Restoring biodiversity through crop mosaics
The mosaic of crops corresponds to the alternating arrangement of different crops on the farm at the landscape level. A mosaic of crops combined with a diversity of land management spread across the entire territory allows the preservation of biodiversity throughout the year[1]. In line with the specificities of the farm, it may be interesting to rethink the distribution and alternation of crops in space without necessarily losing productive area [2]
Objective
The mosaic provides a set of varied resources: food, cover, nesting sites for wildlife on the territory [3]. The alternation of crops combined with long and narrow plots are key elements in preserving entomofauna and birdlife [4]. Indeed, these factors increase the number of interfaces between different environments [5]. One of the benefits of this measure is to limit disturbances related to fieldwork. This lever can be combined with the addition of other land management.
Expert opinion
"The diversification of the crop mosaic is an essential element to restore biodiversity in cultivated agricultural areas. Not only does it help preserve many species, but it also ensures the production of ecosystem services provided to both the farmer and society." François Omnès, Deputy Director of the Actors and Citizens Department at the French Biodiversity Office.
Expected benefits
Throughout the year, each crop provides a different type of cover necessary for small wildlife. The edges of winter cereal fields will be very good cover for ground-nesting birds, such as the grey partridge[6] or the skylark[7]. These species frequent these areas from March (pairing period) to harvest (breeding period). Then, spring crops of industrial type (sugar beet, potato, vegetables…) or maize provide refuge cover for the young after the cereal harvest until their harvest in autumn. Then, catch crops take over once all the crops have been harvested. Once the green manure is destroyed, rapeseed takes over during winter (January to March). For flying insects (ladybugs, bees…), the diversity of environments (crops and land management) provides a diversified food resource spread throughout the year.
Seasonal evolution of space use and crop use by biodiversity
For example, in February it is the hazel that offers this resource, in March the blackthorns, in April the rapeseed and in July/August the sunflowers. A diversity of flowering spread throughout the year favors a great diversity of pollinators[8] but also beneficial insects such as ladybugs or hoverflies. The latter need nectar and pollen [9] to lay eggs and regulate pest populations. For ground-dwelling entomofauna (such as ground beetles), the immediate proximity of these different crops is necessary, as they cannot move more than 80-90 m from the edge [10]
Photo credit: Hubert Compère
Expert opinion
"Each crop will favor its own set of insects, so the more diversified the patchwork, the more diversified the insect populations will be. Likewise for birds, insects move from crop to crop throughout the seasons each time towards the crop where there is the most food resource." Véronique Tosser, Biodiversity Project Manager at Arvalis Plant Science Institute.
How to implement this practice on my farm?
Alternate a winter cereal with another crop grown on the farm while avoiding the formation of large blocks of the same crop. For grouped plots, it is recommended to divide plots into long and narrow strips using a multiple of the widest tool present on the farm to create islands between 150 and 200 m wide. Implementing crop alternation on large narrow plots is relevant and as effective for biodiversity as reducing plot size.
Limitations
Potential costs amount to 10% additional time compared to the time spent on field edges[11]
Feedback from the Agrifaune network: Crop mosaic in the Comté area
The plateaus of Haut Doubs are characterized by large expanses of meadows. This ultra-grassland context is explained by the AOC Comté specifications, which exclude maize silage from the diet of dairy cows. This grass monoculture favors cyclical outbreaks of vole populations, economically impacting farms. To limit populations, farmers resorted to cultivating old meadows that were too infested. They then planted cereal mixtures for 2 consecutive years to diversify the environment and disrupt voles. Cereal mixtures are used as concentrate in dairy cow feed. These cultivated plots also favored the entire small fauna present in these areas. (Agrifaune 25)
Alternation between different wheats with a future spring crop. Photo credit: Charles Boutour
Advice
This practice is recommended for grouped or contiguous plots.
For dispersed plots, it is recommended to engage in dialogue with neighboring farmers to discuss implementation at the territorial scale. When implementing crop alternation, ensure that the return times of the same crop on the plot correspond: the crop rotation times.
To go further
It is possible to add land management between different crops. This further increases the interfaces between different environments. (See Land management favorable to beneficial insects and biodiversity and Organizing plots to increase edge effect).
Sources
- ↑ Sirami C. et al ; 2019, Increasing crop heterogeneity enhances multitrophic diversity across agricultural regions, Proceedings of the National Academy of Sciences, INRA
- ↑ Hendrickx F. et al ; 2007. How landscape structure, land-use intensity and habitat diversity affect components of total arthropod diversity in agricultural landscapes, Journal of Applied Ecology, n°44, p340–351.
- ↑ Bro E. et al. ;2007. Wildlife in cultivated environments, How to manage small game and its habitats, National Hunting and Wildlife Office, 79p
- ↑ Alignier A., Solé-Senan X.O., Robleño I., et al. ; 2020 Configurational crop heterogeneity increases within-field plant diversity. J Appl Ecol. 57:654–663.
- ↑ Bro E. ; 2016. The Grey Partridge. Biology, ecology, management and conservation. Biotope, Mèze, 304p
- ↑ Reitz F. & Mayot P. ; 1997. National grey partridge study: first report. Bull. Mens. ONC n°228 : 4-13
- ↑ Eraud C. ; 2002. Ecology of the Skylark Alauda arvensis in Cultivated Environments, Ecological Characteristics of the Habitat and Conservation Perspectives, Thesis of the Ecole Pratique des Hautes Etudes, ONCFS, Ministry of National Education, Research and Technology, p168.
- ↑ Perovic D. et al. ;2015. Configurational landscape heterogeneity shapes functional community composition of grassland butterflies. J. Appl. Ecol. 52, 505–513.
- ↑ Villenave-Chasset ; 2017. Functional biodiversity, Crop protection and wild beneficial insects, La France Agricole, 148p
- ↑ Collins K.L. et al. ; 2002. Influence of beetle banks on cereal aphid predation in winter wheat, Agriculture, Ecosystems and Environment n°93, p 337–350.
- ↑ Omnès F. et al ; 2011, Territory management, reconciling quality production, environment, biodiversity and landscape on the farm. 4p
Annexes
- Redirect Modèle:Pages liées
