Sunday Times 2
Organic-fertiliser-only policy will plunge Lanka into a food crisis
The cabinet of Sri Lanka on the 29thApril, 2021 has approved a ban on importation of chemical fertilizers and other agrochemicals in the bid to become the first country ever to practice organic only agriculture. The policy document of the present government,“Vistas of Prosperity and Splendour”,which has been mandated by the nearly 2/3rd of the voters at the 2018 Presidential Election, state that Sri Lankan agriculture will promote and popularize organic agriculture during next ten years. Their intention is to protect the health of the people and environment of the country that have been deteriorated due to agrochemicals used in conventional agriculture.
The Government claims that because of chemical fertilizer usage, soil fertility has been degraded, soil acidity increased, biodiversity reduced, and most of all,yield and yield quality has also not been improved. The Government also claims that chemical fertilizer usage has resulted water pollution andaccumulated poisons in foods,resultinggreater incidence of cancer andchronic kidney disease (CKDu) in Sri Lanka. While this writer agrees that chemical nitrogen fertilizer could lead to soil acidification, other issues stated above are common to both organic and inorganic fertilizers,in one way or the other, if poor quality fertilizers are applied against the recommendations made by Crop Research Institutes. The argument that chemical fertilizers have not increased crop yields in a given soil crop-environment cannot be justified either. Therefore, this writeris still trying to understand the other reasons for banning chemical fertilizers in Sri Lanka.
Organic fertiliser, though environment-friendly, has some drawbacks which need to be taken into consideration when policy decisions are made. File pic
The organic movement started in the 20thcentury in German- and English-speaking countries, and was influenced by different groups that promoted rural traditions and the use of biological (instead of synthetic) fertilizers. It has gained popularity since the 1970s with rising public concerns about health and environmental effects of “industrialized” farming.After the green revolution of Dr Norman Borlaug and Dr M.S. Swaminathan in the 1960’s, agriculture used crop varieties that are responsive to readily available nutrient sources. Even in Sri Lanka, plant breeders produced varieties that weremore responsive to nutrient inputs. Therefore, the use of chemical fertilizers became inevitable to achieve higher yields even todate. Due to multiple reasons which are beyond the discussion of this article, farmers apply chemical fertilizers indiscriminately in their agricultural fields resulting many environmental and health issues. To add salt to the wound, the quality of some chemical fertilizers available in the market does not meet minimum standards. Improper usage and poor quality of chemical fertilizers has therefore raised concerns amongenvironmentalists and politicians. Hence,the present government is trying to promote alternative technologies that are only organic. Department of Agriculture has already recommend number of technologies, such as precision farming and promote the application of organic fertilizers, to increases the soil fertility and efficiency of added plant nutrients.
The scientific community is divided on whether organic agriculture could feed the world or not. In May 2007 at the FAO Conference on Organic Agriculture, Dr. Badgely and co-workers contributed to the debate by presenting an analysis supporting the idea that organic agriculturecan significantlyincrease productivity in developing countries andcould feed the entire world. This paper has received much attention in the popular press and science magazines such as the New Scientist. However, in the following year,Dr. Corner pointed out that Dr Badgely’s findings wereinvalid because data weremisinterpreted and calculationsaccordingly wereerroneous. In a recent publication which appeared inthe Annual Review of Resource Economics, Meemken and Qaim reviewed and analyzed the extensive literature on various aspects of organic farming, including production, social well-being, environment, and economics. They concluded that organic farming is not the paradigm for sustainable agriculture and food security, but smart combinations of organic and conventional methods could contribute towards sustainable productivity increases in global agriculture.
Encouraging further deforestation
People who promote organic agriculture assure that land productivity will not be affected in the long run or could sometimes be even higher than that of conventional agricultural systems. Three scientifically more rigorous meta-analyses of organic-conventional crop yield comparisons were published in the last few years. Results of these analyses clearly indicates that across all crops, mean yield reductionin organic agriculture are in the magnitude of 19–25%. Considerable differences can be observed across different crop species, with legumes and fruits showing smaller yield gaps than cereals and root and tuber crops. If that is the case, in order to feed the growing population more lands have to be cleared and brought into agriculture. For an example, reduction of paddy yields by mere 20% will have to increase the conversion of about 33,000hectares of additional lands in to paddy cultivation even though we produce about 0.5 million tons of rice over the self-sufficiency level. In an era where technologies have to be invented and introduced to increase the productivity of lands in order to assure the food security of the country, organic agriculture without proper technological advice for farmers and policymakers could lead to further deforestation in the future.
Availability of organic fertilizers
To supply the crop nutrient demand, an enormous quantity of organic fertilizers and biofertilizers need to be produced within the country.Currently, about 3500 tons of municipal organic wastes are generated per day in the countryand from that, about 2-3 million tons of compost could be produced per year. However, for organic paddy cultivation alone it requires nearly 4 million tons of compost at a very nominal rate of 5 tons per hectare. For tea plantations,this figure could be well over another 3 million tons. However, at present the country is producing only 0.22 million tons of compost through both Department of Agriculture registered producers and by municipal councils. Hence there is a humongous task ahead to produce organic fertilizers in the country. We cannot advocate the importation of organic fertilizers at any cost if we are to safeguard our people and the environment.
Misconceptions on organic agriculture
With all that drawbacks in adopting and implementing organic only agriculture, this writer also believes that the correct usage of organic fertilizers has the edge over chemical fertilizers in environmental point of view. However, environmental benefits alone cannot achieve sustainability in agri-food systems. Among the people who advocate organic-only agriculture, there are some misconceptions that need to be pointed, and then discuss and debated for the better- and well-informed decision making by policymakers.
Misconception 1. Chemical fertilizers are responsible for health and environmental concerns in Sri Lankan agriculture: Some of the health and environmental concerns related to the chemical fertilizer usage are not supported by scientific evidence. The most important example related to this is the incidences of chronic kidney disease of unknown etiology (CKDu) that is prevalent among farmers in the Dry Zone. This has been related to cadmium and arsenic present in Triple Super Phosphate (TSP) importedinto Sri Lanka. Despite the fact that cadmium and arsenic have been found in excess concentrations in fertilizers available in the local market, so far, noscientific evidence has been publishedto prove beyond reasonable doubt, that heavy metals in TSP (or any other chemical fertilizer) is linked to CKDu prevalence in Sri Lanka. Recent scientific evidence confirms that bioavailable, potentially toxic trace metal concentrations in agricultural soils and in drinking waters are well below the EU defined maximum permissible levels. Cyanotoxins, fluorides and hardness in well water have been shortlisted as possible causes according to an article published in the Nature Scientific Reports.
The other health issue that raises concern is the carcinogenicity of vegetables that have high concentration of nitrates. Accumulation of nitrate in leafy vegetables at high levels is a possibility if nitrogen fertilizers are applied in “excessive” quantities. Adding recommended rates of N fertilizer provide only a minimum possibility for accumulation of N in crops.We have observed extremely high phosphorus concentrations in intensively cultivated vegetable fields in the upcountry but there is no immediate health issue related to phosphorus, except the possibility of cyanotoxin producing bacteria proliferation due to high concentrations of phosphorus in water. There is a major environmental issue related to extremely high P in agricultural soils as it could trigger eutrophication in surface water bodies. High P in agricultural soil is due to excess P application, non-availability of P free fertilizer mixture and application of poultry manure. Potassium and Magnesium containing fertilizers are relatively less harmful.
Close look at the causes of issues related to chemical fertilizers; one could find that it is mainly due to the poor quality of the imported fertilizers and their incorrect usage. Fertilizer importers are largely responsible for importing fertilizers containing heavy metals into the country in addition to officers who regulate fertilizer importation. I do not point fingers at farmers for indiscriminate fertilizer application, because firstly, it is only a few commercial agriculture practicing farmers who apply high rates of fertilizers as an insurance dose and even they do it because fertilizers are freely available at subsidized prices. Secondly, they are often ignorant about acute environmental consequences related to bad nutrient management practices.
Misconception 2. Organic only nutrient management technologies are always environmentally friendly: This is another big misconception and those who advocate environmental safety and human health have often overlooked or purposely ignored some negative externalities related to organic farming. Assume anintensively cultivated vegetable cropping system in Nuwara Eliya where very high levels of Phosphorous are present in soil. Since the most limiting nutrient is N, large quantities of organic fertilizers have to be applied. If a minimum of 5000kg of compost,which contains 2% N and 0.5% phosphorus, is applied to meet the N requirement, a farmer will be applying 25 kg of phosphorus every season when environmentalists shout not to apply phosphorus into such lands. Poor farmers cannot change the composition of organic fertilizer available in the market or they produce and contribute to the acceleration of eutrophication and cyanotoxicity thanks to ill-advised organic farming.
Poultry litter is one of the most commonly available organic fertilizer source, next to compost. They containchicken manure that is rich in nitrogen and waste feed that contains high phosphorus. However, recent scientific evidence confirms that there are antibiotic traces present in poultry manure and antibiotic resistance is being developed in soils amended with them. In addition, the quality of the raw materials used in organic fertilizer production is very important to produce anenvironmentally safe organic fertilizer. In a developing country like Sri Lanka where the system is very corrupt, when the raw materials are depleted, commercial producers will resort to using low-quality materials such as sewage sludge, municipal solid waste that are amply and freely available for organic fertilizer production. Such raw materials contain potentially toxic trace metals and sometimes even pathogens and could result in even greater repercussions than what we have now.
Therefore, quality of the organic fertilizers and their correct usage determines the environmental friendliness of organic farming. When we cannot even assure the quality of the chemical fertilizers imported and marketed in the country, how can we set quality standards for an array of different fertilizers and regulate the quality of organic and bio-fertilizers? Do not even think of importing organic or bio-fertilizers as, they can threaten bio-diversity of Sri Lankan soilon one hand. On the other hand,we cannot assure the quality of such fertilizers, and therefore any garbage can be brought in and dumped into our precious natural resource: the soil. The presence of weed seeds, pathogens, toxic heavy metals and organic pollutants need to betested and for that quality standards has to be formulated first.
Misconception 3.Organic-fertilizer-only approaches can always sustain crop productivity: Out of 18 essential elements required for optimum plant growth,nitrogen, phosphorus, potassium and magnesium are deficient inmost agricultural soilsin Sri Lanka. However, some research findings suggests that the application of phosphorus fertilizer over long periods has increased the plant available P levels, and crops are less responsive to phosphorus fertilizers. Even though a cropping system could be productive without phosphorus fertilizer for a short period, in the long run, P fertilizer application or develop technologies to recycle P is essential for sustainable production simply because they are removed from the soil-crop system with the yield.On the other hand, if there is a demand for potassium and magnesium in a given soil-crop system, existing technologies on organic agriculture is not capable of providing these two nutrientssustainably. Both these plant nutrients are not released from agricultural soils at a rate thatplants require. Irrigation water and crop residues can supply a portion of these nutrients but the outflow of them as yields is greater than the supply. Usually, crop residues are used for organic manure production and applied back to cropping fields without a net gain.
Misconception 4.Nutrient requirement of the crop can be provided through organic fertilizers: Nitrogen is the most limiting and most responsive nutrient in Sri Lankan agriculture. In general, annual crops require about 100 kg of N per hectare as readily available chemical fertilizers. Assuming 75% of nitrogen use efficiency in organic fertilizers and 30% in chemical fertilizers, this equals to about 40 kg of N as organic fertilizers. Although commercially available compost has only 1-2% of total N, if we assume 5% of plant available N in an organic fertilizer, to meet crop N requirement we need to apply 800kg of organic fertilizers per hectare as against 220 kg of urea. Therefore, the practicability and advantages of supplying N from outside into the cropping fields as organic fertilizers are questionable. Apart from that huge quantity, in systems where organic N management had been successful in the world, Nitrogen has been supplied as a green manure crop or by introducing a N-fixing legume into the crop rotation. And successful organic agricultural systems integrate animal husbandry as well. Introducing a non-food crop into existing limited agricultural lands even for one season in a crop rotation will reduce the food production in the country. The potential for using dry periods in between the two main cropping seasons needs to be investigated in future research. We have observed that the loss of rice yield due to lack of N fertilizer could vary from 10% to as high as 60%, depending on the soil characteristics, with an average loss of about 35%. If nitrogen-rich organic fertilizers cannot be provided to farmers in required quantities as a result of this new policy decision, yield losses are inevitable.
If we manage Nitrogen requirement by matching Nitrogen requirement of the crop with N availability from organic manures, we are sure to over apply some other nutrients, particularly phosphorus and potassium. Accumulation of phosphorus in intensively cultivated vegetable growing soils is already evident and this is in part due to the application of large quantities of poultry manure. Extremely high phosphorus levels in those soils (about 10-20 fold) has already polluted surface water bodies in that area evident as green colored water which leads to eutrophication. Composition of nutrients in organic manures vary widely and therefore extension services have a daunting task in educating farmers on the appropriate rates of organic fertilizer that are available in a given area. One of the main challenges in site-specific plant nutrient management (precision farming) using organic sources,even for scientists, is their inherent variability in nutrient contents and more importantly nutrient proportions.
Misconception 5. Biofertilizers can supply deficient plant nutrients in organic only agricultural systems:One could argue that what is not provided as organic fertilizers could be supplied as bio-fertilizers in organic agricultural systems. Bio-fertilizers contain micro-organisms that could make plant nutrients available that are otherwise not available; for example, atmospheric nitrogen gas byfixation and fixed phosphorous in soils by dissolution. However, those who have some knowledge on soil microbiology know that microbes that work in one place do not necessarily work in all areas equally. Only the fittest will survive in a different environment.Hence, various microbial species/consortiums need to be isolated for different soil-crop environments to formulate an effective biofertilizer. The number of effective soil micro-organisms hasindeed been isolated in Sri Lankan laboratories and marketed by some companies.Still, their effectiveness in different agro-ecosystems and at all times is questionable. That is the simple reason why biofertilizershave still not been approved by various Crop Research Institutes as blanket recommendations for a given crop.
There can be many bio-fertilizers or organic fertilizers in the world that has shown very promising results in their specific environments. That should not be a reason for us to import such organic and bio-fertilizers from other countries, as organisms present in such fertilizers could become an enormous threat to our soil biodiversity. Testing such fertilizers for their environmental safety and agronomic effectivenessor even setting up quality standards is a daunting task. Therefore, further research is needed to develop effective bio-fertilizers for different soil-crop environments in Sri Lanka in the quest for 100% organic fertilizer based agriculture in Sri Lanka.
Solutions for a sustainable agriculture
It is prudent that the production of high-quality organic fertilizers and effective biofertilizers is a prerequisite to cutdown even a fraction of chemical fertilizers used in Sri Lanka. Much research is still required to be carried outon organic agriculture to identify the most appropriate technologies to make agriculture more environmentally friendly and sustainable. And then, farmers need to be educated on such advanced technologies. Therefore, meticulous planning and a innovative technologies areessential to achieve the expected goals from the new policy change. A considerable period of time is thereforerequired to implement strategies successfully,thus identified.
However, as an immediate solution for concerns related to chemical fertilizer, imposing strict regulations is a more practicable and feasiblesolution. Some regulations are already available in the current Fertilizer Act. For indiscriminate use of chemical fertilizers, we need to educate the farmers more on ill effects related to such practiceswhile providing incentives/subsidies for farmers who adopt eco-friendly fertilizer technologies. Some of such technologies are: site-specific nutrient application based on a need assessment donethrough soil or plant testing, use of good quality organic manures and effective bio-fertilizers to reduce chemical fertilizer usage, application of chemical fertilizers together with organic matter to retain added nutrients without being leaked, application of organic matter into already degraded Sri Lankan agricultural lands to increase soil organic matter contents and thereby improve soil fertility and productivity. Therefore, the present material subsidy given only for chemical fertilizer should be revised to promote good fertilizer practices among farmers.
Potential for urea production using wastes generated from petroleum refineries, such as naphtha and atmospheric nitrogen, can be re-investigated. Phosphorus and potassium deposits available in Sri Lanka should be mined wisely and improve their solubility using environmentallyfriendly technologies. Production of synthetic fertilizers within the country could push Sri Lanka towards a “true” self-sufficiency and save hard earn foreign exchange for other essential purposes. Local production of good quality organic manures and effective biofertilizers should be promoted by providing required technical know-how and financial support for entrepreneurs.
Rather than adopting such feasible strategies step-by-step, the government has banned chemical fertilizer importation overnight. Thiscould plunge Sri Lanka into a food crisis in the coming years due to lowering of land productivity. Therefore, the decision to completely ban chemical fertilizer usage needs to be re-considered without any delay. If not, eventually it is the expectations of the 6.9 million people who voted for the “Vistas of Prosperity and Splendour”,including this writer, as well as that of all otherswill be shattered.
The writer is a Professor of Soil Fertility and Plant Nutrition at the Faculty of Agriculture, University of Peradeniya. (dharmakeerthirs@gmail.com)