Composting in bulk.It is the best known technique and is based on the construction of a pile formed by the different raw materials, and in which it is important:
A) Make a correct mixture .The materials must be well mixed and homogenized, so prior crushing of the woody crop remains is recommended, since the speed of compost formation is inversely proportional to the size of the materials. When the remains are too large, there is a danger of excessive aeration and drying of the heap, which damages the composting process.
It is important that the C / N ratio is balanced, since a high ratio slows the humification rate and an excess of N causes undesirable fermentations. The mixture should be rich in cellulose, lignin (pruning remains, straws and dead leaves) and in sugars (green grass, traces of vegetables and fruit pomace). Nitrogen will be provided by manure, slurry, green legumes and the remains of slaughterhouse animals. We will mix as poorly as possible materials that are poor and rich in nitrogen, and dry and wet materials.
B) Form the heap with convenient proportions .The pile must have sufficient volume to achieve an adequate balance between moisture and aeration and must be in direct contact with the ground. For this, some layers of fertile soil will be interposed between the plant materials.
The location of the pile will depend on the climatic conditions of each place and the time of the year in which it is made. In cold and humid climates, it should be placed in the sun and sheltered from the wind, protecting it from the rain with a plastic sheet or similar that allows oxygenation. In warmer areas it should be placed in the shade during the summer months.
The construction of elongated piles, triangular or trapezoidal section, with a height of 1.5 meters, with a base width not exceeding its height is recommended. It is important to insert a thin 2-3 cm thick layer of mature compost or manure every 20-30 cm in height to facilitate colonization of the heap by microorganisms.
C) Proper handling of the pile .Once the pile is formed, it is important to properly handle it, since the final quality of the compost will depend on it. The heap must be aerated frequently to favor the activity of oxidase by the decomposing microorganisms. Turning the battery is the fastest and most economical way of guaranteeing the presence of oxygen in the composting process, in addition to homogenizing the mixture and trying to ensure that all areas of the battery have a uniform temperature. The humidity should be maintained between 40 and 60%.
If the heap is very caked, has too much water or the mixture is not adequate, undesirable fermentations can occur that lead to toxic substances for plants. In general, a well-made mulch has a characteristic smell.
The handling of the heap will depend on the season of the year, the weather and the conditions of the place. Normally it turns around after 4 to 8 weeks have elapsed, repeating the operation two or three times every 15 days. Thus, after about 2-3 months we will obtain a young compost but it can be used half buried.
