Effect of phosphorus and potassium fertilization on growth and flowering of geranium [electronic resource].

Includes reference.

This investigation was carried out during 2003 and 2004 seasons on a local cultivar ofPelargonium zonale, namely "Rose" growing in plastic pots of20 cm diameter filled with an equal mixture ofpeat moss and sand in a private nursery in Alexandria suburban, aiming to study the effect ofadding five levels ofphosphorus (zero, 25,50,100,200 ppm) and/or five levels ofpotassium (zero, 50,100,200,400 ppm) in 250 ml water three times weekly singly and with all possible combinations between them (5 P₂O₅ K₂O = 25 treatments). Results revealed that adding phosphorus and/or potassium alone or in combination significantly increased all the studied vegetative and flowering characteristics, as compared with the control treatment. Besides, using phosphorus at 200 ppm combined with 400 ppm potassium gave the maximum values ofphosphorus and potassium in the leaves of geranium plant, while the maximum values ofleaf-chlorophyll was found at 100 ppm phosphorus combined with 200 ppm potassium, and the inflorescence red colour was found at 400 ppm potassium alone.Highest amount ofavailable phosphorus or potassium in the soil at the end ofthe experiment wasfound at the highest level ofeach element. In brief, to obtain a flowering potplant ofPelargonium zonale cv. "Rose" with good vegetative andflowering traits, it is recommended to ftrtilize the plants with phosphorus at 100-200ppm combined with potassium at 200-400ppm dissolved in irrigation water three times weeldy with washing the pot soilfor once bi-weeldy to avoid excess salts in the pot medium.

Summary in Arabic.

1