Crop Management Strategies Shape the Joint Temporal Dynamics of Soil Food Web Structure and Functioning
Résumé
The hidden world of the soil biota has been increasingly investigated in the last decades revealing the importance of soil organisms’ networks for soil functioning. Here, we use a modeling approach to investigate how changes in cropping practices influence the structure of soil food web over time and how such dynamic relates to that of soil functioning. In an experimental trial, we tested for change in topsoil food webs after shift from conventional to alternative practices (changes in tillage intensity, amount of residues returned and N fertilization rate). Samplings were made in 16 plots of a randomized complete block design during spring of year 0, 2 and 4 after the onset of the trial. Microorganisms, microfauna, mesofauna and macrofauna were sampled, identified and grouped into trophic groups. We built a general soil food web describing plausible carbon flows between these trophic groups. We modeled the food web in each sampling plot and computed several network indices. At the same dates, soil functions linked to C and N dynamics were measured from soil samples. We used a COSTATIS analysis to investigate relationships between temporal sequences of soil functions and soil food web indices. This study shows that soil food web structure and soil processes related to N and C cycling co-vary following changes in agricultural management practices. Management practices related to tillage exerted stronger effects on soil food web functioning than those related to the export of crop residues or reduction in mineral N fertiliser. Our results provide new insights on soil food webs temporal dynamics, within a restricted panel of agricultural practices.
Auteurs, date et publication :
Auteurs Mickaël Hedde , Valérie Coudrain , Pierre-Alain Maron , Matthieu Chauvat , Nathalie Cheviron , Flemming Ekelund , Christian Mougin , Bruno Mary , Sylvie Recous , Cécile Villenave , Elisa Thébault
Date : 2023