Effect of superabsorbent polymer on root water uptake and quantification of water uptake from soil profile in dry land

Few reports focus on the source of water used in crop uptake from the soil profile following superabsorbent polymer (SAP) application, particularly the quantification of crop water uptake from SAP-treated soil and non-SAP-treated soil. Using column experiments, we investigated the effect of SAP on root water uptake of maize over two years and researched in depth the utilization of water from different soil layers under SAP application by employing stable isotope D/18O. The results suggest that SAP can increase root water uptake by 16.3–27.8% in SAP-treated soil layers. The water used by the crop mainly originated in the 0- to 20-cm soil layer at the jointing stage, 20- to 40-cm at heading stage and 0- to 20- cm during grain filling.