Effects of polyacrylamide-based super absorbent polymer and corn straw biochar on the arid and semi-arid salinized soil

Abstract

Green approaches are much more appreciable during the present scenario. Soil amendments are frequently applied for improving water use efficiency, reducing soil salinity in arid and semi-arid areas, controlling the secondary salinization of cultivated soils, and increasing the carbon sequestration capacity of soils. Thus, lab soil column simulation experiments and field experiments were carried out to evaluate these functions of two separate amendments, polyacrylamide-based super absorbent polymer (SAP) and corn straw biochar at different application rates. The simulation experiments showed that both SAP and biochar inhibited the accumulation of soil salinity, with a reduced rate of 9.7–26.3% and 13.5–37.2%, respectively, dependent on the amendment application rates. The field experiments found different salt inhibition effects of the two amendments with growth stages of maize. Soil salinization was inhibited in the pre-germination and early jointing stages by SAP, but throughout the whole growth period by biochar. Both soil amendments reduced soil electrical conductivity, and biochar increased the soil contents of Ca2+, Mg2+, and K+. Our observations demonstrated that application of biochar and SAP played important roles in increasing soil fertility and inhibiting soil salt accumulation. It provided an effective method to potentially mitigate the environmental crisis and promote sustainable development in agriculture.