The Growth of Pak Choy ( Brassica rapa L.) on the microalgae ( Spirulina platensis) biomass-based nutrient solution

Abstract

Microalgae (Spirulina platensis), as an organic nutrition source, may play an important role in stimulating the nutritional needs of Pak Choy (Brassica rapa) in a hydroponic system. This study aimed to use S. platensis dry biomass as a nutrient source of Pak Choy grown hydroponically compared to commercial hydroponic nutrients (ABmix) as a control in screenhouse conditions. The experiment was arranged in a factorial design, the first factor was maceration time (0, 1, and 2 weeks), and the second was the concentration of S. platensis solution (0.1, 0.5, 1.0 g/l, and ABmix). The experimental design was arranged in a completely randomized design with three replications. The observed variables were plant height, total leaf, fresh weight of root, shoots, total weight, and chlorophyll content. The results showed that there was no interaction in all observed variables. The maceration treatments did not affect the plant growth, except for plant weight (23.6 g) and leaf width (0.8 cm). However, S. platensis concentration treatments affected all observed variables significantly (p<0.01). On the other hand, all treatments showed tip burns three to four weeks after planting. It concluded that organic substances from S. platensis dry biomass have a potential use as hydroponics nutrient solutions. However, further study needs to be conducted to obtain the optimum treatments (concentration and maceration time) to produce healthier vegetables.