Leather Industry Solid Waste as Nitrogen Source for Growth of Common Bean Plants

Table 1

Mineral analysis of leather waste before (wet blue) and after the chromium extraction (collagen)*.

Residue	N	P	K	Ca	Mg	S	Fe	Mn	Zn	Cr
	g kg^−1		mg kg^−1
wet blue (without chromium extraction)	104 (5.19)	10 (0.24)	0.15 (0.01)	0.60 (0.05)	0.44 (0.01)	12 (0.41)	133 (0.94)	2 (0.14)	5 (0.24)	30.050 (5.25)
collagen (after chromium extraction)	146 (3.68)	26 (0.47)	0.14 (0.01)	0.48 (0.02)	0.08 (0.01)	3 (0.14)	70 (0.82)	1 (0.09)	10 (0.09)	125 (0.94)

Chemical methods: Total N = Kjeldahl; P = CNA + H₂O (P₂O₅); K, Ca, Mg, S, Fe, Mn, and Zn = Mehlich 1 [20]; Cr = USEPA 3051 [21]. Values are the mean of three replicates. Numeric values in brackets represent SD (standard deviation).
*Adapted from De Oliveira et al. [18].