Can a superabsorbent polymer synthesised a CaCO3 based biofiller improve soil and plant available water and crop growth under salt stress?

Abstract

ABSTRACT The use of superabsorbent polymers (SAPs) in dryland agricultural areas utilizing brackish irrigation water is a strategy to increase plant available water (AW). However, water retention by SAPs may be adversely affected under salinity. SAP containing calcium carbonate (Ca-SAP) is considered to be more resistant and provide more plant AW under saline conditions compared to conventional SAP (C-SAP) and to control. This research investigated two replicated lettuce trials to evaluate three treatments (Ca-SAP, C-SAP and control) subjected to irrigation water with electrical conductivities of 0.0, 0.5, 1.0, 2.0 and 4.0 dS m−1. Both SAP treatments increased AW by an average of 0.16 m3 m−3 as compared to the control. Decrease in AW with salinity was lower in Ca-SAP (0.07 m3 m−3) as compared with C-SAP (0.13 m3 m−3). Lettuce fresh weight (g plant−1) was higher for Ca-SAP (22.9) as compared to C-SAP (16.4), however, did not differ from control (20.6). As water salinity increased, lettuce fresh biomass was higher in Ca-SAP as compared to C-SAP up to 2 dS m−1 with no significant differences from control. The Ca-SAP is less affected by salts than the C-SAP, although its use did not benefit lettuce growth under saline conditions as expected.