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

Authors: FENG, WEIYING - Beihang University; GAO, JIAYUE - Beihang University; CEN, RUI - China Institute Of Water Resources And Hydropower Research; YANG, FANG - Chinese Research Academy Of Environmental Sciences; He, Zhongqi; WU, JING - Beijing University Of Technology; MIAO, QINGFENG - Inner Mongolian Agriculture University; LIAO, HAIQING - Chinese Research Academy Of Environmental Sciences

Submitted to: Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/31/2020
Publication Date: 11/3/2020
Citation: Feng, W., Gao, J., Cen, R., Yang, F., He, Z., Wu, J., Miao, Q., Liao, H. 2020. Effects of polyacrylamide-based super absorbent polymer and corn straw biochar on the arid and semi-arid salinized soil. Agriculture. 10(11). Article 519. https://doi.org/10.3390/agriculture10110519.
DOI: https://doi.org/10.3390/agriculture10110519

Interpretive Summary: Saline soil is typical of arid and semi-arid areas, which account for 40% of the global land surface area. High soil salinity has a negative impact on crop stomatal conductance, water use efficiency, and growth. 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 lab soil column simulation and field experiments showed that the application of either the water-retaining agent polyacrylamide SAP or corn straw biochar inhibited soil salt accumulation. The SAP had a pronounced effect during the pre-germination and jointing stages. The inhibiting capability was strongest at the application of 45 kg/hm2 SAP. Biochar had a remarkable effect on soil salt accumulation throughout the entire growth period of maize. The optimal application rate of 30 t/hm2 led to a 37.2% reduction in salt accumulation relative to Control. In addition, biochar application should have also brought its ownCa2+, Mg2+, and K+ into soil, thus with extra benefits in promoting crop nutrient take-up and photosynthesis. Biochar has also the potential for increasing soil carbon sinks due to its straw origins. Therefore, in our opinion, the corn straw biochar would be superior to polyacrylamide SAP in remediating salinized soil in arid and semi-arid areas.

Technical Abstract: Soil amendments are frequently applied for improving water use efficiency, reducing soil salinity in arid and semi-arid areas, and controlling the secondary salinization of cultivated 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 reduction 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 the application of biochar and SAP played important roles in increasing soil fertility and inhibiting soil salt accumulation, thus greatly contributed to soil salinization mitigation efforts in arid and semi-arid areas.