For some reason, I do not want to use manure for fertilizer. But what other methods exist to increase the fertility of the site? Personally, I sow white mustard twice a year. It grows pretty quickly. If the green mass is mowed and embedded in the soil during flowering, the soil will be enriched with both organic matter and plant growth stimulator (epin). In addition, siderat roots release substances that repel wireworm. I hope that you share your tricks to help improve the fertility of the site.
I use dried egg shells, which contains salts of potassium, magnesium, phosphates and other organic substances. If the autumn digging, then I use large parts, mashed by hand. For individual dressing, the eggshell is skipped on a coffee grinder and added directly to the hole. The shell regulates the acidity of the soil, thereby increasing fertility.