Effects of super-absorbent polymers on a soil–wheat (Triticum aestivum L.) system in the field

• We test the effects of super absorbent polymers on the soil–wheat system.
• The SAPs were beneficial to the formation of larger aggregates.
• The application of SAPs could potentially help to increase soil microbial activity.
• The influence of SAPs on the wheat yield depended on the application methods.
• This study represents a useful assessment of environmental effects of soil additives.

Super-absorbent polymers (SAPs) have been established as a soil conditioner to reduce soil water loss and increase crop yield. However, there are few studies about how SAPs affect the soil microbial community. In this study, two types of SAPs, Jaguar C (JC) and Jaguar S (JS), were applied at 200 kg ha−1 by bulk and spraying treatments in a field trial to investigate their effects on winter wheat growth, the soil's physical properties and microbial abundance and activity. It was found that the addition of SAPs promoted the formation of macro soil aggregates (particle size >0.25 mm) and soil bacterial abundance under winter wheat cultivation. SAPs also significantly increased the soil water content (SWC) and soil maximum hygroscopic moisture (SMHM) in the booting and filling stages but had no effects on the soil available water-holding capacity (AWC) compared with the control in the filling stage. The effects of SAPs depended on the application strategy, as only the bulk JC treatment improved the wheat yield, soil microbial biomass carbon (MBC) and soil microbial respiration (SMR). The results showed that the application of SAPs did not lead to detectable adverse effects on the soil microbial community and might even enhance soil microbial activity. This study should serve as a useful complementary exploration for the assessment of the environmental effects of soil additives.