). ES and SNPs lowered soil pH by 0.8–1.2 units and improved phosphorus availability by 25–30%. The compost–SNP combination delivered the most significant improvements, enhancing infiltration rate by 60%, total porosity by 15%, and straw yield by 50% in highly saline soils (12.18 dS/m). Additionally, plant height, cob length, and chlorophyll content increased by 20%, 22%, and 40%, respectively, with combined treatments. These findings highlight the efficacy of integrated amendments in alleviating salinity stress, offering a promising strategy for sustainable agriculture in saline environments.