Water stress combining weather condition shapes wheat yield and inter-annual yield variability: Field observations from a six-year study

Irrigation has played a pivotal role in Chinese wheat production and is becoming increasingly crucial in adapting to the changing climate. However, the benefits of water-saving wheat production in the long-term period and its response to climate change have received limited attention. In this study, a 6-year field experiment was conducted to investigate the grain yield and water use with three treatments such as Irrigation three times (I3), Irrigation two times (I2), and disposable pre-sowing irrigation (I0), and their sensitivity to weather conditions. The average yield over six years for the I2 treatment is 8.3 Mg ha⁻¹, similar to I3 treatment while using 10.2 % less irrigation water and improving 8.0 % water use efficiency. In contrast, the grain yield in I0 treatment is 28.4 % lower than I3 treatment while consuming 36.9 % less irrigation water. Furthermore, 90.2 % of the yield decrease in I0 treatment results from the lower ear number. Water stress from jointing to flowering accounts for 58.8 % of ear number decrease. Although interannual yield variation is similar among the three treatments, the source of the variation is very different. Kernel weight explains the yield variation by 92.3 % in I3 treatment and 66.1 % in I2 treatment, while ear number accounts for 60.7 % of the variation in I0 treatment. Minimum temperature for kernel weight in both I3 and I2 treatments and rainfall for ear number in I0 treatment is the most important weather factor, respectively. In summary, this study provides valuable insights into the delicate balance between water conservation and food security while adapting to varying weather conditions.