Chapter 2.6.3 : Soil Sampling for Microbial Analyses

(a) Common experimental designs, including (1) complete randomized; (2) complete randomized block; and (3) split-plot randomized block designs. (b) Typical sampling regimes which can be applied in each of the experimental designs in part (a). doi:10.1128/9781555818821.ch2.6.3.f1

(a) Banded poultry litter (dark spot in soil profile and core) as an example of localized, concentrated nutrients and microbial activity. In this example the treatment (e.g., litter) is applied in a band which concentrates all litterborne bacteria and nutrients into a small section of the applied row. (b) A sample collection template used to identify the litter band and locations flanking the band; thus ensuring a reproducible and representative sample. Sample cores would be collected from atop the band (top through the middle of the triangle) and flanking the band; in this case one band soil core would represent 1/13 of the sample assuming all flanking cores were collected (six on each side). Alternatively, if the study is associated with pathogen die-off in the band, soil cores could be collected exclusively from the middle of the triangle. Photos courtesy of Dr. Haile Tewolde. doi:10.1128/9781555818821.ch2.6.3.f2

Soil cores collected with a (a) core sampler mounted to a tractor capable of reaching approximately 1 m, and a (b) standard soil probe capable of reaching approximately 30–45 cm. Photos courtesy of Drs. Karamat Sistani and Ardeshir Adeli. doi:10.1128/9781555818821.ch2.6.3.f3

Soil core samples collected from a drainage ditch in the Mississippi Delta. The soil was collected shortly following large rain events; hence, collecting intact soil cores using a soil probe is not feasible. Soil core liners, in this case, can be pushed through the soil (inset) and capped at the either end. Alternatively sludge samplers could be used if the soil is too moist to maintain profile integrity. Photos courtesy of Dr. Beth Baker. doi:10.1128/9781555818821.ch2.6.3.f4