## 3 Results
### Environmental Variables in Rice and Wheat  
Differences in soil temperature at 5 cm depth were observed between rice and wheat. The diurnal average soil temperature varied between 27.74 to 28.92 \({}^{\circ}\)C in rice and from 15.38 to 17.53 \({}^{\circ}\)C in wheat (Figure 5), depending on the intensity of incident solar radiation. The diurnal mean air temperature ranged from 31.8 to 38.2 \({}^{\circ}\)C in rice and from 16.3 to 27.6 \({}^{\circ}\)C in wheat, respectively (Figure 5) and the diurnal RH varied between 60-85% in rice and 40-80% in wheat. The relative humidity (RH) and air temperature (AT) showed an opposite diurnal pattern with respect to each other. Soil heat flux (SHF) at 5 cm soil depth was positive from about 12:00 hr to 20:30 hr and was negative from 21:00 hr to 11:30 hr in both rice and wheat. The SHF ranged from \(-\)12.2 Wm\({}^{-2}\) (7:00 hr) to +15.9 Wm\({}^{-2}\) (15:30 hr) in rice and from \(-\)15.6 Wm\({}^{-2}\) (8:00 hr) to +16.2 Wm\({}^{-2}\) (15:30 hr) in wheat. The diurnal values of incident PAR and Net radiation (NR) were higher during the rice than in the wheat season (Figure 5). The peak NR value in rice was 370.3 Wm\({}^{-2}\) and 316.7 Wm\({}^{-2}\) in wheat, with corresponding incident PAR values of 1742 \(\upmu\) mol m\({}^{-2}\)s\({}^{-1}\) in rice and 1519 \(\upmu\) mol m\({}^{-2}\)s\({}^{-1}\) in wheat. The average VPD was 1.75 kPa in rice and 1.48 kPa in wheat. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Crop/Stage**} & \multicolumn{2}{c}{**Crop/Stage Duration (Days)**} & \multicolumn{4}{c}{**Rate (g C m\({}^{-2}\) d\({}^{-1}\))**} & \multicolumn{4}{c}{**Cumulative (g C m\({}^{-2}\))**} \\ \cline{2-13}  & \multirow{2}{*}{**Wheat**} & \multirow{2}{*}{**Rice**} & **Wheat** & **Rice** & **Wheat** & **Rice** & **Wheat** & **Rice** & **Wheat** & **Rice** & **Wheat** & **Rice** \\ \cline{2-13}  & & & \multicolumn{2}{c}{**NEE**} & \multicolumn{2}{c}{**RE**} & **GPP** & **NEE** & **RE** & & **GPP** & \\ \hline \begin{tabular}{c} **Pre-sowing/Pre-transplanting** \\ \end{tabular} & 4 & 4 & 0.69 & 0.88 & 0.7 & 0.89 & 0.01 & 0.01 & 2.76 & 3.52 & 2.8 & 3.56 & 0.04 & 0.04 \\ \hline \begin{tabular}{c} **Sowing/** \\ **germinality/Post-** \\ **Transplantiing** \\ \end{tabular} & 9 & 6 & \(-\)0.27 & \(-\)0.21 & 0.12 & 0.11 & 0.39 & 0.32 & \(-\)2.43 & \(-\)1.26 & 1.08 & 0.66 & 3.51 & 1.92 \\ \hline \begin{tabular}{c} **Early Vegetative** \\ **Stage** \\ \end{tabular} & 11 & 14 & \(-\)1.28 & \(-\)0.31 & 0.79 & 0.42 & 2.07 & 0.73 & \(-\)14.08 & \(-\)4.34 & 8.69 & 5.88 & 22.77 & 10.22 \\ \hline \begin{tabular}{c} **Tilering** \\ \end{tabular} & 27 & 11 & \(-\)3.6 & \(-\)2.25 & 2.01 & 0.99 & 5.61 & 3.24 & \(-\)97.2 & \(-\)24.75 & 54.27 & 10.89 & 151.47 & 35.64 \\ \hline \begin{tabular}{c} **Stem Elongation** \\ \end{tabular} & 28 & 19 & \(-\)6.63 & \(-\)3.41 & 3.21 & 3.53 & 9.84 & 6.94 & \(-\)185.64 & \(-\)64.79 & 89.88 & 67.07 & 275.52 & 131.86 \\ \hline \begin{tabular}{c} **Booting** \\ \end{tabular} & 10 & 13 & \(-\)8.1 & \(-\)6.54 & 3.77 & 6.71 & 11.87 & 13.25 & \(-\)64.8 & \(-\)85.02 & 30.16 & 87.23 & 94.96 & 172.25 \\ \hline \begin{tabular}{c} **Heading** \\ \end{tabular} & 15 & 18 & \(-\)10.43 & \(-\)7.12 & 5.23 & 7.3 & 15.66 & 14.42 & \(-\)125.16 & \(-\)128.16 & 62.76 & 131.44 & 187.92 & 259.56 \\ \hline \begin{tabular}{c} **Ripening** \\ \end{tabular} & 15 & 17 & \(-\)4.34 & \(-\)3.4 & 2.85 & 4.92 & 7.18 & 8.32 & \(-\)86.8 & \(-\)57.8 & 57.05 & 83.64 & 143.6 & 141.44 \\ \hline \begin{tabular}{c} **Harvest** \\ \end{tabular} & 2 & 2 & 0.46 & 0.35 & 1.04 & 0.86 & 0.58 & 0.51 & 0.92 & 0.7 & 2.08 & 1.72 & 1.16 & 1.02 \\ \hline \
\begin{tabular}{c} **Average/Total** \\ **(Crop period)** \\ \end{tabular} & 115 & 98 & \(-\)5.01 & \(-\)3.74 & 2.64 & 3.22 & 7.65 & 7.68 & \(-\)576 & \(-\)368 & 304 & 387 & 880 & 753 \\ \hline
\begin{tabular}{c} **Fallow (after)** \\ \end{tabular} & 91 & 61 & 0.4 & 0.28 & 0.87 & 1.02 & 0.51 & 0.74 & 32.76 & 17.08 & 79.17 & 62.22 & 46.41 & 45.14 \\ \hline \hline \end{tabular}
\end{table}