Influence of Salinity and Fertilization Level on the Nutrient Distribution in Tomato Plants under a Polyethylene Greenhouse in the Mediterranean Area

The experiment was conducted in a polyethylene greenhouse with the 'Pitenza' variety of tomato crop on a sand-mulched sandy loam soil using trickle irrigation. The experimental design was two-factorial with four randomized blocks. The treatments applied were the result of a combination of two irrigation water qualities (C2S1 and C3S2) and three fertilization levels: F1, half of the recommended rate; F2, the recommended rate [i.e., 7.1mmolL-1 of nitrate (NO3 -)-nitrogen (N), 0.5mmolL-1 of phosphoric acid (H2PO4 -)-phosphorus (P) and 3.1mmolL-1 of potassium (K+)], and F3, double the recommended rate. Total content of nutrients [N, P, K, calcium (Ca), magnesium (Mg)] and sodium (Na) were determined for different plant parts (pinch rest, harvested fruit, developing fruit, leaf, and stem) for the whole season. Also, the relative sink strengths between fruit and vegetative plant parts were calculated. The main mineral constituent of the tomato plant was K, surpassing the N content, and the minor constituent was P. With the same level of fertilization, the influence of salinity was significant at F1 (half of the recommended rate) and F2 (the recommended rate) but not at the highest level. Plant nutrient distribution showed the same behavior for N, P, and K, the fruit being the nutrient sink. On the other hand, the same tendency was observed for Ca and Mg, stored mainly in the leaf. Nevertheless, Na presented low levels in young tissues, whereas the levels were higher and similar in fruit, leaf, and stem.