Crop diversification: a key to agriculture that is less dependent on pesticides

Illustration Crop diversification: a key to agriculture that is less dependent o
Illustration Crop diversification: a key to agriculture that is less dependent on pesticides INRAE - Brigitte Cauvin
A major breakthrough has been unveiled in Nature Communications, revealing the results of an in-depth study on the beneficial effect of temporal crop diversification in reducing pesticide use in France. These results, based on a detailed analysis of more than 14,000 observations, pave the way for an in-depth understanding of the links between temporal crop diversity and dependence on pesticides, be they fungicides, insecticides or herbicides.

Crop diversification is emerging as a cornerstone in the transition to sustainable agriculture. Researchers from INRAE and the Institut Agro Dijon have examined the link between the diversity of crop sequences in arable field crops and pesticide use across a very wide range of farming systems and climatic contexts. A relationship little explored to date at this scale.

Their results, based on an analysis of 14,556 observations of a given crop a given year, in 1,334 cropping systems in France, reveal that temporal crop diversification significantly reduces pesticide use for most crops. This analysis was carried out for total pesticide use, as well as by type of pesticide (fungicide, insecticide, herbicide), for the 16 main crops in France.

For example, increasing the number of botanical families (e.g. Poaceae such as cereals, Fabaceae such as legumes and Brassicaceae such as crucifers) from 1 to 4 reduces pesticide use by 19% to 23% for crops such as soybean, beetroot, sunflower and maize. Increasing average number of crops per botanical family reduced pesticide use by a further 14% to 37% for maize, winter pea, oilseed rape and potatoes. On the other hand, these effects are more nuanced for straw cereals, for which no specific effect of diversity was observed. Interestingly, the study also suggests that cover cropping does not contribute to a reduction in the use of pesticides, but rather to an increase in the use of herbicides.

The researchers highlight the importance of adopting a holistic quantification of diversity, taking into account the diversity of botanical families and intra-family diversity (e.g. wheat, barley, oats, rye for cereals; spring pea, faba bean, lupins and lentils for legumes), in order to guide agricultural practices towards a significant reduction in pesticide dependency.

These results mark a crucial stage in the search for more sustainable farming systems, highlighting the essential role of crop diversity in reducing pesticide use.

A NETWORK TO MEET THE CHALLENGEs

The study is based on 14,556 crop management sequences in 1,334 cropping systems of the DEPHY farm network, spread across the whole of mainland France, and described during the period 2010-2022. The study therefore makes the most of the wide diversity of farming practices observed in the network, depending on the region, the year and also the individual strategies of each farmer. The pesticide use indicator selected is the treatment frequency index (TFI), which takes into account the number of treatments, the doses applied and the proportions of surface area treated. The diversity of crop sequences in each cropping system is characterised by the diversity of botanical families and intra-family diversity.

Reference

Guinet M., Adeux G., Cordeau S. et al. (2023). Fostering temporal crop diversi fi cation to reduce pesticide use. Nature Communications 14:7416, ’023 -43234-x

Ma Guinet researcher at Institut Agro Dijon Agroecology joint research unit

Guillaume Adeux INRAE RESEARCHER Agroecology joint research unit