Plows are absent on farms practicing conservation agriculture, and for good reason. When farmers till their fields to destroy weeds and fold in fertilizer, water in the freshly turned soil evaporates. Soil itself can be blown or washed away and carbon held within it released into the atmosphere. Tilling can make a field nutrient poor and less life-giving.
Conservation agriculture was developed in Brazil and Argentina in the 1970s, and adheres to three core principles:
- Minimize soil disturbance: absent tilling, farmers seed directly into the soil.
- Maintain soil cover: farmers leave crop residues after harvesting or grow cover crops.
- Manage crop rotation: farmers change what is grown and where.
The Latin root of conserve means “to keep together.” Conservation agriculture abides by these principles to keep the soil together as a living ecosystem that enables food production and helps redress climate change.
Conservation agriculture sequesters a relatively small amount of carbon—an average of half a ton per acre. But given the prevalence of annual cropping around the world, those tons add up. Because conservation agriculture makes land more resilient to climate-related events such as long droughts and heavy downpours, it is doubly valuable in a warming world.
Brazil and Argentina in the 1970s: Farooq, M., and K. Siddique. “Conservation Agriculture: Concepts, Brief History, and Impacts on Agricultural Systems.” In Conservation Agriculture, 3–20. New York: Springer, 2015.
Annual crops…89 percent of…cropland: Toensmeier, Eric. The Carbon Farming Solution. White River Junction, VT: Chelsea Green Publishing, 2016; FAO Statistical Services online.
Conservation agriculture…acres: Friedrich, Theodor, Rolf Derpsch, and Amir Kassam. “Overview of the Global Spread of Conservation Agriculture.” Field Actions Science Reports, Special Issue 6 (2012); Toensmeier, Solution; FAO Statistical Services online.
South America, North America, Australia, and New Zealand: Friedrich et al, “Overview.”
half a ton [of carbon] per acre: Toensmeier, Solution.
Correction: Conservation agriculture sequesters a relatively small amount of carbon—an average of half a ton per acre.