Organic-fertiliser-only policy will plunge Lanka into a food crisis
The present government’s policy document “Vistas of Prosperity and Splendour” states that Sri Lankan agriculture will promote and popularise organic agriculture during next ten years. Accordingly, the Government of Sri Lanka has recently decided to ban importation of chemical fertilizer and other agrochemicals in a bid to become the first country ever to practise organic-only agriculture.
The Government claims that because of chemical fertiliser usage, soil fertility has been degraded, soil acidity increased, biodiversity reduced, and most of all, yield and yield quality has also not been improved.
They also claim that chemical fertiliser usage has resulted water pollution and accumulated poison in food, resulting in greater incidence of cancer and chronic kidney disease (CKDu) in Sri Lanka. Therefore, the aim of this policy decision is to achieve a sustainable agriculture by protecting the environment and human health.
While I agree that chemical nitrogen fertiliser could lead to soil acidification, other issues stated above are common to both organic and inorganic fertilisers in one way or the other, if poor quality fertilisers are applied against the recommendations made by crop research institutes.
The organic movement started in the 20th century in German- and English-speaking countries and was influenced by different groups that promoted rural traditions and the use of biological (instead of synthetic) fertiliser. It has gained popularity since the 1970s with rising public concerns about health and environmental effects of “industrialised” farming.
After the green revolution of Dr Norman Borlaug and Dr M.S. Swaminathan in the 1960s, agriculture used crop varieties that are responsive to readily available nutrient sources and produce very high yields to feed the growing population.
Even in Sri Lanka, plant breeders produced high yielding varieties that were more responsive to nutrient inputs. Therefore, the use of chemical fertiliser became inevitable to achieve higher yields even to date. (See figure.)
Encouraging further deforestation
The only long-term field experiment in Sri Lanka is available at the Rice Research and Development Institute. According to that data, organic-alone paddy cultivation will reduce yields by 20-30 percent, depending on the cropping season. World scientific meta-data analysis also support similar yield losses. Hence, to feed the growing population, more lands have to be cleared and brought into agriculture. For example, if paddy yields drop by mere 20 percent, the conversion of about 33,000 hectares of additional lands into paddy cultivation will be required to cover up the loss, 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 to assure the food security of the country, organic agriculture without proper technological advice for farmers and policymakers could lead to further deforestation.
To supply crop nutrient demand, an enormous quantity of organic fertiliser and biofertiliser needs to be produced within the country. At present, about 3,500 tons of municipal organic wastes are generated a day in the country and from that, about 2-3 million tons of compost could be produced annually. 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 about 0.22 million tons of compost through both Agriculture - Departmentregistered producers and by local councils. Hence there is a humongous task ahead to produce organic fertiliser within the country. We cannot advocate the importation of organic fertiliser 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, I also believe that the correct usage of organic fertiliser has the edge over chemical fertiliser from an 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 out, discussed and debated for the better- and well-informed decision making by policymakers.
Misconception 1. Chemical fertilisers are responsible for health and environmental concerns in Sri Lankan agriculture:
The incidence of chronic kidney disease of unknown etiology (CKDu), that is prevalent among farmers in the Dry Zone, has been allegedly related to cadmium and arsenic present in Triple Super Phosphate (TSP) imported into Sri Lanka. Recent findings disprove this hypothesis and suggest Fluoride and
hardness or cyanotoxins present in drinking water could very well be the reason for this, not the agrochemicals. Another health issue that raises concern is the carcinogenicity of vegetables that have high concentration of nitrates. We have observed extremely high phosphorus concentrations in intensively cultivated vegetable fields in the upcountry and that could trigger eutrophication in surface water bodies. Both these issues are due to application of chemical fertilisers against the recommendations.
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. Intensively cultivated vegetable growing soils in the upcountry contain very high levels of phosphorous. Precision farming technology emphasises a ban on TSP (Triple Super Phosphate) to such soils to protect surface water bodies from eutrophication. If a minimum of five tons of compost, which contains 2 percent nitrogen and 0.5 percent phosphorus, is applied per hectare, a farmer will be loading 25 kg of phosphorus every season, further accelerating the eutrophication.
Poultry litter is another commonly available organic fertiliser. 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 agricultural inputs is a prerequisite for environmental safety, whether it is in organic or inorganic agriculture.
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 fertiliser production. Such raw materials contain potentially toxic trace elements and sometimes even pathogens. Loading of large quantities of sub-standard organic fertilizers could invite even greater environmental issues than what we have now.
Misconception 3. Organic-fertiliser-only approaches can always sustain crop productivity:
Even though a cropping system could be productive without phosphorus and potassium fertiliser for a short period but would become less productive in the long run. This is simply because phosphorus and potassium are limited in nature and removed from the soil-crop system with the yield. Irrigation water and crop residues can supply a portion of these nutrients but the outflow of them as yields is greater than the supply. Phosphorus and potassium present in crop residues can be applied back to cropping fields as organic fertiliser. But crop-residue-based organic fertiliser is not a solution to gradual decline in these nutrients unless other organic wastes are recycled in cropping fields.
Misconception 4. Nutrient requirement of the crop can be provided through organic fertiliser:
Nitrogen is the most limiting and most responsive nutrient in Sri Lankan agriculture. In general, annual crops require about 100 kg of nitrogen per hectare as
readily available chemical fertiliser. Assuming 75 percent of nitrogen use efficiency in organic fertilisers and 30 percent in chemical fertilisers, this equals to about 40 kg of nitrogen as organic fertilisers. To provide this nitrogen requirement, we need to apply 800 kg of organic fertilizer per hectare as against 220 kg of urea. Therefore, the practicability and advantages of supplying nitrogen from outside into the cropping fields as organic fertilisers are questionable. In systems where organic nitrogen management had been successful in the world, nitrogen has been supplied as a green manure or by introducing a nitrogen-fixing legume into the crop rotation. And successful organic agricultural systems integrate animal husbandry as well.
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 fertiliser production.
Availability of organic fertiliser
Misconception 5. Biofertilisers can supply deficient plant nutrients in organic only agricultural systems:
One could argue that what is not provided as organic fertiliser could be supplied as biofertiliser in organic agricultural systems. Biofertilisers contain micro-organisms that could make plant nutrients available that are otherwise not; for example, atmospheric nitrogen gas by fixation 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. That is the simple reason why biofertilisers have still not been approved by crop research institutes as blanket recommendations for a given crop.
Solutions for a sustainable agriculture
It is prudent that the production of nutrient-rich high-quality organic fertilisers and effective biofertilisers is a prerequisite to cut down even a fraction of chemical fertilisers used in Sri Lanka. For sustenance of the agricultural food systems, chemical fertilisers have to be used. Only the quality-assured chemical fertilisers should be imported. Farmers need to be made aware of negative environmental and health effects due to indiscriminate fertiliser application. Application of organic matter into already degraded Sri Lankan agricultural lands is essential to improve soil fertility and productivity and also to minimise wastage of chemical fertilisers. Therefore, the present material subsidy given only for chemical fertiliser should be revised to promote good fertiliser practices among farmers. Local production of good quality inorganic fertilisers using phosphorous and potassium deposits in Sri Lanka, production of organic manures and effective biofertilisers should be promoted by providing required funding for research, technical knowhow and financial support for entrepreneurs.
Rather than adopting such feasible strategies step-by-step, the government has decided to ban chemical fertiliser importation overnight. This could plunge Sri Lanka into a food crisis in the coming years due to lowering of land productivity. Therefore, the decision to completely ban chemical fertiliser usage needs to be reconsidered without any delay.