Nitrification Process in the Rhizosphere of Rice and Wheat Crop Under the Influence of Elevated CO2 and Temperature in Vertisol of Central India

Abstract

Rise in greenhouse gas (GHG) emission due to anthropogenic activities is the major cause of global warming. Three major GHGs are CO2, CH4, and N2O, whose concentration is rising alarmingly. Among three major GHGs, concentration of CO2 is rising rapidly than other two GHGs. It is predicted that the concentration of CO2 may reach 550 700 ppm by 2050. Rise of CO2 concentration to 450 ppm (equivalent to 2°C rise in atmospheric temperature) may cause catastrophic changes in the environment. Climate change is likely to impact crop productivity. Increase in the mean atmospheric temperature can reduce the duration of growth phase of crops, resulting into low yield. Agricultural productivity at a global scale is projected to decline 3% to 16 % by 2080 under the climate changing scenario. Climate changing factors may influence the nutrient cycling microbes in soil ecosystem by different mechanisms. Elevated CO2 and temperature can influence the metabolism of soil microbes. Climate change factors also can affect the growth of crops thus microbes associated with plant in rhizosphere are influenced. newlineRice-wheat cropping system is dominant across India and it is predicted that climate change may affect the productivity of both crops severely. There are several mechanisms to explain the phenomenon. However, less is unknown in the angle of nitrogen cycling. In soil ecosystem, nitrogen is transformed from one form to another through nitrification and de-nitrification. In nitrification, ammonium is converted to nitrate via nitrite by soil microorganisms. In denitrification nitrate is reduced to ammonium. Nitrification is a key step for plant s nitrogen requirement as most plant acquire this form of nitrogen. Nitrification has been thoroughly studied in agricultural soil ecosystem. However, it is unclear how nitrification occurs in the rhizosphere of rice and wheat under the influence of elevated CO2, (2) elucidate the linkages among plant attributes, soil parameters and nitrification potential in response to elevated CO2, (3) eval