Abstract
A greenhouse pot experiment was conducted to investigate the influence of soil moisture content and plant species on soil
microbial community structure using cultivation-independent methods. White clover and ryegrass were grown individually or in
a mixture. Plants were subjected to soil moisture content corresponding to 60% field capacity (FC) and 80% FC. Total plant biomass
of white clover and ryegrass increased with increasing soil moisture contents. At a given soil moisture content, total biomass of
white clover was lower in the ryegrasseclover (RC) mixture compared with those grown individually, while total biomass of ryegrass
was higher. Microbial community structure assessed by phospholipid fatty acid analysis (PLFA) was more affected by plant
species than soil moisture. Community level physiological profiles (CLPP), in terms of diversity of substrate utilization and average
well colour development (AWCD) were affected by plant species and soil moisture. Soil moisture effects were more pronounced in
clover than in ryegrass. AWCD and diversity of substrate utilization in the ryegrasseclover mix were similar to those of sole clover
while they differed from that of ryegrass suggesting a dominant effect of clover in the mix.
2006 Elsevier Masson SAS. All rights reserved.