Weed emergence patterns in eroded and rehabilitated landscapes

Authors: Sutradhar, Apurba; Amundson, Gary; GULDEN, ROBERT - University Of Manitoba; Schneider, Sharon

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/29/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Soil erosion is a major environmental issue that significantly affects soil properties, crop productivity, weed emergence patterns, and weed growth. Spatial variability in emergence timing, weed seed production, seed viability, herbicide bioavailability, and other factors in an eroded landscape make weed management strategies complicated. Reversing soil erosion by replacing translocated topsoil (soil-landscape rehabilitation) is one method to improve crop productivity of severely eroded land, but bulk movement of soil changes soil properties and weed seedbank that influence weed emergence patterns and growth. Here, we report changes in weed communities in response to soil movement within a hilly landform. Six replicated strips were established that extended from the upper slope to the lower slope positions. Each strip was segmented into six landscape positions designated as crest, shoulder, upper backslope, lower backslope, footslope, and toeslope. Soil-landscape rehabilitation was performed on three strips by moving 15 cm of accumulated topsoil from the lower slope and adding it to the upper slope positions. Adjacent plots were left in their eroded condition. Weed density and species richness were monitored for four years in two 0.5 x 0.5 m quadrats per plot at 3 to 7 days intervals. In the upper slope positions, weeds were dominated by annual grasses, and were highest in the most eroded landscape positions. Improving soil characteristics for crop growth by moving soil within the landscape did not result in higher weed density where soil was added. The density of weeds was lower where soil was removed in the first two years after soil movement, likely through removal of weed seeds with soil. Within three years of soil movement, weed abundance and species richness were the same in areas of soil removal and no soil removal. Bulk soil movement within an eroded landform to improve productivity did not worsen weed issues.