INFLUENCE OF DIFFERENT DEPTHS OF PLOWING ON THE PHYSICAL PROPERTIES OF A CLAY SOIL AT GUYENNE, QUEBEC

An experiment was initiated in 1955 to study the effect of plowing to depths of 6, 12 and 24 inches on the physical properties of a Guyenne clay soil. A 4-year crop rotation was established. Soil core samples were taken in 1957, 1959 and 1960 and determinations of bulk density and porosities were made. The soil particle-size distribution was determined for all tillage treatments in 1960.Plowing to a depth of 24 inches resulted in higher bulk density and lower non-capifiary porosity values in the surface 6-inch soil layer of soil than the 6- and 12-inch plowing. The 18- to 24-inch soil layer was less packed than the corresponding undisturbed layers at the same depth, as a result of deep tillage. The clay content of the 0- to 6-inch layer of soil was also increased by 24-inch plowing. Year-to-year data showed the importance of seasonal climatic conditions on the soil physical properties.