Why do some fertilizers need to be fermented before use, while others do not?

We grow our own crops and often use various organic fertilizers, such as chicken manure, sheep manure, soybean meal, rapeseed cake, and so on. Of course, we also use inorganic fertilizers. At this point, some people may wonder what inorganic fertilizers are. We'll talk about that later. Among these fertilizers, some need to be fermented before use, while others don't need to be fermented and can be used directly.

First, there is the wood ash. Wood ash is the residue left after various plants are burned. In fact, wood ash belongs to inorganic fertilizer, but most people consider it as organic fertilizer. All kinds of rice straw, corn stalks, and branches are composed of organic matter. However, after burning, all the organic matter is burned up, and only inorganic matter remains, which is inorganic fertilizer. Therefore, our wood ash is inorganic fertilizer. Wood ash does not need to be fermented and can be used directly. If it is fermented, the alkalinity and potassium content will decrease, so it should not be fermented before use.

The second type of vegetable seed cake. The vegetable seed cake is extremely beneficial for all kinds of fruit and vegetable crops. It not only enhances the sweetness but also improves the texture and quality of the vegetables. Moreover, after fermentation and reuse, it is still usable. Therefore, the vegetable seed cake can be used whether it is fermented or not. 
The third type is soybeans. The amount of soybeans used is relatively small. After soaking them in water and cooking them in a pot, they can be used directly. Soybeans can be used to make fertilizer as they can replenish nitrogen. However, when using them, it is essential not to come into direct contact with seeds and root systems. They should be kept at least 5 centimeters away from the seeds and roots. If the soybeans are used for oil extraction, there will be soybean meal, and this should also be avoided from coming into direct contact with the roots.

The fourth type is tea bran cakes. Many people think that tea bran is mainly used for repelling insects. In fact, it can also be used directly as fertilizer. However, it should be kept away from seeds and root systems. These are all points that need to be noted.

Among these, fermentation is not necessary for all organic fertilizers. All of them should be fully decomposed and matured before being used. Especially for some animal manure, not being decomposed and used can easily cause soil salinization and plant burn, and there are also some pathogenic bacteria and insect eggs in it, which is very bad for growing vegetables. When fertilizing our vegetables, it's like eating food - you can eat it raw if it's suitable, but don't eat it raw. Never eat it randomly. 
The ones that are most commonly used are things like sheep manure, chicken manure, human excrement and urine, etc. These must be properly decomposed and fermented before they can be used. Some people might say that the manure they have at home can be used directly. However, it's important to note that the manure at home is usually stored in a septic tank first, and then used. The septic tank is basically a simple form of fermentation. 
Apart from manure, there are also some things in our daily life that can be turned into organic fertilizer through fermentation. The first one is kitchen waste, such as non-salted, separated leftovers, expired grains, cooking oil, milk, beer, bean residue, etc. Don't underestimate these useless things. After you undergo fermentation treatment, they will all become excellent organic fertilizers. Moreover, mixing these things with fertilizers like soybean meal, chicken manure, etc. for fermentation can not only enhance the efficacy of the organic fertilizer but also increase its quantity. 
The second part is some fallen leaves, pine needles, rice husks, coffee grounds, soybean stalks, etc. Collect these things more frequently. Then mix them together with things like chicken manure or soybean meal for fermentation. Not only does this process speed up the fermentation process, but the resulting fertilizer will have a very loose texture and excellent efficacy. 
Understanding the functions of each type of fertilizer will enable everyone to use the fertilizers without worrying about this or that in the future.