Fruit Yield and Quality of Fig (Ficus carica L.) are Affected by Foliar Sprays of Potassium Sulfate

Fruit yield and quality in fig (Ficus carica L.) are highly influenced by mineral nutrition, especially Calcium (Ca) and potassium (K). In this study, the impact of soluble potassium sulfate (K۲SO۴) foliar application on yield, fruit quality, and leaf nutrient content was assessed during three consecutive years (۲۰۱۷- ۲۰۱۹) on fig cv. ‘Bouhouli’ grown in Northwest Tunisia. Potassium sulfate was sprayed at ۲% concentration on leaves of ‘Bouhouli’ trees twice each year during fruit development. This improved fruit weight by ۲۹.۵% and ۳۴.۹% in the first and second years, respectively, while yield and fruit quality were improved in ۲۰۱۸ only. The fruit ostiole-end cracking, which is one of the fruit quality criteria, was reduced under potassium treatment by ۳-fold (۱۷%) compared to the control (۵۳%), in ۲۰۱۸. Also, potassium treatment increased significantly the content of total soluble solids in the fruits during the first two seasons. Besides, K leaf concentration significantly increased after the ۲% K۲SO۴ treatment in ۲۰۱۸ and ۲۰۱۹. These results suggest that potassium sulfate foliar sprays could be used as part of an efficient and sustainable fertilizer program to improve fig tree yield and fruit quality.

Keywords:

Fig cracking , Fig quality traits , Fig yield , Ostiole-end splitting.