Application of inorganic and liquid organic bio-fertilizers affects the vegetative growth and rhizobacteria populations of eight banana cultivars

Abstract

Banana (Musa spp.) is one of the fruit crops widely planted and consumed in Indonesia. In the commercial cultivation of bananas, large amounts of inorganic fertilizers are intensively applied to the soil to improve its yields. However, improper continuous application of those inorganic fertilizers can be hazardous to the environment, especially hampering soil fertility. The reduced inorganic fertilizer rate combined with eco-friendly bio-fertilizer has been widely accepted as an alternative approach to ensure sustainable agriculture production and is expected to include banana production. This research evaluated the application of liquid organic bio-fertilizer (LOB) in banana plantations by observing their effects on plant vegetative growth and soil microbial population. The LOB combined with inorganic fertilizer were tested in composition of 1) 100% inorganic fertilizer (NPK), 2) 50% NPK + 100 % LOB, 3) 100% LOB; on eight banana cultivars, i.e., Mas Kirana (AA), Cavendish (AAA), Barangan (AAA), Raja Bulu (AAB), Raja Lido (AAB), Raja Sereh (AAB), Tanduk (AAB), and Kepok (ABB). The results showed that for most of the cultivar tested, liquid bio-fertilizer could be applied in combination with the reduced NPK fertilizer rate to give not significantly different results than 100% inorganic fertilizer vegetative growth rate on the early development of banana. The liquid organic bio-fertilizer application also generally improved soil microbial population, including PGPR with a specific function such as IAA (indole-3-acetic acid) producing activity, phosphate solubilizing, and protease enzyme activity. The application LOB alone was insufficient to support vegetative banana growth to the level incurred by the moderate rate of inorganic fertilizer application.