## 2 Materials and Methods  
### Experimental Settings and Design, Crop Management, and Soil Sampling  
The experiment was carried out at the experimental field of the Department of Agricultural Science in Portici (Naples, 40\({}^{\circ}\) 48.870\({}^{\prime}\) N; 14\({}^{\circ}\) 20.821\({}^{\prime}\) E; 70 m a.s.l.) under a plastic greenhouse (2020-2021). The species chosen for the test was wild rocket (_Diplotaxis tunifolia_ L) cv. \"Reset\", marketed by Maraldi Sementi Sri (Cesena--FC, Italy), with the following characteristics: green leaves with medium-sized lobes, high potential yield, and a noticeable flexibility in terms of growing conditions that makes it useful for cultivation in any season. For the test, pots with a 0.38 m\({}^{2}\) surface and a 0.70 m height were used; they were filled with a sandy soil, whose physical and chemical properties are reported in Table 1.  
Three seedling groups per pot (about 15-20 seedlings each) were transplanted on 8 October 2020, and harvested 6 consecutive times from 25 November 2020 until 20 May 2021, hereafter referred to as I, II, III, IV, V, and VI. Regarding fertilization, only nitrogen in the form of ammonium nitrate (26%) was applied, provided at a rate corresponding to 18 kg ha\({}^{-1}\) per each cycle. For the first cycle, it was added 18 days after transplant (DAT), while in the successive cycles this was carried out at approximately 4 days after harvest (DAH) of the previous growing cycle, ranging between 2 and 9 DAH depending on the conditions. No pesticide treatments were carried out. The experimental design was a split-plot design, with saline irrigation as the main experimental factor and biostimulant application as the subfactor. The saline irrigation treatments included the following: EC0: irrigation with tap water; EC2: irrigation with water that had an EC of 2.0 dS m\({}^{-1}\); EC4: irrigation with water that had an EC of 4.0 dS m\({}^{-1}\); and EC6: irrigation with water that had an EC of 6.0 dS m\({}^{-1}\). There were three biostimulant application treatments: 1. untreated--control; 2. treated with Auxym(r), a tropical plant extract hereafter referred to BA; and 3. treated with Trainer(r), a protein hydrolysate derived from legumes, hereafter referred to BT. Both biostimulants are marketed by Hello-Nature Italia Srl (Rivoli Veronese, Italy), and they were applied as a foliar spray three times per each cycle (except for the last cycle, which was shorter; therefore, only two applications were performed) at doses of 2 mL L\({}^{-1}\) and 3 mL L\({}^{-1}\) for Auxym(r)and Trainer(r), respectively. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameters** & **Unit** & **Mean Value** \\ \hline Sand & \% & 91.0 \\ Silt & \% & 4.5 \\ Clay & \% & 4.5 \\ N—total ([PERSON] method) & \% & 0.101 \\ P\({}_{2}\)O\({}_{5}\) ([PERSON] method) & mg kg\({}^{-1}\) & 253.0 \\ K\({}_{2}\)O (tetraphenylborate method) & mg kg\({}^{-1}\) & 490.0 \\ Organic matter & \% & 2.5 \\ Electrical conductivity & dS m\({}^{-1}\) & \\ pH & & 7.4 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Physical and chemical properties of the test soil. Starting with harvest II, the formation of new leaves was taken into account to decide when to perform the first biostimulant application. All of the treatments were replicated 3 times for a total of 36 pots. The water losses were calculated by the Hargreaves method [38], and were fully restored by 26 irrigations over the six cycles. The desired EC for saline treatments was obtained by adding NaCl to tap water, as reported by [PERSON] et al. [39]. A total of 28.5 L per pot was applied with 34.6, 69.1, and 103.7 g of NaCl per pot in the EC2, EC4, and EC6 treatments, respectively. At the first cycle, the first three irrigations were made with tap water for all of the treatments in order to promote the rooting and establishment of seedlings.