Project Drawdown defines conservation agriculture as an annual crop production system that provides biosequestration via crop rotation, cover cropping, and reduced tillage. This solution replaces conventional annual cropping systems with tillage.
The three components of conservation agriculture are: minimal soil disturbance (no-till or reduced tillage), permanent soil cover (cover crops), and diversified crop rotations. It is suited to both mechanized and unmechanized contexts. Climate mitigation from conservation agriculture is through reduced emissions from tillage and soil carbon sequestration.
Conservation agriculture is modeled as a bridge technology, which transitions to regenerative annual cropping over time. Converting from conservation agriculture to regenerative annual cropping only requires the addition of one more practice (compost application, organic farming, or green manure use). The soil health movement, the International Federation of Organic Movements’ “Organic 3.0,” and the many farmers working to implement organic no-till agriculture are all evidence that this transition is underway.
Total Land Area
The total land area allocated to conservation agriculture and regenerative annual cropping is the same: 685 million hectares of nondegraded croplands with minimal slopes, which is allocated differently under different custom adoption scenarios. In all scenarios, conservation agriculture grows until at least 2030 and then starts declining, but never shrinks below its 2018 rate of 148 million hectares.
Six custom adoption scenarios were developed for conservation agriculture. All begin with current adoption of 148 million hectares. Some scenarios use the current global adoption rate of 0.36 percent, while others use 1.24 percent, which is the rate from South America, the highest regional rate. The conservative scenarios assume adoption to continue through 2050, while the aggressive scenarios assume that the adoption of conservation agriculture will reach its peak by 2030 and begin to decline as land area under conservation agriculture converts to regenerative annual cropping. This conversion was assumed based on the increasing demand for organic and semi-organic agricultural products.
Impacts of increased adoption of conservation agriculture from 2020 to 2050 were generated based on two growth scenarios. These were assessed in comparison with a Reference Scenario, in which the solution’s market share was fixed at the current levels.
- Scenario 1: This scenario was determined through analysis of the six custom adoption scenarios, in which the land area under conservation agriculture reaches to its peak (407 million hectares) by 2039 and then declines to 373 million hectares by 2050. The 34 million hectares lost from conservation agriculture are assumed to be converted to regenerative agriculture.
- Scenario 2: In this scenario, the land area under conservation agriculture reaches its peak (332 million hectares) by 2039 and then declines to 303 million hectares by 2050; the difference of 29 million hectares is added to regenerative annual cropping.
Usually, the adoption area under any solution increases from the Plausible to Drawdown Scenario; however, this is not the case for conservation agriculture, due to its transition to regenerative annual cropping. Thus, a continuous decrease in conservation agriculture leads to a continuous increase in regenerative annual cropping from the Plausible to Drawdown Scenarios.
Emissions, Sequestration, and Yield Model
Sequestration rates are set at 0.78, 0.38, 0.61, and 0.25 metric tons of carbon per hectare per year for tropical humid, temperate/boreal humid, tropical semi-arid, and temperate/boreal semi-arid zones, respectively. These are the result of meta-analysis of 59 data points from 40 sources. Emissions reduction rates from conservation agriculture are 0.23 tons of carbon dioxide-equivalent per hectare per year, based on meta-analysis of 14 data points from seven sources.
Yield gains compared to business as usual annual cropping were set at 6 percent, based on meta-analysis of 12 data points from five sources.
Financial inputs for conservation agriculture were determined via meta-analysis. First costs are estimated at US$355.05 per hectare; for all agricultural solutions, it is assumed that there is no conventional first cost, as agriculture is already in place on the land. Net profit is US$650.65 per hectare per year, compared to US$407.47 for the conventional practice. Net profit is calculated at US$530.39 per hectare per year for the solution (based on meta-analysis of 19 data points from six sources), compared with US$474.21 per year for the conventional practice (based on 36 data points from 19 sources). While the operational cost is calculated at US$599.03 per hectare per year for the solution (based on 17 data points from four sources), compared with US$943.57 per year for the conventional practice (based on the 30 data points from 12 sources).
Project Drawdown’s Agro-Ecological Zone model allocates current and projected adoption of solutions to the planet’s forest, grassland, rainfed cropland, and irrigated cropland areas. Adoption of conservation agriculture was constrained by several factors. These include: limiting adoption to cropland of minimal slope, competition for said cropland with rice solutions, and a higher priority for regenerative annual cropping. The combined conservation agriculture/regenerative annual cropping practice is assigned third-level priority for nondegraded cropland of minimal slopes. Only rice-based solutions are more highly prioritized.
Total adoption in the Scenario 1 is 400 million hectares in 2050, representing 54 percent of the total available land. Of this, 224.64 million hectares are adopted from 2020 to 2050. The impact of this scenario is 13.4 gigatons of carbon dioxide-equivalent sequestered by 2050. Net cost is US$91.9 billion. Lifetime savings in net profit is US$113.1 billion, and operational cost is US$2.8 trillion. Yield reduction of 169 million metric tons is accounted between 2020 and 2050. Yield gains result in an additional yield of 1.5 billion metric tons of rice between 2020 and 2050.
Total adoption in the Scenario 2 is 327 million hectares in 2050, representing 44 percent of the total available land. Of this, 155.40 million hectares are adopted from 2020 to 2050. The impact of this scenario is 9.43 gigatons of carbon dioxide-equivalent by 2050. Net cost is US$65.23 billion. Lifetime savings in net profit is US$77.7 billion and operational cost is US$1.9 trillion. Yield reduction of 169 million metric tons is accounted between 2020 and 2050. Yield gains result in an additional yield of 1.1 billion metric tons of rice between 2020 and 2050.
Project Drawdown’s conservation agriculture mitigation impact is somewhat higher than Intergovernmental Panel on Climate Change (IPCC) benchmarks, which estimate 0.8 gigatons of carbon dioxide equivalent per year by 2030 for cropland management, excluding rice and agroforestry (Smith, 2007). Griscom et al. (2017)’s “Natural climate solutions” calculate 0.31–0.52 gigatons of carbon dioxide equivalent per year in 2030 for cover cropping, one of the six practice of regenerative annual cropping. The Project Drawdown model shows 0.3–0.5 gigatons carbon dioxide equivalent per year by 2030 for conservation agriculture and 0.5–0.7 for regenerative annual cropping, for a combined 0.86–0.98 gigatons carbon dioxide equivalent per year in 2030.
This study was constrained by limited access to financial data at the farm, regional, and global levels. Future work should include collecting additional data on first costs and net profit per hectare.
Conservation agriculture is already a potent global force for climate change mitigation. Project Drawdown's model builds on this success, and projects evolution and improvement in the practice (in the form of regenerative agriculture) to keep it a critical agricultural mitigation strategy into the future.
 Determining the total available land for a solution is a two-part process. The technical potential is based on the suitability of climate, soils, and slopes, and on degraded or nondegraded status. In the second stage, land is allocated using the Project Drawdown Agro-Ecological Zone model, based on priorities for each class of land. The total land allocated for each solution is capped at the solution’s maximum adoption in the Optimum Scenario. Thus, in most cases the total available land is less than the technical potential.
 All monetary values are presented in 2014 US$.