Colombo, September 29: On Tuesday, the media quoted the Director General of the Department of Agriculture, Dr. Ajantha De Silva, as saying that harmful bacteria (Erwina) was detected even in the freshly submitted sample of the organic fertilizer imported from a particular company in China.
On Wednesday, the Minister of Agriculture, Mahindananda Aluthgamage, said the presence of Erwina had not been confirmed, but the sample did have harmful bacteria. Even more alarmingly, the Minister revealed that the polluted stocks imported from that company had already been distributed among farmers by changing the laboratory records!
He then made the welcome announcement that government has banned imports from the Chinese company in question (identified as Qingdao Seawin Biotech Group Co., Ltd.,).
This controversy throws up three issues: (1) whether it is prudent to import organic fertilizer when it is well known that organic fertilizer has a greater chance of getting polluted (2) whether it is prudent to rely only on organic fertilizer (3) whether it is legal to import organic fertilizer.
Writing in The Island, Dr. Janendra De Costa, Professor of Crop Science at the University of Peradeniya, said: “Almost all organic fertilizers, being material of plant, animal or human origin, retain a diverse population of micro-organisms. Unlike inorganic fertilizers, which are inert material, organic fertilizers are live material. Micro-organisms, whether in soils, plants or any other location or entity, are often highly environment-specific. Introduction of such alien micro-organisms to Sri Lankan soils could cause all types of unforeseen interactions with local micro-organisms. Some of these interactions could have environmental repercussions, which are irreversible as once released to the soil, these alien microorganisms cannot be recalled.”
“Therefore, it is always advisable and safer to develop organic fertilizers locally rather than importing,” he said.
Imported organic fertilizer could be cleaned, but only to an extent, de Costa says. Sterilization is done by fumigation. “However, the large quantities of organic fertilizers that are required to be imported and the toxicity levels of the chemicals that are used in fumigation, could lead to environmental issues that the organic fertilizers are aiming to prevent,” De Costa points out.
And additionally, given Sri Lanka’s poor record of regulation, implementation and enforcement of quality standards on items, both imported and locally-produced, De Costa wonders if sterilization would be done properly. Indeed, the fudging of the laboratory data in the case of the organic fertilizer stock recently imported from a Chinese company does not inspire much confidence in the Lankan regulatory system.
Inherently Polluting
Organic fertilizers, whether imported or home-made, could be poisonous, warns Peradeniya University soil scientist Dr.Warshi S. Dandeniya and her collaborator Serene Caucci. In their paper: Composting in Sri Lanka: Policies, Practices, Challenges, and Emerging Concerns they say that organic fertilizers commonly called ‘compost’ can be a carrier of potentially toxic trace elements.
“The long-term use of compost in large quantities and/or application of poor-quality compost to the soil can deteriorate environmental quality and pose a threat to the safety of food. The progressive accumulation of toxic trace elements such as lead and cadmium in soils has been reported in several studies where there has been a long-term application of compost produced from Municipal Solid Waste (MSW).”
“Contamination of food items with potentially toxic trace elements and human pathogens due to the application of compost to crops has been reported in the literature on the subject,” Dandeniya and Caucci point out.
Poultry litter/manure is a source of antibiotic resistance determinants and, therefore, imposes a “silent threat” to environmental quality and health, they say. And night soil (human faeces) could also get mixed up with the organic fertilizer. Organic pollutants such as detergents and antibiotic resistance determinants and pathogens surviving in night soil and septic waste, and the fate of these constituents during composting, have not been studied extensively in Sri Lanka, they point out.
The two soil scientists warn that microbial pathogens and parasites could spread in the environment through flies and dogs found at the composting sites.
“Bio-aerosols and volatile compounds could enable transmission from composting sites to other environments with the wind. Leachates coming out from compost piles during the production process, and runoff water from the composting sites, could contaminate both surface and groundwater,” Dandeniya and Caucci submit.
Writing in www.manthran.com, agricultural scientist Lal de Silva says that while compost improves the water holding capacity, aeration, and the biological properties of the soil through beneficial bacteria, it is deficient in Nitrogen compared to chemical fertilizer.
According to de Silva, while 100 kg of Urea will give 46 kg of Nitrogen, 100 kg of compost will give 1 to 2 kg of Nitrogen. “If we assume that compost will give 1.5% Nitrogen, we have to apply 30 times the quantity of compost to supplement the quantity of Urea. So 150 kg Urea will be equivalent to 4500 kg. of compost per ha. (4.5 tons of compost per ha). At present the extent under tea in the country is 200,000 ha. So if Urea is to be replaced with compost, the total compost requirement for tea in the country will be 900,000 tons,” he contends.
Problems in Imports
Since Sri Lanka does not produce enough compost, and the policy now is not to use chemical fertilizer at all, compost has to be imported. But the Plant Protection Act No. 35 of 1999 prohibits the mixing of any soil particles or living organisms with the soil of the country. “This is a very fine piece of legislation which protects the country from the invasion of harmful microbes such as bacteria, fungi and weed seeds,” Lal de Silva contends.
He draws attention to the fact that there are certain weeds such as Striga which can cause an enormous threat to rice plants. “This particular plant is a parasitic plant which gets attached to the roots of plants and it grows inside the soil and is not visible as only the flowers of this weed comes outside the soil. As it is a parasite and also as it is not visible, it grows under the soil (in the roots of the host plant) and remains extremely difficult to control. Several strains of the weed Striga are already present in India and Philippines. If we import compost from abroad, there is an extremely likely threat to our agriculture,” he warns.
Of the global antibiotic produced, 50 to 80% are used on animals and poultry. It is said that 30% of the antibiotics are excreted unchanged and mixed with the soil. These organic materials could also have heavy metals such as Arsenic, Cadmium and Lead than the inorganic fertilizers.
To stop the introduction of harmful microbes, imported compost will have to be sterilized. But it is extremely difficult to sterilize compost, as chemicals such as Methyl Bromide or Phosphine cannot be used to fumigate. They are banned pesticides, de Silva points out.
Also, unlike inorganic fertilizer, any organic manure or compost produced either in Sri Lanka or abroad, will not have a standard quality. This is also a major area of concern. The Lankan government says that it will help farmers make their own compost but can the farmers do it in the quantities they need? And can they ensure quality?
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