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Polluting soils lead to greater havoc than polluting oceans
The consequences of wastes released from the burned ship to our ocean have become the priority in many news bulletins of all media during the last few days. The immediate impacts of waste on aquatic living creatures were evident and heartbreaking. However, damages caused by wastes on the delicate network of marine food webs of our western ocean and smoke drifted away with polyaromatic hydrocarbons along with other toxic substances are yet to be evident, perhaps after latent periods of weeks to decades. Besides, immediate negative impacts on the accessibility for toxin-free seafood, local and foreign seafood market, and livelihood of all those in the value chain will be inevitable. Although there is a discussion on seeking compensation for the damage done, it may not be estimated in monetary terms.
A farmer adds fertiliser to his crops in Saliyawewa Pic by Jayarathna Wikramaarachchii
The consequences of introducing organic fertilizers produced withcontaminated wastes onto agricultural fields would lead to greater chaos than witnessed in the ocean. Over more than a month, mass media has allocated significant time on banning the importationof chemical fertilizers and other agrochemicals on 29th April 2021 by the cabinet of Sri Lanka. This decision towards an abrupt paradigm shift in the agriculture sector had terrified all concerned professionals in the agriculture sector. They had appealed from the government for a gradual phase-out plan following a scientific approach pointing out that the long-term repercussions would be unbearable to the economy, environment and society 1 otherwise. They also tried their best to make the public aware of thepros and cons of this decision through a range of communication modes, but those seemed to beorchosento be unheard of by the government. As a follow up action, cabinet approval has been granted on 31st May 2021 to import organic fertilizers to satisfy the nutrient requirements of crops grown in the forthcoming Maha season. Although this decision is clearly contrary to the rational of feeding the nation with healthy food and saving foreign currency by the said ban, developing regulations are in progress to import organic fertilizers.
Application of a wide range of organic materials including crop residues, animal manure and compost to agricultural soils is not neweven in conventional agriculture across the world. They have been recommended as a soil amendment and sometimes as a nutrient supplement depending upon theirnutrient contents and quantities available. Thenatural substances containingcarbon makes soil doall wonders for our living includingkeeping soil live and supporting 25% of the earth’s biodiversity, providing food for human and other organisms, retaining and cleaning up water and regulating the earth’s climate,to mention a few. The decline of soil C would deprive soils of providing ecosystems services and functions vital for life on earth. Therefore, any soil scientist, agriculturist and environmentalist would encourage the practice of adding good quality organic materials to agricultural soils,aiming to strengthen theservices offered. However, such good quality materials are not abundant for the usage of agricultural lands due to various reasons. Therefore,abundant wastes are processed and used as a soil amendment. The best examples arecompost prepared with municipal wastes, and sludge. Such inputs may not offer intended benefits always if they contain substances harmful to living organisms such as heavy metals, pesticide residues, polyaromatic hydrocarbons, radionuclide etc., and a group of emerging pollutants including pharmaceutical, endocrine disruptors, hormones, biological pollutants, e-wastes and plasticizers. Due to difficulties in visually perceiving the pollutants in soil or assessing them and their impacts on – and off-site, the Food and Agriculture Organization has acknowledged that soil pollution is a hidden danger. Sincethe threatsimposed by soil contaminants on soil organisms, quality of food, water and air, and the whole ecosystem are increasing at an alarming rateworldwide, the Environmental Assembly of the United Nations passed a resolution in 2017 urging all governments to establish regulations to limit accumulation of contaminants in soils and to facilitate remedial measures.
Agricultural scientists claim that the application rates of agrochemicals in Sri Lanka is much lower than other countries in the region. In my opinion, such comparisons are meaningful if interpreted along with types of crops, yields and use efficiencies. It is not a secret that a considerable proportion of local farmers apply chemical fertilizers often and animal manure sometimes in excess. Indiscriminate use of pesticides,occasionally mixing in dangerous ways, is also a common practiceof particularly those grow vegetables. Research conducted at the Department of Soil Science, University of Peradeniyaover about two decades hasrevealedthat soil microbial communities have been affected severely due to pesticides such asmancozeb and elevated levels of hazardous heavy metals in soils. However, the detrimental impacts of adding chemical fertilizers like urea and TSP on soil microorganismsareunlikely except for the temporary suppression of beneficial functions such as nitrogen fixation. Soils with imbalanced nutrients and low microbial diversity often make soils unhealthy and crops grown in such soils will be prone to pests and diseases. The response of famers to such risks is to applyhigh doses ofpesticides indiscriminately making the scenario worse. Further, emerging threats were also identifiedon food chain contamination with heavy metals in a few locations. Therefore,we have initiated official discussions with the Central Environmental Authority to develop guidelines to control soil pollution.
As such,incorporating imported organic fertilizers having toxic substances and alien organisms to our agricultural soils would further jeopardize the existing networks of soil biota. If the toxic substances becomesoluble in soil water, those will be taken up by plants or leached down to the ground water thus exposing organisms to contaminated food and water. Besides, some sensitive populations of soil organisms will also be killed,resulting in perhaps irreversible changes in biological communities.Some toxic organic substances may persist but keep accumulating in soils slowly and reach threshold levels later. There will be more serious consequences of introducing alien organisms to soils. There are research evidence that a few species of microorganisms are found in many soils of all continents but a vast majority is unique to each soil ecosystem. Some of the keystone species, who are responsible for performing ecosystem services and functions, may be unique or endemic to each soil ecosystem.Alien microorganisms live in wastes are usually fast growers and adapted to live with contaminants therein. Adding such opportunistic microorganisms to agricultural soils willbe a threat toindigenous microbial communities. The outcome of such threats would become visible after months or years in terms of increase in incidents of crop diseases, yield reduction, water pollution and a general reduction in essentialecosystem services. Plant, animal and human pathogens may also be available in organic fertilizers and no need to explain the consequences of introducing them to our soils. Irrespective of imposing such long-lasting threats to our biodiversity and health by imported organic fertilizers, the Minister of Agriculture very confidently said, only sterilized organic fertilizers without any microorganisms will be imported. Although this could be ignored as another bluff but it seems that the regulations have been developed aiming for this purpose.
A concerned researcher shared a document developed by Sri Lanka Standard Institute(SLSI) on specifications for sterilized solid organic fertilizers SLS-1704: 2021 with me. Thepurpose of this document is to set guidelines for approving sterilized solid organic fertilizers for agricultural purposes. It is interesting to know that thousand to million kilograms of bulky sterilized solid fertilizers are availablein international markets. Yet, none of them will be free of microbes, because common methods used for sterilizing purposes such as heat, chemicals or UV cannot completely kill them in a solid material as they hide or remained dormant. Such hidden organism could even escape from drastic changes in pH in a solid material carried out aiming for sterilization. How about the contamination occurs during the processing, packing and shipping of such bulky materials? What would happen to organic and inorganic forms of nutrients and toxic substances available in the processed product during sterilization? Some of the simple substances are more likely to be denatured and new complex molecules will also be formed perhaps combining with contaminants. The product will be then another synthetic material unknown to the natural soil ecosystem.
The SLSI committee, which set standards for solid organic fertilizers, has identified limits for potentially toxic elements to assure that the solid organic fertilizers will be safe.However, they will be more meaningful if limits on loading rates are also recommended along with the concentration limits. It is has been said that the product should be free from any persistent organic pollutants, but aliphatic and polyaromatic hydrocarbons, antioxidents and radioactive traces etc.have not been included. It is essential to include themethods that will be used to assess the antibiotics or their residues, all organic pollutants and microplastics.
The SLSI has also developed draft standards for liquid fertilizers. The biogenic sources of liquid fertilizers are plant and fresh animal manure. Epiphytic and air-born microorganisms are found in liquid fertilizers in addition to those added deliberately to enhance the fermentation process. The absence offecal coliform and Salmonellahas been included as a criterion. It is also essential to include absence of plant pathogens and alien microbes in case of importation,as standards, and methods to detect their presence.
All in all, it seems that these guidelines have been prepared either in a hurry or without the inputs of experts. It is crucial to amend themaddressing the highlighted gaps and legislations in effect, if the committee wishes to safeguard the biodiversity of the country and health of soils and living organisms. Then the issue arises on testing organic fertilizers owing to their heterogeneity even within one and between consignments. I am certain that laboratory facilities and methods are not available at present for certain analysis and implementing the guidelines therefore will be questionable.
If solid or liquid fertilizers are made available in commercial scale, then recommendations must be made for crops by respective responsible research institutes. So far,practice is to conduct research in the fields of research institutes and thencarryout adaptive trials in farmer fields representing different soil types and agro-climatological regions. Government has taken steps to facilitate scale up the production of organic fertilizers locally aiming to make them available in the Maha season. Accordingly, it is obvious that existing procedures to approve organic and other fertilizers will not be in effect. There are calculations done for supplement rates of organic fertilizers based on nitrogen removal by crops. In my opinion, such calculations could be used for designing experiments. Even for such, nitrogen derived from soils and nitrogen fixing bacteria should be included. Theonly option left out for the research institutes isto make blanket recommendations disregarding the variability of soils in general or at site specific manner based on soil tests.Farmers will be not have any directives and risks of crop failure will be significant.
There are also claims that biofertilizers and biostumulantsetc could do marvellous without chemical fertilizers. Only nitrogen fixing bacteria could bring nitrogen into soils, fulfilling about 30% and 50% of the crop nitrogen requirements by free living and symbiotic bacteria, respectively. All others either make unavailable forms of nutrients available or increase nutrient accessibility of the plant either improving root growth or directly connecting to roots. Over a decade of our field research providesevidence that biofertilizersare crop-specific and become successful only in soil types that they could survive. The yield increases varied depending upon optimum soil conditions provided in terms of soil moisture, pH and availability of carbon and other nutrients. Nevertheless, research evidence collected on the success of biofertilizersin fields added with chemical fertilizers in the past would have little relevance in fields under organic farming practices unless retested and proven. Under any circumstances, biofertilizers should not be imported and introduced to our soils. Those alien microbes could be aggressive and may possess genes detrimental to indigenous organisms. Once introduced, there is no way of taking them out or stop their activity.
We are a country blessed with incredible soil diversity, climatic zones and biota, and good quality water and air. Soils are the foundations of all these treasures and citizens will enjoy these benefits only if the soils are protected. The addition of low-quality wastes and alien organisms to our agricultural soils will make themon the verge of destroying forever.Remediatingpolluted soils is very expensive and perhaps impossible. That is the very reason for introducing UN resolution urging governments to clean up soils that have already been polluted. It takes 100 to 1000 years to generate top soil that enables the establishment of suitable vegetation. Healthy soils assure healthy food and healthy life. Our decedents will lose the right to a healthy life if our arbitrary actions lead to barren lands and polluted water.
A former President of the USA, Franklin Roosevelt (1933-1945), once said that ‘The nation that destroys its soil, destroys itself’. No one else but only H E president could read between the lines of this statement as a former USA citizen of several decades and as a responsible president. By amending the first cabinet paper and withdrawing the second, he could demonstrate to the world that he is not a failure but a saviour of a nation largely irrational and deaf and dumb to scientific facts.
The decision to move to organic farming appeared to be appreciated by a vast majority of consumers because the over use of agrochemicals during crop production and managing postharvest losses are well known to the public. This common practice is due mainly to a poor extension service resulted by an abrupt decision taken in the early 90’s by the then president to transfer KVS positions to ‘gramasevaka’. Eventually, the role of extension officers was taken over by the agrochemical companies. Belief in heavy metals in agrochemicals as the leading cause of CKDU prevailing in the North central province is the other contributing factor for the wide acceptance of the proposed change. This misconception was propagated by a group of pseudoscientists without having concrete scientific evidence on food and water contamination with residues of such metals. Many deliberations were made by soil scientists at that time to make all stakeholder categories aware of scientific data on heavy metal levels in our soils and food but failed in convincing the majority that the levels are safe. Responding to the demand of those pseudoscientists backed by medical practitioners and other social groups, perhaps with selfish motives, glyphosate was banned by the previous government, but illegal formulations became available shortly after imposing the ban. With the involvement of a group of patriotic and opportunistic businessman who heavily involved in the propaganda campaign against the agrochemicals, a liquid formulation was introduced as an alternative to chemical fertilizer in selected Mahaweli systems but ended up as an utter failure. The ongoing discussion on cabinet decision is no different to previous discussionsthat led to banning of glyphosate. Those who do organic farming on-ground are rarely taking part in these discussions and therefore practical realities of practicing organic farming in the country have not beenrevealed adequately. Lack of such information hinders developing a road map to address issues that might arise in future. It is not fair to put the farmer in further troubleas he is struggling to pay loans, overcome the shortages of labour, protect the crop and their own lives from numerous pests and elephants etc.
As a society, neither we have learned from the past mistakes nor make decisions based on scientific evidence. In order to avoid repeating the same mistake, it might be useful toimpose strict guidelines on getting the service of experts by ministries for nationally important assignments and introduce provisions to appoint an expert committee to grant approval for scientists to make public statements based on their research findings. I also believe thattrade unions should refrain from making official statements on issues out of their periphery. For example, medical practitioners better refrain from making statements on issues in agriculture and agricultural professionals making statements on controlling Covid-19. These measures would at least assure addressing nationally important issues following scholarly conversations and scientific approaches with the participation of knowledgeable stakeholders.
1. http://www.sundaytimes.lk/210613/
http://www.sundaytimes.lk/210523/sunday-times-2/why-soil-science-society-is-concerned-about-organic-fertiliser-imports-444557.html
(The writer is Professor of Soil Science at the University of Peradeniya.)