Effect of super absorbent polymer sodium polyacrylate on the bacterial community and associated chemistry of loessial soil

ABSTRACT

Super absorbent polymers (SAPs) have been applied as soil conditioners to reduce soil water loss, but there are few studies about how SAPs affect structures of soil bacterial community, and these associated chemical residues are uncertain. Treatments under different soil moisture conditions by application of sodium polyacrylate in repacked soil columns were used to investigate their effects on the soil bacterial community structures by Illumina MiSeq sequencing. Alpha diversity analysis showed that adding SAPs had an impact on bacterial diversity. On phylum level, adding SAPs significantly reduced the amount of Actinobacteria (1.9–2.4-fold), Bacteroidetes (1.1–2.1-fold) while increased the amount of Firmicutes (1.9–4.6-fold). At genus level, effects of SAPs on the soil bacterial community structures varied with the soil moisture conditions. Under water deficit, SAPs reduced the soil pH, which promoted the proliferation of Lactobacillus (9.9–29.1-fold), and acid production by these bacteria might further promote the reduction of pH, potentially inhibiting growth of Acidobacteria (1.3–1.8-fold) and Chloroflexi (1.6–2.3-fold). The pyrolysis analysis showed that some substances such as methanesulfonyl chloride, long-chain amides and esters, were only derived from water-saturated soil treated with SAPs, which might subsequently have negative impacts on the environment and associated agriculture.

KEYWORDS:

• Soil moisture
• Illumina MiSeq
• alpha diversity
• cluster analysis
• pyrolysis analysis

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Special Fund for Agro-Scientific Research in the Public Interest [grant 201503116-12], National Key Research and Development Program of China [grant 2017YFD0300410-02] and National Natural Science Foundation of China [grant 41601226]