An investigation of the effects Ca:Mg ratio on plant nutrient uptake and yield of 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. In 2000, a second experiment was initiated on an acid soil to investigate the effects of Mg content in liming material. In both experiments, cotton tissue was tested for nutrient content at first square, first bloom and first open boll. Results from the 2000 Ca:Mg experiment showed that soil Ca:Mg ratios significantly altered on potassium(K) and calcium (Ca) tissue concentrations. The significant differences were more evident later in the season but did not cause significant differences in yield. Analysis of data from the lime study did not show significant differences in tissue nutrient contents among lime treatments despite different rates of pH change. Red (dolomitic) lime did not increase soil pH as quickly are white (calcitic) lime. However, both liming materials increased cotton yields significantly on an acid soil as compared to the untreated check.