Potential Change of Soil Microbial Diversity in Anticipated Atmospheric-CO2 Elevation Triggers Rhizosphere Activation: A Meta-analysis.
Abstract One of the key challenges in present time to meet out growing global food demand without damaging environment under constant threats of climate-extremes. Enhancement of nutrient use efficiency and build up intrinsic system tolerance through soil microbial manipulation has gained significant international support to address this challenge. Impact of elevated carbon dioxide (CO2) on soil microbial diversities both at present and future climatic scenario in spatial and temporal scale is highly debated with respect to its effects on soil functioning, nutrients dynamics and crop productivity and its practical consequences on resource conservation and food security. We conducted a meta-analysis on global database using 572 observations from 202 studies to investigate the effects of elevated CO2 on soil microbial biomass carbon (MBC), yield and structural (soil microbial populations) and functional (soil enzymatic activities) diversities across 22 countries and 108 crop species. Overall, our results revealed that MBC and functional diversity increases with elevated atmospheric-CO2 irrespective of temperature zone and crop type. However, data trends showed structural diversity has been gradually adapted under elevated CO2 across the region over decadal scale. Anticipated elevation of atmospheric CO2 increase rhizospheric activities and could make soil more input demanding and more so in temperate region. Therefore, to fetch the benefits of CO2 fertilization and to meet out the higher demand both plant and soil (microbes), real time judicious nutrient supply is necessary; otherwise, soil priming, loss of fixed soil carbon reserve and land degradation might threat the future food security.