Fertility Evaluation of Limed Brazilian Soil Polluted with Scrap Metal Residue

Table 4

Dry matter yield, element concentration, and adequate nutritional range for corn grown in the soil mixtures studied.

Attributes	Proportion of contaminated soil (%)						Equation	Regression coefficient^a
	0	25	50	75	100	Adequate range		𝑅^2
Dry matter (g pot^−1)	13.3	12.9	12.4	12.4	13.1		—	NS
N (g kg^−1)	29.1	27.7	26.9	27.2	26.5	27–35^b	𝑦=2.9𝐸−04𝑥^2−5.2𝐸−02𝑥+28.9	0.27*
P (g kg^−1)	1.10	0.90	0.94	1.14	1.13	2.0–4.0^b	𝑦=6.1𝐸−05𝑥^2−4.9𝐸−03𝑥+1.1	0.28*
K (g kg^−1)	39.3	47.9	48.1	49.7	49.9	17–35^b	𝑦=0.3𝑥+40.2	0.73*
Ca (g kg^−1)	7.3	8.6	8.9	9.1	9.1	2.5–8.0^b	𝑦=−3.1𝐸−04𝑥^2+4.8𝐸−02𝑥+7.4	0.48*
Mg (g kg^−1)	3.6	5.1	5.6	5.7	5.8	1.5–5.0^b	𝑦=−3.61𝐸−04𝑥^2+5.5𝐸−02𝑥+3.7	0.76*
S (g kg^−1)	1.2	1.8	2.0	2.0	2.2	1.5–3.0^b	𝑦=−1.1𝐸−04𝑥^2+2𝐸−02𝑥+1.3	0.75*
B (mg kg^−1)	25.7	315	572	779	950	10–25^b	𝑦=12.5𝑥+24.8	0.91*
Cu (mg kg^−1)	7.5	8.9	11.6	9.8	13.0	6–20^b	𝑦=−1.2𝐸−04𝑥^2+5.9𝐸−02𝑥+7.7	0.51*
Fe (mg kg^−1)	66.8	83.4	93.0	86.0	80.5	30–250^b	—	NS
Mn (mg kg^−1)	112	43.8	46.0	55.2	67.5	20–200^b	𝑦=0.02𝑥^2−2.23𝑥+104.4	0.77*
Zn (mg kg^−1)	46.1	276	328	359	454	15–100^b	𝑦=6.92𝑥+71.5	0.81*
Cd (mg kg^−1)	0.22	0.34	0.32	0.26	0.42	0.1^c	—	NS
Cr (mg kg^−1)	0.80	0.56	1.22	0.84	0.30	0.20^c	—	NS
Ni (mg kg^−1)	0.60	0.10	2.60	0.10	0.10	0.19^c	—	NS
Pb (mg kg^−1)	0.58	0.82	6.32	12.1	0.70	0.02^c	𝑦=0.3𝑥−1.5	0.30*

aSignificant at 𝑃<0.05 (*) and not significant (NS).
^bvan Raij et al. [34].
^cU. C. Gupta and S. C. Gupta [35].