Compost is one of the best natural fertilizers that can be used in agriculture. Compost is a relatively safe fertilizer that is more difficult to overuse than mineral fertilizers, but its excessive application can still lead to problems in the soil and environment. Proper dosage depends on the composition of the compost and the specific characteristics of the soil. Excessive use of compost, like any other organic fertilizer, can lead to negative effects such as:
- Overfertilization of the soil with nutrients – for example, an excess of nitrogen or phosphorus can cause groundwater contamination.
- Disruption of microbial balance – too much organic matter can lead to anaerobic decomposition and the production of undesirable gases (e.g., methane).
- Soil salinization – if the compost contains high concentrations of salts (e.g., from certain food waste), it may harm plants.
- Water retention issues – an excessive amount of organic matter can sometimes lead to excessive moisture retention or, conversely, hinder water absorption by the soil.
It successfully replaces purchased natural fertilizers. Using compost improves soil structure and enhances air-water relations. On light soils, it increases water retention capacity, while it loosens heavy soils. Compost is a complete multi-component fertilizer, containing all the essential macro- and micronutrients necessary for plants life. Along with compost, beneficial microorganisms enter the soil, improving root condition and thus enhancing plant health. Additionally, compost supplies the soil with its most important component – humus. The composting process allows for better management of organic matter on a farm. Instead of losing them or using them inappropriately, it is better to turn them into a valuable fertilizer.
Compost is an organic fertilizer containing decomposed plant and animal residues. Compost in which humification processes have been completed cools down and takes on characteristics similar to humus from good garden soil. It is slightly moist, dark in color, amorphous in form, and has a pleasant scent of moist garden soil. Partially decomposed compost, in which the composting process is not yet complete, can also be used as mulch. Since humification processes have not been completed, it still absorbs a considerable amount of nitrogen. Applying undecomposed compost directly into the soil depletes it of nitrogen, making it unsuitable for use in the root zone of growing plants. However, it can be used as a mulch – a layer spread on the soil surface.The best-decomposed compost is vermicompost, produced with the help of composting earthworms. Vermicompost is considered one of the best types of compost due to its stable organic matter, rich nutrient content, and beneficial microorganisms. The decomposition process by earthworms makes nutrients more available to plants, and it is more quickly integrated into the soil compared to traditional compost. Vermicompost also improves soil structure and supports microbial health, helping to combat soil pathogens. However, its production is slower and more controlled, and it is typically more expensive than regular compost. While vermicompost offers many advantages, other compost types may be more suitable in certain conditions. It is obtained by introducing a special hybrid of the Red Californian compost worm (Red Hybrid of California), bred in the USA, into the compost pile. This worm rapidly decomposes the top 20 cm of compost and does not burrow deeper. Many products labeled as “biohumus” are actually solutions of vermicompost. The slowest decomposition occurs in anaerobic composting, which is carried out using polyethylene bags. Bags with a capacity of 100–150 liters and thick walls (2–3 mm) are filled with plant residues, moistened with one liter of liquid manure, and supplemented with 0.5 kg of lime per bag to neutralize acids produced in anaerobic processes. The bags are tightly sealed and covered with a thick layer of straw. This compost is ready no sooner than one year after preparation.
Key Factors Affecting the Composting Process
The composting process depends on several key factors that influence its efficiency:
- Moisture is crucial since microorganisms responsible for decomposing organic matter require water for biochemical processes. The optimal moisture level is around 50-60%.
- Temperature plays an important role, as decomposition occurs more quickly under appropriate conditions (40-60°C). High temperatures also help eliminate pathogens and weed seeds.
- Shredding the material speeds up composting because it increases the surface area available for microorganisms, making organic matter more accessible to them.
- Oxygen is essential for aerobic bacteria, which drive the proper composting process. Regularly turning the compost pile prevents anaerobic conditions, which would otherwise cause unpleasant odors.
- Inoculation—adding mature compost or soil rich in microorganisms—can accelerate decomposition by introducing active bacteria and fungi.
- The carbon-to-nitrogen ratio (C:N) should be around 25-30:1. A proper balance between carbon-rich materials (e.g., dry leaves, branches, straw) and nitrogen-rich materials (e.g., kitchen scraps, fresh grass clippings) ensures optimal microbial activity and effective decomposition.
Three Main Phases of Composting
- Mesophilic Phase (Initial Phase) – lasts a few days. Mesophilic microorganisms (thriving at 20–40°C) begin breaking down easily decomposable organic substances, leading to an increase in temperature.
- Thermophilic Phase (Main Phase) – lasts from a few weeks to several months. Thermophilic microorganisms break down more complex compounds like lignin and cellulose. The temperature can reach 50–70°C, which helps eliminate pathogens and weed seeds.
- Maturation Phase (Stabilization Phase) – lasts several months. As the temperature drops, mesophilic microorganisms complete the decomposition process, and the compost gains a stable structure and nutritional value.
Once the process is complete, the compost is ready to be used as fertilizer.
Composting is an effective method of processing organic waste that benefits both the environment and gardeners. The main advantages include improving soil quality, reducing the amount of waste sent to landfills, and producing natural fertilizer that enriches plants with essential nutrients. However, composting requires proper knowledge and attention to avoid unpleasant odors or uncontrolled pest infestations. Although the process may take time and patience, the benefits far outweigh any potential difficulties.