Effect of agricultural management on soil nematode trophic structure in a Mediterranean cereal system

In the context of agrarian practices in organic agriculture, the use of organic amendments is considered a way to restore biodiversity in the edaphic environment. However, large differences may exist among the different organic amendments, according to their nature and degree of decomposition. The aim of this work was to compare the effects on the nematofauna of organic compost and conventional management, in a cereal–fallow–vetch crop rotation system, and to assess the utility of nematodes as an indicator of management changes in land use and soil conditions. Bacterial-feeders predominated in the nematode community, while the least opportunistic groups had a very low occurrence. Thus, the abundance models obtained for the nematofaunal trophic structure showed best fit to a logarithmic series. Fluctuations in the nematode populations were associated with seasonal variations characteristic of the Mediterranean climate. No statistically significant differences among the fertilization treatments included in the study were observed in our study, and thus the organic amendment did not lead to any change in trophic diversity. For the rehabilitation of agricultural soils that have progressively lost a great part of their biodiversity, adequate management of the organic matter is required, introducing a source of energy to allow the functioning of the edaphic system, and thereby restoring the lost biological diversity.