Sustainable water consumption of rice (Oryza sativa L.) as influenced by superabsorbent polymer in water stressed conditions

Abstract

Sustainability in irrigation and agriculture has received widespread attention among researchers across the globe in the recent decade. To ensure food security and to protect water resources, agricultural and irrigation practices need to be amended with innovative technology that conserves water and increases productivity. The application of SAP or hydrogel as soil conditioners was identified as a possible solution to increase water use efficiency in irrigation. This study aimed to evaluate the swelling properties of hydrogel and its effects of hydrogel application to the soil on plant. Paddy was chosen for plant growth assessment due to its large water footprint. Laboratory scale experiments were carried out in growth bags for control group (TC1) supplied with excess water supplied and treatment groups (20% - TC2, 40% - TC3, and 60% - TC4 deficit supply of water) amended with hydrogel under drip irrigation. Hydrogel exhibited an equilibrium swelling of 513.3 (TH1 - deionized water), 188.8 (TH2 - groundwater) and 121.9 (TH3 - 0.5 % saline water) times its dry weight respectively. The water retention time in hydrogel was maximum for saline water, followed by groundwater, and deionized water. Seed treatment of paddy showed the optimum dosage of hydrogel to be 1.25% by weight of seeds. The plant height at 2 weeks after sowing showed significant trend of increasing plant height in the order of TC1 (17 cm) > TC2 (23 cm) > TC3 (24 cm) > TC4 (28 cm). The results support the hypothesis that hydrogel can be advantageously used in soil conditioning as an effective way to protect irrigation water resources and to ensure food security.