Determining the Al Tolerance and Optimum Soil pH of Winter Canola in the Southern Great Plains.

Abstract:

A growing interest in winter canola (Brassica napus L.) across the southern Great Plains has brought about many issues regarding production.  One of the issues to be addressed is winter canola’s tolerance of aluminum when growing on acid soils.  The objectives of this study were to determine the maximum aluminum concentration and minimum pH for canola production.  To evaluate this, a field experiment was conducted in north-central Oklahoma comparing 8 different winter canola varieties over a natural occurring pH gradient (ranging from approximately 4-6.5).  Yield will be measured in June of 2007 and 2008 and post harvest soil samples will be taken to determine the current year’s aluminum concentration and pH.  Canola grain yield decreased linearly below a soil pH of 5.8, which corresponded to a KCl exchangeable Al concentration of 18 mg kg^-1. Consideration will have to be given to soil pH in order to optimize winter canola grain yield in the southern Great Plains.