Background: Hygroscopic salts are often applied as foliar fertilizers and calcium (Ca) salts have been used as model for cuticular permeability studies, with focus on their Point of Deliquescence (POD). Aim: This study was aimed at characterizing water sorption and desorption processes at 20, 30, and 40°C temperature (T), of two model Ca salts commonly used as foliar sprays. Methods: Trials were developed with pure Ca‐chloride and Ca‐nitrate salts in addition to 2 M and 150 mM Ca solutions. Salts were analyzed by Dynamic Vapour Sorption (DVS) and climate chamber experiments. Results: For both Ca salts, water sorption and desorption processes followed hysteresis curves which varied with T. Salt POD was T‐dependent and generally decreased with increasing T. For both Ca salts, the process of efflorescence began at or below 10% RH, at a certain level of water desorption Ca‐salts becoming highly concentrated solutions (HCS). Conclusions: Owing to the low point of efflorescence (POE) of both salts, drops of Ca‐chloride and Ca‐nitrate supplied as foliar sprays will not fully dry under normal RH and T conditions in most world areas. Both Ca salts have a similarly high foliar penetration potential despite their different POD. The significance of the results for the potential absorption of foliar fertilizers and salts by the foliage is discussed under an agronomic and eco‐physiological viewpoint.

中文翻译：

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两种模型钙盐的盐分水合和液滴干燥：对叶面养分吸收和沉积的影响

背景：吸湿性盐通常用作叶面肥料，钙 (Ca) 盐已用作表皮渗透性研究的模型，重点是它们的潮解点 (POD)。目的：本研究旨在表征通常用作叶面喷雾的两种模型钙盐在 20、30 和 40°C 温度 (T) 下的吸水和解吸过程。方法：除了 2 M 和 150 mM Ca 溶液外，还使用纯氯化钙和硝酸钙盐进行了试验。盐分通过动态蒸汽吸附 (DVS) 和气候室实验进行分析。结果：对于两种 Ca 盐，水吸附和解吸过程遵循随 T 变化的滞后曲线。盐 POD 依赖于 T，并且通常随着 T 的增加而降低。对于两种 Ca 盐，风化过程在 10% RH 或以下开始，在一定程度的水解吸下，钙盐变成高浓度溶液（HCS）。结论：由于两种盐的风化点 (POE) 较低，作为叶面喷雾提供的氯化钙和硝酸钙滴在世界大多数地区的正常 RH 和 T 条件下不会完全干燥。尽管它们的 POD 不同，但两种钙盐都具有类似的高叶面渗透潜力。从农艺学和生态生理学的角度讨论了结果对叶子潜在吸收叶面肥料和盐分的重要性。尽管它们的 POD 不同，但两种钙盐都具有类似的高叶面渗透潜力。从农艺学和生态生理学的角度讨论了结果对叶子潜在吸收叶面肥料和盐分的重要性。尽管它们的 POD 不同，但两种钙盐都具有类似的高叶面渗透潜力。从农艺学和生态生理学的角度讨论了结果对叶子潜在吸收叶面肥料和盐分的重要性。