TABLE 1.

Analysis of soils and sediment used for DNA extraction

Soil or sedimenta	Soil horizon	Texture (%)			pHb	Organic carbon content (mg g [dry wt]−1)c	Bacterial content (109 cells g [dry wt]−1)d
		Sand	Silt	Clay
Collamer silt loam (agricultural)	A1	13	71	16	6.5	38	1.9 ± 0.5
Collamer silt loam (forest)	01	17	70	13	6.1	75	4.3 ± 1.4
Wetland sediment (silt loam)		17	68	15	5.7	442	11.0 ± 4.1

^aSee text for details. 

^bMeasured after equilibration with distilled water. 

^cMass loss of dried material during ignition. 

^dMicroscopic counts obtained with triplicate samples and 15 fields by using acridine orange direct counting procedures (2, 10).