Superabsorbent polymers and sanitary sewage change water availability during the cowpea emergence phase

Superabsorbent polymers (SAP) enhance water retention and facilitate seed emergence, though studies predominantly use high-quality water, neglecting SAP performance with alternative sources like sanitary sewage. Addressing the imperative to reduce fresh water demand, especially in water-scarce regions, SAP and sanitary sewage emerge as potential agricultural alternatives, partially fulfilling crop water and nutritional needs. This study assessed the impact of SAP and synthetic sanitary sewage (SSS) on substrate attributes and cowpea emergence in a randomized factorial design (8 x 2), incorporating varying SAP doses (0-0.14%) and hydration sources (SSS and distilled water). Cowpea was cultivated in polystyrene trays under controlled conditions. While SAP and SSS augmented water retention, total dissolved solids, pH, and electrical conductivity (ECse) also increased. Increased ECse negatively affected cowpea germination, emergence speed index (ESI), and time to 50% emergence. In conclusion, applying SAP near cowpea seeds impeded emergence, warranting the exploration of alternative strategies. Despite the rise in ECse, SSS demonstrated benefits for germination, establishing itself as a viable water source for cowpea emergence. This study underscores the necessity for further research into SAP applications and recognizes synthetic sanitary sewage as a promising, waterconserving source for sustainable cowpea growth.