Fresh water shortage is a major problem for grain production in the low plain around Bohai Sea in the North China Plain. Relative abundance of shallow saline groundwater could serve as an alternative water resource for use during dry seasons. A continuous 8-year field study was conducted from 2015 to 2023 to assess the effects of salt content in irrigation water on soil salt accumulation and crop production. Fresh water (FW) with electrical conductivity (EC) at 1.6 dS/m and three levels of saline water (SW) with EC at 4.7 (SW1), 6.3 (SW2) and 7.8 dS/m (SW3) were used for irrigation. Results showed that a single irrigation event at the jointing stage of winter wheat increased grain production averagely by 18.6 %, 22.5 %, 12.9 % and 9.5 % compared with a rain-fed treatment (RF) under FW, SW1, SW2 and SW3, respectively. With an additional irrigation applied at flowering stage, both irrigations using FW increased the yield by 28.6 %, and both irrigations using SW2 increased the yield by 19.3 % compared with RF. Negative effects of salt on winter wheat overshadowed the positive effects of increased water supply under two irrigations both using SW. With an irrigation at maize sowing and the subsequent summer rainy season, the yield of maize following winter wheat was not affected by a one-time SW irrigation to the previous crop, but showed a 5.3 % yield reduction when two irrigations of SW were applied. There was no apparent salt accumulation in the top 1 m of the soil profile, but a slight increasing trend in the salt content in the 1–2 m layer of the soil profile under SW2 and SW3 irrigation. No apparent changes in soil physical properties were observed for continuous application of SW. It was suggested that SW with EC not exceeding 6.3 dS/m should be applied for a single irrigation during the winter wheat season. This practice could alleviate the fresh water shortage in this region and allow for the maintenance of a relatively stable yield of winter wheat and maize without the risk of salt accumulation in the soil.

中文翻译：

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华北平原冬小麦-玉米种植系统长期盐水灌溉对土壤盐分及作物产量的影响——以案例研究为例


淡水短缺是华北平原环渤海低洼平原粮食生产面临的主要问题。相对丰富的浅层咸水地下水可以作为旱季使用的替代水资源。从 2015 年到 2023 年，我们进行了一项为期 8 年的连续田间研究，以评估灌溉水中含盐量对土壤盐分积累和作物生产的影响。使用电导率 （EC） 为 1.6 dS/m 的淡水 （FW） 和 EC 为 4.7 （SW1）、6.3 （SW2） 和 7.8 dS/m （SW3） 的三个盐水 （SW） 进行灌溉。结果表明，与 FW、SW1、SW2 和 SW3 雨养处理 （RF） 相比，冬小麦拔节期单次灌溉事件平均提高了粮食产量 18.6 %、22.5 %、12.9 % 和 9.5 %。在开花期进行额外灌溉后，与 RF 相比，使用 FW 的两种灌溉都使产量提高了 28.6 %，使用 SW2 的两种灌溉都使产量提高了 19.3 %。盐对冬小麦的负面影响掩盖了在两种使用 SW 的灌溉下增加供水的积极影响。在玉米播种和随后的夏季雨季进行灌溉后，冬小麦之后的玉米产量不受对前一季作物的一次性 SW 灌溉的影响，但在施用两次 SW 灌溉时，产量降低了 5.3%。在 SW2 和 SW3 灌溉下，土壤剖面顶部 1 m 没有明显的盐分积累，但土壤剖面 1–2 m 层的含盐量呈轻微增加趋势。连续施用 SW 未观察到土壤物理性质的明显变化。建议 EC 不超过 6 的 SW。在冬小麦季节，单次灌溉应施用 3 dS/m。这种做法可以缓解该地区的淡水短缺，并允许维持冬小麦和玉米相对稳定的产量，而不会有盐分在土壤中积累的风险。