# Influences of Extreme Weather Conditions on the Carbon Cycles of Bamboo and Tea Ecosystems
## 2 Materials and Methods
### Study Sites and Data
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Bamboo Plot** & \multicolumn{2}{c}{**4–7 cm**} & \multicolumn{1}{c}{**7–12 cm**} & \multicolumn{1}{c}{**21–34 cm**} \\ \hline  & 5 cm & 0.58 (0.61, 0.65) & \(-\) & \(-\) \\  & 10 cm\_1 & \(-\) & 0.56 (0.63, 0.65) & \(-\) \\ B1 & 10 cm\_2 & \(-\) & 0.53 (0.57, 0.70) & \(-\) \\  & 10 cm\_3 & \(-\) & 0.56 (0.58, 0.54) & \(-\) \\  & 30 cm & \(-\) & \(-\) & 0.36 (0.40, 0.49) \\ \hline  & 5 cm & 0.61 (0.64, 0.62) & \(-\) & \(-\) \\  & 10 cm\_1 & \(-\) & 0.63 (0.64, 0.60) & \(-\) \\ B2 & 10 cm\_2 & \(-\) & 0.53 (0.54, 0.47) & \(-\) \\  & 10 cm\_3 & \(-\) & 0.54 (0.60, 0.49) & \(-\) \\  & 30 cm & \(-\) & \(-\) & 0.55 (0.52, 0.53) \\ \hline  & 5 cm & 0.59 (0.61, 0.62) & \(-\) & \(-\) \\ B4 & 10 cm & \(-\) & 0.50 (0.55, 0.50) & \(-\) \\  & 30 cm & \(-\) & \(-\) & 0.51 (0.52, 0.51) \\  & 40 cm & \(-\) & \(-\) & 0.47 (0.48, 0.47) \\ \hline
**Tea Plot** & \multicolumn{2}{c}{**4–6 cm**} & \multicolumn{1}{c}{**6–11 cm**} & \multicolumn{1}{c}{**29–49 cm**} \\ \hline  & 5 cm\_1 & 0.22 (0.21, 0.32) & \(-\) & \(-\) \\  & 5 cm\_2 & 0.64 (0.64, 0.41) & \(-\) & \(-\) \\ T2 & 10 cm\_1 & \(-\) & 0.09 (0.09, \(-\)) & \(-\) \\  & 10 cm\_2 & \(-\) & 0.43 (0.44, 0.28) & \(-\) \\  & 30 cm & \(-\) & \(-\) & 0.52 (0.54, 0.74) \\ \hline  & 5 cm\_1 & 0.60 (0.63, 0.74) & \(-\) & \(-\) \\ T3 & 5 cm\_2 & 0.24 (0.23, 0.22) & \(-\) & \(-\) \\  & 10 cm & \(-\) & 0.60 (0.65, 0.72) & \(-\) \\  & 30 cm & \(-\) & \(-\) & 0.36 (0.44, 0.55) \\ \hline  & 5 cm\_1 & 0.62 (0.67, 0.75) & \(-\) & \(-\) \\  & 5 cm\_2 & 0.39 (0.39, 0.42) & \(-\) & \(-\) \\ T4 & 10 cm\_1 & \(-\) & 0.65 (0.68, 0.80) & \(-\) \\  & 10 cm\_2 & \(-\) & 0.40 (0.41, \(-\)) & \(-\) \\  & 30 cm & \(-\) & \(-\) & 0.47 (0.55, 0.61) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Hourly (daily, monthly) \(R^{2}\) between observed and simulated soil water content. SR (heterotrophic respiration (HR) + root respiration (RR)) was measured from bimonthly to monthly from 13 April 2016 to 18 October 2017 using the closed chamber technique [24]. For the gas flux measurements, a series of three aluminum unvented chambers (open bases of 50 cm \(\times\) 50 cm \(\times\) 30 cm) at each site (bamboo plot: B1-B4; tea plot: T1-T4) were inserted into the soil to a depth of 15 cm to ensure an airtight seal and left throughout the cropping cycle (Figure 2c,d). Gas sampling was normally carried out between 09:00 and 11:00, which was assumed to be representative of the daily mean [24]. The modeling results supported this assumption, with a difference of less than 7% between the daily and mean values between 09:00 and 11:00 (see Section 3). To ensure adequate mixing of air within the chamber, the chamber air was mixed using a 60-mL syringe before sampling, and four gas samples were taken from each chamber headspace (0, 10, 20, and 30 min after closure) using a 30-mL syringe (Terumo, Tokyo, Japan) for transport back to the laboratory. Three samples were taken at each site at each sampling time. Carbon dioxide (CO\({}_{2}\)) concentrations in the gas samples were analyzed in the laboratory using a gas chromatograph (Varian 3800). The SR (CO\({}_{2}\) flux) \(F_{CO2}\) (\(\mu\)mol m\({}^{-2}\) s\({}^{-1}\)) was calculated as follows:  
\[F_{CO2}=\rho\cdot h\cdot\frac{273}{273+T}\cdot\frac{dC}{dt}\cdot 3.788 \tag{1}\]  
where \(\rho\) is the density of CO\({}_{2}\) (g cm\({}^{-3}\)), \(h\) is the height of the closed chamber from the soil surface (cm), \(T\) is the air temperature in the chamber (\({}^{\circ}\)C) measured using a thermometer (Figure 2c), \(C\) is the measured CO\({}_{2}\) concentration in the gas samples (ppm), \(t\) is time (10 min in this study), and 3.788 is a unit conversion factor.