| In 1991, a project was initiated at Quinn and Ormstown, two sites with soils representative of Quebec's present-day agriculture. Three field management techniques were studied related to their possible impact on the soils: tillage, rotation, and N fertilization. The three treatments were randomly assigned in two blocks of a split-split-plot design. The main treatment, tillage, had two levels, conventional tillage (CT) and no-till (NT). The sub-treatment was represented by five 4-year rotations, starting from 1991 as follows: CCCC (continuous corn), CSAC (corn-soybean-alfalfa-corn), CSCS (corn-soybean-corn-soybean), SCSC (soybean-corn-soybean-corn) and SSSS (soybean monocrop). The third factor was N fertilization, at three different rates: 0, 90, and 180 kg/ha, excepting the continuous soybeans which received lower rates of, respectively, 0, 20 and 40 kg N/ha. Soil sampling was performed in 1994, during the last year of the 4-year rotations, at two different moments over the growing season, June and August, for all analysed soil properties, except aggregate stability and organic matter for which samples were taken only in September. (Abstract shortened by UMI.)... |
