The Effects of Potassium, Calciumand Irrigation Treatments on theYield and Quality of Tomatoes (Lycopersicon Esculentum Mill)

Abstract

Five experiments were conducted to investigate the effects of potassium (K), calcium (Ca), and irrigation on yield and quality in tomatoes. K at 3 g/plant in a box containing 2.7 m^ of soil decreased the pH and incidence of blotchy ripening of the fruit, and increased the incidence of cracking and the K content of the fruit juice. Four sprays of 0.2% CaCl2 increased the total weight yield of fruit. The average fruit weight increased at the higher irrigation frequency but the number of flowers, fruit number, soluble solids content, titratable acidity, blotchy ripening, and the K content of juice decreased. K at 122 and 244 kg/ha in the field decreased pH and increased the titratable acidity and K content of the fruit. Ca and irrigation treatments had no main effects on yield and quality but there was a three-way interaction among treatments, on pH and titratable acidity. Irrigation decreased the K content of the juice. The effects of ten treatments, being a control and combinations of three rates (6 1 , 1 2 2 , and 244 kg/ha) and times of application ( 1 week, 3 weeks and a split dose 1 and 3 weeks after transplanting) of K were studied in two experiments. Treatments influenced soluble solids content and leaf K content in one experiment only. Three irrigation frequencies (irrigated every 2 days, every 4 and 6 days, and every 6 days) were imposed on tomato plants grown in boxes. Frequent irrigation increased average fruit weight and the incidence of severe blotchy ripening, and decreased the soluble solids content and titratable acidity of the fruit. K and Ca treatments had little influence on yield and blossom-end rot (BER). High K levels, however, affected quality by increasing fruit acidity and promoting uniform pericarp colouration. Increasing irrigation frequencies promoted larger fruit size but decreased fruit soluble solids content and acidity.