A review of soil nematodes as biological indicators for the assessment of soil health

Abstract

Healthy soils are essential for sustainable agricultural development and soil health requires careful assessment with increasing societal concern over environmentally friendly agricultural development. Soil health is the capacity of soil to function within ecological boundaries to sustain productivity, maintain environmental quality, and promote plant and animal health. Physical, chemical and biological indicators are used to evaluate soil health; the biological indicators include microbes, protozoa and metazoa. Nematodes are the most abundant metazoa and they vary in their sensitivity to pollutants and environmental disturbance. Soil nematode communities are useful biological indicators of soil health, with community characteristics such as abundance, diversity, community structure and metabolic footprint all closely correlated with the soil environment. The community size, complexity and structure reflect the condition of the soil. Both free-living and plant-parasitic nematodes are effective ecological indicators, contributing to nutrient cycling and having important roles as primary, secondary and tertiary consumers in food webs. Tillage inversion, cropping patterns and nutrient management may have strong effects on soil nematodes, with changes in soil nematode communities reflecting soil disturbance. Some free-living nematodes serve as biological models to test soil condition in the laboratory and because of these advantages soil nematodes are increasingly being used as biological indicators of soil health.

Impact of Super-High Density Olive Orchard Management System on Soil Free-Living and Plant-Parasitic Nematodes in Central and South Italy

“…Nematodes were extracted by the cotton-wood filter method and identified to the genus or family level as described by Landi et al [ 17 ]. Soil nematode communities and their relationships with soil properties were investigated based on the following population parameters: (i) abundance of nematode taxa at the family level, (ii) ratio of obligate plant parasites (Pp) to bacterivores (B) and fungivores (F) (Pp/(B+F)) [ 27 ], (iii) maturity index [ 28 ] and the food web indicators (BI, basal index; EI, enrichment index; SI, structure index; CI, channel index) according to Ferris et al [ 14 ], (iv) diversity-weighted abundance based on nematode biomass (θ) and arranging soil nematode population on a functional basis into detritivores (bacterial and fungal feeders), plant-parasitic nematodes, and predators (including omnivores) [ 29 , 30 ], and (v) prey-to-predator θ mass ratio to evaluate regulation function [ 17 , 30 ].…”

Effects of fertilizer and weed species richness on soil nematode community in a microcosm field experiment

“…The effect of plant species richness on the soil nematode community depended on experimental duration (Eisenhauer et al, 2012). Soil nematodes contribute to nutrient cycling and have important roles in the soil food web as consumers at various levels (Lu et al, 2020). Compared to weed species richness, NPK fertilizer may have more effects on abundance and community structure of soil nematodes, which are ascribed to the high nutrient content in the soil resulting from use of fertilizer.…”

Efficiency of Penicillium canescens in Dissipating PAH in Industrial Aged Contaminated Soil Microcosms and Its Impact on Soil Organic Matter and Ecotoxicity

“…The use of free-living nematodes (principally C. elegans) for evaluating soil toxicity is just the beginning especially for organic pollutants. The advantages of C. elegans are a short lifespan, simple and inexpensive cultivation (300-350 eggs per nematode), and a rapid response to environmental change [34]. C. elegans can be used to rapidly assess chemical toxicity, with soil pollutants inhibiting C. elegans growth and reproduction [35].…”