Ramirez-Builes Victor Hugo, Küsters Jürgen, Thiele Ellen, Leal-Varon Luis Alfredo, Arteta-Vizcaino Jorge
Center for Plant Nutrition and Environmental Research Hanninghof, Yara International, 48249 Dülmen, Germany.
Yara Colombia, Zona Industrial Mamonal, Cartagena 130009, Colombia.
Plants (Basel). 2023 May 19;12(10):2033. doi: 10.3390/plants12102033.
Chloride (Cl) is applied in coffee at rates as a "macronutrient" in the form of muriate of potash (MOP). Potassium (K) is one of the most demanded nutrients by the coffee plant, and MOP is one of the most used fertilizers in coffee production. No scientific evidence shows how Cl applied with MOP influences coffee growth, nutrient uptake, and nitrogen use efficiency (NUE). In order to address these questions, a greenhouse trial over two years and a field trial over four years were conducted. The trials were designed to test the influence of variable Cl/S ratios on biomass accumulation, nutrient uptake, and NUE. A significant effect of the Cl rates on growth was observed under greenhouse conditions but a non-significant effect on yield under field conditions. Cl and S significantly influenced the NUE in coffee. The results allow us to conclude that Cl rates need to be balanced with S rates, and that Cl applied at macronutrient rates can improve the NUE in coffee between 7 and 21% in greenhouse conditions and between 9% and 14% in field conditions, as long as the rates do not exceed 180 mg L Cl and 80 mg·L S in the greenhouse and 150 kg·ha·year Cl and 50 kg ha·year S in the field. With the aim to improve the NUE in coffee, the Cl content in leaves in coffee should be lower than 0.33% of dry matter, and in soil lower than 30 mg·L. In practical terms, coffee farmers need to balance K-based fertilizers to avoid the excessive Cl applications that reduce the nutrient use efficiency, especially the NUE.
氯（Cl）以氯化钾（MOP）的形式作为“大量营养素”施用于咖啡中。钾（K）是咖啡植株需求量最大的养分之一，而MOP是咖啡生产中最常用的肥料之一。没有科学证据表明与MOP一起施用的Cl如何影响咖啡生长、养分吸收和氮素利用效率（NUE）。为了解决这些问题，进行了为期两年的温室试验和为期四年的田间试验。这些试验旨在测试不同Cl/S比率对生物量积累、养分吸收和NUE的影响。在温室条件下观察到Cl施用量对生长有显著影响，但在田间条件下对产量无显著影响。Cl和S对咖啡中的NUE有显著影响。结果使我们得出结论，Cl施用量需要与S施用量相平衡，并且只要温室中Cl施用量不超过180 mg·L且S不超过80 mg·L，田间Cl施用量不超过150 kg·ha·年且S不超过50 kg·ha·年，以大量营养素比率施用的Cl可使温室条件下咖啡的NUE提高7%至21%，田间条件下提高9%至14%。为了提高咖啡中的NUE，咖啡叶片中的Cl含量应低于干物质的0.33%，土壤中的Cl含量应低于30 mg·L。实际上，咖啡种植者需要平衡钾肥的施用，以避免因过量施用Cl而降低养分利用效率，尤其是NUE。
