Is the effect of tillage on the vertical distribution of the weed seeds similar in all soil types?
It has been established that soil physical properties that influence freezing and thawing, rates of drying, and surface cracking can affect vertical distribution in the soil. Very few studies however, have looked at the affect of tillage systems on the vertical distribution of the seeds in different soil types. Evidence exists that tillage type has differential effects on seed depth across different soil types. We present here examples of the vertical distribution of weed seeds in a loamy sand soil, silt loam soil, clay loam and a clay soil in Ontario and southwestern Quebec. Under a moldboard plow system, 12% of the seeds are present in the top 5 cm of the loamy sand soil as compared to 37% and 46% in the silty loam and the clay soils (Figures 1, 2, and 3). Therefore, more seeds may be brought to the surface in sandy soils than in other soil types when they are inverted by a moldboard plow. In the sandy soil, the depth of burial of the weed seeds in the soil profile increased as the d
