While it is the use of chemical fertiliser and insecticides that has helped agriculture meet demands of rising populations, it is now proving the block to ensuring sufficient food in coming decades. An alternative is to switch to farming without the use of chemicals and relying on natural fertilisers and pest control. Measures like this, however, would call for more land, including land where fodder for livestock is grown, to be brought under cultivation of food grain. And organic farming may still fall short of the quantity of food grain required.

Adrian Muller, Christian Schader, Nadia El-Hage Scialabba, Judith Brüggemann, Anne Isensee, Karl-Heinz Erb, Pete Smith, Peter Klocke, Florian Leiber, Matthias Stolze and Urs Niggli, from institutes of research in agriculture, ecology and environment in Switzerland, Austria, Aber-deen and Potsdam, and the Food and Agriculture Organisation of the United Nations in Rome report in the journal, Nature Communications, a comprehensive study of the economy of implementing rising levels of organic farming. While going organic is the way to escape chemical
poisoning that conventional farming involves, the paper proposes a strategy to make the organic route practical.

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In 1798, Thomas Malthus said that the growth of population was so fast that food production would not keep up with the demand for food. The prediction of food scarcity did not come about, however, because synthetic fertilisers, insecticides and irrigation helped multiply agricultural produce. The world’s production of rice and wheat grew ten-fold since 1800 and by a factor of 2.5 since 1950. And the growth of world population, from 1 billion in 1800, to the present 7.6 billion, has been slower than what Malthus feared. But  population is expected to rise to 9.6 billion by 2050, and with consumption of food having risen faster than production, whether there would be enough food in the coming decades is still in question.

The problem is that al-though the land under crops has increased, the real driver of high production has been the greater output possible with synthetic fertilisers. In traditional farming, plants convert the sun’s energy into food, but only with the help of trace but essential traces, of phosphates, active nitrogen and some others. These agents enable plants to grow naturally in soil through breakdown of organic matter or from the plentiful, inactive nitrogen in the atmosphere by the action of microbes or energetic events like lightning.

As agriculture depletes the soil, these nutrients need to be replenished. This can be done by leaving the land fallow, to regenerate, or by alternating crops or adding manure. Manure, by composting organic matter or the excreta of animals, is rich in active nitrogen and has been a traditional fertiliser. A far richer source of active nitrogen, however, is in the form of chemicals like ammonium phosphate, urea or superphosphate. The content of plant nutrients in these compounds can be 30 per cent by weight, against only 4 per cent in the case of natural fertilisers.

Manufacture of chemical fertiliser became a major industry in the early 20th century and agricultural production rocketed. With the use of fertilisers rose large farms of one sole crop. This prevented natural pest control by a mix of species gro-wing together and created the industry of chemical insecticides. It was only later in that the spotlight turn-ed on the damage done by chemicals in the soil, apart from the coal burned to power factories.

The downside of chemical fertilisers is that they are toxic if not used with plenty of water. And then the run-off water carries excess chemicals to poison ponds, waterways or fresh water sources. The high rate of production also creates imbalance in soil nutrients, calling for a cycle of additives. The Stockholm Resilience Centre has placed biochemical poisoning as one of the nine boundaries of pollution, which the Earth should not cross, and a boundary that active nitrogen discharge has crossed.

The general solutions that are considered are switching to organic farming, releasing land from cultivation of fodder for livestock and avoiding waste or loss of food, which the FAO has found to be 30 to 40 per cent. With urban settlements pressing for expansion and encroachments of forests, finding land for agriculture is a challenge. Change in land use, in fact, is another of the nine planetary boundaries identified by the Stockholm Centre. Studies in the field, however, the Nature Communications paper says, have not followed a de-tailed food systems app-roach that acc-ounts for the interplay of the three strategies along the way to assuring a certain calorie intake for the world population. Nor, the paper says, have they “captured the main agronomic characteristics of organic agriculture in a systematic way”.

The current study steps in with a software model, which is able to remedy this shortfall by considering the different factors involved in a mix of strategies and evaluating the land use needed to assure sufficient food calories, at different levels of organic farming. The model hence simulates changes in each of the different factors, to picture what happens in different conditions.

The first result is a formal assessment of the land use involved if we were to shift to degrees of organic farming from 20 to 100 per cent. Against the present (2005-2009) land use, at 1.5 billion hectares, the projection for 2050, with no changes in the manner of farming — is an increase to 1.7, 2.0 and 2.3 billion hectares depending on climate change with low, medium or high impact. And then, for higher levels of organic farming, the land use rises to 2.75 billion hectares with 100 organic farming and high climate impact.

The simulation examined how land use was affected by levels of  saving land for livestock fodder for agriculture and by steps to contain waste or loss. The results are displayed in the figure. Under conditions of zero per cent, 25 per cent and 50 per cent waste reduction, and then zero per cent, 50 per cent and 100 per cent reduction of land used for fodder, the percentage change in land required for crops are shown, under different levels of organic farming, according to less and greater impact of climate change.

The boxes with negative figures represent conditions where the land use is less than the reference level. We can see that even 100 per cent organic farming becomes feasible under conditions of medium impact of climate change, 50 per cent reduction of waste and 100 per cent reduction of use for fodder.

As greater organic farming implies improvement first in pollution by active nitrogen and then of the consumption of power and water, this study allows planning for the level of organic farming that is feasible or desirable, while considering the extent of limiting waste or reducing competing demands for use of land. The separate targets, organic yield and production, reducing animal numbers and consumption of animal products and then waste and loss, could hence be implemented in part and in combination, in place of being maximised in isolation, the study says, to help increase the sustainability of the global food system.

The writer can be contacted at response@simplescience.in