How do you demonstrate that using dung on the soil can improve their crops?

Using dung as fertilizer can improve soil structure, provide essential nutrients for plant growth, and increase soil water retention. This can be demonstrated through conducting controlled experiments where one plot of land is fertilized with dung while another is left unfertilized, and then comparing the growth and yield of crops in both plots. Additionally, analyzing the nutrient content and soil health parameters before and after applying dung can provide scientific evidence of its benefits.