Tracking the Tango Between Tillage, Soil Health, and Weeds: Progress Report 2021

This BIOAg project tests how reintroducing tillage affects soil health and weeds after long-term reduced disturbance in western Washington. Two randomized, replicated trials were established at the WSU Mount Vernon NWREC. Trial 1 compares continued no-till orchardgrass with a one-time spring tillage event followed by no-till. Trial 2 compares two tillage sequences (rototiller vs power harrow systems) in kale. The team measured soil hydro-physical properties (bulk density, penetration resistance, gravimetric water content, and saturated hydraulic conductivity), collected repeated soil samples for biological indicators (including PLFA microbial biomass/community composition), and monitored weed populations through seedbank sampling, in-season density counts, and seed production estimates for key species. Early results show one-time tillage reduced saturated hydraulic conductivity and water content and increased weed densities in the orchardgrass trial.