← Elaine Ingham · Research and publications
When food declines, predators change too
An experiment in a Georgia no-tillage system showed how interventions in microbial groups affect soil feeding relationships.
Study published:
The experimental intervention
Researchers used streptomycin and captan to reduce groups of microorganisms. Streptomycin reduced bacterial populations. Captan reduced fungal activity and total fungal biomass. [1]
Consequences through the food web
Fungal reduction was followed by a temporary decline in fungal-feeding nematodes as their food diminished. Plants died within 2–4 weeks in the streptomycin treatment, which the authors interpreted as an indirect effect mediated by bacteria. [1]
Relationships give numbers meaning
A population decline may reflect a change in its food supply. Monitoring several groups together helps explain these dependencies and avoids rushed conclusions from a single indicator.
Implications for management
The work shows why assessing an intervention requires a wider view of soil. Microorganisms, their consumers and roots share a system whose responses may emerge at different times.
Sources and references
- Ingham, E.R., Parmelee, R.W., Coleman, D.C. & Crossley, D.A. (1991). Reduction of microbial and faunal groups following application of streptomycin and captan in Georgia no-tillage agroecosystems. Pedobiologia, 35, 297–304. DOI: 10.1016/S0031-4056(24)00070-2 Original publication and study record