Despite the important role of silicon (Si) for the better utilization of plant nutrients, it is not well understood how the combinations of Si and P (phosphorus) will behave as a co-fertilizer for better yield performance and nutrient uptake in saline soil. Hence, the experiment was set-up to assess the effects of different combinations of Si×P fertilization on rice (Oryza sativa L.) productivity and nutrient use efficiency in saline soil. Combinedly, three levels of Si (Ca2SiO4: 0, 300 and 600 kg Si ha− 1) and four levels of P (TSP: 0, 13.2, 26.4 and 39.6 kg P ha− 1) were applied to a salt-tolerant rice (Binadhan-8) variety. Our findings indicate that the Si×P combination significantly improved rice growth and yield parameters, except plant height and unfilled grain number. We also found a strong positive correlation between the Si×P combination and other essential nutrients (N, P, K and S), implying that the interactive effects of Si×P fertilization increased nutrient uptake and NUE. The combination of Si300:P26.4 was identified as the optimum dose, which increased grain yield by 41.66%, straw yield by 55%, N uptake by 216%, P uptake by 193%, K uptake by 263% and S uptake by 130% over control. We conclude that the Si300:P26.4 combination could be an effective dose for improving rice performance and nutrient management in saline soil. The study’s limitation is that, despite using Ca-silicate as a source of Si fertilizer, the potential effect of Ca was not considered, which could have an impact on soil P unavailability.
