Effects of Potassium in Liquid Feed, Lime Type in the Base Dressing and Cultivar on the Yield, Quality and Composition of Tomatoes Grown in Peat

Three concentrations of K in the liquid feed, two lime sources and three cultivars were compared in a long-season crop of tomatoes grown in a peat substrate with 14 1 per plant. Increasing the K concentration from 180 to 280 mg/l increased the yield but a further rise to 380 mg/l did not give a significant increase. The higher levels of K reduced uneven ripening and increased the levels of soluble solids, titratable acidity and electrical conductivity of the fruit purée. The use of dolomitic limestone only or a blend of dolomitic and ground limestones as lime sources had no effect on fruit yield, visual quality or composition. Two modern cultivars, Sonatine and Virosa, had better early yields than Ailsa Craig, an old cultivar, but similar total yields. Ailsa Craig produced a much higher proportion of fruit with uneven ripening, and early in the season its fruit had a lower soluble-solids content than did the modern cultivars. A seasonal decline in the electrical conductivity of the fruit purée was noted.