Effect of Nutrient Solution pH on Growth and Yield of Broccoli

Abstract

In an experiment aimed at optimizing the pH of the nutrient solution for the growth, yield, and quality of broccoli (Brassica oleracea var. italica) in a deep water culture hydroponic system (DWC), five pH treatments were included: P1 = pH level 4, P2 = pH level 5, P3 = pH level 6, P4 = pH level 7, and P5 = pH level 8. The study took place at Patuakhali Science and Technology University in Bangladesh. Various parameters related to plant growth, yield, and quality were measured during the study. The results revealed that both high (8.0) and low (4.0) pH treatments led to a decrease in broccoli plant biomass, yield, and quality. However, at pH level 6.0 (P3), the highest values were recorded for leaf area (407.42 cm²), shoot length (28.77 cm), root length (32 cm), curd diameter (14.83 cm), curd fresh weight (242.33 g), and dry weight (28.33 g) at 60 days after transplanting (DAT). The number of leaves per plant, TSS (Total Soluble Solids), total phenols, and titratable acidity content of broccoli curd did not show significant differences among the different pH treatments. The lowest values for leaf area (235.23 cm²), shoot length (19.83 cm), and root length (23 cm) were observed at pH level 8 (P5). Additionally, the lowest curd diameter (8.83 cm), curd fresh weight (76.67 g), and dry weight (9.80 g) were recorded at 60 days after transplanting (DAT) in treatment P1 (pH level 4.0). Based on the criteria of broccoli growth and quality, the optimal pH treatment for broccoli in a deep water culture hydroponic production system was found to be pH level 6.0 (P3). The study concluded that both high and low pH levels limited nutrient uptake, thereby negatively affecting the quality, growth, and yield of broccoli.