Effect of Soil Solarization on Native AM Fungi and Microbial Biomass

Abstract

An experiment was conducted to study the effect of soil solarization on native arbuscular mycorrhizal (AM) fungi and soil microbial biomass. Solarization was done using transparent polyethylene (TPE) sheets of 0.05 and 0.10 mm thickness for 20, 40, and 60 days. Sunflower crop was taken after solarization. In plots solarized with 0.05 mm TPE sheets, soils solarized for 60 days had lesser number of infective propagules of AM fungi compared to those solarized for 40 or 20 days. However in soils solarized with TPE sheets of 0.10 mm thickness, no significant difference in spore numbers was found. Mycorrhizal colonization was significantly less in solarized soils, except in soils solarized with 0.10 mm TPE for 60 days. Soil microbial biomass increased as solarization period increased from 20 to 60 days in plots solarized with both 0.05 and 0.10 mm TPE. The yield of sunflower was significantly more in plots solarized for 60 days with TPE sheets of 0.05 or 0.10 mm thickness. There was a significant positive correlation between soil microbial biomass and seed yield. Though not significantly, soil microbial biomass and AM colonization were positively correlated, suggesting that mycorrhizal colonization might be stimulating soil microbial biomass. Therefore, even though microbial biomass correlated significantly with seed yield (r = +0.677*), the increase in seed yield could be attributed to an interaction effect of both AM colonization, and soil microbial biomass. This is the first report bringing out the various factors like solarization, AM colonization and soil microbial biomass on seed yield of sunflower.