Short canola rotation

[Ron]

how short can you push the new canola varieties. no blackleg in area. Schlerotinia rampant last year. Thinking of can/wheat/can to get perenial weeds under control with rup varieties. there is more money in $6.00 canola than $2.00 barley. (actually I will be happy if there is any money in it)

[mhartman]

A canola-wheat-canola rotation will create a moderate risk of yield reduction due to diseases like blackleg, sclerotinia,alternaria, seedling disease complex. The level of risk will depend on the amount of disease in the canola crop 2 years ago. A reasonable guess would be a 10% yield reduction if disease wasn't a problem 2 years ago. However, DON'T push a short rotation in hopes of getting perennial weeds under control with Roundup Ready varieties. Remember, perennial weeds are not controlled well by in-crop herbicides because the sap flow is mainly FROM roots at that stage. Good perennial control by herbicides need sugar flow and thus herbicide transport INTO the roots. A far more effective timing for perennial weed control is pre-or post-harvest due to increased flow of the herbicide into the root buds. So keep your rotation in better balance and use pre-harvest glyphosate to combat the perennials.