Prospects of Bacillus spp. as consortium in bio-fertilizer for phosphate solubilization

Abstract

The matter of degrading agricultural land resource and their desertification has been a subject of concern all over the world. This has led a peer pressure on farmers to increase agricultural production within a limited space. So, for these many years the use of chemical fertilizers has been extensive in the agricultural community which can even double the production. But these fertilizers are also associated with serious health and environmental problems like soil pollution. Chemical fertilizers are also responsible for degrading the quality of soil by increasing acidity, lacking soil micronutrients eventually leading to desertification of soil. It is known that soil naturally contains several microorganisms including bacteria and fungi which are beneficial to plant. They are associated with the plant growth and its productivity. Many of them; especially bacteria are responsible for providing the essential macronutrients like nitrogen, phosphate, sulfur etc. by converting their insoluble forms into soluble forms. Phosphate is the second most important key nutrient required by plants. It plays a key role in plant growth and development. On average, soil contains 400–1000 mg kg−1of total P, of which only 1.00–2.50% is available to plants for uptake. Phosphorus is found in soil in both mineral and organic forms. Most of the organic phosphate (20 to 80%) has been found to be inert. This study is an approach to learn the effects of phosphate solubilizing bacteria on insoluble phosphate and as a bio-fertilizer by integrating it with residual biochar. The bacteria used in this study was isolated and indentification was done by morphological, biochemical and molecular techniques. Thus isolated bacteria was subjected to phosphate solubilization test and its effects as biochar on plants. Our study finds out that the isolated bacteria of Bacillus spp. have certain ability to solubilize insoluble phosphate present in hydroxyapatite into soluble forms. The concentration of soluble phosphate in the media was found in average of 7.93µg/ml in case of B. subtilis and 13.4µg/ml in case of B. megaterium. These bacteria along with others when integrated with biochar showed positive results on plant development. Our study also suggests that biochar could be used as artificial soil in marginalized land and deserted areas.

Keywords: Soil macronutrients, phosphate, soil microorganisms, bio-fertilizer, residual biochar, hydroxyapatite, artificial soil