No-Till and Conservation Agriculture
Sowing into unploughed soil under crop residue, made possible by herbicides, spread after the Second World War; conservation agriculture covered 205 million hectares, 14.7 percent of the world's cropland, in 2018/19.
Open in the interactive tree →The 1930s Dust Bowl, a drought and wind-erosion disaster across about 100 million acres of the US Great Plains, led to the Soil Conservation Service in 1935. In the 1940s Edward Faulkner's book Plowman's Folly attacked deep ploughing, and after the Second World War herbicides such as paraquat made it possible to kill weeds without tillage; early adopters included farmers in Kentucky and, from 1971, researchers in Brazil. Kassam and colleagues counted 205.4 million hectares of conservation agriculture, with permanent soil cover and crop diversity, in 102 countries in 2018/19. It cuts erosion and keeps water in the soil but often relies on herbicides such as glyphosate and can delay spring planting.
Prerequisites
- Soil Science1883Soil science tied erosion to bare, ploughed ground.
- Synthetic Pesticides1939Herbicides such as paraquat replaced the plough as the way to kill weeds.
Unlocks
- Stopping Soil LossopenNo-till with soil cover is a main farm practice against erosion.