Macrofauna communities and their relationship with soil structural quality in different land use systems

Abstract

Context Soil structural quality (Sq) influences soil water dynamics, greenhouse gas emissions and plant productivity in natural and agricultural environments. Hence, assessing soil structural quality using simple methods is crucial to identifying potential impacts of different land uses. Aims Identify correlations between Sq and macroinvertebrate communities in seven land use systems (LUS). Methods Seven LUS were studied: native mixed ombrophylous forest (NF), native grassland (NG), native grass pasture (NP), Eucalyptus sp. plantation (EP, 20-years-old), no-tillage annual cropping (NT), integrated crop–livestock (ICL) and crop–livestock–forestry (ICLF). Each LUS had three plots and Sq and macrofauna community were evaluated. Sq was assessed through visual evaluation of soil structure (VESS) – a Sq score was assigned to each identified layer. Soil macrofauna were hand-sorted from each of these layers. Soil samples were taken in each LUS to describe selected chemical and physical attributes related to soil quality. Results All LUS had non-degraded soil structure quality (Sq ≤ 3); however, with differences in Sq among LUS mainly in deeper layers. The VESS showed better Sq in NF (1.53) and NP (1.85) compared to the other LUS, with highest Sq scores for ICL and NG. The NP had the largest macrofauna communities (12 183 ind. m−2), comprising mainly termites and earthworms, with taxa richness highest in NF. Conclusions Correlations between soil macrofauna (i.e. total density, termites and other groups) and Sq were observed, demonstrating that larger macrofauna populations were associated with better soil structural quality. Implications Biological indicators, like soil macrofauna, can be easily measured at low cost and linked to visual Sq, facilitating simultaneous assessment of soil physical and biological health.