Exploring the relationship between key soil health indicators and nematode community composition in agroecosystems

Abstract:

Soil health has gained prominence in recent years because of its close association with ecosystem function and crop productivity. New soil health indicators including rapid respiration, permanganate oxidizable carbon, and soil protein have become increasingly popular due to their ability to reflect important nutrient cycling processes while also being very sensitive to changes in management. However, several questions remain regarding how these new soil health metrics are related to biological activity in the soil, especially in terms of soil food web structure and function. This study utilizes two identical long-term trials located in the Midwestern part of the United States with contrasting soils to assess the relationship between key soil health metrics and nematode community composition. The trial is a randomized complete block design with three replicated blocks. The main factor is tillage and the sub-factor is rotational diversity. Nematode community assemblage was most diverse in the no-till corn-alfalfa rotation relative to the other systems. Rotation had little effect on nematode community assemblage in the chisel tilled systems, demonstrating that soil disturbance influences nematode community structure more so than rotation. No-till substantially increased all three soil health indicators at both sites, but the magnitude was greatest at the clay site relative to the sandy site. The corn-alfalfa rotation significantly increased mineralizable C relative to continuous corn and the corn-soy rotation. Correlation analyses demonstrated that there was a weak but positive correlation between nematode diversity and mineralizable C, which demonstrates the important linkages between nematode community composition and soil health.