Effect of plant sound wave technology to increase productivity of mustard greens (Brassica juncea L.)

Plant sound wave technology (PSWT) is the use of sound waves to improve crop productivity and quality through optimization of stomata opening so that plants are able to absorb nutrients and water optimally. The purpose of this study is to test PSWT to increase the vegetative growth of mustard greens (Brassica juncea L.). The type of music used in PSWT is Javanese gamelan entitled Puspawarna. PSWT exposure time is given to plants in the morning and evening. The frequencies used are 3-5 kHz, 7-9 kHz, and 11-13 kHz. The mixture of organic planting media i.e. roasted husk, cocopeat, and moss with a ratio of 2: 2: 1 for soil, organic planting media, and organic fertilizer. Observations were made on plant height, plant length, wet weight, stomata opening, leaf chlorophyll, leaf area, and the number of plant leaves. The results showed that the frequency and the mixture of organic planting media significantly affected the wet weight, plant length, stomata opening, plant height, leaf chlorophyll, leaf area, and the number of leaves. The best PSWT method for growing mustard greens is using a frequency of 3-5 kHz with moss as the organic planting media. The maximum yield of vegetative growth resulted in the most optimal stomatal openings of 70.84–159.46 µm, with a plant height of 19.47 cm, plant length of 29.47 cm, leaf area of 31.99 cm2, number of leaves is 5.33 strands, leaf chlorophyll of 31.60 cci, and wet weight of 5.01 g.