Use of saline water for irrigation is essential to mitigate increasing agricultural water demands in arid and semi-arid regions. The objective of this study is to address the potential of using straw biochar as a soil amendment to promote wheat production under saline water irrigation. A field experiment was conducted in a clay loam soil from eastern China during 2016/2017 and 2017/2018 winter wheat season. There were five treatments: freshwater irrigation (0.3 dS m−1), saline water irrigation (10 dS m−1), saline water irrigation (10 dS m−1) combined with biochar of 10, 20, 30 t ha−1. Saline water irrigation alone caused soil salinization and decreased wheat growth and yield. The incorporation of biochar decreased soil bulk density by 5.5%–11.6% and increased permeability by 35.4%–49.5%, and improved soil nutrient status. Biochar also reduced soil sodium adsorption ratio by 25.7%–32.6% under saline water irrigation. Furthermore, biochar alleviated salt stress by maintaining higher leaf relative water content and lower Na+/K+ ratio, and further enhanced photosynthesis and relieved leaf senescence during reproductive stages, leading to better grain formation. Compared to saline water irrigation alone, biochar application of 10 and 20 t ha−1 significantly increased wheat grain yield by 8.6 and 8.4%, respectively. High dose of biochar might increase soil salinity and limit N availability. In the study, biochar amendment at 10 t ha−1 would be a proper practice at least over two years to facilitate saline water irrigation for wheat production. Long-term studies are recommended to advance the understanding of the sustainable use of straw biochar.

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The coastal regions of eastern China have substantial potential for agricultural production. Freshwater scarcity makes the utilization of plentiful brackish water a vital issue in this area. We aim to assess the effects of cycle irrigation with fresh and brackish water on soil salinity and maize (Zea mays L.). A pot experiment was performed with two typical coastal soils (sandy loam and silt loam) and one local maize cultivar. The maize growing season was divided into three phases (development, mid‐, and later stage). Cycle irrigation was conducted using brackish water (5 g NaCl L−1) during one stage and freshwater for the remaining stages. Cycle irrigation using brackish water at the development stage caused both osmotic and ionic stresses on the maize, leading to significantly‐reduced evapotranspiration (ET), increased stem and leaf Na+/K+ ratio, and stunted growth. The decline of kernel number and 100‐grain weight resulted in severe yield loss. Cycle irrigation with brackish water at the mid‐stage induced less adverse effects on crop growth, while the decrease in kernel number remarkably reduced the yield. Cycle irrigation with brackish water at the later stage minimized the impacts of saline irrigation on soil salinity and maize productivity. Nonetheless, salt leaching by off‐season rainfall and low salinity water and soil salt monitoring should be considered before the next season. Compared to sandy loam soil, silt loam displayed higher soil salinization, and lower maize growth and yield. Additional field research is recommended to facilitate the reliable use of coastal soil and water resources. Core Ideas Cycle irrigation with fresh and brackish water in two coastal soils is studied. Cycle irrigation using brackish water is effective when freshwater is scarce. Brackish water is proposed to be used at maize later reproductive stages. Sandy loam soil is preferable for cycle irrigation compare to silt loam soil.

The considerably high evapotranspiration and the low leaching fraction of the soil in arid regions are likely the primary causes of the enhanced soil salinity in such regions. Winter irrigation has proven to be very effective for promoting the leaching of salts from the rooting-zone. In this study, we investigated the effects of different irrigation methods (flood irrigation and drip irrigation) and winter irrigation quotas (450, 1350, 2250, 3150, 4050, and 4950 m 3 /hm 2 ) on soil salinity and plant growth in an arid region. The sum of EC e in the 0–100 cm soil layer was 56.26–29.32 ms/cm under flood irrigation, 61.37–17.90 ms/cm under drip irrigation, and 64.13 ms/cm under no irrigation. The survival rates of jujube trees reached 65% and 77%, respectively, for drip irrigation and flood irrigation with a quota of 2250 m 3 /hm 2 . Furthermore, at irrigation quotas in excess of 3150 m 3 /hm 2 the ground diameter and height of jujube trees were significantly greater than those observed under nonwinter irrigation and several other winter irrigation treatments. These findings indicated that winter irrigation significantly reduced soil salinity, changed the soil salt distribution, created a good environment for the growth of jujube trees and improved the survival rate of young jujube trees, especially under winter drip irrigation with a quota of 3150 m 3 /hm 2 . In addition, 1-year-old jujube trees emerging in spring may benefit from an EC e lower than 5 ms/cm.