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Updated: Aug 5, 2026

Investigation of Plant Interactions Across Common Mycorrhizal Networks Using Rotated Cores
Published on: March 26, 2019
Earthworm effects on plant growth-defence relationships covary with rhizosphere multitrophic associations under low
Nan Jin1, Zhenggao Xiao2, Yan Du1
1Soil Ecology Laboratory, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China.
Abstract:
Growth and resistance are fundamental components of plant health impacted by soil biota and nutrient availability. While aboveground responses to nitrogen (N) availability are increasingly studied, how soil macrofauna modify plant growth and defence across field N-availability gradients remains unclear. Through a field experiment manipulating earthworm occurrence across a straw-quality-mediated N-availability gradient, we show that earthworm effects on plant performance were associated with rhizosphere cross-trophic association complexity (CTC), a composite index of co-occurrence links among trophic groups. Decreasing N availability shifted plant allocation from growth towards defence. Under N-replete conditions and high N availability, earthworms did not affect plant defence traits but reduced shoot and root biomass, respectively. Conversely, earthworms reduced Helicoverpa armigera growth under intermediate N availability and increased shoot biomass by 16% without weakening jasmonate (JA)-mediated defence under low N availability. Earthworms increased CTC only under intermediate and low N availability. This complexity correlated positively with soil mineral N under both conditions, and with leaf JA and shoot biomass under intermediate and low N availability, respectively. Our results suggest that N availability modulates earthworm effects on plant growth and resistance alongside changes in multitrophic association complexity, highlighting a novel soil fauna-plant health framework for lower input crop management.
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