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Juliana Albertengo’s ancestors would be astonished by her farm at El Fortin in north-eastern Argentina. Thirty years ago, her family abolished a custom practised over centuries – ploughing and tilling the soil. Burning harvest stubble to clear the fields before the next planting season, an ancient tradition that produces the short-lived climate pollutant black carbon, had also ceased.
Instead of burning, ploughing (turning over) or tilling (raking) the earth before planting new seeds, the farmers at El Fortin now spread residues of plants, such as stubble and leaves, on the ground after harvest. These decay and merge with the soil, which stays untouched until planting begins. This alternative farming technique, entitled conservation agriculture, conserves soil fertility rather than tradition and reduces the agriculture sector’s contribution to air pollution and climate change. Its worldwide adoption would avert 10-20% of the black carbon emissions arising from open burning.
Conservation agriculture, also known as ‘no till’ or ‘no burn’ agriculture, was to revolutionise farming in Argentina and Brazil in the late 20th century. It has since been replicated by other farmers across the world. But the technique needs to spread further – not only to conserve the soil but reduce emissions of black carbon.
Black carbon is both a powerful climate forcer and dangerous air pollutant. It has a warming impact on the climate that is 460-1,500 times stronger than CO2 per unit of mass. The resulting emissions from burning plant waste is likely to cause a 0.4°C temperature increase in the next 20 years. At the same time, the black carbon emitted is deposited on glaciers in mountain ranges such as the Andes and Himalayas, melting them.
This could lead both to the loss of land glaciers but also changes in water supply, precipitation and weather patterns, increased methane and CO2 release from permafrost and seabed, as well as sea level rise.
The black carbon has another effect. As a key component of fine particulate matter (PM2.5) air pollution, it is the leading environmental cause of poor health and premature deaths.
Many traditional farmers view plant residue as harmful waste and thus remove it after harvest by open burning, ploughing or tilling. However, leaving plant waste in the fields reincorporates the nutrients the plants have taken from the soil, creating a virtuous circle. Pilots by conservation farmers have shown that switching to conservation agriculture improves the volume of crops harvested per hectare, raising farmers’ incomes and standard of living. It produces major savings in fuel and labour costs.
“The farmer enjoys many, many benefits from not tilling or burning and these go well beyond the individual farming business. It is good for food production internationally, the health of humanity, and the environment,” says Juliana Albertengo. An advocate farmer and expert advisor to the Climate and Clean Air Coalition’s agriculture initiative, she views the experience of Argentinian farmers as a good basis for modelling change in the rest of the world and disseminating knowledge of the technique.
Though conservation agriculture is now practised in 90% of Argentinian farmland, it required more than a decade to establish, and many prejudices to overcome. “In the 1980s, people described pioneers of conservation agriculture as crazy,” Juliana Albertengo says. Among the misconceptions entrenched in the Argentinian farming community, and in many farms around the world today, was the view that ploughing and tilling destroyed weeds, loosened the soil and prevented waterlogging. Farmers believed ploughing also enriched the soil by turning it over, and that plants would grow better.
“They were mistaken. Instead, it decreases soil fertility by removing the topsoil, which contains most of the nutrients,” she says. “The energy created from ploughing also converts particles of soil into thinner particles, which reduces soil infiltration, so that water does not integrate into the earth. By contrast, keeping plant residue in place creates mulch when it rains. This increases yield and decreases water loss.”
Farmers tied to the older custom of burning the soil believe this not only clears but purges it. Burning residue also saves money. Indeed, it is the cheapest way to remove residue. However, it actually has destructive impacts on both soil and air quality.
Farmers are closer to the soil than anyone on the planet, so why are they making such fundamental errors? Studies suggest this is explained by the use of fertiliser and subsidies, especially in the maturer lands of Europe and Asia, which conceals the true soil condition from the labourer. In Argentina, however, farmers were luckier than most, working the Pampas – South American lowlands that contain among the most fertile soils in the world. Fertiliser was used in lower quantities than elsewhere, so soil changes became perceptible.
Around 40 years ago, farmers observed frequent run-off: water channelling sideways into gullies running out of the fields instead of being absorbed by the soil. After establishing that this was caused by soil erosion, they decided to keep the soil covered in order not to lose soil particles as well as nutrients. “There were almost instant results, and the erosion stopped immediately,” says Juliana Albertengo. Innovations from pioneering farmers caught on, and the uptake of the farming method climbed steadily throughout the 1990s.
Richer soil, produce and yields have been the outcome – but there were plenty of barriers to overcome first. Sowing new seeds in soil covered with residue is quite different than bare ground. It requires new tools, such as a seeder to cut into the soil and close furrows left after sowing. Early pioneers patented such machinery – but they also needed to sell it. However, they had a strong trump card. Stopping ploughing saved enormous amounts of money in fuel for ploughing machinery, and considerable fertiliser costs. Those savings could be used to buy the new seeders.
Once the technology had been invented, the switch was not instant despite the obvious financial gains. “A farmer observing changes from one year to the next will find a lot of causes that explain an improved yield. Could this be because there has been more rain? Or that it rained just at the point when the corn flowered? It may take five years for them to distinguish the difference arising from conservation agriculture,” explains Juliana Albertengo. Once that was established, conservation agriculture rippled across the entire farming community as word of the benefits spread. The obvious benefits of the technique meant it was adopted without government intervention.
Many farmers continue to burn, especially in South Asia. The seasonal burning of crop residues, including residue from rice harvesting, is a major contributor to air pollution and smog in India.
Farmers everywhere plough. Farmers face similar barriers in different agricultural conditions but conservation agriculture is technically feasible almost anywhere. In the Indian Himalayas, financial objections are greater than in Argentina. Smallholders there plant seeds manually. No-till seeders cost USD 10-20 – a modest sum in many countries. But farmers in India cannot afford even that upfront payment without assistance.
In the European Union, the farming subsidies, which are absent from Argentina and many other lower and middle-income countries, act as a disincentive to experimental farming. In Iowa and other northern US states, the objections are provoked by the local climate. “The winters there are very hard and cold, and the farmers like to plant corn early in the year. But they say that if the soil is covered with residue it will not warm up as quickly as bare soil in order to be ready for planting”, Ms. Albertengo says.
It would be simplistic to assume that Argentina’s experience can be transposed identically across the world. However, specific incentives encourage change, such as the use of demonstration projects. Experience shows farmers enjoy more free time through conservation agriculture and make more money to buy more plots of land. However, long-standing beliefs in traditional systems mean resistance is ingrained.
“Farmers are the same all over the world. They need to see to believe,” says Juliana Albertengo. Demonstration pilots financed by the Coalition in Peru and the Indian Himalayas – areas with poorer smallholders than those in Argentina -- allow the farmers to view the evidence for themselves. In the Peruvian community of Huayao, farmers observed two plots on a daily basis – one managed through conservation agriculture and the other through traditional agriculture. The conservation agriculture plot doubled yield and decreased costs by approximately one-third, showing economically viable alternatives to burning.
In both Peru and the Indian Himalayas, black carbon from open burning is thawing glaciers and creating irrigation problems. That alone provides a powerful argument for encouraging these farmers to change.
Paradoxically, the lack of government assistance may create a further incentive. “In developing countries, where there are no farming subsidies, every dollar counts. That means farmers may adopt a more creative outlook”, says Juliana Albertengo.
Training and outreach programmes are helping farmers learn about alternative machinery and new approaches to land management and fertiliser use. Juliana Albertengo is working with Coalition partner the International Cryosphere Climate Initiative to help raise awareness further afield and encourage peer group discussion among Himalayan and Peruvian farming communities.
Government incentives were absent from the Argentinian transition but tax breaks and regulatory intervention are possible options to help countries shift more quickly. Above all, the word needs to spread through the industry’s grassroots as it did in Argentina. Perhaps, a few years down the line, further proof will have converted more farmers into conservation agriculture advocates.
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