Response of tomato plant to foliar application of calcium and potassium nitrate integrated with different phosphorus rates under sandy soil conditions.

Tomato is strategic export vegetable crop in Egypt and the world. So, two field experiments were conducted to study the effect of three phosphors rates (0, 14 and 28 kg P fed-1); five foliar treatments (0, 0.3 and 0.6% of Ca and 0.5% and 1% of K) and their interactions on tomato growth and yield. The used experimental design was a split block design with three replicates. Plant height, leaf area, fresh and dry weight (g) of leaves, fruit yield (Mg fed-1), fruit diameter, N, P, K and Ca content (%) in leaves and uptake in fruits and lycopene content (mg kg-1) were determined. The obtained data reveals that all the used treatments significantly affected the previous parameters. Data also show that phosphorus treatment of 14 kg P fed-1 gave the bsults of leaf area (cm2), fresh weight of tomatoes leaves, potassium content (%) in leaves, fresh weight of four fruit, fruit diameter and tomatoes yield (Mg fed-1). In addition, foliar application treatments at 0.3 Ca and 0.5% K recorded the highest results of plant height, leaf area (cm2), fresh weight of tomato leaves, N, P contents in leaves, weight of four fruits, fruit diameter, tomato yields (Mg fed-1), Fruit lycopene content (mg kg-1), N and P uptake by fruits . The highest tomato yields (Mg fed-1) values were 18 and 18.06 Mg fed-1 recorded with 14 kg P fed-1and 0.3% calcium as a foliar application followed by 14 kg P fed-1 and 0.5 % potassium which recorded 17.36 and 17.32 Mg fed-1 respectively in both seasons. Generally, it concluded that the interaction between the treatment of 14 P fed-1 and 0.3% calcium or 0.5 % potassium as a foliar application enhanced tomato yield and nutrient uptake.