The Conservation Tillage Productivity Centre is in its final year of activity and has completed its seventh year of the Rotation X Tillage study at Minto, Manitoba. This paper will illustrate the significance of some of the findings. The success of a farming operation can be looked upon using the barrel stave example of limiting factors. An illustration of the principle of limiting factors. The level of water in the barrels above represents the level of crop production.
Water is represented as being the factor that is most limiting.
Even though the other elements are present in more adequate amounts, crop production can be no higher than that allowed by the nitrogen. Zero tillage offers the cheapest and surest way to increase available water in most of the prairie region. Considering reduced evaporation in fall and spring plus reduced runoff of heavy rainfall the extra moisture available under zero tillage cropping conditions can be substantial. From practical experience on our own farm at Minto, we believe zero tillage offers a true yield advantage in approximately 7 out of 10 years when compared to conventional tillage due to this moisture advantage. In 1 or 2 years out of 10 there will probably be no difference in yield due to ideal moisture conditions and in the other 1 or 2 years out of 10, zero tillage may have a slight disadvantage due to excessive moisture.