## 2 Materials and Methods
### Eddy Covariance and Meteorological Instrumentation  
An eddy covariance (EC) system was used to monitor NEE and ET, being subsequently used to obtain GPP. A fully equipped flux tower (Table 1) was initially deployed at the central location of the almond orchard in Las Tiesas at the beginning of the 2016 growing season, with its instrumentation being completed in 2017 (Figure 1), registering data for the first 3-year period (2017-2019). At the beginning of 2020, the tower was relocated in the commercial almond orchard of Tarazona, again at the central location of the plot, and data were collected for the second 3-year period (2020-2022). \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Variable** & **Instrument** & **Model** & **Manufacturer** & **Installation Height** \\ \hline \multirow{2}{*}{Net radiation} & \multirow{2}{*}{Net radiometer} & NR-Lite (2017–2019) & [PERSON] \& Zonen, & \\  & & CNR1 (2020–2022) & Delft, The Netherlands & & \\ \hline \multirow{2}{*}{Sensible heat flux} & \multirow{2}{*}{3-D Sonic Anempometer} & \multirow{2}{*}{CSAT3} & Campbell Sci. Inst., & \multirow{2}{*}{4 m (2017 \& 2018)} \\  & & & Logan, UT, USA & & 6 m (2020 \& 2021) \\ \hline \multirow{2}{*}{Latent heat flux} & Open-path & \multirow{2}{*}{LI-7500} & \multirow{2}{*}{LI-COR Inc., Lincoln, NE, USA} & \multirow{2}{*}{7.5 m (2022)} \\  & gas analyzer & & & Lincoln, NE, USA & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Detailed features of the equipment installed in the flux tower located in LTs (2017–2019) and TzM (2020–2022). Figure 1: Location of the two almond orchards and the eddy covariance tower installed at each study site. Pictures show the evolution of the almond trees during the experiment at both Las Tiesas (ES—LTs; 2017–2019) and Tarazona de la Mancha (ES—TzM; 2020–2022). The EC system was mounted on the tripod (Figure 1) and comprised a sonic anemometer (CSAT-3, Campbell Sci. Inst., Logan, UT, USA) and an open-path infrared gas analyzer (LI-7500, LI-COR Inc., Lincoln, NE, USA). Based on the footprint analysis, the EC instruments were initially positioned at a height of 4 m above the ground surface to avoid contributions from areas beyond the boundaries of the almond field. This position was later raised to 5 m in the 2019 season to maintain a minimum distance of 1.5 m from the canopy top. In 2020, the tower was installed with a similar setup in Tarazona, but raising the EC instruments 6 m above the soil surface in this case, and subsequently to 7.5 m in 2022 (Table 1). The flux tower was also equipped with a net radiation sensor (NR-Lite in Las Tiesas, and CNR1 in Tarazona, Kipp & Zonen, Delft, The Netherlands), with 2 and 4 heat flux plates, respectively (HFP01 SC, Hukseflux, Delft, The Netherlands), buried at 8 cm depth on both sides of the row. Soil temperature was measured using thermocouples (TCAV, Type E, Campbell Sci. Inst., Logan, UT, USA) at depths of 2 and 4 cm, and soil moisture was measured at a depth of 6 cm with volumetric moisture sensors (CS650, Campbell Sci. Inst., Logan, UT, USA) to account for heat storage in the soil layer above the plates. The other meteorological variables measured were air temperature/relative humidity (model MP100, Campbell Scientific Instrument, Logan, UT, USA) and rainfall (model ARG100, Campbell Scientific Instrument, Logan, UT, USA). All the data were recorded as 15-minute averages, using CR10X and CR1000 data loggers (Campbell Scientific Instrument, Logan, UT, USA), being subsequently processed to derive 30-minute, hourly and daily fluxes. The study period covered from July to September in 2017, May to October in 2018, July to September in 2019, July to September in 2020 and April to October in 2021 and 2022 (Table 2). The dataset encompassed the full Stage III phenological phase (increase in seed weight) for all six years, as well as significant portions of Stage II (embryo growth) and Stage IV (post-harvest).