Introduction

From the beginning of 19th century, human population has been grown up to 7 fold that leads to the overexploitation of the natural resources of planets. These natural resource exploitations include loss of biodiversity, change in climate, and disturbance in the nitrogen cycle. For social and political consideration, reduction of biodiversity and changes in climate have become major issues. With these issues, the disturbance in the nitrogen cycle is also a worldwide problem that needs higher consideration. As the demand for food is increasing with the growing population, the revolution in the agriculture has a gigantic influence on the universal biogeochemical cycle. ¬¬¬Approximately 1011 kg of nitrogen fertilizers is assessed per year. While more than 60% of the fertilizer is not absorbed by the plants and go into the groundwater. For cyano-bacterial and algal blooms are not reached to the plant by the nutrient ‘Nitrogen’. And these nutrients released into the groundwater, drifts into the sea where they cause intense variations in marine microbial populations and disturb the whole marine food chain.

In developing countries, the fertilizers are used in excess for enhancing the potential of plants. It is necessary for developing countries to increase their yield per hectare noticeably. Here it becomes difficult to understand how plant growth can be improved without using the costly and environment damaging synthetic fertilizers. According to report, the crop harvest per hectare will be increased by 2050. The deforestation is a temporary solution of the ability of crop yield areas.

The lands which have been converted into fields can be used for increasing the crop yield. Another way for increasing yield is to investigate on to the natural abilities of plants. Before century, it was observed that soil is rich with microbes around the plant roots. This soil was termed as rhizosphere. These soil microorganisms showcase a significant role in plant health and in the procedure that takes place in the rhizosphere. Now, these microorganisms can be utilized to escalate the plant development in a viable manner. The important goal of rhizosphere plant-microbe studies is connecting the capability of microbes to offer plants with vital micro and macronutrients (Tkacz and Poole, 2015). Plant root growth is enhanced by the good soil structure and results in greater extraction of water and nutrients. The fertility of the soil is increased when released organic compound from soil microbes helps in the binding of individual soil particles into aggregates (Coyne and Mikkelsen, 2015).

Soil Microbes and Plants

Even though, the soil is a rich source of nutrition to plants for the plant physiologists. But it is also considered a complex ecosystem that contains bacteria, protists, fungi and animals. Soil-dwelling organisms interact with the plants in different ways that have the complete series of ecological prospects such as exploitative, commensal, competitive, mutualistic and neutral. New plant science is engaged in the studies of lessening pathogenic effects like herbivory, infection and attenuating abiotic stress conditions.