The Impact of Agricultural Practices on Soil Organisms: Lessons Learnt from Market-gardens

Intensive agriculture practices have an important impact on soil biota, which can affect dramatically soil quality. In order to limit this impact, alternative agricultural practices are more and more applied. However, these practices are still in progress and thus, it is necessary to investigate their impact on soil activity. In this context, we studied the impact of agricultural practices (intensive and agroecological) in vegetable cropping systems in Guadeloupe. The first aim of this study was to identify practices developed in vegetable cropping systems and explain their level of eco-agriculture. We conducted a survey on the whole territory which gave us a better understanding of vegetable cropping systems in Guadeloupe. We selected a representative subset of 18 farms located on vertisols. The second aim of the study was to establish a typology of cropping practices in these vegetable cropping systems in vertisol. We performed a PCA and a HCA on the 18 farms. These methods allowed us to build a typology in which farms were distributed between two types. In type A, farmers are using intensive agricultural practices while in type B, farmers are using alternative agroecological farming practices. Then, we collected soil fauna, during the rainy season in type A and type B farms in order to demonstrate the relationship between cropping systems and the quality of soils proxied by biological indicators. We hypothesized that the use of synthetic fertilizers and herbicides in intensive agriculture affected soil fauna activity. The results showed no significant difference between soil fauna abundance in both types. However, the taxonomic richness and the abundance of litter transformers were higher in type B. Taxonomic richness and soil fauna functional diversity thus strongly depend on agricultural practices in vegetables cropping systems in Guadeloupe.