The Soil Science Society of Sri Lanka has, in a letter sent to President Gotabaya Rajapaksa, expressed its concerns over moves to import organic fertilisers. The Soil Science Society of Sri Lanka (SSSSL) is one of the oldest professional societies in the country with a history of 52 years. The membership includes soil scientists representing [...]

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Why Soil Science Society is concerned about organic fertiliser imports


The Soil Science Society of Sri Lanka has, in a letter sent to President Gotabaya Rajapaksa, expressed its concerns over moves to import organic fertilisers.

The Soil Science Society of Sri Lanka (SSSSL) is one of the oldest professional societies in the country with a history of 52 years. The membership includes soil scientists representing the university academia, the Department of Agriculture, the Department of Export Agriculture, research institutes and the private sector.

As one of the key stakeholders of the precious soil resource of Sri Lanka and agriculture at large, we believe that it is our responsibility to express our concerns on the importation of organic fertilisers.

Lanka's soil scientists urge a cautious approach to the introduction of imported organic fertiliser to Sri Lanka's agri sector

The SSSSL welcomes the Government’s initiative to introduce a green socio-economy using eco-friendly technologies and promote organic-only agricultural systems in the country. Accordingly, the Government on April 27 decided to ban the import of agro-chemicals, including chemical fertilisers.

As a scientific community, we recognise the benefits of judicious application of good quality organic fertilisers to soil. Some of these benefits include improving soil fertility, increasing soil biodiversity, mitigating climate change, and enhancing water retention. Thus, the application of organic fertilisers is considered to be an important practice in sustainable soil management.

In Sri Lanka, recommendations for nutrient management are made based on the outcome of long-term research. Accordingly, crop research institutes have included organic fertilisers along with chemical fertilisers in their current fertiliser recommendations as a supplement to meet crop nutrient requirements and/or soil amendments.

At present, animal wastes (cattle manure and poultry manure), green manure and compost are the most commonly used organic fertilisers by farmers. Application of these organic fertilisers is popular for vegetable crops, but not for rice and other crops, including plantation crops. It is apparent that the use of organic fertilisers is limited at present due to several reasons such as poor quality, bulkiness, labour intensiveness and high cost of transportation.

The subsidy scheme extended to chemical fertilisers stands as a major obstacle for the promotion of organic fertiliser usage in Sri Lanka. Further, the production and availability of organic fertilisers within the country are not adequate to meet the present recommendations of the crop research institutes.

Nutrient cycling in an agricultural system is not closed because with each harvest we are removing considerable quantities of nutrients from the soil. Therefore, we need to replenish at least the quantity removed through fertiliser application.

Here we present two examples showing the requirement of compost (form of organic fertiliser commonly used in the country) for two crops, if the nutrient requirement is to be fully supplemented with organic fertilisers.

n From a field that produces a yield of 5 t/ha paddy, about 50kg of nitrogen (N) is removed from the soil with every harvest. To replace at least the amount of N removed back to the soil, we need to apply 8.6 tons of compost containing 2% N, 20% moisture and having 35% efficiency during the initial 3-5 years. At a nominal price of Rs.12/kg of compost, a farmer has to spend about Rs. 103,000/ha. In comparison, if he applies chemical fertilisers, the cost will be only around Rs. 26,000/ha (without subsidy).

n For tea, the situation is almost similar. In a field that produces 1.7 tons of made tea/ha/year, the N outflow from the soil is nearly 60kg, and to replenish this using compost, the planter has to apply about 10.2 tons of compost per hectare costing nearly Rs. 122,400/ha. In comparison, the cost of chemical fertilisers works out to only Rs. 72,000/ha (without subsidy).

Also, to compensate for the nutrients removed with every harvest, these quantities need to be repeatedly applied to obtain such yields every season. Depending on the biological fertility of the soil, the amount to be applied as compost could be slightly lower than the above estimate. However, when making recommendations with organic fertilisers as the sole nutrient source, crop responsiveness is also need to be considered. Compost-only nutrient-management practices will not be economically sustainable especially for large-scale producers. Integration of animal manures, N-fixing biofertilisers and/or high N-containing other liquid organic fertilisers into nutrient-management strategies in organic-only agriculture will ease out the need for large quantities of compost to some extent.

Application of liquid organic fertilisers containing high N content is, however, challenging in tea, because foliar applications may leave residues which could affect the flavour and the export quality standards of tea. Further, the application of liquid organic fertilisers cannot provide the expected benefits on soil health as its contribution to improve soil nutrient pools and soil organic carbon is minimal.

Based on total extents, for rice and tea alone, the requirement of organic fertiliser having at least 2% N content would be 11.5 million tons per year. When the recommendation is made to go 100% organic, then the availability of materials would be the main constraint. To meet the nutrient demand for crop cultivation and assure food security, the country will have to consider importing organic fertilisers.

Here we wish to highlight our major concerns on the importation of organic fertilisers and we kindly request the Government to give due consideration to the following facts before rushing to take a decision to import organic fertilisers.

Reasons for our concerns on
importing organic fertilisers

n There is a risk of introducing invasive species, weeds, pathogens (including zoonotic pathogens which are naturally transmitted from animals to humans such as viruses, bacteria, protozoa and helminth parasites) through imported organic fertilisers. Such organisms could cause disease outbreaks in crop, livestock and human society leading to heavy economic losses. Facilities available in the country to test for biological contaminants are not adequate and not up to date.

n Biofertilisers, a group of fertilisers often considered under organic fertilisers, are preparations containing large number of living microbial cells with high ability to colonise soil. Thus, imported biofertilisers may directly introduce alien species threatening the biodiversity and functioning of the agricultural systems largely driven by the microbial activity. Importation of biofertilisers should not be considered at all.

n Organic fertilisers are usually added in large quantities and that means contaminants will also be applied in large quantities posing a high risk of contaminating our soils and water resources. Once the pollutants enter into our eco-system and destroys it, it is not easy to recover from the damage.

n At present, a strict regulatory framework is not in place in the country to ensure biosafety, quality, handling and safe use of the imported organic fertilisers.

n There are no standards in place or facilities available to test for emerging pollutants (micro-plastics, antibiotic residues, organic pollutants, biological contaminants etc.) which are commonly found in organic fertilisers.

n The Government will have to import only certified products where there is traceability to identify the source materials and ascertain quality and such products will be expensive. This will lead to increased cost of production and ultimately high prices of agricultural produce which will have negative effects on both local and export markets.

n Local products available at present cannot compete price-wise with products in international markets. Hence, importation will discourage local production of organic fertilisers.

n Importing bulk quantities of carbon rich organic fertilisers is not favourable in carbon footprint. This will affect our claims in carbon trading and certification of export goods.

Based on the facts we have set forth, as a Scientific Society, we are not in agreement with importing organic fertilisers.

Until such time when we reach self-sufficiency in good quality organic fertilisers, we recommend practising integrated plant nutrient management, a widely adopted practice in many parts of the world and scientifically proven to be economically feasible and environmentally sustainable. Here, we wish to propose actions to be undertaken during the transition to an eco-friendly organic fertiliser-based agriculture.

The way forward for an eco-friendly organic fertiliser-based
agricultural system

n Develop animal husbandry to obtain raw material.

n Expand the cultivation of green manure crops in marginal lands.

n Develop and introduce regulations to ensure quality production and proper usage of organic fertilisers.

n Provide incentives to promote commercial scale production of organic fertilisers (compost, biofertilisers, liquid organic fertilisers, etc.) and develop new technologies.

n Strict regulations and mechanisms need to be established for source separation of municipal biowaste to produce good quality compost at local council level.

n Use biological resources within the country to produce good quality bio-fertilisers and liquid organic fertilisers.

n Promote mechanised compost production.

n Identify value chains and means of supporting circular economy to improve resource use efficiency within the country for the betterment of agricultural production.

n Promote on-farm production of organic fertilisers.

n Practise proper land-use planning to improve resource use efficiency.

n Continue research to identify organic fertiliser requirements for different crops and optimise recommendations, production potentials of organic fertilisers and impacts to the national food production.

n Assess the impacts on soil carbon storage and soil fertility improvements under gradual transition to organic fertiliser usage so that we can claim for carbon credits.

n Promote research to generate long-term data based on green socio-economic agriculture.

• Make decisions based on well-informed and time-tested scientific facts rather than polarising towards ideas of few scientists.

The SSSSL welcomes the policy initiative of the Government to promote the usage of organic fertilisers in the country’s agricultural sector. We have no doubts on the benefits of using organic fertilisers and the expected improvements to the soil and environment. However, we request you to give due consideration to the concerns we have set forth in this article.

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