This article attempts to capture some of the literature review in respect of recent global trends pertaining to “integrated nutrient management systems” with special reference to nitrogen.
Exactly two years ago, at a time when the world grapples with the menace of air pollution killing seven million people prematurely every year, the UN Environment Programme (UNEP) convened a two-day event at which member states came together to adopt what is being called the “Colombo Declaration” with an ambition to halve nitrogen waste by 2030. Whilst it is a critical element for building structures of living organisms, nitrogen overuse has negative impacts on the planet, biodiversity and is a contributor to the climate crisis.
“Our failure to use nitrogen efficiently is polluting the land, air and water. The usefulness of nitrogen has come at a terrible cost” said Joyce Msuya, UNEP deputy executive director. As part of the Declaration, the environment ministers and officials representing the governments endorsed United Nations plans for a campaign on sustainable nitrogen management called “Nitrogen for Life”, which stems from the Sustainable Nitrogen Management Resolution which was adopted during the fourth session of the UN Environment Assembly held from 11 – 15 March 2019 at the UNEP headquarters in Nairobi, Kenya.
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| Sri Lanka Tea Board Chairman Jayampathy Molligoda |
Member States recognized the urgency of addressing nitrogen management in meeting biodiversity goals, while offering huge economic opportunities in reducing reactive nitrogen that is wasted every year, as well as reducing eutrophic zones affecting fishing and tourism industries. “This is a historic moment for Planet Earth. For the first time governments have agreed to work together on a major quantitative global goal for improved nitrogen management” said, Prof. Mark Sutton, INMS project director. “The aspiration to halve nitrogen waste by 2030 offers a $100 billion opportunity to mobilize innovation for the nitrogen circular economy, while contributing to the environment, health and livelihoods”.
(1) Scientific view on impact of excessive use of agro chemicals:
Historical background: During the period 1910-30, scientific advancement called ‘Haber- Bosch process’ enabled fixing atmospheric nitrogen by converting it into ammonia and developed the first industrial-scale application of nitrogen fertilizers- started producing on a large scale to boost crop growth Today, the Haber Bosch process is a key part of the conventional process of crop cultivation worldwide giving ‘nitrogen’.
However, the scientists have found that the Haber Bosch Process leads to Biodiversity Loss and serious land degradation, soil fertility issues leading to crop decline in d long term.
(a) The Haber Bosch Process has an ecological impact since soil fertilizers are easily soluble in water and as a consequence, easily transported from their designated soil in run-off waters.
(b) Soil erosion and runoff from fertilized land contribute to lakes and streams full of nutrients AND nitrates concentration beyond a limit, in drinking water is toxic to animals and humans especially, infants.
(c) When they reach large water bodies, unnatural growth of ‘algae’ that covers the surface of the water body, prevents sunlight from reaching submerged species.
(d) As a consequence, submerged organisms are unable to do photosynthesis and die.
(e) Moreover, ‘algae’ also consume most of the water’s oxygen, often leading to fish dying from oxygen deprivation and to further impacts across the ecosystem due to their absence.
One of the most common causes is nitrate in drinking water which can be originated by the leaching of nitrogen fertilizer into groundwater-drinking water.
According to Professor Nishibayashi from the University of Tokyo, he and his team found, in a study published in Nature, a new way of synthesizing ammonia which is far cleaner, easier and cheaper than the Haber Bosch process. The “SWAP process creates ammonia at 300-500 times the rate of the Haber-Bosch process and at 90 percent efficiency.”
Scientific view of impact:
Nutrient run-off from farms laced with synthetic fertilizer has adversely affected land ecosystems, according to the United Nations-backed Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). Human health is also at risk. Agricultural ammonia emissions can combine with pollution from vehicle exhausts to create dangerous particulates in the air and exacerbate respiratory diseases, including COVID-19. One study has estimated that air pollution may increase mortality associated with COVID-19 by 15 per cent.
To stem the tide of nitrogen pollution, a growing number of governments, companies and international bodies, including the United Nations Environment Programme (UNEP), have been working with scientists to better understand the risks associated with human use of nitrogen, and to raise awareness.
To that end, almost exactly a year ago United Nations Member States endorsed the ‘Colombo Declaration on Sustainable Nitrogen Management’, which sets an ambition to halve nitrogen waste from all sources by 2030. UNEP also recently established the global “Halve Nitrogen Waste” campaign, highlighting the fact that improving nitrogen use efficiency not only supports climate, nature and health goals but also saves US$100 billion globally annually.
One alternative is to migrate into organic input applications to be used in agriculture. A movement and a revolution on organic fertiliser inputs is going on throughout the world to develop a sustainable alternative to the people and the farmers. This is because the synthetic fertiliser and agro chemical usage raised food productivity at the cost of the health of people and environment (soil quality decline and land degradation) and also it was noticed that much higher doses have to be used than earlier days to maintain the agricultural productivity. Organic Fertilizers developed through modern biotechnological research are much more efficient than before and have potential to replace or significantly reduce the use of chemical fertilizers.
However, the negative side is some organic fertiliser, say composting, manure made out from urban waste may contain toxic substances and pathogens, which may pass into the human ‘food- chain’ when used in farms. VERMICOMPOSTING system by waste eater earthworms can provide a completely disinfected & detoxified vermicompost- free of all chemicals & pathogens. (vermi-compost- is the product of the decomposition process using various species of worms, usually red wigglers, white worms, and other earthworms, to create a mixture of decomposing vegetable or food waste, bedding materials, and vermicast. This process is called vermicomposting, while the rearing of worms for this purpose is called vermiculture)
Earthworms’ bio-accumulate & biodegrade all the toxic substances & kills pathogens in the medium in which it inhabits. Vermicompost is also more powerful than other bulky organic fertilizers and can give farm yields significantly higher % over chemical fertilizers. The views of some authors that use of vermicompost & other organic fertilizers give good results after some years of use have some scientific reasons. The physical, chemical & the biological properties of soil have been badly damaged by years of use of agrochemicals and it takes some time to restore their natural fertility.
(2) Organic-based fertilizers and the European Commission’s growth strategy:
Organic-based fertilizers play an increasingly significant role in supporting and implementing the targets set out in Europe 2020, the European Commission’s growth strategy. Organic-based fertilizers include three specific product categories: organic fertilizers, organo-mineral fertilizers and organic soil improvers. ECOFI defines and differentiates these three linked product categories as follows:
(i) Organic fertilizer: a fertilizer whose main function is to provide nutrients under organic forms from organic materials of plant and/or animal origin.
(ii) Organo-mineral fertilizer: a complex fertilizer obtained by industrial co-formulation of one or more inorganic fertilizers with one or more organic fertilizers and/or organic soil improvers into solid forms (with the exception of dry mixes) or liquids.
(iii) Organic soil improver: a soil improver containing carbonaceous materials of plant and/or animal origin, whose main function is to maintain or increase the soil organic matter content. This is how organic-based fertilizers support the three pillars of the strategy:
(a) Smart growth – for an economy based on research, knowledge and innovation.
Our members are part of a research-based, knowledge-intensive and innovation-driven sector that is pioneering solutions to challenges throughout the value chain in agriculture, food and nutrition.
(b) Sustainable growth – for a resource-efficient, greener and more competitive economy. The materials that compose organic-based fertilizers, the beneficial natural processes they generate, and the ways in which they are produced contribute to the sustainable, resource-efficient and low-carbon economy that Europe is committed to building.
(c) Inclusive growth – for a high-employment economy with social and territorial cohesion. The organic-based fertilizers industry generates local employment opportunities and regional economic development across both rural and urban areas, nurturing more vibrant manufacturing and farming communities.
(3) Pros and cons of organic fertiliser usage:
Globally, synthetic fertilizers are behind the bulk of global food production and they’re especially important in developing countries. However, initiatives to stake out a more sustainable way of growing food are plentiful. A recent study from the Soil Association, a United Kingdom-based charity and advocate of organic farming, calls for much greater attention to nitrous oxide emissions in global greenhouse gas accounting; more integrated efforts to tackle nitrogen excess as a climate, nature and health issue; and incentives for better nitrogen management at farm level.
Global trend is towards organic inputs usage in the production system, thus avoiding or largely excluding the use of synthetic fertilizers, pesticides, growth regulators and livestock feed additives and rely on crop rotation, crop residues, animal manures, legumes, green manures, off-farm organic wastes and mineral bearing rocks etc. This aspires to a combined mixture of organic, environmental, social and ethical objectives. For instance, compost provides air, water, organic matter, and microorganisms to your plants, thus enhancing their growth. It also maintains a healthy atmosphere for the soil and hence keeps insects, plant diseases, and weeds away.
Many organic materials serve as both fertilizers and soil conditioners; they feed both soils and plants. Microbial biomass was often greater in organic than conventionally managed soils. Organic fertilizers are carbon-based compounds that increase the productivity and growth quality of plants. The majority of organic fertilizers can be prepared locally or on the farm itself. Use of these organic fertilizers ensures that the food items produced are free of harmful chemicals. However, it should be noted that many kinds of manure are not allowed in organic agriculture: those from intensive livestock farms are likely to be tainted with antibiotics, pesticide residues or heavy metals.
Regarding synthetic fertilizers, the benefits are more evident, both for the crop and the environment, in the short term. Although use of inorganic fertilizers contributes with immediately available nutrients to the plant, it is easy to employ them excessively or deficiently. Besides the chance of contamination of surrounding and underground water, and the increase of toxic salts in the soil when applied in large quantities, soil degradation is a significant risk in the single use of chemical fertilizers, since it eliminates useful microorganisms for plant nutrition. The simple fact is synthetic fertilizers fail to amend the substrate - they only feed the plant. Chemical fertilizers do not amend the soil(positively).
(4) Application of CRFs or SRFs considered to be a Best Management Practice:
It is true that unlike closed system, the agricultural system needs balanced nutrients in the form of nitrogen and P, K at least as replacement basis (refer my fb post on 24th April before announcing cabinet decision on 28th and in May’21) Nutrient management is closely associated with fertilizer type, application rate, application time, and application placement. The Association of American Plant Food Control Officials defines CRFs as fertilizers that contain a plant nutrient in a form the plant cannot immediately absorb.
Uptake is delayed after application, so that CRFs provide the plant with available nutrients for a longer time compared to QRFs, such as urea. Controlled-release fertilizers are typically coated or encapsulated with inorganic or organic materials that control the rate, pattern, and duration of plant nutrient release. Polymer-coated urea exemplifies CRFs (Du et al. 2006; Loper and Shober 2012).
Quick-release fertilizers are water soluble and readily available for plants to take up when they are properly placed at the right time. Controlled-release fertilizers (CRF) contain a plant nutrient in a form that delays its availability for plant uptake and use after application, or that extends its availability to the plant significantly longer than “rapidly available fertilizers” such as ammonium nitrate or urea, ammonium phosphate, and potassium chloride. Controlled-release fertilizers can dynamically release nutrients and meet the crop’s changing nutrient demand throughout its growth cycle, maximize nutrient use efficiency, and minimize environmental concerns. Slow-release fertilizers (SRF) generally have a slower release rate of the nutrient than conventional water-soluble fertilizers and CRFs.
However, the rate, pattern and duration of release are not well controlled, because they are dependent on microbial activity that is driven by soil moisture and temperature conditions. Slow-release fertilizers can occasionally be released very quickly when excessive moisture and high temperatures occur in the same period of time. Use of CRFs or SRFs can reduce nutrient losses, increase nutrient-use efficiency, and protect the environment. Thus, the application of CRFs or SRFs is considered to be a Best Management Practice (BMP) tool for crop production.
When organic fertilizers are applied, soil microorganisms themselves degrade them until they become water-soluble compounds that plants take advantage of. Another valuable feature is that they achieve the increase of activity in bacteria and fungi that benefit the soil. In fact, this kind of fertilizers boost the proliferation of fungi responsible for plants to take advantage of nutrients. Thus, organic fertilizers improve soil structure, help to retain nutrients, allow carbon fixation in the substrate and enhance the ability of the crop to absorb water.
But organic farming methods are not the only example of sustainable nutrient management: agroecological approaches, including conservation, low-input, and minimum tillage agriculture, are all recognized as “nature-positive” and regenerative practices. From farm to fork, 80% of nitrogen is wasted and lost to the environment, according to a study by the Centre for Ecology & Hydrology in the United Kingdom. More efficient use of animal manure and greater use, in rotations, of nitrogen-fixing crops – such as legumes which convert nitrogen from the air into a form that is biologically useful – will be crucial to replace synthetic nitrogen as part of the process of rebuilding soil fertility.
(5) Conclusion:
There is a school of thought that as a key component of agricultural sustainability, organic fertilizer contributes greatly to improving soil fertility. The artificial fertilizer had a short-term benefit, but it had severe long-term side effects such as soil toxicity and decline in soil fertility. The use of organic fertilizers has the advantage of improving soil structure, texture and aeration, increasing the soil’s water retention abilities and stimulating healthy root development. Organic fertilizer has many sources such as minerals, animal source, sewage sludge and plants. Vegetables, animals and residue materials had a contribution to improve soil organic matter content in soil.
Therefore, one can argue that the use of organic fertilizer or combined application is more beneficial than artificial fertilizers in order to preserve soil properties and increase soil productivity.
In conclusion it can be stated that, integrated nutrient management system could be used as a continuous improvement of soil productivity on a longer term basis through appropriate use of organic inputs and their scientific management for increments of optimum growth, yield and quality of different crops.
This is the global trend and the State policy shift of production, import & supply of organic fertiliser and prohibition of use of agro-chemicals well-articulated in the cabinet paper ratified in April ’21 should be viewed in that perspective. Let us focus on integrated soil fertility management strategy and balanced nutrient management policy.
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