Epigeal arthropod diversity in conservation agriculture and the ecosystem services it provides
Conventional agricultural practices, for example, deep ploughing and continuous tillage loosens the soil, disrupts soil structure and leaves the soil surface relatively bare without plant residues to protect it. Soil erosion and degradation are of major concern for most farmers. It is especially the loss of fertile top soils that results in reduced soil productivity in conventional farming systems. Conservation agriculture (CA) is a practice used to manage agro-ecosystems to enhance and sustain productivity while increasing profits and conserving the environmental resources. Farmers started to adopt CA by implementing minimum soil disturbance, crop rotation and retention of crop residues on the soil surface to combat soil deterioration brought on by conventional cultivation practices. One major threat that farmers perceive in adopting CA is the possibility that it may support pest populations by providing different habitats. Due to the lack of knowledge of the effect of CA on arthropod communities in South Africa, this study was conducted to generate information regarding the adoption of CA in the North-West and Free State areas. The aim of this study was to compare arthropod biodiversity and ecosystem services between CA and conventional farming systems. A passive sampling method, dry pitfall traps, were used to collect soil dwelling arthropods during each of the 2014/15, 2015/16 and 2016/17 cropping seasons. There was higher abundance and diversity of arthropods in CA systems and a positive relationship was observed between ecosystem services in terms of seed and pest predation and increased predator diversity in CA fields. CA systems therefore supported natural enemies by creating a more stable system that provided improved habitat conditions and necessary resources, compared to conventionally tilled fields.