PS 20-23 - How soil health interactions contribute to nematode community in wheat-fallow cropping systems in northeastern Oregon

Abstract: Nematodes, though small creatures, can play a large role in soil ecosystems. Their feeding habits contribute to stability in soil food webs, influence plant growth and crop productivity, and can cause economic impact in agricultural systems. Plant parasitic nematodes, such as root-lesion (Pratylenchus spp.), deteriorate roots and reduce the efficiency of nutrient and water uptake, affecting crop yield. This study aims to analyze the interactions that exist between the nematode community and agricultural practices used in a semi-arid region of northeastern Oregon. Different fertilizer treatments (nitrogen (N), manure, pea vine) and residue-burning treatments (spring, fall burn) were studied in a wheat-fallow long-term experiment initiated in 1931 at the Columbia Basin Agricultural Research Center, located near Pendleton, Oregon. A control treatment of no fertilizer and no burning was also applied. We considered the entire nematode community and five trophic groups (root-lesion, fungal-feeding, bacteria-feeding, spiral, stunt) are present in sampled soil. We found that the abundance of each trophic group may be treatment dependent. Our results indicate that the abundance of root-lesion nematodes is related to N-fertilizers and spring burn treatments, the abundance of fungal-feeders is related to N-fertilizer treatments, the abundance of bacteria-feeders is related to no-burn treatments, and the abundance of spiral and stunt nematodes is related to pea vine and manure treatments. These treatments have direct effects on soil Total Carbon (TC), Total Nitrogen (TN) and pH and we obtained data for these variables from each treatment. We predict that changes in these soil health characteristics between treatments is what results in differences in the nematode community. These relationships demonstrate the role of soil health on nematode abundance and draw attention to the role nematodes could play in plant-soil interactions. Additionally, understanding these interactions can give insight into how field management practices influence plant-parasitic nematodes.