不同氮肥与矿化度水平微咸水喷灌对冬小麦光合特征及产量的影响

为寻求合理的微咸水利用方式,揭示微咸水喷灌下作物生理生长响应机理,在河北低平原地区开展了冬小麦微咸水喷灌试验,研究了225 kg·hm-2施氮量条件下不同矿化度(2、3 g·L-1)微咸水灌溉和不同施氮量条件(高氮275 kg·hm-2,中氮225 kg·hm-2,低氮175 kg·hm-2)下2 g·L-1矿化度微咸水喷灌对冬小麦光合特性、生长和产量的影响.结果 表明,与淡水喷灌相比,采用矿化度3 g·L-1微咸水喷灌会导致冬小麦叶片蒸腾速率(Tr)、气孔导度(Gs)和净光合速率(Pn)显著下降,但叶片水分利用效率提高了37.0％～106.8％;2 g·L-1微咸水喷灌高氮和中氮处理的Gs、Pn与淡水喷灌无显著差异,且拔节期高氮处理的叶片Pn略高于淡水喷灌处理5.0％.2 g·L-1微咸水喷灌对冬小麦的叶面积指数和株高影响不显著,3 g·L-1矿化度微咸水喷灌对冬小麦的叶面积指数和群体密度造成不利影响.2 g·L-1微咸水喷灌3个处理冬小麦产量与淡水喷灌处理均无显著差异,但3 g·L-1矿化度处理冬小麦平均产量比淡水喷灌处理显著降低了25.9％.综上所述,矿化度不大于2 g·L-1的咸淡混合水喷灌适用于河北低平原地区冬小麦田间灌溉,添加适量氮肥会促进作物产量的增加.

Effect of brackish water sprinkling irrigation with different nitrogen and salinity levels on photosynthesis characteristics and yield of winter wheat

The study aims to obtain a suitable alternative of brackish water irrigation pattern and reveal the physiological growth response mechanism of crops under brackish water sprinkling irrigation. A field experiment was conducted in a low plain area of Hebei Province, north China. Effects of different salinity(2 g·L^-1, 3 g·L^-1)brackish water irrigation under the same nitrogen application rate(225 kg·hm^-2) and different nitrogen application rates(high N: 275 kg·hm^-2, medium N: 225 kg·hm^-2, low N: 175 kg·hm^-2)with 2 g·L^-1 brackish water sprinkler irrigation on photosynthetic characteristics, growth and yield of winter wheat were studied. The results showed that compared with sprinkler with fresh water, transpiration rate(T_r), stomatal conductance(G_s), and net photosynthetic rate(P_n)of wheat by sprinkling with 3 g·L^-1 brackish water showed a significant decrease in trend, but the water-use efficiency of leaf increased by 37.0%~106.8%. The G_s and P_n of 2 g·L^-1 brackish water sprinkling treated with high N and medium N were not significantly different from that of freshwater sprinkling, and P_n of the leaf treated with high N at jointing stage was 5.0% slightly higher than those treated with freshwater sprinkling. Sprinkling with 2 g·L^-1 brackish water had no significant influence on leaf area index and plant height of winter wheat, while sprinkling with 3 g·L^-1 had adverse effects on leaf area index and population density of winter wheat. Compared with sprinkling with freshwater, the yield of 2 g·L^-1 brackish water treatments were not statistically significant. However, compared with freshwater treatment, the yield of 3 g·L^-1 treatment was significantly reduced by 25.9%. In conclusion, sprinkling irrigation system with no more than 2 g·L^-1 mixing of brackish and fresh water can be used for field irrigation of winter wheat in this region, and adding an appropriate amount of nitrogen fertilizer may promote the increase of crop yield.