Crop rotation consists of the organization of the succession of crops on a given field. The rotation is organised in a regular cycle which can be more or less long. It is called biennial when two species are cultivated successively from one year to the next, triennial for three species, etc. In an agroecological perspective, it is considered that a crop rotation must be diversified in terms of cultivated plant families.
With a diversified crop rotation, pests and pathogens find it more difficult to find their host species (1). Also, heterogeneous growth periods of crops break the weeds’ development cycle. Finally, compared to a monoculture, a diversified crop rotation makes it possible to limit soil impoverishment. The presence of legumes in the rotation provides nitrogen to the soil (2). The different types of crop residues improve the structure and life of the soil and promote stock recovery of nutrients necessary to the plants. The complementarity between the root systems of the different crops also has a positive effect on the soil’s structure (3). Crop rotation therefore provides three types of benefits for the soil: biological (1), chemical (2) and physical (3).
In order to reduce the use of chemical inputs, the implementation of long-lasting and diversified crop rotations is encouraged through catch crops, the establishment of legumes, undersown crops, etc. The duration of the rotation and the species chosen depend strongly on the context. Consequently, setting up a crop rotation requires technical knowledge and high expertise. The benefits of a rotation are observable in the long term (5 to 10 years) but again depend on the context (economic, geographic, climatic…).
References to explore
Archambeau M. 2008. Rotation et salissement. Agriculture de conservation.com
Archambeau M. 2015. Agroscope de Changins : travail du sol, fertilisation et couverts végétaux. TCS n°83 – juin/juillet/août 2015.
Bonin L. 2014. Valoriser les rotations et les périodes de semis.
Moyen P. 2016. Rotation, agriculture. Encyclopædia Universalis.