Introduction to Organic Fertilizers in Sustainable Agriculture
Organic fertilisers are important for sustainable production systems because they can replace pesticides and inorganic fertilisers. Soil fertility needs to be maintained for agricultural production and environmental health. Good fertilisers need to support plant growth and animal nutrition with all the essential nutrients. Currently, the amount of organic fertiliser use is decreasing – unfortunately. All organic fertilisers are derived from nature: from the excreta of animals and plants to the minerals present in the earth. The nutrient content of soil differs depending on the type of fertiliser used.
What are organic fertilisers, exactly? Organic fertilisers are any material that contains an enriched organic mass, from bone meal to manures to the compost pile and seaweed extracts. As Jacob Mittleider, a world-renowned agronomist, observed, ‘The use of organic fertiliser is not only to feed the plants this growing season, but to build the soil structure and fertility for the coming centuries of crops.’
Traditional animal-based fertilisers are like manure, bone meal and fish emulsion, all having high nitrogen and phosphorus content.
Plant-based fertilisers are produced using compost, crop residue and green manure, which are especially abundant in nitrogen.
Mineral-based fertilisers, such as rock phosphate and greensand, provide minerals such as potassium and phosphorous without the addition of synthetic chemicals.
Role in Sustainability: Organic fertilisers have an important role in sustainable agriculture practice because of the many advantages they provide in maintaining soil health. First, they help to make the soil hold more water, resulting in the soil being able to stay wetter for longer periods of time. This, in turn, promotes and maintains a high level of biological activity and soil structure.
Second, the plants are less likely to topple over or be washed out of the soil due to heavy rain or severe winds because the roots are more firmly anchored in the soil structure, considerably reducing crop loss. Additionally, organic fertilisers support soil biota, which facilitates more efficient nutrient recycling in the soil, making fertiliser more effective and minimising the amount that is lost. ‘Organic fertilisers do not simply add nutrients to the soil but also create a live, biologically active soil!’ says Mittleider.
It is through the constant application of organic fertilisers that farmers and gardeners can ensure that the agriculture system balances plant health and productivity, so that the agriculture system will remain a productive and environmentally friendly one for generations ahead. This is holistic fertilisation. The environment has nothing to fear from it, and crops have everything to gain.
Benefits of Using Organic Fertilizer
For these reasons, the introduction of organic fertiliser enhances soil fertility, with benefits that go far beyond the nutritional needs of the plants. It is the stepping-stone toward an agricultural production system that is more sustainable and humane, one that respects and regenerates the natural environment.
Nutrient Release Dynamics: Organic fertilisers generally have slow-release properties. For instance, synthetic fertilisers provide plants with nutrients quickly, but when the nutrients enter the soil they are sometimes washed away by rain quickly, because there is little attendant organic matter in the soil to protect these nutrients. Organic options slowly release nutrients, and this is more sympathetic to plant growth cycles. Plants take up nutrients little and often. Dr Linda Chalker-Scott, a horticultural scientist told me ‘because the slow-release mechanism of organic fertilisers minimises nutrient leaching and loss, they are very efficient and minimal impact fertilisers compared to inorganic fertilisers that release nutrients very rapidly.’
Its Effects on Soil Structure and Fertility: By adding extra organic materials to the soil, organic fertilisers promote longer-term effects on soil structure, improving soil fertility. Deep-rooted perennial plants are able to increase soil organic matter by large amounts. They make the soil more sponge-like and provide better aeration and moisture retention, promoting a thriving soil biotic community that supports the roots of plants. ‘The organic matter contained in these fertilizers act like a sponge,’ Dr Chalker-Scott says, ‘which can retain water and nutrients that are vital for better plant growth and promoting soil resilience against erosion and degradation.
Environmental Benefits: The favourable environmental impact of organic fertiliser is also significant. They reduce demand for chemical inputs, which are often implicated in detrimental environmental effects, including waterway pollution from runoff, as along with fertilising crops, their use contaminates groundwater and marine ecosystems. Also, as Chalker-Scott points out, ‘the use of organic fertiliser feeds biodiverse microbial life in the soil, translating to improved soil health and nutrient recycling – that is, reduced footprint through lower greenhouse gas emissions associated with synthesising and applying chemical fertilisers in the first place.’
In conclusion, it can be said that apart from helping plants to grow organically, using organic fertilisers also contributes to an overall ecological management at a global scale, retaining biodiversity, utilising water, and minimising our carbon footprint. For this reason, use of organic fertilisers by farmers and gardeners contributes to a more environmentally friendly agricultural model.
Best Practices in Applying Organic Fertilizer
Using organic fertiliser efficiently means having knowledge of optimal timing, the proper methods and how it relates to other agricultural practices, in order to achieve the best outcomes with respect to increasing crop yields for diverse crops under different agricultural conditions.
Soil needs to be spiked with fertiliser at the right time – in order to jumpstart flowers or vegetables with food at the beginning of the growing season, for instance. But that timing could vary even more depending on the type of crop grown and soil conditions. ‘For temperate climates, organic fertiliser should be applied in the fall,’ says Harold van Es, professor of soil science at Cornell University in New York. ‘That’s when temperatures decrease, and a lot of nutrients will break down, which are needed in the spring by the crops.’ In tropical climates where vegetables can be grown year round, try to coincide your application of fertiliser with the start of the rainy season to avoid leaching.
Dosage Considerations: The amount of organic fertiliser used should be based on the level of nutrients already present in the soil, and what the crop requires. Soil testing is the key info here, giving you detailed recommendations on what’s actually inside the soil in terms of the nutrient balance, along with the pH. Dr van Es notes: ‘Over-application can be as detrimental as under-application, and soil tests can help avoid both the environmental and economic costs of delivering nutrients at the wrong level.
Co-ordination with Sustainable Methods: Organic fertilisers are not magical on their own. They work best when they’re integrated into sustainable methods, such as crop rotation, intercropping, and reduced tillage. Crop rotation is the practice of growing two different crops in the same area – switching to another crop the following year, and so on. If done in a way that two crops in the rotation don’t share the same pests or diseases – and if plastic mulch is used in between – crop rotation helps the soil avoid depletion. This practise also reduces the risks of pests and diseases, and helps to improve the soil structure and organic matter. It enhances its resilience and liveliness.
Intercropping is the practice of planting two or more crops very close to each other. While some intercrops are entirely different – like mixing corn with kidney beans – others are complementary because they have different rooting behaviours. The dense root structure of the one It helps in both enhancing soil health and nutrient uptake, and also reduces the risks of weed and pest incursions. Reduced tillage is the practice of retiring the plough and abandoning the plans to turn over the crop residue every year. This technique can conserve the soil structure, improve the soil’s water-holding capacity, and sequester more carbon in soil particles.
Technological Advances in Organic Fertilizer Production
Nowadays, organic fertilisers are produced through a number of technologies, which greatly increase the efficiency of these natural nutrients. Moreover, the progress in composting technologies and converting waste to organic fertilisers play an important role to help modern agriculture to be sustainable.
Numerous new composting technologies have emerged since the traditional practices were first employed. These include in-vessel composting, vermicomposting and anaerobic digestion. In-vessel composting provides more control of the environmental factors, accelerating the decomposition of organic matter and minimising odour. As Nancy Sullivan, an environmental engineer who attended the webinar, explains: In-vessel composting systems can control the temperature, moisture content, and aeration that facilitate organic matter breakdown.
They therefore provide more control of the process, allow operations in different seasons, and shorten the treatment cycles.Composting organic matter with the aid of earthworms is known as vermicomposting, and this process results in highly nutritious compost rich in microorganisms. Meanwhile, anaerobic digestion of organic matter produces both compost and biogas. Nancy Sullivan further comments: The anaerobic digestion of organic matter includes a dual purpose technology to provide waste management and transform it into energy. It thus can fit in the circular economy in agriculture.
Waste to Wealth: Utilising agricultural, municipal and industrial solid and liquid wastes for the production of organic fertilisers is becoming a trend towards sustainability. Such processes involve the treatment of organic wastes into compost that can be used for soil amelioration. ‘Using waste instead of discarding it creates fertiliser from what would have been waste, solving the output problem of producing fertiliser, while producing a beneficial commodity from what would have been a potential pollutant,’ says Dr Sullivan. Doing this reduces the use of landfills, decreases emissions of greenhouse gas and provide renewable source of nutrients for agricultural crops.
Technology only improves the nutrient quality of the fertiliser and its efficient application to the soil and the crop Dr Robbie Sullivan, an international expert on organic agriculture at the University of Western Australia, agrees, noting that high-tech tools such as global positioning systems (GPS) and sensors can aid organic farmers in applying fertiliser more precisely and efficiently. ‘Technology can help tailor fertiliser applications to crop needs, and can reduce fertiliser application and losses,’ he explains.
Case Studies: Successful Implementation of Organic Fertilizer Programs
From the removal of most of West Africa’s coastal forests by the seventh century, to the fields of Oregon clear-felled to plant bitter wheat, or the savannahs of Laos ploughed into charcoal and dust to plant hurting rice, the story is told everywhere of a world changing in ways that make it less habitable to plants, animals, and people. Evidence from many parts of the world – from fertiliser ‘hot spots’ in Taiwan, Cameroon, Venezuela, and China – shows that sound organic fertiliser practices benefit the land when they are followed.
Case Study 1. Integrated Nutrient Management in India: In the Indian state Tamil Nadu, the government-funded programme took an integrated nutrient management (INM) approach focusing on the conjunctive use of organic manure with the chemical fertiliser to enhance paddy yields. As observed by Dr Amanpreet Chopra, an agricultural scientist involved in the project: ‘Balanced use of organics with minimal chemical inputs resulted in 25 per cent more produce when compared with the traditional chemical-only mode of production.’ This generated not only more yields but also sustained the soil health across the growing seasons.
Case Study 2 Organic Vineyards in France: A growing trend toward organic viticulture in France is seeing the rampant use of organic fertilisers in vineyards as a new money-maker for the wine industry. Farmers report that the use of organic fertilisers has resulted not only in the production of better grapes and greater yields, but also enhances the soil biodiversity and reduced instances of disease outbreaks. Dr Henri Bouchard, Viticulturist: Organic fertilisers have reinforced the natural balance of soil ecology and are important to the longevity of our vineyards.
Case Study 3: Community Composting in Urban Gardens in New York, USA: Some urban community gardens in New York City have introduced localised composting systems to manage the amount of organic waste produced, recycling the garbage as fertiliser for the garden. Not only has this initiative lessened the amount of waste sent to landfills, but it has given power to urban communities to grow their own healthy food, says Dr Lisa Goldman an urban sustainability expert: ‘These gardens are proof that urban areas can become a driver towards sustainable agriculture through closed-loop systems that foster food security.
Takeaways: These five case studies illustrate the versatility of organic fertiliser use, spanning various environmental and scale domains. Several common takeaways can be drawn:
Education and training: Some of the most successful programmes include meaningful education and training components to help farmers and other stakeholders understand how organic fertilisation can benefit them and how to best practice it.
Community Involvement: Engaging the community leads to greater acceptance and sustainability of organic practices.
The government and policies: Appropriate policies and subsidies can greatly enhance the use of the organic fertilisers above.
These examples demonstrate the enormous potential to use organic fertilisers to increase crop yields and quality while also enhancing environmental sustainability and community health. Given the widespread applicability and success of these programmes, expanded use and innovation with organic fertilisers are welcome and much needed.
