Soilborne nematodes as bioindicators of soil health in cropping systems: a systematic review
Simamkele Makeleni, Alen Manyevere, Chuene Victor Mashamaite, Ndivhuwo Ramatsitsi
Abstract
Agricultural intensification is widely adopted to meet the rising global population and increasing food demand. However, it poses a significant threat to the achievement of Sustainable Development Goal 15, Life on Land, due to the negative impacts on soil health. As the most abundant soil metazoans, nematodes have been used as a tool for assessing soil health and quality. This systematic review assessed how conventional agriculture (CTA) and conservation agriculture (CA) affect nematode population density and diversity, and the role of nematodes in improving soil health. A search on various databases yielded 1809 records, of which 36 articles met the inclusion criteria, with most studies in China, the U.S.A. and South Africa. Practices associated with CTA were shown to increase plant-parasitic nematodes (PPN) including Meloidogyne, Rotylenchulus and Pratylenchus. Conversely, CA practices were reported to increase abundance and diversity of free-living nematodes (FLN) including Cephalobus, Eucephalobus and Rhabditis. Soil physicochemical properties also affect the abundance and diversity of nematodes. Several papers reported that crop rotation, cover cropping and no-till promote soil health whilst suppressing PPN and promoting FLN. This review can be used as a guide to develop cropping systems that improve crop output while reducing the negative effects of destructive nematodes.