Discussion on the use of coffee grounds as a source of nitrogen or carbon in composting
The matter of composting is related to the generation of humus, which is conducive to soil fertility and nourishes all things. The role of coffee grounds in the composting process is either a source of nitrogen or a source of carbon, which is the focus of horticulture and agronomy.

Considering the chemical composition, coffee grounds are rich in nitrogen elements. Under the action of microorganisms, nitrogen-containing substances can be converted into a state that can be absorbed by plants through a series of biochemical reactions. In the early stage of composting, microorganisms need nitrogen for reproduction to synthesize key substances such as protein and nucleic acid, and the nitrogen from coffee grounds is then used for it, which can be one of the nitrogen sources.

However, coffee grounds also contain carbonaceous components. Carbon-containing compounds such as cellulose and lignin are stored in it. During the composting process, the carbon source is the energy supply of microorganisms. Microorganisms decompose the carbon source and release energy to maintain their life activities. The carbon of coffee grounds, after gradual degradation, participates in the construction of compost organic matter, which can be evidence of carbon sources.

However, coffee grounds are considered a nitrogen source or a carbon source, and it is not a generalization. The composting environment and the ratio of other materials have an impact. If the compost material has more carbon and less nitrogen, the coffee grounds will show the effect of nitrogen source, adjust the carbon-nitrogen ratio, and promote the balanced growth of microorganisms. On the contrary, if the material is rich in nitrogen and lack of carbon, the coffee grounds will be used as a carbon source to supply energy and adjust the structure.

It is important that coffee grounds are both nitrogen and carbon sources in compost, and their roles vary according to the specific situation. Only by making good use of their properties and rationally deploying them can compost be efficient, high-quality fertilizers can be obtained, which is beneficial to ecology and agriculture.