09-08-2013, 03:50 PM
Sequestration of microbial biomass carbon in mycorrhizosphere under different agroclimatic zones of jammu
ABSTRACT
Soils with a total global storage of approximately1500 Gt C hold three times as much carbon as the terrestrial biosphere and about twice as much as the atmosphere. A dynamics of carbon in soil is closely related to microbial diversity, predominantly symbiotic organisms. In the present study attempt was made to calculate microbial biomass carbon (MBC) in each mycorrhizosphere to assess the role and importance of AM species for carbon dynamics in the soils from three agroclimatic zones of Jammu region viz sub-topical (300-1000m AMSL), intermediate (1000-1500m ASML) and temperate (1500-2500m ASML), for sequestered microbial biomass carbon under the influence of different isolated AM species using chloroform fumigation method. Mycorrhizas increase the microbial and enzyme activity in the soil thereby raising the MBC. A present investigation revealed that the microbial biomass carbon in different soils of sub-tropical zone inoculated with G. mosseae, varied between 183 to 282 µg C g-1 soil where as it ranged from 176 to 254 and 181 to 260µg C g-1 soil in Gigaspora sp and Glomus fasciculatum inoculated soils, respectively. In this zone, MBC in Kotlibhagwan soils (255 µg C g-1 soil) was followed by Chowkichora (221 µg C g-1 soil), Banota (210 µg C g-1 soil), Jhajarkotli (204 µg C g-1 soil) and Thein soils (180 µg C g-1 soil). The least microbial biomass carbon was found in Tikri soils (168 µg C g-1 soil). In temperate zone, the maximum biomass carbon was observed in soils inoculated with Glomus mosseae which was significantly higher than other two species under study. Location with highest microbial biomass carbon was observed in Batote soils (376 µgCg-1 soil) which were significantly higher over rest of the locations except Assar (371 µgCg-1 soil). All the three AM inoculants had significantly increased the microbial carbon biomass over control. A positive correlation was observed between clay and organic carbon with soil aggregation as influenced by AM inoculation (r=0.916*, r=0.912* and r=0.785* for three different AM species owing to their direct intraradical access to plant carbon