Compost materials, processing, types, uses

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Anthony Golden
Compost materials, processing, types, uses

The compost or compost It is the product resulting from aerobic fermentation or controlled biological oxidation of organic materials. This process is called composting and allows the recycling of organic plant and animal waste to obtain fertilizer..

The origin of this practice is lost in human prehistory, with historical references in various civilizations. In China, Japan and India, more than 4,000 years ago, techniques similar to today's composting were already used.

Compost preparation. Source: Pavel Ševela, CC BY-SA 3.0 , via Wikimedia Commons

On the other hand, in Europe there are written references dating from 1182 where recipes for making compost are described in detail. However, Sir Albert Howard is recognized as the father of modern composting..

For its preparation, various organic materials of both plant and animal origin are used. Among them crop residues, food residues, animal excrement, egg shells and others.

Composting requires a series of stages, including the collection and adaptation of the raw material, the mixing phase, and periodic turning. There are different types of compost, from traditional compost to hot compost, coffee compost, avicompost to Japanese bokashi..

Article index

  • 1 History of composting
    • 1.1 Prehistory
    • 1.2 Ancient history
    • 1.3 Modern era
  • 2 Compost materials
    • 2.1 Harvest remains
    • 2.2 Food scraps
    • 2.3 Animal excrement
    • 2.4 Permissible materials in small quantities
    • 2.5 Organic industrial sludge
    • 2.6 Additional materials
    • 2.7 What materials should be avoided?
  • 3 How is compost made? Stages
    • 3.1 1. Obtaining the raw material
    • 3.2 2. Preparation of raw material
    • 3.3 3. Formation of the piles
    • 3.4 4. Irrigation and periodic turning
    • 3.5 5. Removing the compost
  • 4 Phases of the composting process
    • 4.1 Initial or mesophilic phase
    • 4.2 Thermophilic phase
    • 4.3 Cooling phase
    • 4.4 Ripening phase
  • 5 Types of compost
    • 5.1 Traditional or basic
    • 5.2 Manure or hot
    • 5.3 Avicompost
    • 5.4 Vermicompost
    • 5.5 Compost coffee
    • 5.6 Bokashi
  • 6 Uses of compost
    • 6.1 Recycling of organic matter
    • 6.2 Organic fertilization of crops
    • 6.3 Soil recovery
  • 7 References

Compost history

Prehistory

The origin of the recycling of organic waste to later serve as fertilizer for crops is lost in human prehistory. In archaeological excavations, villages have been found that deposited their waste in areas also used for cultivation..

Old history

There are some references in different civilizations regarding the practice of composting. For example, in China, Japan and India there are references of more than 4,000 years of the processing of agricultural and livestock waste to use them as fertilizers.

Also in the Rome of the Emperor Augustus, in 50 BC. C., the waste of the city was collected to use it in agriculture. The first reference to compost processing in Europe is a manuscript from 1182 found in Trujillo, Spain, and which is attributed to the Templar master Gualdim Pais.

In this manuscript there are recipes for processing agricultural and livestock waste and obtaining fertilizer, called Living Humus or Fertile Gold. For this, the cultivation, type of soil, humidity were considered and it consisted of a process of turning piles that lasted about 90 days..

Was modern

In the 15th century, in Florence, farmers entered the city every morning to collect waste. These were then used in the fertilization of their farmland.

However, Sir Albert Howard is recognized as the father of modern composting in English, for having experimented with different methods in Indore (India), where he worked as a technician and agricultural consultant between 1924 and 1931, developing the method that he called the Indore Process..

Sir Albert Howard

With this process he obtained humus from agricultural and livestock remains. The description of his method was published in 1931 in his work The Waste Products in Agriculture (Waste products in agriculture).

That same year, the first industrial composting plant based on the Indore Process was installed in Wijster, Holland. Later, in 1937 in Denmark, the first closed composting system was developed, called the “DANO drum system”..

Later, composting systems appeared that controlled basic parameters of the process. Such is the case of the system of the University of Beltsville (USA) in 1970, which controlled oxygenation and that of Rutgers University (USA) focused on temperature.

Compost materials

The different materials that are used in the mixture for the preparation of the compost vary depending on their content of moisture, nitrogen and carbon. On the other hand, in addition to the materials to be composted, water is added if it is dry materials.

Harvest remains

One of the main ingredients for composting is the remains of the crops. The properties that these materials contribute will depend on the type of crop from which said remains come..

For example, the bagasse of sugarcane has a high content of sugars that provide a large amount of carbon. Carbon and nitrogen are provided in the case of corn crop residues..

Food scraps

Materials for obtaining compost. Source: The original uploader was Airelle at French Wikipedia., CC BY-SA 3.0 , via Wikimedia Commons

Food waste, whether from agribusiness, markets or households, varies considerably in its composition. They can include only plant or animal derivatives or combinations of both.

Fruit peels, cereal scraps, egg shells, and fats are common. Each one will provide particular nutrients in addition to the common ones such as carbon, nitrogen and phosphorus..

For example, egg shells are especially rich in calcium, while banana peels provide potassium. Although eggshells are very slow to decompose, a process that can be accelerated by spraying or using a little vinegar.

Animal excrement

Animal excreta are especially rich in nitrogen and provide high humidity to the mix. They can vary in their composition depending on whether they are excreted from cattle or birds and provide potassium, iron, calcium, zinc and other elements..

Allowable materials in small quantities

Wood ash, newspaper, and cardboard are added to some composting mixes. However, it should be taken into account that these types of materials are accepted in composting in small proportions. In the case of wood ash, an excess acidifies the compost, in addition to weighing it down and subtracting nitrogen.

Organic industrial sludge

Compost is also prepared from waste sludge from industries such as paper mills and breweries..

Additional materials

There are some materials that are added during the process or at the end to improve the mix or correct pH. For example, lime is used for this last purpose in those cases where the acidity is excessive and also to avoid bad odors. Minerals can also be added by spraying rocks that contain them.

What materials should be avoided?

In the previous selection, avoid including all types of synthetic or toxic material. On the other hand, do not use paper or cardboard with plastic covers or with colored inks or oils or carbon ashes..

Similarly, as far as possible it is not advisable to include materials with very slow decomposition. Such is the case of hardwood and corozos or fruit bones such as peaches and avocados, among others..

How is compost made? Stages

The total process to obtain the compost can last from 3 to 9 months, depending on the climate of the area. However, if it is carried out in closed facilities with controlled conditions, the process is much shorter.

To compost, the following general steps are followed:

1. Obtaining the raw material

The raw material has diverse origins, including waste from vegetable markets and urban organic waste. As well as remains of crops or animal production.

2. Preparation of the raw material

Depending on the nature of the material obtained, some pre-treatment may be necessary. Especially aimed at reducing the size of the components by grinding or grinding.

Care must be taken that the resulting particles are not too small, as this cakes and compacts the mixture, making aeration difficult. The suitable size is 2 to 5 cm.

3. Formation of the piles

Piles for compost. Source: Goyojona, CC BY-SA 4.0 , via Wikimedia Commons

There are several methods for composting, but in any case there is always a place where the piles or heaps of the mixture are formed. Be it in holes in the ground, in trenches, in drums or in various types of pots. These piles should be easy to turn periodically to promote uniform aeration and oxidation..

4. Irrigation and periodic turning

The batteries must be turned periodically to guarantee their oxygenation and watered in case of excessive moisture loss. Similarly, the temperature of the mixture must be controlled so that it does not exceed 60 ° C. This is due to the fact that a temperature higher than this would kill the microorganisms that carry out the oxidation of the mixture..

Not all composting methods require turning, as there are static ones, where aeration is done by convection. In other cases, forced aeration methods by blowing or air extraction are used..

5. Removing the compost

Once the cycle is finished and the quality of the product has been verified, the compost is extracted for use.

Stages of the composting process

The materials that make it up go through different phases until they form compost:

Initial or mesophilic phase

Mesophilic (medium room temperature) organisms such as fungi, protozoa and various bacteria participate here. The pH falls around 5 due to the presence of organic acids and the temperatures rise and the temperature rises between 40 to 45 ° C.

Thermophilic phase

It occurs after approximately three days, although it depends on the material used and the conditions. Thermophilic organisms act (capable of surviving temperatures of 50 ° C or higher). In this phase, the pH becomes alkaline (8 to 8.5) due to the conversion of ammonia into ammonia and temperatures are around 60 to 70 ° C.

Cooling phase

Once most of the carbon and nitrogen have been consumed, the temperature drops, hovering around 40 or 45 ° C. This allows mesophilic organisms to reappear..

Ripening phase

In this phase, the temperature drops and stabilizes, while the pH reaches a value between 7 and 8. This maturation process is the longest and allows the formation of humic and fulvic acids that make up the humus..

Compost types

Traditional or basic

It is the classic way in which all kinds of organic waste are mixed and subjected to periodic tumbling. Depending on the raw material, its characteristics will vary, as well as the problems in its elaboration..

Manure or hot

This is based on the use of manure and water for its production, so the mixture reaches high temperatures. It is a compost with a high nitrogen content and attracts many flies in the production process..

Avicompost

This is a system in which an area is established where organic vegetable waste is added and chickens are introduced. They feed on waste and excrete, incorporating chicken manure into the mix.

The hens are then removed from the site, watered with water, and sealed to allow the thermophilic phase to occur. Later it is uncovered and the hens are introduced again, which feed on worms and other organisms. By repeating this process, a very nutritious compost with a magnificent structure is obtained..

Vermicompost

Vermicompost. Source: Malcolm Fowles, CC BY-SA 4.0 , via Wikimedia Commons

This is the compost in whose elaboration earthworms act specially added so that they fulfill the process in the mixture. As they feed on the material, they degrade it, forming solid and liquid humus. It is the one obtained in the process called vermiculture, whose base is the excrement of the red worm.

Coffee compost

This is a very special type of compost that originates from the remains of the coffee harvest, particularly the husk. Its structural and nutritional properties are highly appreciated, especially the high nitrogen content.

Bokashi

This is the so-called Japanese compost, although some do not consider it a proper compost. This is because it is based on anaerobic fermentation (without oxygen), where temperatures of 70 ° C are reached. For this, a mixture of rice husk, chicken manure or manure, molasses, charcoal, litter, yeast, soil, agricultural lime and water is used..

Compost uses

Recycling of organic matter

Composting is a means of recycling organic waste of various kinds. Unpleasant odors and harmful organisms are removed by the process.

Organic fertilization of crops

Organic fertilization with compost. Source: SuSanA Secretariat, CC BY 2.0 , via Wikimedia Commons

Compost or compost is a very low-polluting organic fertilizer, which provides crops with essential nutrients. On the other hand, it favors the structural properties of the soil, improving its aeration, moisture retention and nutrient exchange capacity. It is used in food and industrial crops, gardening, and seedlings.

Soil recovery

It is very useful for the recovery of eroded or degraded soils, by improving the structure. The increase in organic matter increases the capacity of the soil to retain moisture and facilitates the cohesion of the particles. This contributes to reducing soil loss due to erosion..

References

  1. Friends of the Earth (2004). Basic Manual to make compost. Home composting pilot project. Ministry of the Environment, Spain.
  2. Friends of the Earth (2008). Composting Manual. Ministry of the Environment and Rural and Marine Affairs, Spain.
  3. Álvarez de la Puente, J.M. (2010). Composting Manual for Organic Agriculture. Department of Agriculture and Fisheries. Junta de Andalucía.
  4. Barrena-Gómez, R. (2006). Composting of organic solid waste. Application of respirometric techniques in monitoring the process. Doctoral Thesis. Autonomous University of Barcelona.
  5. Guo, L., Wu, G., Li, C., Liu, W., Yu, X., Cheng, D. and Jiang, G. (2015). Vermicomposting with maize increases agricultural benefits by 304%. Agronomy for Sustainable Developmentustainable Development.
  6. Román, P., Martínez, M.M. and Pantoja, A. (2013). Farmer's Composting Manual, Experiences in Latin America. FAO Regional Office for Latin America and the Caribbean. Santiago de Chile: Food & Agriculture Org.
  7. Romero-Conrado, A.R., Suárez-Agudelo, E.A., Macías-Jiménez, M.A., Gómezcharris, Y. and Lozano-Ayarza, L.P. (2017). Experimental design to obtain compost suitable for agricultural use from Kraft paper sludge. Magazine Spaces.

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