Changes in fruit yield and quality in response to foliar and soil humic acid application in cucumber

This study was designed to determine the influence of foliar and soil humic acid (HA) treatment on fruit quality and yield of cucumber grown under soil conditions in a greenhouse. Different concentrations of HA (0, 10, 20, 30 and 40 ml/L) were applied to cucumber plants through either foliar spraying or drenching in the root area. Foliar and soil HA applications led to significantly higher mean fruit weight, early and total yield than the control. HA treatments had no significant effect on skin chlorophyll b, mesocarp chlorophyll a, b and total chlorophyll contents, fruit length and diameter. Both soil and foliar HA treatments significantly increased total and reducing sugar contents. Moreover, HA application significantly influenced fruit skin total chlorophyll content and this effect was mainly on chlorophyll a content. The study shows that cucumber fruit yield and quality can significantly be improved with soil and foliar HA application.   Key words: Cucumber, humic acid, quality, yield.