Perennial grain cultivation promotes functional nematode diversity in soil

Perennial cropping systems are known to highly support soil fauna and its diversity. This has already been investigated for grassland and bioenergy systems. Recently, perennial wheat (Kernza®) is increasingly recognised throughout European agriculture. However, the detailed impacts of perennial grain on soil functioning are not well investigated yet.

Within the EU-Biodiversa project NAPERDIV nematode communities, among other research areas, were investigated in a Pan-European transect from South France to Belgium to South Sweden representing a climatic gradient from south to north and variations in soil conditions. Additionally, two soil depths (5-15 cm; 25-35 cm) were investigated.

In total, nematodes from 31 families were identified, with the perennial cropping system having a greater number of taxa and biomass. Additionally, this cropping system was characterised with system stability and food web complexity due to greater proportions of predators and  omnivores and a higher maturity index, channel index and structure index as compared to annual wheat. In contrast, the enrichment index was highest in the annual cropping system, representing nutrient enrichment and rapid responses of opportunistic nematodes. Nematode diversity was greater for the upper soil depth.

In summary, nematode communities mainly reflect the impact of land-use, tillage, fertilisation, and soil organic matter on their feeding behaviour. The promotion in diversity for the perennial cropping system for all study sites shows that differences in soil and climate conditions do not interfere with the beneficial effects of perennnial wheat.