Impact of Wheat Cropping Systems and Nitrogen Fertility on Nematode Community Structure.

Nematodes occupy a central position in the soil food web, occurring at multiple trophic levels and potentially providing useful insights into the structure and function of the soil food web. Limited data is available on nematode community structure in cropping systems of the semiarid Northern Great Plains (NGP). Our objective was to determine how nematode community structure was affected by wheat cropping systems and nitrogen level on a 14-year-old rotation study. We compared 7 no-till treatments (wheat-chemical fallow, continuous wheat, wheat-lentils, wheat-cover crop-pea hay, wheat-herbicide terminated cover crop-pea green manure, organic wheat-lentils, and former Conservation Reserve Program converted in 2013 to wheat-lentils) and a tilled wheat-fallow treatment. Each treatment, except for the organic system, had a high and low nitrogen level split plot factor. We hypothesized that cropping systems which exclude fallow and tillage would positively impact the nematode community which, in turn, would self-regulate PPNs. Nematode community structure was compared amongst treatments using maturity, plant parasitic, structure, and enrichment indices as well as species total, richness, and diversity composition for year 14 of the study. Nematode faunal analysis was performed to assess relative disturbance and resource availability.