. 2022 Jul 28;15(15):5233. doi: 10.3390/ma15155233

Table 2.

The content of nickel, zinc, and copper in the soil (mg kg⁻¹ d.m.).

Material	Petrol Dose (cm³ kg⁻¹ d.m. of Soil)				Average	r
Material	0	2.5	5	10	Average	r
Nickel (Ni)
Without amendments	14.56 ^ab	17.03 ^cd	17.55 ^de	17.03 ^cd	16.54 ^A	0.647
Compost	21.45 ^g	20.41 ^fg	19.11 ^ef	14.04 ^ab	18.75 ^B	−0.979
Bentonite	15.08 ^ab	13.65 ^a	14.17 ^ab	15.86 ^bcd	14.69 ^C	0.519
CaO	15.73 ^bcd	15.60 ^bc	14.95 ^ab	15.21 ^abc	15.37 ^C	−0.691
Average	16.71 ^I	16.67 ^I	16.45 ^I	15.54 ^II	16.34	−0.951
LSD_p_≤0.01 for:	petrol dose—0.54, materials—0.54, interaction—1.09
Zinc (Zn)
Without amendments	29.44 ^bcd	33.57 ^defg	29.46 ^bcd	23.88 ^a	29.09 ^A	−0.766
Compost	34.90 ^efg	35.01 ^efg	36.55 ^g	35.32 ^fg	35.45 ^B	0.328
Bentonite	30.97 ^bcdef	30.84 ^bcdef	27.27 ^abc	26.92 ^ab	29.00 ^A	−0.880
CaO	28.64 ^bc	30.25 ^bcd	31.84 ^cdef	30.65 ^bcde	30.35 ^A	0.607
Average	30.99 ^I	32.42 ^I	31.28 ^I	29.19 ^II	30.97	−0.736
LSD_p_≤0.01 for:	petrol dose—1.37, materials—1.37, interaction—2.74
Copper (Cu)
Without amendments	2.58 ^a	2.80 ^ab	2.83 ^abc	2.90 ^abcde	2.78 ^A	0.872
Compost	2.60 ^a	2.80 ^ab	3.30 ^def	3.40 ^f	3.03 ^B	0.922
Bentonite	3.28 ^cdef	3.35 ^ef	3.30 ^def	3.35 ^ef	3.32 ^C	0.603
CaO	2.80 ^ab	2.85 ^abcd	3.20 ^bcdef	2.85 ^abcd	2.93 ^AB	0.185
Average	2.82 ^I	2.95 ^I,II	3.16 ^III	3.13 ^II,III	3.01	0.833
LSD_p_≤0.01 for:	petrol dose—0.14, materials—0.14, interaction—0.28

r—correlation coefficient. Values with different letters are significantly different at p ≤ 0.01: ^I–III for the petrol dose, ^A–C for the material amendments and ^a–g for the interaction between the petrol dose and the material amendments (ANOVA, Tukey’s HSD test).