Conservation agriculture, a general practice that entails minimal or no tillage of soil, is rapidly becoming more common. Conservation agriculture constituted 2.8 million hectares worldwide in 1973/74 1, 45 million hectares in 1999 1, 72 million hecatures in 2003 1, 106 million hectares in 2008/09 1, 157 million hectares in 2013 1, 180 million hectares in 2015/16 2, and 205.4 million hecatures in 2018/19, or 14.7% of world cropland 2.
Under no-till farming, a new planting is done through the residue of the old rather than through tilling. The following increases in yields from no-till farming have been estimated from several studies.
Avoiding tillage may allow the soil to sequester more carbon, though this effect is disputed. The following are the soil carbon sequestration potential of no-till farming, as estimated from several studies. Under the largest estimate, applied over 1.5 billion hectares of cropland, the theoretical carbon sequestion potential is the equivalent of 5.5 billion tons of CO2 per year, or a bit over 10% of world emissions.
The following additional benefits and drawbacks of no-till farming have been estimated.
| Study | Quantity | Impact of No-Till Relative to Tilled Farming |
|---|---|---|
| Lal et al. | Soil loss | 20% |
| Lal et al. | Fertilizer usage | Savings, unquantified |
| Derpsch | Erosion | 4% |
| Derpsch | Fuel consumption | 34% |
| Zhao et al. | Methane emissions | 70% |
| Zhao et al. | Nitrous oxide emissions | 120.8-182.1% |
| Karayel | Water quality | Improved |
| Elias et al. | Pesticide runoff | Increased |
| Gattinger et al. | Herbicide applied | Increased |
Cover-cropping is an important aspect of regenerative agriculture with many purported benefits 12. One benefit is carbon sequestration potential, though studies vary widely as to how great this may be.
Poeplau and Don 14 also estimate that the world potential carbon sequestion for cover cropping is 120 million tons of carbon per year, or 320 million tons CO2, about 8% of world emissions.
Cover cropping is estimated to reduce yields of maize (corn) by 5.5% and soybeans by 3.5% 15. Cover cropping requires additional land use in providing the seeds of 3.8% of the land covered 16.
As of 2017, 5% of United States cropland was under cover crops 17.
Kassam, A, Friedrich, T, Derpsch, R, Kienzle, J. "Overview of the Worldwide Spread of Conservation Agriculture". Field Actions Science Reports, The Journal of Field Actions 8. October 2015. ↩ ↩2 ↩3 ↩4 ↩5
Ruiz-Espinosa, L.I., Verhulst, N., van Ogtrop, F., Cross, R., Govaerts, B., van Rees, H., Trethowan, R. "Quantifying the adoption of conservation agriculture: Development and application of the Conservation Agriculture Appraisal Index". Agricultural Systems 220: 104095. October 2024. ↩ ↩2
Derpsch, R., Friedrich, T., Kassam, A., Li, H. "Current Status of Adoption of No-till Farming in the World and Some of its Main Benefits". International Journal of Agricultural and Biological Engineering 3(1). 2010. ↩ ↩2
O'Connor, C. "Farmers Reap Benefits as No-Till Adoption Rises". Natural Resources Defense Council. November 2013. ↩
Zhao, X., Liu, S., Pu, C., Zhang, X., Xue, J., Ren, Y., Zhao, X. Chen, F., Lal, R., Zhang, H. "Crop yields under no-till farming in China: A meta-analysis". European Journal of Agronomy 84, pp. 67-75. March 2017. ↩
Du, Z., Angers, D., Ren, T., Zhang, Q., Li, G. "The effect of no-till on organic C storage in Chinese soils should not be overemphasized: A meta-analysis". Agriculture, Ecosystems & Environment 236, pp. 1-11. January 2017. ↩
Lal, R., Reicosky, D., Hanson, D. "Evolution of the plow over 10,000 years and the rationale for no-till farming". Soil and Tillage Research 93(1), pp. 1-12. March 2007. ↩ ↩2
VandenBygaart, A. "The myth that no-till can mitigate global climate change". Agriculture, Ecosystems & Environment 216, pp. 98-99. January 2016. ↩
Elias, D., Wang, L., Jacinthe, P. "A meta-analysis of pesticide loss in runoff under conventional tillage and no-till management". Environmental Monitoring and Assessment 190, Article Number 79. 2018. ↩
Gattinger, A., Jawtusch, J., Muller, A., Mäder, P. "No-till agriculture - a climate smart solution?". MISEREOR. November 2011. ↩
Karayel, D., Šarauskis, E. "Environmental Impact of No-Tillage Farming". Journal of Environmental Research, Engineering and Management 75(1), pp. 7-12. 2019. ↩
Clark, A. "Ecosystem Services from Cover Crops". Sustainable Agriculture Research and Education. 2015. ↩
Blanco-Canqui, H. "Cover crops and carbon sequestration: Lessons from U.S. studies". Soil Science Society of America Journal 86(3), pp. 501-519. May/June 2022. ↩
Poeplau, C., Don, A. "Carbon sequestration in agricultural soils via cultivation of cover crops – A meta-analysis". Agriculture, Ecosystems & Environment 200, pp. 33-41. February 2015. ↩ ↩2
Deines J. M., Guan K., Lopez B., Zhou Q., White C. S., Wang S., Lobell D. B. "Recent cover crop adoption is associated with small maize and soybean yield losses in the United States". Global Change Biology 29(3), pp. 794-807. November 2022. ↩
Runck B. C., Khoury C. K., Ewing P. M., Kantar M. "The hidden land use cost of upscaling cover crops". Communications Biology 3(1): 1-4. June 2020. ↩
Popkin, G. "A pillar of the climate-smart agriculture movement is on shaky ground". Food & Environment Report Network. December 2022. ↩