How does the production of farm manure improve fertilizer efficiency?

How to improve the fertilizer efficiency in the production of farm manure? Also ask experienced netizens to help introduce the method of farm manure, which has a wide variety and a wide range of sources, large quantity, easy to use local materials, local use, and relatively low cost, so it is very popular among farmers. therefore, the farming network has sorted out several efficiency-increasing methods in the production process of farm manure, which are listed in detail below for netizens' reference. Method 1. Add ferrous sulfate to human urine: add 500-600 grams of ferrous sulfate per 100 kilograms of human urine, which can convert ammonium carbonate in human urine into stable ammonium sulfate, which can protect fertilizer and deodorize and prevent nitrogen volatilization. Method 2. Add calcium superphosphate to plant ash: soak 3 kilograms of plant ash to 15 kilograms of water, then add 1 kilogram of calcium superphosphate, stir evenly, add 50 kilograms of water 6 hours later, and spray the clear liquid after static precipitation. the fertilizer effect similar to potassium dihydrogen phosphate can be obtained. Method 3. Add ammonium bicarbonate when composting farm manure: cut plant stems and leaves into pieces, add 0.5% 1% ammonium bicarbonate and an appropriate amount of human feces and urine, then cover and seal with mud, and become an efficient organic fertilizer after ripening. Fourth, add calcium superphosphate to barnyard manure: add 20% superphosphate to barnyard manure and stir it evenly. After 20 days of stacking, it can not only prevent the volatilization and loss of nitrogen nutrients in barnyard manure, but also accelerate the ripening process of barnyard manure and increase the content of available phosphorus. Why farm manure is mature before it can be used? what is humic acid?