Nitrogen Immobilization in Plant Growth Substrates: Clean Chip Residual, Pine Bark, and Peatmoss

Table 5

Total inorganic nitrogen (NH₄ and NO₃) mineralization in clean chip residual, pine bark and peatmoss substrates.

Substrate^z	Nitrogen mineralization (mg/kg)
	0 mg N	1 mg N^y	2 mg N	3 mg N	MSD N-rate^x
		0–7 days
0.48 cm CCR	31	28	37	128	16
0.95 cm CCR	44	77	262	515	174
PB	44	56	440	1458	459
PM	1753	2549	3359	5264	790
MSD Substrate	130	174	250	850
		0–15 days
0.48 cm CCR	58	61	42	50	55
0.95 cm CCR	53	52	64	168	79
PB	5	88	293	1572	442
PM	1619	2937	3610	5869	588
MSD Substrate	169	281	169	630
		0–30 days
0.48 cm CCR	101	148	99	80	67
0.95 cm CCR	114	116	102	310	119
PB	75	108	152	1061	82
PM	2530	3591	4043	6149	768
MSD Substrate	342	429	356	402
		0–60 days
0.48 cm CCR	63	87	91	117	44
0.95 cm CCR	91	142	121	142	34
PB	33	39	58	761	94
PM	1806	2632	3533	5404	783
MSD Substrate	44	150	205	734

^zCCR:  clean chip residual, PB:  pine bark, and PM:  sphagnum peatmoss.
^y2000 ppm stock solution of NH₄NO₃ (0, 0.5, 1.0, 1.5 mL).
^xMSD based on Waller-Duncan 𝑘 ratio 𝑡-tests (𝛼  =  0.05).