Improvement Effects of Different Environmental Materials on Coastal Saline-Alkali Soil in Yellow River Delta

Abstract

Based on the characters of coastal saline-alkali soil in Yellow River Delta, four kinds of soil with the total salt content of 0.13%, 0.24%, 0.86%, 2.07% respectively, were used as the research objects in this study. Leaching experiment of soil improvement were operated by using flue gas desulfurization gypsum and humic acid as the soil amendments through single or combined application. After leaching, the pH values, EC and the total salt content including Na+, Ca2+ and Mg2+ of four times leachate were analyzed. Meanwhile, the sodium adsorption ratio (SAR) was also calculated in order to evaluate the amendment efficiency. The results showed that: the pH values of the leachate of flue gas desulfurization gypsum without (treat A) or with humic acid (treat C) were significantly lower than that of control group (treatment CK) and humic acid (treatment B), while the EC values were significantly higher. For the saline-alkali soil, all of treatment A, B and C could decrease soil pH, exchangeable Na+ and soil SAR. Treatment B could decrease the total salt content insignificantly, while treatment A and C could increase the total salt content significantly. By analyzing the results, it was found that treatment C had the most significant improvement effect, comparing with the treatment CK. PH was decreased respectively 0.26%, 0.83%, 1.05% and 1.83%, Na+ was decreased respectively 82.4%, 92.6%, 89.1% and 78.6%, SAR was decreased respectively 97.4%, 98.5%, 97.7% and 94.7%. The experimental results demonstrate that a combined application of flue gas desulfurization gypsum and humic acid is a potential method to improve coastal saline alkali soil in Yellow River Delta on the basis of ensuring the irrigation amount.