EFFECTS OF BIOGAS SLUDGE COMPOST MIXED WITH PLANT MATERIALS ON THE GROWTH OF CHINESE WATER SPINACH

Abstract

 This study aimed to evaluate the effectiveness of compost derived from biogas sludge of cassava processing combined with plant materials, namely water hyacinth and Samanea saman leaves, on the growth of Chinese water spinach. A pot experiment was conducted using three compost treatments: Treatment A (biogas sludge alone), Treatment B (biogas sludge mixed with water hyacinth at a 1:1 ratio), and Treatment C (biogas sludge mixed with Samanea saman leaves at a 1:1 ratio). The composts were fermented for 45 days and then mixed with soil at a 1:1 ratio, with a total pot weight of 3 kg. Each treatment was replicated three times and compared with a control consisting of soil only. Growth parameters, including leaf number, plant height, stem circumference, and fresh weight, were measured at 25 days after planting. The results indicated that Treatment C (biogas sludge mixed with Samanea saman leaves) produced the highest growth in all parameters, with an average leaf number of 20, plant height of 4.12 cm, stem circumference of 5.84 cm, and fresh weight of 12.43 g. In contrast, the control exhibited the lowest growth (leaf number 11.88, plant height 3.07 cm, stem circumference 4.12 cm, and fresh weight 3.67 g), while Treatments A and B showed intermediate results. The study demonstrated that compost incorporating biogas sludge and plant materials can effectively enhance the growth of Chinese water spinach. Notably, Treatment C was the most effective in promoting plant growth, improving soil quality, and maintaining ecological balance.