Weed emergence patterns as affected by soil hydrothermal properties in eroded and rehabilitated landscapes

Authors: Schneider, Sharon; Sutradhar, Apurba; KORDBACHEH, FARNAZ - University Of Manitoba; GULDEN, ROBERT - University Of Manitoba

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/17/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The community composition and emergence timing of weed populations are critical to effective herbicide management. Soil water, heat, nutrients, and other factors influencing weed populations vary with topographic position and extent of erosion. In a 5-year field study, we evaluated the abundance, species richness, and emergence timing of weeds as affected by (a) year, (b) landscape position, and (c) soil-landscape rehabilitation treatment. Replicate plots were established in an eroded prairie landscape and six landscape positions were identified in each plot: crest, shoulder, upper backslope, lower backslope, footslope, and toeslope. The crest, shoulder, and upper backslope are areas of soil loss by tillage and water erosion; the footslope and toeslope are areas of soil deposition. Half of the plots were subjected to soil-landscape rehabilitation, in which 15-20 cm of soil were removed from positions of soil deposition and added to positions of soil loss by erosion. Plots were managed in a corn-soybean rotation with biannual tillage and conventional herbicide management. We monitored the abundance, community composition, and emergence timing of weeds in each of the six landscape positions along the crest-to-toeslope transect of each plot. This experiment was part of a larger experiment that evaluated a broad suite of soil properties at this site, including soil moisture and temperature. Weed seed banks were redistributed during soil-landscape rehabilitation, which affected subsequent community composition. Total abundance was affected by year, landscape position, and soil-landscape rehabilitation treatment. Species richness varied between years, but not between landscape position or soil-landscape rehabilitation treatments. Correlation and multivariate analysis are being conducted to evaluate relationships between weed emergence and soil hydrothermal conditions, soil nutrient status, and other factors. These results can be used to better predict the impact of climate change on weed dynamics and herbicide management.