Reduced Fertilization to Improve Sustainable Use of Resources and Preserve Postharvest Quality of Fresh-Cut Wild Rocket (<em>Diplotaxis tenuifolia</em> L.) in Soil-Bound and Soilless Cultivation

Wild rocket plants were cultivated in a plastic greenhouse into two independent sectors, one for soil-bound (SbS) cultivation and another equipped for soilless (ScS) cultivation systems. In both SbS and ScS, the crop was subjected to treatments consisting in a high-compared to a low-input fertilization program (HF and LF treatment, respectively). Water use efficiency (WUE) and partial factor productivity (PFP) for nutrients (N, P, K, Ca and Mg for ScS, and N for SbS) were measured. Rocket leaves, separated for cultivation system and fertilization program, collected at different cuts during the growing cycle, were cold stored at 10 °C until 16 d. At each sampling day (at harvest and during the storage), sensory parameters, respiration rate, dry matter, colour, electrolyte leakage, antioxidant activity, total phenols, total chlorophyll and ammonia content were evaluated. In ScS, the PFP for all nutrients supplied as fertilizers showed a significant increase with the LF treatment, with values higher than 30 % for N, K and Ca. As for the postharvest performance, rocket leaves cultivated in ScS showed better qualitative traits than those cultivated in SbS, as suggested by the lower values of ammonia content and electrolyte leakage recorded at the end of storage in samples grown in ScS. Moreover, in ScS, data showed a lower membrane damage in LF than HF rocket leaves. Finally, regarding total chlorophyll content, even if no effect of treatments was recorded in SbS, rocket cultivated in ScS, showed a better retention of this parameter applying LF than HF treatment. In addition to this, a PLS model (R2 = 0.7) able to predict the cultivation system, using as variables total chlorophyll content no-destructively measured, was implemented.