The development of bacterial communities as affected by pH and soil type

摘要

A study was made of the effect of liming (Ca(OH)2) on the numbers and biomass of bacteria (B) determined by a direct method in two types of soil: loamy sand (ls) and a loose sandy soil (lss) during 90 days in laboratory conditions. The liming of lsscaused a marked and comparatively permanent increase in the bacterial biomass highly correlated (r=0.8) with changes in soil acidity. The raising of pH from 4.5 to 7.0 and 9.0 brought about an increase in the mean size of biomass by 74% and 170%, respectively, in comparison with the control. Also the liming of ls with its relatively high native pH of 7.7 to pH 9.0 and 11.0 caused the mean size of B to increase by 30% and 40%, respectively. The response of bacterial communities in this soil to the raising of pH was less enduring than that found in lss, although even after 3 months their biomass sizes were 10% greater than in the control.