Field trials were established in 2006 at Gluszyna Lesna (52°18' N, 16°55' E), a 300 hectares Agricultural Farm, near Poznan. Winter wheat, variety Tonacja was the test plant. Three kinds of calcium-bearing fertilizers i.e., (i) CaO – 80% CaO, (ii) CaO + MgO – 60/20 (% basis) CaO/MgO, (iii) CaCO₃ – 52% CaO, were applied at four rates: 0, 500, 1000, 1500 kg CaO·ha^-1 at the first decade of September 2006. Nitrogen was applied once as NH₄NO₃ at tillering at the rate 120 kg·ha^-1. Soil samples were collected at the depths 0-20 cm at harvest. Soil chemical analyses involved: pH (1 mole KCl·dm^-3), exchangeable aluminum (Al_ex), exchangeable base cations (Ca_ex, Mg_ex, K_ex and Na_ex, extracted by 1 mole CH₃COONH₄·dm^-3 (pH 7.0). Since soils were acid, the effective CEC (CEC_e) was then obtained by summation of extractable acidity assessed in 1 mole KCl·dm^-3 and exchangeable base cations. From these, indices such as Ca_sat (Ca saturation); Al_sat (Al saturation) and CAB (Calcium-Aluminum Balance), were calculated and applied for testing winter wheat (yield, mainly) response to calcium and aluminum interactions under acid and very acid soil conditions. Results have revealed, that part of CAB indices shifted towards aluminum for both calcium-bearing fertilizers, i.e., CaO and CaO + MgO, as a result of Al prevalence over Ca in investigated soils. This implies the worsening of plant growth conditions related to the shortage of adequate calcium levels and hence relatively low grain yields. It appeared also, that grain yield remained still relatively appreciable, (CAB raised up to 1.00) for both cases i.e., CaO and CaO + MgO. The effect of CaO + MgO on plant growth was mediated by nitrogen and magnesium. The application of CaCO₃ raised CAB indices above 1.0 and even up to 1.4, which was the highest among these three fertilizers. Of additional value was the response of winter wheat yield to calcium and aluminum levels expressed as Ca_sat, Al_sat. It was shown, that irrespective of applied calcium-bearing fertilizers i.e., CaO, CaO + MgO, and CaCO₃, grain yield increased along with Ca saturation levels. However the opposite trend was observed in the case of Al_sat, where the increase in aluminum saturation led decidedly and systematically to yield decrease being the lowest at Al_sat ca 35–40% (CaO, CaO+MgO) and 25% (CaCO₃).