The effect of humic acid on the desalinization of coastal clayey saline soil

There is a lack of research on the effect of humic acid on salinity adsorption and leaching of saline-alkali soil. We used humic acid as a modifier. Saline soil adsorption and leaching tests were carried out in the laboratory and the field to study the effect of humic acid on water, salt, and wheat yield in coastal clay saline soil. Compared to the CK (non-humic acid treatment), the laboratory tests show that soil water content, salt adsorption, salt leaching, and salt removal efficiency, all showed a trend of increasing first and then decreasing, with the increase of humic acid, and increased by 0.1–1%, 0.5–4%, 3–11%, and 1–8% under T1-T8 (humic acid treatments), respectively. Field tests show that in all humic acid treatments soil salinity in 0–20 cm and 0–60 cm was reduced, and the water content and wheat yield was increased, compared to CK. When the humic acid content was 0.149 g/kg (T2 treatment), the soil salt removal effect and wheat yield were optimized. Overall, humic acid can effectively reduce the salinity in clay saline soil, improve its ability to hold water, and inhibit salt accumulation and soil salinization. This research contributes to the improvement of saline-alkali soil in the Yellow River Delta.