Epsilon Archive for Student Projects

Abstract

The rising global food requirement, alongside the necessity of reducing farming dependency on synthetic fertilizers, has been driving the interest in bio-derived products such as biostimulants. Brown juice (BJ), a low-cost by-product derived from the protein fractionation of sugar beet leaves, has the potential to be used as a biostimulant. This study evaluated the biostimulant effects of BJ on growth indexes, yield, and biochemical quality in Baby-Leaf and Webbs-Wonderful lettuce (Lactuca sativa L.) varieties.

Greenhouse experiments were conducted using a randomized complete block design (RCBD) with four treatments: control, nutrient control, 2% BJ (BJ1), and 4% BJ (BJ2) and two application methods (i: leaf application and ii: soil drenching). Growth and yield traits like leaf count, leaf fresh and dry weights, dry root weights were measured after harvest. Biochemical quality was analysed through ascorbic acid (vitamin C), and antioxidant activity (FRAP). Statistical comparison with ANOVA and Tukey’s HSD test was employed to compare treatment effects and interactions between varieties.

Results indicated BJ1 significantly boosted root weight and dry biomass of Baby-Leaf lettuce (mean dry root weight (DRW) 1.90 g under leaf BJ1 compared to 0.41 g in controls), while Webbs-Wonderful reacted more moderately (mean DRW 1.25 g under leaf BJ1 compared to 0.29 g in controls). Biochemically, BJ1 enhanced vitamin C content, and antioxidant activity in Baby-Leaf lettuce, and Webbs-Wonderful, on the other hand, showed little biochemical reaction to BJ treatments.

Overall, the findings show that BJ can be used as a variety- and concentration-dependent biostimulant to promote both growth and nutritional quality. Aside from crop yield, the valorization of sugar beet residues in a biorefining concept and to obtain BJ as a biostimulant/biofertilizer also reveals its potential in enabling sustainable and circular agriculture production systems in the future.