## 2 Materials and Methods
### Climate Data  
Slight fluctuations in temperature occurred among the different growth stages. The mean temperature was 24.60 \({}^{\circ}\)C (Figure 3). Relative humidity was significantly higher in July and August, reaching a maximum of 100%, compared with other months (Figure 3). It was found that, from the calculation of the food and agriculture organization (FAO) Penman-Monteith Equation (2), reference crop evapotranspiration (ET\({}_{\text{o}}\)) and precipitation were 501 and 261 mm, respectively (Figure 4). The average ET\({}_{\text{o}}\) was 3.61 mm d\({}^{-1}\), with remarkable seasonal variation; ET\({}_{\text{o}}\) increased from April to July and then declined significantly after August, along with the decrease in solar radiation intensity and temperature. In August, lower ET\({}_{\text{o}}\) was positively related to lower temperature and higher relative humidity.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Growth Stage** & **Precipitation** & **Irrigation Only** & **Straw** & **Organic Manure** & **No Mulching** \\  & & & **Mulching (JG)** & **Mulching (NF)** & **(WG)** \\ \hline \multirow{7}{*}{Seeding-Jointing} & 26 April–28 April & \multicolumn{4}{c}{Covers all three treatments: 0.00} \\  & 28 April–1 May & 38.97 & 38.76 & 39.13 \\  & 2 May–22 May & \multicolumn{4}{c}{Covers all three treatments: 29.90} \\  & 23 May–8 June & \multicolumn{4}{c}{23 May–25 May} & 5.94 & 6.02 & 5.98 \\  & Total Irrigation from Seeding to Jointing Stage & \multicolumn{4}{c}{Covers all three treatments: 0.60} \\  & \multicolumn{4}{c}{Irrigation Deviation} & 74.81 & 74.72 & 75.01 \\  & \multicolumn{4}{c}{Irrigation Deviation} & \(-\)0.19 & \(-\)0.28 & +0.01 \\  & 9 June–13 June & 87.06 & 86.95 & 87.10 \\  & 14 June–24 June & \multicolumn{4}{c}{Covers all three treatments: 5.50} \\  & 25 June–27 June & 38.24 & 38.09 & 38.12 \\  & 25 June–15 July & \multicolumn{4}{c}{Covers all three treatments: 54.70} \\  & Total Irrigation from Jointing to Heading Stage & \multicolumn{4}{c}{185.50} & 185.24 & 185.42 \\  & \multicolumn{4}{c}{Irrigation Deviation} & +10.50 & +10.24 & +10.24 \\  & 16 July–20 July & 62.88 & 62.90 & 62.84 \\  & 20 July–28 July & \multicolumn{4}{c}{Covers all three treatments: 35.70} \\  & \multicolumn{4}{c}{Irrigation Deviation} & 98.95 & 98.60 & 98.54 \\  & \multicolumn{4}{c}{Irrigation Deviation} & \(-\)11.42 & \(-\)11.40 & \(-\)11.46 \\  & 29 July–4 August & \multicolumn{4}{c}{Covers all three treatments: 100.50} \\  & 5 August–7 August & \multicolumn{4}{c}{4.38} & 4.44 & 4.40 \\  & 5 August–8 September & \multicolumn{4}{c}{Covers all three treatments: 34.80} \\  & \multicolumn{4}{c}{Irrigation from Filling to Ripening Stage} & 139.68 & 139.74 & 139.70 \\  & \multicolumn{4}{c}{Irrigation Deviation} & \(-\)0.32 & \(-\)0.26 & \(-\)0.30 \\ Total Water Supply (Irrigation Plus Precipitation) in Whole Growing Season & \multicolumn{4}{c}{500.00} & 500.00 \\  & \multicolumn{4}{c}{Irrigation Deviation} & \multicolumn{4}{c}{Covers all three treatments: 261.60} \\  & \multicolumn{4}{c}{Irrigation Only in Whole Growing Season (No Decimals)} & 239.00 & 239.00 & 239.00 \\ \hline \hline \end{tabular} Note: N represents no irrigation; + represents irrigation increment and needs to be subtracted from the next irrigation; – represents irrigation loss, and needs to be added at the next irrigation. Date between precipitation and irrigation is continuous because the precipitation during the days of irrigation is automatically counted as the amount of precipitation in the interval between that irrigation and the next irrigation.  
\end{table}
Table 1: The irrigation regimes across the growing season (mm, April–September 2017).