Researchers have analyzed the likelihood of higher yields in conservation agriculture compared to conventional agriculture. This farming practice could be more resilient to global warming by 2050, especially for corn and in arid regions.
Conservation agriculture limits water and wind erosion and also improves soil carbon storage. It is sometimes the subject of scientific controversy and has been accused of reducing yields. A study by researchers from AgroParisTech and INRAE, published in the journal Nature Climate Change, showed that conservation agriculture often works well for growing crops in areas of high water scarcity. The productivity of this farming system may also be more resilient to future climate change than conventional plow-based agriculture.
This study is based on a synthesis of research articles published between 1983 and 2020. The first task of the researchers was to select articles analyzing farming systems that followed the three main rules of conservation agriculture. These are no-tillage, crop diversification (at least three different crops must be planted in succession), and, finally, the maintenance of permanent soil cover.
Eight different crops were studied: wheat, corn, barley, sorghum, rice, cotton, sunflower, and soy. The originality of this study lies in the fact that it analyses the productivity of conservation agriculture at the global level. The researchers not only studied the current impact of this practice on yields but also made projections taking into account climate change up to 2050. The data were processed using artificial intelligence models. These allowed us to model the likelihood that conservation agriculture would give better yields, rather than the difference in yields compared to conventional agriculture. “We tried to build quantitative models, but they didn’t work when we tried to make predictions about the future climate,” explains Benoît Gabrielle, professor, and researcher at AgroParisTech. It is easier to predict the likelihood of an increase or decrease in yields, and we managed to validate our model.
Better yields in arid regions
The work shows that in arid and water-scarce regions, better yields can be achieved through conservation agriculture. These regions are in north Africa the southern part of Europe and the western and southern parts of the US. The explanation is quite simple,” says the scientist. Conservation agriculture allows more organic matter to be retained in the soil, making it more water-retentive and therefore more available for crops.
The study showed that in 60% of wheat-growing areas in temperate climate zones, yields increase thanks to conservation agriculture. Climate change by 2050 will have little impact on this trend, with a probability of change ranging from -10% to +10%, depending on the region of the world considered. However, for corn, the impact is more visible. The increase in yields applies to three-quarters of the world’s current agricultural land, irrespective of climatic zone. As the climate changes, the likelihood of yield increases further, up to 20% in tropical areas. “In temperate regions of our hemisphere, corn is sown in April and harvested in October or November. It, therefore, grows mainly in warm weather when there is less water. The fact that conservation agriculture allows better water retention in the soil is a benefit for this crop. This agronomic practice is a good way of adapting crops to climate change, especially corn.
Research has also highlighted the impact of good agronomic practices on yields. In addition to following these three basic rules, conservation agriculture is made even more productive by fertilizing the soil and protecting plants from weeds and diseases.