Effects of Calcium and Magnesium Lime Sources on Yield, Fruit Quality, and Elemental Uptake of Tomato

Tomato ( Lycopersicon esculentum Mill. cvs. Better Boy and Walter) were grown on an acid soil (pH 4.9) with initially low Ca and Mg levels which was limed with Ca(OH) 2 and MgO in varied mole ratios. In 1980, marketable fruit yields were lower with the 100% Ca(OH) 2 or 100% MgO lime ratio. In 1981, lime source had no effect on marketable fruit yields. Fruit blossom-end rot was most severe when no Ca was applied, while cracking appeared more severe with high levels of Ca application. Leaf Ca and fruit pH were higher for ‘Walter’ than for ‘Better Boy’. The Ca to Mg mole ratio of leaf tissue sampled at early fruiting was a good indicator of the Ca-Mg status of tomato in 1980, when highest fruit yields were obtained over a relatively narrow range of the leaf Ca to Mg mole ratio, with both Ca and Mg deficiency limiting yields. The leaf Ca to Mg mole ratio was well-correlated with the soil test Ca to Mg mole ratio during a given year, but the relationships were different between years. Yield and elemental uptake by tomato relative to levels of Ca and Mg application varied between years as a consequence of the differing climatic conditions in a hot, dry year (1980) versus a cooler, moister year (1981).