ROLE OF HUMIC SUBSTANCES, SEAWEEDS an‎d MINERAL FERTILIZERS IN IMPROVEMENT OF CUCUMBER PRODUCTION

A field experiment was conducted to evaluate the effect of humic and fulvic acids as well as seaweeds in combination with different rates of mineral fertilizers (NPK) on production of cucumber plants. Humic and fulvic acids were added at two rates i.e. 16 and 12 L fed-1, while dry seaweed was added at rates of 3 and 2 kg fed-1. Untreated control was included. Mineral fertilizers (NPK) were added at 100%, 75% and 50% of the recommended rates required for cucumber plants. Different combinations between organic additives and mineral fertilizers were undertaken. Data show that sole application of organic acids and mineral fertilizers has an effective role on enhancement of cucumber fruits. Since there was a little bit significant difference between the different mineral fertilizers doses we can recommend, from the economical view point, the use of medium dose (75%) in combination with any of the used organic additives as an appropriate treatment that gave remarkable yield of cucumber fruits. N uptake by fruits was enhanced by either individual or combined treatments. This phenomenon was pronounced at high rate of mineral fertilizers and organic additives. Application of mineral fertilizers at rate of 75% in combination with each of the organic additives could be selected, from the economical view, as the most appropriate treatment that induced higher P uptake by cucumber fruits. Sole application of humic acid or seaweeds resulted in highly significant increase in K uptake by cucumber fruits as compared to the untreated treatment. This was more pronounced at high rate of organic addition. Combination between each of the organic substances and medium rate of mineral fertilizers could be selected as suitable strategy for potassium nutrition of cucumber. In addition, this strategy is economically profitable for farmers.