Foliar application of liquid biofertilizer of brown alga Stoechospermum marginatum on growth, biochemical and yield of Solanum melongena

Background Seaweed extracts are used as nutrient supplements, biostimulants and or biofertilizers as an alternative to chemical fertilizers in agriculture. The study was set up to evaluate the biofertilizing efficiency of liquid extracts of brown marine alga Stoechospermum marginatum on growth, biochemical and yield of brinjal, a vegetable crop. To achieve the objectives, liquid extracts at different concentrations were prepared and applied as foliar spray on the brinjal seedlings raised in experimental pots maintained under natural conditions. Results After 30 and 180 days, the growth and biochemical parameters and yield attributes were monitored, respectively. The results exhibited that shoot and root length, total fresh and dry weight, leaf area and the content of moisture, photosynthetic pigments, protein, amino acids, reducing sugar, ascorbic acid and nitrate reductase activity were found to be enhanced in the leaves of brinjal plants which received 1.5 % of Stoechospermum marginatum extracts. Similarly, number of fruits and fruit weight were also increased at lower concentration only (1.5 %). In contrast, liquid extracts at high concentration (5 %) was found to have inhibitory effect on brinjal plants as compared to the control sprayed with water. Conclusions The study evidence that lower concentrations were found to show promoting effect on growth and productivity of brinjal plants. The fertilizing efficiency of liquid extracts of testing marine alga might me due to the presence of micro and macro nutrients, growth hormones and vitamins at preferential levels. It can be concluded that seaweed extracts could be used as eco-friendly liquid biofertilizer to substitute chemical fertilizer and also play a pivotal role in organic farming practices toward sustainable agriculture.