What beans and seeds can be used as a garden fertilizer? how should they be prepared? can i grind up soybeans?

could i grind up, say flaxseeds and spread them in the garden?

What beans and seeds can be used as a garden fertilizer? how should they be prepared? can i grind up soybeans?
Grind any and all seeds then sun dry them and mix with bone meal and commercial compost or make a compost from the seeds. 6 months in a pile, and letting the heat work, should ready you for the next growing season.