An investigation of the effects Ca:Mg ratio on plant nutrient uptake and yield in cotton is being conducted at the University of Missouri—Delta Center, Portageville, Mo. Different rates of gypsum (CaSO4) and epsom salt (MgSO4) were applied to plots to create Ca:Mg ratios ranging from 3.8 to 11.7. Soil samples were collected and analyzed prior to and after the growing season. Cotton tissue was tested for nutrient content at first square, first bloom and first open boll. Results from 1999 showed that soil Ca:Mg rations did not have a significant effect on potassium or micronutrient uptake. Cotton yields were not significantly different between treatments.