LAUSR

Soil saline-alkalization is becoming a ma-jor constraint for agricultural production, seriously threatening global ecosys-tems and food security. An estimated 50% of total agricultural land will be salinized by 2050 due to factors such as low precipitation, high surface evapora-tion, poor cultural practices, over application of chemical fertilizers and so on [1]. It is important to note that approximately 60% of the saline soil has con-current alkalization problems, conferred by high amounts of sodium carbon-ate (Na 2 CO 3 ) or sodium bicarbonate (NaHCO 3 ). Compared with pure neu-tral salt stress, combined saline-alkaline stress always results in higher cellular ox-idative stress, more serious trophic ion imbalance, reduced osmotic adjustment capacity, and reduced uptake rates of es-sential nutrients [2]. According to the salt concentration and pH value of the soil, saline-alkaline stress can be classi-fied into three levels: mild (salt content ≤ 0.3%, pH 7.1–8.5), moderate (salt content 0.3%–0.6%, pH 8.5–9.5), and severe (salt content ≥ 0.6%, pH 9.5) stresses [3]. With the progress of saline-alkaline tolerant crop breeding, the mild and moderate saline-alkaline soils are ex-pected