The decrease in food resources for farmland birds in Deux-Sevres (France) is related to the decrease in grassland cover in agricultural landscape, and also to intensive management of alfalfa grasslands. Grasshoppers are among the major invertebrate inhabitants in grasslands and are central resources in the trophic network. Previous studies have shown that grasshopper abundances in alfalfa crops were rather low in the study area (intensive farmland in the south of the city of Niort in Deux-Sevres) compared with other grasslands. In this study grasshopper abundances in alfalfa crops were investigated in relation to plant community structure and grassland management. The effectiveness of agri-environmental agreements in enhancing grasshopper abundance was evaluated. Results suggested that an extensive management of alfalfa crops (no pesticides and no cutting from the end of May to the end of August) enhanced grasshopper abundance and plant species richness. Plant community structure in alfalfa (number of plant species, number of botanical families, Shannon index) was linked to grasshopper abundance.