Evaluation of infiltration parameters estimation methods in furrow irrigation with the presence of superabsorbents

A solution for optimal management of water resources is to add superabsorbents to the soil to increase water consumption efficiency. Due to the importance of soil infiltration in the design and evaluation of surface irrigation methods, several methods including multi-level optimization, Elliott and Walker two-point method, IPARM and SIPAR-ID were used in this study to estimate the volume of infiltrated water in soil with the presence of superabsorbents. This study was carried out during spring and summer of 2019, in experimental filed of Aboureyhan College of Tehran University. With 5 times irrigation in 10 furrows, two dosages of A200 and Stockosorb superabsorbents (16 and 32 g/m2) and two flow rates (0.3 and 0.6 Ls-1). According to the results, adding superabsorbent to the soil increased soil infiltration. The effect of superabsorbent was reduced with the increase of the flow rate to the furrows (In low flow rate from 5.9% to 18.9% and 5.5% to 18.1% in high flow rate). Stockosorb superabsorbent had a greater effect on increase of water infiltration in the soil compared to A200 (3.4% and 3.3% for low and high dosages of superabsorbent and low flow rate and respectively 0.5% and 1.7% in high flow rate). Multi-level optimization method estimated soil infiltration parameters with the lowest relative error (1%). Having high relative error, the SIPAR-ID model did not perform properly during the evaluation. Results also showed that with increasing the flow rate to the furrows, the performance of the IPARM model and two-point method decreased.