Agriculture based on three main agronomic principles applied simultaneously: direct sowing without any soil tillage, permanent (plant or organic) soil cover and diversification of crop rotation. The main objective of this combination of principles is to reduce soil degradation and, ultimately, improve fertility by intensive use of biological and ecological processes of the soil ecosystem, intended to replace certain inputs. Issues of wind and water erosion in the United States and Brazil led to this evolution of agriculture. The spread of these practices has been relatively slow in France.

Each principle is comprised of a set of practices. However, conservation agriculture doesn’t limit itself to the addition of practices, indeed there are interactions between components of the system. For instance, the diversification and lengthening of crop rotation, paired with the establishment of intermediate crops, aim at reducing weeds and other pests. This thus makes it possible to reduce phytosanitary inputs and, eventually, nitrogen fertilizers if the cover crops together with cash crops contain legumes. The other main benefits brought by conservation agriculture are reduction of worktime and  fossil energy consumption per hectare, improvement of soil biological activity, increase rate and sustainable management of organic matter, reduction of erosion and limitation of soil evaporation. Conservation agriculture requires greater technical competence than needed for tillage, in order to ensure good seeding and crop emergence.

The systems encountered in conservation agriculture are very varied as the choice of practices is made according to the characteristics of the production situation (soil climate, socio-technical context…). In addition, the principles are often partially applied, corresponding most of the time to transition stages, which increase this diversity.

Conservation of soil living organisms falls within the preservation of biodiversity and the maintenance of soil fertility, which are principles of agroecology.