JIA-2019-11

2481 ZHANG He et al. Journal of Integrative Agriculture 2019, 18(11): 2472–2482 salinity (groundwater depths of 0.7 m in Y1, 0.6 m in Y2) (Tables 3–5 and Figs. 5–7). Similarly, in a greenhouse study, simulating the combined effects of soil drought and salinity using seven types of salt, cotton roots were affected significantly by the drought×salt treatment as compared to the single effects of each treatment (Zhang et al . 2013). In our study, the photosynthesis rate, grain yield, and flour quality reduced considerably under slight drought and medium salinity (2.3 m in Y1) (Tables 3–5 and Figs. 5–7). It is noteworthy that the above mentioned studies were performed in controlled conditions and not in the field. In the greenhouse experiments, the pot soils were not a part of the field soil, while in this research, the PVC tubes were a part of the field soil. Zhang H et al . (2017), as previously mentioned, conducted a similar experiment with cotton in coastal saline soil and found that cotton growth was better under slight drought with medium salinity in a relatively dry weather and standard soil moisture and low salinity as compared to water logging with high salinity in a relatively wetter weather. They also discovered that the optimal fitting groundwater depth was 1.87 m in 2013 and 1.73 m in 2014 (Zhang H et al . 2017). Such results are almost similar to our results (2.0 m in Y1 and 2.1 m in Y2); the little difference can be due to the morphological and physiological differences of the two crop plants (Fig. 8). In addition, compared with Zhang H et al . (2017), this study also found that the booting stage was the most sensitive stage of wheat response to soil moisture and salinity. Therefore, it is important to take some measures in wheat at the booting stage to alleviate the negative effects of soil water logging and salinity stresses. Finally, the suitable treatments were 1.9 and 2.3 m in Y1 (fitting result, 2.0 m), and, 1.8 and 2.2 m in Y2 (fitting result, 2.1 m). The little differences in the two years can be due to the different weather conditions. Additionally, the optimal range of SRMC in S1 and S2 were 58.67–63.07% and 65.51–72.66% in Y1, 63.09–66.70% and 69.75–74.72% in Y2. The corresponding values for EC 1:5 were equal to 0.86–1.01 dS m –1 and 0.63–0.77 dS m –1 inY1, 0.57–0.93 dS m –1 and 0.40–0.63 dS m –1 inY2, respectively. Briefly, the growth conditions of wheat under varying levels of soil moisture and salinity was investigated in this research, which could be used to improve wheat growth and yield in coastal saline soils. Nevertheless, future research may be about modeling the effects of soil moisture and salinity in combination with the other parameters such as fertilizer on crop yield. 5. Conclusion The SRMC was positively correlated with EC 1:5 , and the stress of water logging with high salinity for cotton growth was greater than that of slight drought with medium or low salinity. Higher rates of photosynthesis, grain yield, and flour quality were resulted under standard soil moisture and medium salinity (groundwater depth at 1.9 m), slight drought, and medium salinity (2.3 m); however, the values were larger under slight drought with low salinity (2.2 m) and standard soil moisture and medium salinity (1.8 m). The most sensitive stage of wheat growth to soil moisture and salinity was the booting stage. Ultimately, the most optimal groundwater depths were 1.9 and 2.3 m in Y1 and 1.8 and 2.2 m in Y2, and the optimal ranges of SRMC and EC 1:5 in S1 and S2 were 58.67–63.07% and 65.51–72.66% in Y1, 63.09–66.70% and 69.75–74.72% in Y2; 0.86–1.01 dS m –1 and 0.63–0.77 dSm –1 inY1, 0.57–0.93 dSm –1 and 0.40–0.63 dS m –1 inY2, respectively, in coastal saline soils. Acknowledgements This work was funded by the National Key R&D Program of China (2017YFD0201900), the Fundamental Research Funds for the Central Universities, China (KYYJ201802), the earmarked fund for ChinaAgriculture Research System (CARS-15-14). We thank Dr. Rizwan Zahoor, Dr. Babar Iqbal, Dr. Kamran Shinwari, Dr. Wei Jiaping, and MSc Zhou Ying, from Nanjing Agricultural University for reviewing the manuscript. References Gan Y T, Liu L P, Cutforth H, Wang X Y, Ford G. 2011. Vertical distribution profiles and temporal growth patterns of roots in selected oilseeds, pulses and spring wheat. Crop & Pasture Science , 62 , 457–466. Ghobadi M E, Ghobadi M, Zebarjadi A. 2017. Effect of waterlogging at different growth stages on some morphological traits of wheat varieties. International Journal of Biometeorology , 61 , 635–645. Haddadi B S, Hassanpour H, Niknam V. 2016. Effect of salinity and waterlogging on growth, anatomical and antioxidative responses in Mentha aquatica L. 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