The viability test of phosphate solubilizing microbes on carriers during storage

Abstract

Excessive use of inorganic fertilizers, especially during the green revolution, has caused pollution and contamination of the soil due to accumulated residues. The inorganic fertilizer residues then cause soil compaction, loss of available nutrients and soil organic matter, loss of soil biodiversity which indirectly reduces soil fertility and makes plants more susceptible to disease. Biofertilizers have the potential to optimize soil response to fertilization, improve soil health, and even reduce the need for inorganic fertilizers to achieve sustainable agriculture. One of the types of microbes contained in biological fertilizers that have been proven to be able to replace the need for inorganic P fertilizers and improve soil health and productivity is a group of phosphate solubilizing microbes. The quality of biofertilizers is also determined by the carrier material capable of supporting the growth of inoculants. The purpose of this study was to test the viability of phosphate solubilizing microbes on carriers during storage The microbes used were Bacillus subtilis, Pseudomonas mallei, Burkholderia sp, and Trichoderma harzianum, while the tested carrier material were hydrogel and kaolin. The results showed that hydrogel and kaolin as carriers were able to support the growth of P-solubilizing microbes inoculants during storage (until 126 day). The number of viable populations of each isolate that makes up the biofertilizer consortium was in the high population range up to 1012 cfu. g-1.