DOES COMPOST USE AFFECT MICROARTHROPOD SOIL COMMUNITIES?

A 20-year period of soil survey data highlighted the progressive loss of soil organic matter content in northern Italy agricultural lands. Because this trend is related to the decrease in the availability of manure obtained by zoo-technical activity, the national authorities have stimulated the use of compost in order to reduce the soil fertility loss. This study aimed to evaluate the effects of tillage activity, compost and manure fertilisation on soil microarthropod community. Samples were taken from a sorghum monoculture and a peach orchard over a five-year period from 2003 to 2007. The abundances of soil microarthropod groups were generally evaluated at order level. The Acari/Collembola ratio (A/C), Shannon diversity index (H'), evenness index (E), QBS-ar index and V index were also calculated. The peach orchard showed a higher share of typical steady soil organisms (Diplopoda, Diplura and Pauropoda) and QBS-ar scores compared with the sorghum monoculture, highlighting its suitable conditions for soil fauna. In the sorghum monoculture, tillage reduced Symphyla abundances and taxon richness, whereas the same effect on Acari abundances and QBS-ar values seemed to be lightened by compost fertilisation. Significant effects of compost use were observed only for Acari in the sorghum monoculture, and for Collembola and Diplura in the peach orchard. In all these cases abundance increases were noticed. Detrimental effects of compost on the density or diversity of soil microarthropods were not found in any of the tested cultivation typologies, supporting the use of these substances to add organic matter into soil.