Effect of Concentration and Frequency of Gamal Leaf Liquid Organic Fertilizer on the Growth and Production of Mustard Greens (Brassica juncea)

Green mustard is a vegetable that is rich in carbohydrates, protein, good fats and vitamins A, B, C, E, and K, which are useful for a healthy body. The right fertilizer concentration can optimize plant growth. Different frequency of fertilizer application will affect plant growth.. This research was conducted in Simanindo Village, Simanindo District, Samosir Regency, North Sumatra with an altitude of ± 913 masl from June to July 2023. This study used a randomized complete block design (RCBD) with 2 treatment factors and 3 replications. The first factor was the concentration of gamal leaf liquid organic fertilizer: 80, 100, 120, and 140 ml/liter. The second factor is the frequency of application gamal leaf liquid organic fertilizer: 2 WAT; 1 and 3 WAT; 1, 2, and 3 WAT. The results showed that the concentration of gamal leaf liquid organic fertilizer had an effect on plant length, number of leaves, apparent stem diameter and fresh selling weight. The highest fresh weight was found in the concentration of 140 ml/liter. Application frequency of gamal leaf liquid organic fertilizer affects plant length, number of leaves, apparent stem diameter and selling fresh weight. The highest selling fresh weight was found in the frequency of 3 times application at 1, 2, and 3 WAT. The interaction between concentration and frequency of application gamal leaf liquid organic fertilizer had no significant effect on all parameters. Keyword: Gamal leaf liquid organic fertilizer, concentration, frequency of application, mustard green.