The Science of Compost Formation
Only by understanding the composting cycle can we achieve the full potential of a superior quality organic fertiliser through compost which will, in turn, improve the soil quality of the farm. First, we need to understand the bio-oxidative composting process. In composting process, organic matter is degraded by microorganisms to convert it into stable humus. The composting cycle consists of four stages: mesophilic stage, thermophilic stage, cooling stage and maturation stage.
The first, or mesophilic phase, initiates when organic matter is layered and microorganisms begin to work on the more readily decomposable components, which begin to heat up, driving the compost into the thermophilic phase, with temperatures of 40ºC-70ºC. This heating is essential, inasmuch as it kills pathogens and weed seeds, making the compost safe to use in agriculture.
These are three of the most important factors in the production of good compost: the carbon-to-nitrogen (C:N) ratio, the amount of moisture and the amount of air or other forms of oxygen. All composts need a relatively high carbon-to-nitrogen ratio. A good compost pile will have a ratio of about 30:1, which will give microorganisms the right amount of carbon for energy and the right amount of nitrogen for protein. Good compost also needs some moisture, not too much, but not too little, either. The best compost pile will be damp, but not sopping wet. Excessive moisture can lower the temperature and lead to anaerobic conditions, which not only slow down the decomposition process, but produce horrible odours. The air or oxygen, which is needed to facilitate efficient decomposition, is provided by turning, and a good dark and moist compost pile will need turning every three to 10 days.
Temperature control is another key factor in creating a high-quality product. Compost temperature often touches 150 degrees Fahrenheit when managed correctly, which is hot enough to break down compost material and destroy pathogens.
As Emily Robertson, an expert in organic waste management in the UK, puts it: ‘Composting is not just a process of heaping up and forgetting about it, but involves actively managing the microclimate to optimise [microbial] activity to make gold of waste’. The precise balance of conditions is what converts ‘ordinary’ organic waste into something useful, a soil amendment that can boost the health and fertility of soil.
This fundamental scientific understanding of these processes helps enable the production of good quality organic fertiliser, but also to empower farmers and gardeners to better manage their organic waste production in a more sustainable way. This basic knowledge of composting processes is key to also understanding the applied benefits of compost for growing crops, and to consider this in the diverse agricultural land use systems of Europe.
Benefits of Compost in Crop Cultivation
Compost is widely considered the ‘gold standard’ of organic fertilisers for agriculture because it can promote healthy plants and soils in a multitude of ways – in parts of Europe, the use of compost in crop production has resulted in significant increases in crop yields and soil quality, all without synthetic fertilisers.
One of the nutritional benefits of compost are the slowrelease nutrients within it via the release of essential nutrients like nitrogen, phosphorus and potassium. The slow release prevents leaching of nutrients and also supplies plants with a constant supply throughout their life cycle, improving plant health and development. The nutritional benefits of compost also include micronutrients and microbes that aid in the development of soil structure, nutrient availability and resistance of plants to diseases and pests.
And there are other examples from Europe of the role that compost can play in agricultural success. In Italy, a comparison of vineyards found that those that used compost had grapes with better appearance and a greater yield: the reasons for these improvements are because compost added more organic matter to the soil and created greater activity in the soil microbes. In the Netherlands, compost had been shown to improve the quality of potatoes grown in the field and cut down on soil-borne diseases.
One of the leading international experts on composting and agroecological practices, Dr Fiona Borthwick, highlights its ecological advantages: ‘By using compost as a fertiliser within crop systems, we not only increase soil fertility, but are also contributing to a sustainable model of agriculture, by recycling nutrients and reducing waste and chemical inputs.’ We are also working towards better health via the environment.
Essentially, by making crops thrive with a high nutrient content and having excellent soil-building qualities, without the need for chemical fertilisers, compost remains a valuable natural resource in agricultural production and, in organic farming in particular, its use is central to maintaining soil health. The use of compost in food production will only expand in the coming years as more importance is placed on its role in the environmental sustainability of farming and, more importantly, as a means to enhance both crop yield and quality.
Compost Application Techniques
Use of compost as organic fertiliser in Europe requires specific best practices for the application of compost that maximises soil and plant health and also contributes towards the sustainability of agricultural practices.
One of the primary ways of applying is based on the a crop or plant’s development: adding compost for planting may help young plants grow in a nutrient-rich environment conducive to root growth. Adding compost for perennials in early spring or late fall can help uptake nutrients and grow cycles.
It is very important to get this timing of the compost application during the changing season right. In temperate European climates, if you spread compost early in the spring, it will replenish nutrients that were lost by winter crops, while the organic matter will also activate microbial life in the soil before the spring planting season. If there are winter crops, adding compost in the fall improves soil structure and fertility to help those plants overwinter, allowing them to get an early start on spring growth.
Appropriate application methods include broadcasting, banding or side-dressing compost apply methods for crops and crop types at different growth stages Broadcasting, which is spreading compost uniformly around the field, is common for large-scale agriculture. Banding, which is placing the compost into rows or bands near the roots, is appropriate for crops like maize and tomatoes grown in rows (row crops), because nutrients reach the plants from a concentrated area for effective delivery. Mainly, side-dressing is applying compost around the base of the plants, such as adding N and other nutrients near high-yielding rice fields.
Soil specialists, such as the soil scientist Helga Willer at the Research Institute of Organic Agriculture, emphasise the need for careful application: ‘Good application techniques for compost as fertiliser,’ she explains, ‘will not only improve nutrient uptake by plants, but also minimise the risk of runoff and nutrient leaching into the environment.’ Here lies the key to “good application” technique. It allows for optimal use of nutrients by making them available where and when the plants need them. Plant nutrients are valuable resources, and like all resources, we have an interest in conserving them and using them efficiently.
By practising these techniques, organic compost will be used more efficiently, as it acts as an agronomic factor to increase the health of soils and sustain food production. The strategic application of compost is a crucial part of the growing sustainability of European agriculture.
Innovations in Compost Technology
As more specialists have unblocked the process of composting, the technology has been further developed to accelerate the decomposition process and make compost richer in nutrients as an organic fertiliser. These developments are essential to increase the use of compost in industrial-scale farming systems, which is a requirement for farmers who want to use more compost on their fields.
Another is the innovation of aerated static pile composting. Instead of continually turning the mixture in windows, piles of organic materials are layered and a system of pipes is integrated that allow air to freely move through the compost, providing airflow over the entire mass. This innovation does away with the major costs of the more primitive system – labour associated with turning and machinery for mixing the materials – which can take weeks. It also increases aeration, allowing optimal temperatures throughout the pile, dramatically reducing the time it takes for the material to break down, and decreases volatilisation of the precious nitrogen in the material.
Another state-of-the-art technology to speed up compost production in microbe-rich hot piles is bioaugmentation. It’s the practise of adding selected strains of bacteria or fungi to composting piles expressly to increase the decomposition of tough plant materials like lignin and cellulose. Microorganisms selected for this service are very adept at degrading complex organic compounds, meaning a lot of carbon will be released for plants to capture. The addition of these microbes will improve the composition and consistency of the final product.
Likewise, vermicomposting, which uses earthworms to process organic waste, is becoming more commonplace: the worms eat the organic matter, and their faeces (castings) are more nutrient-dense than the compost bin solution. Vermicomposting both accelerates composting and augments the microbial diversity of the compost for healthy soils and plants.
As Sofia G Fernandes, an expert in sustainable waste management in Portugal explains: ‘[C]ompost technology innovations are changing the paradigm of waste management in agricultural systems by improving the efficiency and output of composting procedures, thus making available to the farmer a high-quality organic alternative to mineral fertilisers.
These innovations in the production of compost not only advance sustainable forms of farming but also contribute to environmental policies that strive to reduce the amount of waste and promote organic farming. It is expected that these developing technologies will become widely adopted and contribute to future forms of farming, especially in supplying substantial amounts of sustainably produced agricultural inputs.
Challenges and Solutions in Compost Usage
While the use of compost as organic fertiliser has a long and remarkable history for good reasons, the decision to adopt this practice can be influenced by diverse factors that affect either its efficiency or its usefulness to the extant agricultural system. These conditions must be understood and addressed in order to make compost as efficient as possible within existing European agricultural settings and practices.
A major, broad problem is that quality of compost varies widely – which can have a strong impact on the fertiliser it produces. Dearth of inputs? Find out here Various factors – starting materials, conditions used in composting, and age of compost – significantly impact nutrient levels as well as contaminant levels such as metals or pathogens. It’s therefore important to employ rigorous quality controls, with frequent testing to verify quality. Developing standardised guidelines for composting can help to ensure a high-quality product that can be relied upon by farmers.
A second important challenge is the logistical constraints of collecting, transporting and applying compost, particularly when it comes to large-scale farming operations. Though farms can create their own compost on-site, this process can be labour intensive and space-intensive. This means it takes a long time for the material to fully mature, and requires significant handling and storage, all of which incur high costs and create considerable logistical challenges. Creating pelletised compost products can make the product easier to transport and apply, and localised compost programmes that foster a community of compost users by minimising transport investment are another useful innovation.
Even larger challenges include the public perception gap and lack of public awareness and education. Many producers and consumers are still unaware of the benefits of compost, and/or how to apply it effectively. Creative educational campaigns and quarterly workshops can be designed to increase the public’s awareness of the benefits of compost, the proper application, and how to manage soil health in general.
Dr Lucas Grant, a soil scientist and composting technology expert, reinforced the point about social support: ‘Community composting initiatives and government subsidies for organic farming can enable compost use as organic fertiliser. This is significant as those measures bridge the economic and logistical gap, creating a culture for sustainability.’
These three challenges have to be addressed through more innovation in technical solutions, engagement with communities, and by policies that support all of this. Then we will have a fertiliser as sustainable as compost to underpin a healthier and more resilient future for European farming.
