How Extending Rotations Can Pay Dividends. Three crops (canola, CWRS wheat & soybean) make up the lion’s share (nearly 3/4) of annual crop production in Manitoba. There are more than a dozen other crops, which are adapted here, that could be used to lengthen rotation intervals. But why do that? As farms grow and evolve, it might be easier to keep things simple. Does it make economic sense to seek greater diversity in crop selection? Crop rotation is a fundamental aspect of managing crop pests, weeds and diseases. This talk will explore the place of rotation intervals in designing strategies and coping with the top disease threats to “the big three.” We’ll also cover some of the major disease issues in those other crops.