**3. Main problems related to the over-exploitation of natural reserves of P and chemical fertilisers**

Global food production needs to be increased due to the rapidly increasing world population [20]. The low bioavailability of phosphate directly affects to not being able to fulfil the required amount of crop production. Due to the low bioavailability, an extra amount of phosphate has to be utilised as fertilisers to provide the optimum requirement of P of plants. Therefore, it is directed to high utilisation, and the peak extraction of phosphate will take place in 2030 [22]. Besides the depletion of natural P resources,

*Managing Soil and Plant Nutrients: Role of Microbial Phosphate Solubilisation DOI: http://dx.doi.org/10.5772/intechopen.112640*

over-exploitation of natural reserves of P and excessive use of chemical P fertilisers lead to several environmental and agricultural problems such as soil degradation, groundwater contamination, eutrophication and climate change [10, 21]. Hence, it is highly required for sustainable utilisation of phosphate to minimise wastage [4]. State-of-theart technique to use microorganisms to solubilise the insoluble forms of phosphates and increase their bioavailability is an effective option [10, 23].
