Posted 11/3/2006 09:44 (#57692 - in reply to #57618) Subject: RE: Variable Rate Lime, P,K
West-Central Illinois
I believe that you may on target with your thinking that the eroded soils may require more N. The reasons that you stated later regarding lower OM makes good sense. The only caution that I would make is that these soils probably also have a lower yield potential, so fertilizing by soil type (mapping unit) may get you even closer.
Illinois and Iowa are collaborating on a "new" method for determining N needs. Although it is strictly based on economics, the research supports your idea in that on the lower OM soils in Southern IL, where productivity is relatively low, more N is required than on the deeper prairie soils of Central Illinois.
Variable Rate Lime, P,K
