Organic Amendments and Earthworm Addition Improve Properties of Nonacidic Mine Tailings

Table 3

Selected chemical properties of amended mine tailings sampled 24 hours after experimental setup. Means ± standard deviation (𝑛=3). Values designated by the same letter (within a column) are not significantly different from each other (𝑃<0.05).

Treatment	pH (water)	EC (dS m^−1)	NH4^+-N (mg kg^−1)	NO3^−-N (mg kg^−1)	Total N (g 100 g^−1)
Treatments with 10% biosolids
T1-WO	7.37±0.03 c	3.19±0.05 d	345±20 c	0.3±0.1 a	0.34±0.03 b
T2-WO	7.72±0.06 a	2.34±0.04 e	254±9 d	0.3±0.1 a	0.30±0.04 b
T3-WO	7.35±0.01 c	3.16±0.06 d	261±70 d	1.9±0.2 a	0.30±0.09 b
T4-WO	7.43±0.02 bc	5.29±0.12 b	387±19 c	0.1±0.1 a	0.35±0.01 b
Treatments with 20% biosolids
T5-WO	7.24±0.06 d	4.69±0.09 c	615±10 a	0.2±0.03 a	0.60±0.02 a
T6-WO	7.45±0.03 b	3.50±0.06 d	491±25 b	1.3±0.1 a	0.57±0.04 a
T7-WO	7.26±0.02 d	4.44±0.27 c	524±31 b	0.9±0.3 a	0.64±0.06 a
T8-WO	7.27±0.05 d	6.34±0.06 a	654±26 a	0.3±0.3 a	0.60±0.07 a

Concentrations are expressed on an oven-dry equivalent basis.
For reference, pH and EC of pure mine tailings were 8.31±0.05 and 1.80±0.04 dS m⁻¹, respectively (𝑛=3).