## 2 Materials and Methods
### Yield, Yield Quality Indicator, Water Productivity, and Main Quality Parameters  
At harvest, the marketable and discarded fruit were counted and weighted to estimate the total and marketable yield (t ha\({}^{-1}\)). Moreover, the synthetic yield quality indicator of tomato production (Yield Quality, YQ, t ha\({}^{-1}\)) was calculated as reported by [PERSON] et al., 2019 [4]. A revised water productivity indicator (WP\({}_{\text{YQ}}\)) was then computed considering the ratio between the YQ indicator and total water applied to the crop (irrigation and precipitation) [4].  
Figure 2: Flowchart of the smart irrigation water system (PlaSoMan) based on the monitoring of plant water status (CWSI) and moisture soil level.  
The quality parameters were evaluated on a sample of 10 marketable fruits from each plot. The soluble solids (\({}^{\circ}\)Brix) were measured with a digital refractometer (model DBR35, XS Instruments; Giorgio Bormac s.r.l., Carpi (MO), Italy). Titractable acidity (TA; g citric acid 100 mL\({}^{-1}\) fresh juice) and pH were measured according to AOAC, (1995 [18]). The color parameters were measured using a CM-700d spectrophotometer (Minolta Camera Co. Ltd., Osaka, Japan) as the CIELAB coordinates (i.e., L\({}^{*}\), a\({}^{*}\), b\({}^{*}\)) on four randomly selected areas of the fruit surface. Then, the a\({}^{*}\)/b\({}^{*}\)ratio was calculated, which represents an index that describes well the color changes of tomato fruit [19; 20].  
Lycopene, vitamin C, and beta-carotene content were determined following the procedure described in [PERSON] et al. (2014) [21] on tomato pulp (1 g), obtained using a blender at 12,000 rpm for 10 min.  
To determine the lycopene content, we macerated the tomato pulp with a 1% metaphosphoric acid solution and then filtered it. We also used 10 mL of metaphosphoric acid solution to wash off any residue. The resulting residue was then macerated with 20 mL of acetone, filtered, and the absorbance of the filtrate was read at 440 nm against acetone as a blank using a spectrophotometer. We repeated this analysis three times and calculated the mean. Finally, we determined the concentration of lycopene as [21]:  
\[\text{Lycopene }\Big{[}\frac{\text{mg}}{\text{100 mL}}\Big{]}=\frac{\text{ Mean absorbance }\times\text{dilution factor}}{\text{Slope}}\]  
To obtain the concentration of lycopene, we used a slope of 0.095 calculated from the standard curve of lycopene.  
To determine the vitamin C content, we macerated 1 g of tomato pulp with 20 mL of 0.4% oxalic acid solution and filtered it. Next, we added 0.2 mL of 0.01% methylene blue solution to 1 mL of filtrate in a test tube. We also added 1 mL of acetate buffer pH 4.2 and made the solution up to the 5 mL mark using distilled water. The spectrophotometer was used to read the absorbance of the solution and vitamin C was calculated as [21]:  
\[\text{Vitamin C }\Big{[}\frac{\text{mg}}{\text{100 mL}}\Big{]}=\frac{\text{ Mean absorbance }\times\text{dilution factor}}{\text{Slope}}\]  
We calculated the slope (0.0693) from the standard curve of vitamin C using known concentrations of vitamin C against absorbance.  
To determine the \(\beta\)-carotene content, 1 g of tomato pulp was mixed with a 10 mL combination of acetone and n-hexane (1:1) and filtered. Next, 10 mL of 50% (NH4)2 SO4 solution was added and vigorously shaken before allowing it to settle. The upper layer was then collected, and the spectrophotometer was used to read the absorbance at 450 nm against hexane as a blank [21]:  
\[\text{Beta}-\text{carotene }\Big{[}\frac{\text{mg}}{\text{100 mL}}\Big{]}=\frac{ \text{Mean absorbance }\times\text{dilution factor}}{\text{Slope}}\]  
The slope (1.249) was obtained from the standard curve of beta-carotene plotted using a known concentration of beta-carotene against absorbance.