Influence of Agricultural Inputs on Earthworms in Kérou and Banikoara, Bénin

The biological quality of soils in agriculture refers to the abundance, diversity and distribution of living organisms and their participation in soil biological activities. The present work is part of the ecotoxicological risk assessment of agricultural inputs on the earthworm community and therefore its biological quality. The work was carried out in three villages of the communes of Kerou and Banikoara in North Benin.The methodology consisted of enumeration of the earthworm community and the trace of elements in their flesh. Nine 1-m² plots were placed in each study field. In a second step, ecotoxicological analyzes were carried out on some earthworms taken from the different sites. After analyzing the collected data, it appears that the site 1 which is a cotton field receiving mineral and organic fertilizers has an abundance and a high ecological diversity of earthworms compared to sites 2 and 3 which receive only mineral inputs. In addition, ecotoxicological analyzes showed a high presence of nitrogen, phosphorus, potassium, nitrate and ammonium in the earthworms of sites 2 and 3 compared to site 1. It has therefore been proven in this study that the use of nitrogen fertilizer in the intense cotton crop disturbs the earthworm community.