Dr Parakrama Waidyanatha
Posted on February 6th, 2022

Courtesy Island

Numerous positive claims are often cited for organic farming such as being environmentally friendly, superior food quality free from pesticides and other toxins, efficient energy use and sustainable food production. Much of these are highly contestable, and the most critical issue, why it is expanding only at a snail pace, is hardly discussed.

As shown in Fig.1, organic farming, despite it commencing in the 1960s, yet comprises only a very small fraction, 1.5%, of the global farmlands of which 66% is pasture; and it is expanding at only 2% annually. Only 16 countries have over 10% of their agricultural land organic, the highest extent of 46% being in Liechtenstein, a very small country (principality) in Europe, of 160.5 square kilometers with a population of 38,137 people.

Nearly all these 16 countries (with over 10% organic farmland) have pastures and animal production as the principle agricultural pursuit, and the main fertilizer for pasture is farmyard manure. The elite in rich countries love organic beef steaks though costly!

Nitrogenous fertilizer scarcity the biggest constraint to organic farming

Of the four main nutrients components in fertilizers, nitrogen (N), phosphorus (P), potassium

Why is organic farming expanding only at snail’s pace globally?

(K) and magnesium (Mg), the last three have natural sources approved for use in organic farming. Rock phosphate (P), muriate of potash or potassium chloride( K) and Epsom salt or magnesium sulphate(Mg) are natural deposits. Magnesium and calcium can also be supplied via dolomite, another natural mineral deposit.

Whereas muriate of potash and Epsom salt are readily soluble and hence can be taken up by roots; rock phosphate is insoluble and is made available to plants in the soil very slowly via solubilization with acids in the soil and microbes. Rock phosphate, therefore, usually cannot meet the P demand of seasonal crops. The answer has been super-phosphate manufactured by adding sulphuric acid to rock phosphate which makes its use prohibitive in organic farming. On the other hand, copper sulphate manufactured using sulphuric acid and copper metal or copper oxide is widely used as a fungicide in organic agriculture.

However, according to the founding concepts of organic farming based on philosophical views about nature, not biological science, even synthetic mineral fertilizer use is prohibitive. Natural means and methods were assumed to be superior. However, this argument is not consistent with science.

Nitrogenous fertilizer scarcity is the biggest constraint to expansion of organic farming as synthesized ammonium compounds such as ammonium sulphate and urea are prohibitive. Mineral deposits of sodium nitrate or Chile saltpetre from Chile and Peru are used as a nitrogenous fertilizer sources in organic farming in some European and other countries, but not permitted in others because the use of soluble fertilizers is considered to be contrary to organic farming principles. Then how can the use of copper sulphate be condoned? The International Federation for Organic Agriculture Movements (IFOAM) should review some these conditions that should vastly enable expansion of organic farming.

One of the ‘environmentalists’ objection to production of ammonia and urea is the very high energy consumption amounting to 1% of the global energy or 173 KWh and the related greenhouse gas emissions. The reaction of the synthesis of ammonia using atmospheric nitrogen and hydrogen from methane, via the Haber- Bosch process is carried out at very high temperatures of 400-450 degrees C and a high pressure of 210 atmospheres.

Urea manufacture also accounts for a large water consumption of 12.8 cubic metres/ton of which 95% is clean water. On the other hand, global conventional agriculture is heavily dependent on it and the reputed geographer and economist Prof. Vaclav Smil, of the University of Manitoba some years ago calculated that 40% the global population is alive on account of availability of urea for crop production.

There is much research in progress for synthesis of ammonia and urea with far less energy use. For example a Chinese research team led by Shuangyin Wang reports (Nature Communications Vol.12 Article number 4080; 2021) an electrochemical method, still at research stage, of urea synthesis from nitrogen and carbon dioxide at room temperature using some metal catalysts (MBenes). Concurrently, several projects are under way on urea production from the same raw materials using solar and wind energy. If these technologies become feasible for industrial urea manufacture, would IFOAM approve use of such urea in organic agriculture, now that an exception has been made by way of copper sulphate use as a fungicide in organic farms?

One of the complaints of our farmers who have switched to organic farming is the very slow decomposition of organic vegetative material, especially grass and straw in the preparation of compost. This is because of their very high carbon-nitrogen ratio. Microbes require soluble nitrogenous compounds, amino acids etc, for their growth and multiplication, a pre-requisite for decomposition of the organic matter, which provides them the nutrients and energy needed. Much labour is needed for collecting, heaping and churning the organic matter from time to time for accelerating the decomposition; and many organic fertilizer producers surreptitiously mix a little urea to increase the nitrogen content in the organic mass, which helps rapid decomposition, although it is against the organic principles.

Much of the organic material such as compost used in organic farming usually contains only about 2% nitrogen implying that to provide 100kg/ha of nitrogen at least 5 tons/ha of such material has to be applied as against 217 kg of urea ,for example, which contains 46% nitrogen. A high nitrogen demanding crop such as tea or leafy vegetables would require 10 to 20 tons per hectare per year or season to meet the crop nitrogen demand supply of which should be impractical for large scale use.

Crop rotation with leguminous crops is a common way of providing at least a part of the nitrogen. However, such crops should be worked into the soil for optimum benefit which means that the cropping intensity is reduced leading to less crop yield per unit time in such organic farming approaches.

On the whole organic crop yields are lower than conventional ones. For example, Holger Kirchman, Professor of Soil fertility and Plant Nutrition of the Swedish University of Agricultural Sciences (Outlook on Agriculture 2019, Vol. 48(1) 22–27) estimates that on average yields of organically cropped legumes were 20% and non-legumes 40% lower than those of conventionally grown crops.

Overall the yield was 35% lower for organic crops than conventional. Since yields are lower under organic, more land is required to produce the same amount of crop. A 35% yield gap means that 50% more arable land is required to produce the same yield. A demand for 50% more farmland imposes huge land use changes implying wide-ranging environmental consequences that follow when converting to organic farming.

By 2050 the global population is to reach 10 billion, and according to the UN, about two-thirds of the predicted growth in population between 2020 and 2050 will take place in Africa implying the huge demand for land for food production. Organic farming then is not the answer but conventional farming, with modern technologies involving genetic engineering and other technologies for optimizing land productivity.

Pesticides

A serious limitation to the expansion of organic farming is the inadequacy of effective organic pesticides. Consequently sulphur and copper sulphate as mentioned above are widely used in organic farming as fungicides. Both their use especially in organic farming has reports of ill-health among workers.

Several toxic plant extracts are used in organic farming for insect control such as rotenone and pyrethrums.

They cause environmental and health risks. Rotenone is moderately toxic to birds and highly toxic to fish, and kills bees when used in combination with pyrethrum. According to the Occupational Safety and Health Administration of the U.S , it can also cause damage to the human liver and kidney. Research has established a connection between rotenone and Parkinson’s disease. Pyrethrum has also been shown to be toxic to many animals. Apart from being a human carcinogen, it has been shown to be toxic to some fish and even kill lizards.

Unavailability of effective weed killers (herbicides) for organic agriculture is a further serious constraint to its expansion. This was dramatically shown here in the last Maha season, when with the virtual 100% overnight shift to organic farming, and application of nanourea (‘Nanoraja’) and other fertilizer concoctions to paddy crops, the accelerated growth of weeds relative to the rice, competitively suppressing the rice yields.

Health risks with organic fertilizers

Organic fertilizers although an essential source of plant nutrients and soil conditioners, may carry infectious agents and toxic materials such as antibiotics. They are reported to be mostly introduced into the food chain via animal and human excreta. The recent highly controversial shipload of organic matter from China that was identified by the local Quarantine authority to contain a pathogen is a case in point.

Numerous pathogens, bacteria, viruses and parasitic organisms have been reported as the cause of food –borne epidemics. Antibiotics and other medications used for treating animals from organic fertilizer sources can enhance the occurrence of resistant strains of microbes that can harm human health via consumption of organic foods. Sub-lethal concentrations of antibiotics in organic food products can induce antibiotic resistance. In fact the WHO has directives on the reuse of organic matter sources, especially excreta.

Heavy metals such as cadmium, zinc, arsenic and lead can accumulate far more in organic fertilizer applied soils than from chemical fertilizers because huge quantities of it are applied (usually 10 tons/ha) than chemical fertilizer; and although similar concentrations (quantities as parts per million) are present in both sources, the amounts entering the soil and crops are far greater with organic fertilization. This is evident from substantially higher concentrations reported both in organically fertilized soils and organic vegetables and fruits.

In conclusion, that organic farming is natural is no argument for its expansion because growing populations and the consequent demand for food would, under organic farming, mean clearing more forest and other lands for agriculture because of its inherently lower yields. The way forward as pointed out by the FAO and other international organizations and scientists is via generation of new technologies (genetic engineering) to produce more crops per unit of land and water, apart from population control.

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