The Impact of Ammonium to Nitrate Ratio on the Growth and Nutritional Status of Kale

Abstract

The effect of four NH4:NO3 ratios in the nutrient solution (0:100; 25:75; 50:50 and 75:25) on growth and nutrient concentrations of four kale (Brassica oleraceae L. var. acephala) hybrids: ‘CN KAL 1029’, ‘Redbor’, ‘Winnetou’, ‘Reflex’ and one indigenous cultivar: ‘Ntopia Mytilinis’ was investigated. In the first four weeks of cultivation none of the NH4/NO3 ratios applied induced adverse effects on most growth characteristics determined whereas plants grown with 75% NH4-N accumulated higher leaf N, P, K, Fe, Mn, Zn and Cu concentrations. After an eight week period, plants under 75% NH4-N showed significant reductions in many growth parameters suggesting a probable preference of kale plants grown for a prolonged period towards either a complete exclusion of NH4 from the nutrient solution or a 25:75 or a 50:50 NH4/NO3 ratio. Among the genotypes tested, ‘Ntopia Mytilinis’ produced the greatest yield with the lowest leaf nitrate accumulation. 
 
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 In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue.
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From urine to food and oxygen: effects of high and low NH4+:NO3- ratio on lettuce cultivated in a gas-tight hydroponic facility

“…(2020) reported a higher chlorophyll concentration in lettuce seedlings exposed to an NH 4 + :NO 3 - ratio 25:75 than both 100:0, 50:50 and 0:100. Studies of other species also show varying results, for example, an increase in chlorophyll content with increasing NH 4 + :NO 3 - ratios was not discovered in kale ( Assimakopoulou et al., 2019 ). Different theories are proposed to explain an increased chlorophyll content as a response to high ammonium.…”

Presentations at the 2022 MELiSSA Conference – Current and Future Ways to Closed Life Support Systems

“…Song et al (2021) demonstrated that lettuce and cabbage chlorophyll content was higher in plants exposed to an NH 4 + :NO 3 ratio of 50:50, than both 0:100 and 100:0, while Zhu et al ( 2020) reported a higher chlorophyll concentration in lettuce seedlings exposed to an NH 4 + :NO 3 ratio 25:75 than both 100:0, 50:50 and 0:100. Studies of other species also show varying results, for example, an increase in chlorophyll content with increasing NH 4 + :NO 3 ratios was not discovered in kale (Assimakopoulou et al, 2019). Different theories are proposed to explain an increased chlorophyll content as a response to high ammonium.…”

Efecto de la Relación Nitrato: Amonio en Solanum nigrescens Mart. & Gal.

“…La mayor concentración de Mn se obtuvo en la relación 25:75 y la menor concentración con la relación 75:25. Estos resultados concuerdan con lo reportado por Assimakopoulou et al (2019), en col rizada (Brassica oleraceae L. var. Acephala) las cuales acumularon una mayor concentración de Zn, Mn y Cu, con la aplicación de una solución con 75% de NH 4 + .…”