Sandy soil has a low capacity to retain nutrients, so you should primarily use natural fertilizers such as compost and cow manure to improve the soil. If you use chemical fertilizers, choose one containing Potassium and apply it in small amounts multiple times, rather than a large amount all at once.

You should correct sandy soil into a rich soil by adding compost or organic manure. Then use urea in withing 20 days aftering sowing. Then, use balance compound fertilizer like 15-15-15 ratio or 16 -16 -16 after 40 days to 60 days after sowing. Then your higher yield is sure.