Table 5.

Sand versus clay and soil blend culture experiments. Average colony forming unit (CFU) per 10 tryptic soy agar plate set.

Soil Composition	Experiment 1	Experiment 2	Average CFU of Experiment 1 and 2
100% sand	11.4	11	11.2
80% sand/20% clay	11	13.8	12.4
60% sand/40% clay	12.6	12.1	12.4
40% sand/60% clay	13.5	14	13.8
20% sand/80% clay	14.7	13	13.9
100% clay	14.4	13.4	13.9

Each 9-gram sample was spiked with 1350 Bacillus atrophaeus subsp. globigii endospores.