Purpose: The use of nano-sulfur (NS) as a suspension to mitigate calcium carbonate (CaCO3) of calcareous sandy soil is a new strategy and has not yet been tested.
Methods: In a pot experiment, this study evaluated four NS suspensions containing 15, 30, 60, and 90 kg NS ha−1, plus the control (distilled water only, 0 NS). Pots were incubated under laboratory conditions for two months. Then, total, active, and active/total CaCO3, as well as the CaCO3-related properties were estimated.
Results: The suspension containing 90 kg NS ha−1 was superior, while that containing 30 kg NS ha−1 was optimum. However, from an economic perspective, the suspension containing 15 kg NS ha−1 was preferred. With the optimum suspension, active, total, and active/total CaCO3 reduced by about 24%, 40%, and 22% compared to the control, respectively. Furthermore, the CaCO3-related properties, such as pH decreased by 0.48 unit and sodium adsorption (Na-adsorption) ratio by 18%, while soluble Ca2+, K+, SO42−, water stable aggregate index, and macro- to micro-pore ratio increased by about 100%, 44%, 19%, 33%, and 60% compared to the control, respectively. In general, the optimal active CaCO3 for better soil properties improvement is less than 10%.
Conclusion: The NS suspension has a high corrective power on CaCO3 and its related properties in the short term (60 days). However, regular application is recommended to continue pH reduction and neutralize CaCO3. Therefore, NS suspension may be an effective option when an immediate reaction from the amendment is needed, especially at critical stages of growth.