Alterações no carbono orgânico do solo de campo natural submetido ao plantio de <i>Pinus taeda</i> em três idades

Cassol, Paulo Cezar; Fachini, Leandra; Mafra, Álvaro Luiz; Brand, Martha Andréia; Simonete, Marcia; Coimbra, Jefferson Luís Meirelles

doi:10.5902/198050986301

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Artigos • Ciênc. Florest. 29 (2) • Apr-Jun 2019 • https://doi.org/10.5902/198050986301 copiar

Alterações no carbono orgânico do solo de campo natural submetido ao plantio de Pinus taeda em três idades

Autoria SCIMAGO INSTITUTIONS RANKINGS

Resumo

O plantio de pinus em áreas de campo natural (NG) pode alterar as formas e estoques de carbono orgânico (OC) do solo. Visando quantificar essas alterações, foram determinados os teores e estoques de OC total (TOC) e das frações particulada (POC) e associadas aos minerais (MAC) em cinco camadas, entre 0,0 e 0,4 m de profundidade, do solo sob usos com NG e plantios de pinus aos cinco (P5), 16 (P16) e 21 (P21) anos. O estudo foi realizado em áreas de Cambissolo Húmico na região do planalto sul de Santa Catarina. O teor de TOC, nas diferentes camadas e usos, variou entre 15,0 e 44,5 g kg^-1 e seu estoque, na soma das camadas, entre 86 e 144 Mg ha^-1. O teor de POC variou entre 2,1 a 23,2 g kg^-1 e seu estoque, entre 7,4 e 21,8 Mg ha^-1, enquanto o teor de MAC variou entre 12,2 e 23,7 g kg^-1 e seu estoque, entre 79 e 122 Mg ha^-1. Em geral, os teores e estoques de TOC e das frações MAC e POC do solo aumentam com a idade dos plantios de pinus até 21 anos. Os teores de TOC e POC e o estoque dessa fração, em geral diminuem com a profundidade do solo sob NG e P5 e P21, mas o teor de MAC e os estoques dessa fração e do TOC geralmente não variam entre as camadas até 0,40 m de profundidade.

Palavras-chave:
Matéria orgânica; Sequestro de carbono; Reflorestamento

Table 1 Mean* clay, silt and sand contents in five layers (0.00-0.05; 0.05-0.10; 0.10-0.20; 0.20-0.30; and 0.30-0.40 m) of a Cambissolo Húmico, dystrophic, on the southern highland of Santa Catarina state under natural grassland (NG) and Pinus taeda plantations in the second rotation, aged five (P5), 16 (P16) and 21 (P21) years.

Particle-size fraction	Land use
Particle-size fraction	NG	P5	P16	P21
	g kg^-1
Clay	319 B	284 B	382 A	178 C
Silt	220 C	272 B	291 B	323 A
Sand	461 A	444 A	327 B	499 A

Table 2 Pearson’s correlation coefficient between the contents of total organic carbon (TOC), particulate organic carbon (POC) and mineral-associated organic carbon (MAC), and the contents of soil particle size fractions (sand, clay and silt) in the 0.00–0.40 m soil layer of a Cambissolo Húmico, dystrophic, on the southern highland of Santa Catarina under grassland (NG), and Pinus taeda plantations in the second rotation, aged five (P5), 16 (P16) and 21 (P21) years.

Particle-size fraction	Organic carbon fraction
Particle-size fraction	TOC	POC	MAC
Sand	0.15^ns	0.08^ns	0.21^ns
Clay	-0.53^**	-0.48^**	-0.44^**
Silt	0.60^**	0.65^**	0.33^*

Table 3 Soil bulk density of a Cambissolo Húmico, dystrophic, on the southern highland of Santa Catarina state under grassland (NG) and Pinus taeda plantations in the second rotation, aged five (P5), 16 (P16) and 21 (P21) years.

Layers (m)	Land use
Layers (m)	NG	P5	P16	P21
	g dm^-3
0.00 - 0.05	1.2 b A	0.9 b B	1.0 c B	0.8 b C
0.05 a 0.10	1.4 a A	1.4 a A	1.1 b B	0.9 a C
0.10 a 0.20	1.5 a A	1.4 a A	1.2 a B	0.9 a C
0.20 a 0.30	1.4 a A	1.4 a A	1.2 ab B	0.9 a C
0.30 a 0.40	1.4 a A	1.4 a A	1.2 ab A	1.0 a B

Table 4 Content of total organic carbon (TOC), particulate organic carbon (POC) and mineral-associated organic carbon (MAC) in five layers of a Cambissolo Húmico, dystrophic, on the southern highland of Santa Catarina under natural grassland (NG) and Pinus taeda plantations in the second rotation, aged five (P5), 16 (P16) and 21 (P21) years.

Layers (m)	NG	P5	P16	P21
	TOC g kg^-1
0.00 - 0.05	27.2 a B	23.8 a B	23.7 a B	44.5 a A
0.05 - 0.10	24.3 a B	17.9 b C	24.0 a B	44.2 a A
0.10 - 0.20	20.2 b B	15.1 b C	22.2 a B	40.0 b A
0.20 - 0.30	18.3 b BC	15.0 b C	21.3 a B	40.9 b A
0.30 - 0.40	15.2 c C	16.2 b C	20.8 a B	34.0 c A
Mean* (0.00 - 0.40)	19.86 BC	16.78 C	22.03 B	39.81 A
	POC g kg^-1
0.0 - 0.05	9.1 a B	10.7 a B	9.2 a B	23.2 a A
0.05 - 0.10	6.2 b B	4.8 b B	7.6 ab B	20.5 b A
0.10 - 0.20	3.8 c B	2.9 b B	6.0 b B	19.6 b A
0.20 - 0.30	2.6 c C	2.3 b C	6.5 ab B	17.5 c A
0.30 - 0.40	2.1 c B	2.1 b B	5.0 b B	13.0 d A
Mean* (0.00 - 0.40)	4.03 C	3.76 C	6.47 B	17.98 A
	MAC g kg^-1
0.0 - 0.05	18.2 a A	13.1 a B	14.5 a B	21.3 ab A
0.05 - 0.10	18.0 a B	13.1 a C	16.3 a BC	23.7 a A
0.10 - 0.20	16.4 ab B	12.2 a C	16.3 a B	20.4 b A
0.20 - 0.30	15.8 ab B	12.7 a B	14.9 a B	23.4 ab A
0.30 - 0.40	13.1 b B	14.1 a B	15.8 a B	21.0 ab A
Mean* (0.00 - 0.40)	15.85 B	13.02 B	15.6 B	21.82 A

Table 5 Stocks of total organic carbon (TOC), particulate organic carbon (POC) and mineral-associated carbon (MAC) in five layers of a Cambissolo Húmico in the Southern highlands of Santa Catarina under native grassland (NG), and Pinus taeda plantations with five (P05), 16 (P16) and 21 y ears (P21), in the second rotation. Means of seven samples.

Layers (m)	NG	P05	P16	P21
	TOC Mg ha^-1
0.00 - 0.05	16.0 a	10.2 b	11.4 b	16.6 a
0.05 - 0.10	17.1 b	12.6 c	13.1 c	19.9 a
0.10 - 0.20	29.4 b	20.9 c	27.6 b	36.5 a
0.20 - 0.30	26.0 b	20.8 c	26.2 b	38.4 a
0.30 - 0.40	20.5 c	21.9 bc	25.4 b	32.7 a
Sum 0.0 - 0.40	109.0 b	86.4 c	103.7 b	144.1 a
	POC Mg ha^-1
0.00 - 0.05	2.0 b	2.0 b	1.3 c	3.0 a
0.05 - 0.10	1.5 b	1.5 b	1.2 b	3.2 a
0.10 - 0.20	1.9 b	1.7 b	2.2 b	6.2 a
0.20 - 0.30	1.2 c	1.4 c	2.4 b	5.3 a
0.30 - 0.40	0.8 c	1.2 bc	1.8 b	4.1 a
Sum 0.0 - 0.40	7.4 b	7.8 b	8.9 b	21.8 a
	MAC Mg ha^-1
0.00 - 0.05	14.1 a	8.3 b	10.2 b	TTT13.8 a
0.05 - 0.10	15.6 a	11.0 b	11.8 b	16.3 a
0.10 - 0.20	27.4 ab	19.2 c	25.4 b	30.4 a
0.20 - 0.30	24.8 b	19.4 c	23.8 b	33.1 a
0.30 - 0.40	19.7 b	20.7 b	23.7 b	28.6 a
Sum 0.00 - 0.40	101.6 b	78.6 c	94.9 bc	122.2 a

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[TFN1] Means followed by different letters in the row differ from each other by the Least Significant Difference (LSD) test at 5% probability.

[TFN6] * Weighted average, considering four layers with a thickness of 0.10 m, where the two uppermost layers were computed by their mean content.