The crops in the Myriad World Continent had a very short ripening period. They could harvest at least four times a year, and the yield per acre was much higher than before. Most of the land belonged to the Dawn Dynasty. They only gave the civilians the right to use all the land, but they could not be bought or sold. That basically prevented land annexation.
Moreover, after becoming cultivators, common rations could no longer satisfy cultivators' needs for nutrition and energy. The value would be greatly reduced if it were just to fill their stomachs.
Common rations were almost uneaten and piled up like mountains for a kingdom like the Dawn Dynasty, where all civilians could cultivate and step onto the path of transcendence.
Therefore, after the appearance of spiritual grains, the cultivators' need for ration was alleviated.