JIA-2019-11

2478 ZHANG He et al. Journal of Integrative Agriculture 2019, 18(11): 2472–2482 for S1 and S2 under the six groundwater treatments in Y1 and Y2 (Fig. 3), which is similar to the previous studies on SRMC (Xia et al . 2016; Zhang H et al . 2017) and on salinity content (Zhang H et al . 2017). With the groundwater depth increasing, the upward movement of ground water (due to the capillary effect) including salt becomes more difficult (Xia et al . 2016). However, in a research conducted in the greenhouse condition, it was demonstrated that the salinity contents were positively correlated with the groundwater depth when it was less than 1.2 m, and it was negatively correlated with the groundwater depth when it was more than 1.2 m (Xia et al . 2016). At lower positions, the soil moisture contents were higher, and the accumulated salinity on the soil surface could lead to higher osmotic pressure and lower evaporation rate (Jordán et al . 2004; Ibrahimi et al . 2014). Nevertheless, our experiment was conducted under field conditions, and the rainfall data are listed in Fig. 1. Thus, our results on salinity are partly different from Xia et al . (2016). When the groundwater depth is more than 1.2 m, the phreatic water evaporation is unavailable, and a part of the salt is accumulated in the soil (Ibrakhimov et al . 2007; Seeboonruang 2013). From the seedling to ripening stages, the SRMC values for S1 were less than the S2 values for all treatments (Fig. 3). However, the EC 1:5 values showed the inverse trend (Fig. 3). The results on SRMC were similar to the results by Xia et al . (2016). Due to the groundwater evaporation, the salts are transported upward (Wu et al . 2009). Zhang H et al . (2017) previously Table 4 Total aboveground biomass (g/plant) at different growth stages Groundwater depth (m) Seedling stage Jointing stage Heading stage Filling stage Ripening stage 2013–2014 0.7 0.9 c 2.5 e 3.8 f 7.1 e 6.2 e 1.1 1.2 c 4.9 d 8.6 e 17.7 d 16.9 d 1.5 1.8 b 8.8 c 17.5 c 27.8 b 26.5 b 1.9 3.0 a 12.9 a 27.0 a 35.3 a 34.0 a 2.3 2.7 a 11.5 b 24.9 b 34.0 a 32.5 a 2.7 1.6 b 8.0 c 15.2 d 23.8 c 22.1 c 2014–2015 0.6 0.6 c 1.9 f 3.2 f 6.4 e 5.7 e 1.0 1.0 c 4.1 e 8.0 e 17.0 d 16.3 d 1.4 1.6 b 7.6 d 14.3 d 23.9 c 22.0 c 1.8 3.0 a 12.0 b 25.6 b 35.7 a 33.0 a 2.2 3.5 a 13.6 a 27.9 a 36.7 a 33.7 a 2.6 2.1 b 9.5 c 18.2 c 26.5 b 24.5 b All values are means of three replications; values followed by different lowercase letters within the same column are significantly different at P <0.05 probability level. Table 5 Wheat grain yield, yield components and flour quality under different groundwater depths in 2013–2014 and 2014–2015 Groundwater depth (m) 1) Effective panicles per pot (no./pot) Spikelet per panicle (no./panicle) 1000-grain weight (g) Grain yield (g/pot) Protein content (%) Starch content (%) 2013–2014 0.7 23.0 d 40.0 e 23.0 d 21.2 d 9.3 d 70.2 d 1.1 36.5 c 45.2 d 27.6 c 45.7 c 10.2 c 73.4 c 1.5 43.4 b 48.7 b 34.8 b 73.6 b 11.3 b 76.0 b 1.9 48.9 a 50.6 a 38.8 a 96.1 a 12.4 a 77.8 a 2.3 48.5 a 50.0 a 38.3 a 93.1 a 12.4 a 77.8 a 2.7 42.5 b 47.0 c 33.9 b 67.9 b 11.1 b 75.3 b CV% 23.9 8.4 19.0 43.3 ND ND 2014–2015 0.6 21.5 e 41.0 d 22.9 e 20.3 e 9.3 e 71.2 d 1.0 35.8 d 46.0 c 27.1 d 44.7 d 10.0 d 73.9 c 1.4 39.3 c 48.5 b 33.0 c 63.1 c 10.6 c 74.6 c 1.8 48.4 a 51.2 a 38.8 a 96.5 a 12.1 a 76.5 b 2.2 49.1 a 51.3 a 39.2 a 99.0 a 12.5 a 78.2 a 2.6 42.9 b 49.0 b 35.6 b 75.0 b 11.2 b 75.7 b CV% 25.8 8.1 20.0 45.9 ND ND 1) CV, coefficient of variation. ND, no data; all values are means of three replications; values followed by different lowercase letters within the same column are significantly different at P <0.05 probability level.