## 2 Materials and Methods
### Case Study
\begin{table}
\begin{tabular}{l c c c c c c} \hline \hline  & \multicolumn{6}{c}{**Production (t)**} & \multicolumn{1}{c}{**Mean (t)**} \\ \cline{2-7}  & **2015** & **2016** & **2017** & **2018** & **2019** & \\ \hline _Agrigento_ & & & & & & \\ - & Horticultural open field crops & 322,937 & 302,870 & 300,227 & 307,831 & 316,093 & 309,991 \\ - & Horticultural greenhouse & 100.0 & 93.8 & 93.0 & 95.3 & 97.9 & \\ - & Horticultural greenhouse & 21,932 & 14,449 & 12,826 & 13,017 & 13,093 & 15,064 \\ \hline _Caltanissetta_ & & & & & & \\ - & Horticultural open field crops & 99,284 & 114,852 & 115,566 & 85,641 & 71,303 & 97,329 \\ - & Horticultural greenhouse & 100.0 & 115.7 & 116.4 & 86.3 & 71.8 & \\ - & Horticultural greenhouse & 41,725 & 41,725 & 41,698 & 41,696 & 41,696 & 41,708 \\ \hline _Catania_ & & & & & & \\ - & Horticultural open field crops & 59,667 & 59,685 & 47,401 & 59,846 & 60,039 & 57,328 \\ - & Horticultural open field crops & 100.0 & 100.0 & 79.4 & 100.3 & 100.6 & \\ - & Horticultural greenhouse & 750 & 750 & 750 & 750 & 750 & 750 \\ - & Horticultural greenhouse & 100.0 & 100.0 & 100.0 & 100.0 & 100.0 & \\ \hline _Enma_ & & & & & & \\ - & Horticultural open field crops & 7265 & 7970 & 8550 & 7750 & 7535 & 7814 \\ - & Horticultural greenhouse & 100.0 & 109.7 & 117.7 & 106.7 & 103.7 & \\ - & Horticultural greenhouse & 695 & 1265 & 1265 & 1265 & 1265 & 1151 \\ \hline _Messina_ & & & & & & \\ - & Horticultural open field crops & 18,290 & 36,379 & 36,555 & 37,055 & 37,445 & 33,145 \\ - & Horticultural open field crops & 100.0 & 198.9 & 199.9 & 202.6 & 204.7 & \\ - & Horticultural greenhouse & 3181 & 1705 & 1818 & 1818 & 1818 & 7794 \\ - & 100.0 & 5.4 & 5.7 & 5.7 & 5.7 & \\ \hline _Palermo_ & & & & & & \\ - & Horticultural open field crops & 85,253 & 84,611 & 106,318 & 106,939 & 109,989 & 98,622 \\ - & Horticultural open field crops & 100.0 & 99.2 & 124.7 & 125.4 & 129.0 & \\ - & Horticultural greenhouse & 20,173 & 19,664 & 19,666 & 19,736 & 20,051 & 19,858 \\ - & Horticultural greenhouse & 100.0 & 97.5 & 97.5 & 97.8 & 99.4 & \\ \hline _Ragusa_ & & & & & & \\ - & Horticultural open field crops & 52,057 & 52,640 & 71,350 & 82,100 & 83,300 & 68,289 \\ - & Horticultural open field crops & 100.0 & 101.1 & 137.1 & 157.7 & 160.0 & \\ - & Horticultural greenhouse & 239,300 & 232,300 & 209,250 & 220,300 & 243,000 & 228,830 \\ - & Horticultural greenhouse & 100.0 & 97.1 & 87.4 & 92.1 & 101.5 & \\ \hline _Syracuse_ & & & & & & \\ - & Horticultural open field crops & 111,035 & 122,614 & 123,920 & 124,616 & 125,591 & 121,555 \\ - & Horticultural open field crops & 100.0 & 110.4 & 111.6 & 112.2 & 113.1 & \\ - & Horticultural greenhouse & 45,240 & 44,224 & 45,320 & 44,815 & 45,412 & 45,002 \\ - & 100.0 & 97.8 & 100.2 & 99.1 & 100.4 & \\ \hline _Trapani_ & & & & & & \\ - & Horticultural open field crops & 32,458 & 27,120 & 25,380 & 24,390 & 21,900 & 26,250 \\ - & Horticultural open field crops & 100.0 & 83.6 & 78.2 & 75.1 & 67.5 & \\ - & Horticultural greenhouse & 9704 & 9704 & 9754 & 10,474 & 10,434 & 10,014 \\ - & 100.0 & 100.0 & 100.5 & 107.9 & 107.5 & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Sicilian production of horticultural crops (t) and trend of evolution (%). Concerning open field horticultural areas, and also horticultural greenhouse production, Messina data are outliers and cannot be considered. In the selected time interval, overall, the production of horticultural crops registered a slight increase (+3.3%), despite a decrease in the quantities produced in greenhouses (\(-1.7\%\)). Regarding horticultural greenhouse production, there is a common trend across the region: Greenhouse horticulture productions are constant from 2015 to 2019. Only the province of Enna recorded a doubled production: From 695 t in 2015 to 1265 t in 2019, with the same cultivated area of about 10 ha (as shown in Table 1).