INFLUENCE OF LAND-USE INTENSITY ON SOIL NEMATODE COMMUNITIES AND THEIR RELATIONSHIP TO RHIZOCTONIA SOLANI DISEASE SUPPRESSION

Abstract

ABSTRACT Soil organic matter (SOM) degradation linked to intensive management across PEI may negatively impact soil nematode communities and disease suppression. Soil nematode communities (Chapter 2), Rhizoctonia solani soil concentrations (Chapter 3), and soil properties were assessed across three land-use intensities (pasture/forest systems<four year grain rotations<three year potato rotations) from PEI field soils in 2018 and 2019. Nematode faunal indices were then tested for their ability to predict soils suppressive to R. solani disease in soybeans (Chapter 3). Nematode indices reflected degraded nematode communities in high intensity potato rotations, while the community as a whole responded to low intensity vegetation gradients. R. solani field soil concentrations were negatively correlated with several indicators of SOM content, while POM C and ACE protein were positively correlated regardless of environmental conditions. Although nematode faunal indices were not good indicators of R. solani suppressive soils, the fungivore Aphelenchidae was positively associated with hypocotyl disease ratings.