Compost
[2] Composting can be a multistep, closely monitored process with measured inputs of water, air, and carbon- and nitrogen-rich materials.
Aerobic bacteria and fungi manage the chemical process by converting the inputs into heat, carbon dioxide, and ammonium ions.
Active management of the pile (e.g., turning over the compost heap) is needed to maintain sufficient oxygen and the right moisture level.
[3] Composting is an ongoing and dynamic process; adding new sources of carbon and nitrogen consistently, as well as active management, is important.
It requires assembly of at least 1 cubic metre (35 cu ft) of material at the outset and needs turning every two days after an initial four-day phase.
[20] Such short processes involve some changes to traditional methods, including smaller, more homogenized particle sizes in the input materials, controlling carbon-to-nitrogen ratio (C:N) at 30:1 or less, and careful monitoring of the moisture level.
Piles smaller than 1 cubic metre (35 cu ft) tend not to reach and maintain high temperatures.
[27] Compost is a good source of biocontrol agents like B. subtilis, B. licheniformis, and P. chrysogenum that fight plant pathogens.
The reduced volume of materials being picked up by trucks results in fewer trips, which in turn lowers the overall emissions from the waste-management fleet.
[1] The amount of manure composted on a livestock farm is often determined by cleaning schedules, land availability, and weather conditions.
Nitrogen, which serves as a building block for important plant amino acids, is found in solid human waste.
[38][39] Phosphorus, which helps plants convert sunlight into energy in the form of ATP, can be found in liquid human waste.
In the case of home composting, a wide range of microorganisms, including bacteria, viruses, and parasitic worms, can be present in feces, and improper processing can pose significant health risks.
[42] In the case of large sewage treatment facilities that collect wastewater from a range of residential, commercial and industrial sources, there are additional considerations.
Unlike feces, urine does not attract disease-spreading flies (such as houseflies or blowflies), and it does not contain the most hardy of pathogens, such as parasitic worm eggs.
[54] In-vessel composting systems can consist of metal or plastic tanks or concrete bunkers in which air flow and temperature can be controlled, using the principles of a "bioreactor".
The practice of making raised garden beds or mounds filled with rotting wood is also called Hügelkultur in German.
[58][60] Buried wood acts like a sponge as it decomposes, able to capture water and store it for later use by crops planted on top of the bed.
dictates the ratio of the blend, and maturity is important to insure that oxygen deprivation will not occur or that no lingering phyto-toxins remain.
[76] Non-aerated compost tea is cheaper and less labor-intensive, but there are conflicting studies regarding the risks of phytotoxicity and human pathogen regrowth.
[77] Aerated compost tea brews faster and generates more microbes, but has potential for human pathogen regrowth, particularly when one adds additional nutrients to the mixture.
[77] Adding nutrients to compost tea can be beneficial for disease suppression, although it can trigger the regrowth of human pathogens like E. coli and Salmonella.
There are also a range of specialist composts available, e.g. for vegetables, orchids, houseplants, hanging baskets, roses, ericaceous plants, seedlings, potting on, etc.
[83] There are process and product guidelines in Europe that date to the early 1980s (Germany, the Netherlands, Switzerland) and only more recently in the UK and the US.
About 26 American states now require composts to be processed according to these federal protocols for pathogen and vector control, even though the application to non-sludge materials has not been scientifically tested.
Ultimately the idea of composting diapers was abandoned, partly since it was not proven scientifically to be possible, and mostly because the concept was a marketing stunt in the first place.
For a considerable fee, the applicant may display the USCC logo on products, agreeing to volunteer to customers a current laboratory analysis that includes parameters such as nutrients, respiration rate, salt content, pH, and limited other indicators.
The Sierra Club recommends that home gardeners avoid the use of sewage sludge-base fertilizer and compost, in part due to potentially high levels of PFASs.
[104] Early proponents of composting in farming include Rudolf Steiner, founder of a farming method called biodynamics, and Annie Francé-Harrar, who was appointed on behalf of the government in Mexico and supported the country in 1950–1958 to set up a large humus organization in the fight against erosion and soil degradation.
[105] Sir Albert Howard, who worked extensively in India on sustainable practices,[103] and Lady Eve Balfour were also major proponents of composting.
