This study was conducted during two successive seasons of 2016 and 2017 on Crimson seedless grapevines (Vitis vinifera L.) in
a private vineyard located at El-Khatatba region, Minofia governorate, Egypt. The vines were 6 years old and spaced 2.0 m within vines
and 3.0 m between rows and grown in a sandy soil under drip irrigation system. This investigation was conducted to study effect of
potassium sulphate (60, 90, 120 and 150 kg/fed.) and foliar spray magnesium sulphate (0.0, 100, 200 and 300 ppm) as well as their
combination in order to assure optimum growth and maximum productivity with high fruit quality.The obtained results showed that the
largest leaf area and the thickest cane were resulted from the combinations of potassium at 150 kg/fed., especially those received
magnesium at the high level (300 ppm) and medium level (200 ppm) in the two seasons. The highest values of berry length, width and
weight were registered by the combined treatment between potassium fertilization at 150 kg/fed. and 300 ppm magnesium in the both
seasons. The best cluster weight and yield/ fed. were scored by the combination of the high rate of both potassium and magnesium
fertilizer in the two seasons. The combined treatment between potassium and magnesium at the high level achieved the highest values of
red berries % and the lowest values of green berries % in the two seasons. Whereas, the highest record of pink and green berries % were
gained by combined treatment received the lowest rate of potassium fertilizer and magnesium foliar spray at 0.0 ppm in the two seasons.
The highest values of total sugars %, TSS % and anthocyanin content as well as the lowest value of acidity % were scored by the
combined treatment between the high rate of potassium fertilization and magnesium foliar spray at 300 ppm in the two seasons. The
highest leaf content of N, P and K % were obtained by those fertilized by the high rate of both potassium and magnesium in the two
seasons. Thereby, it could be recommended that foliar application with magnesium at 300 ppm and potassium fertilization at 150 kg/fed.
could be used to improve growth, yield and quality berries of Crimson seedless grapes. |
