Carbon stocks and lability in land use and management systems in southwestern Goiás, Brazil

Ribeiro, Diego Oliveira; Gonçalves, Gabriel Rosa; Rubio, Giovana Oliveira; Castoldi, Gustavo; Vendruscolo, Eduardo Pradi; Souza, Zaqueu Henrique de

doi:10.1590/1983-40632023v5374416

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Research Article • Pesqui. Agropecu. Trop. 53 • 2023 • https://doi.org/10.1590/1983-40632023v5374416 copy

Carbon stocks and lability in land use and management systems in southwestern Goiás, Brazil

Estoques e labilidade de carbono em sistemas de uso e manejo do solo no sudoeste goiano

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

The southwest region of the Goiás state, Brazil, is suitable for several agricultural activities, even in more fragile soils such as Typic Quartzipsamments. This study aimed to evaluate the carbon stocks and lability of a Typic Quartzipsamment under land use and management systems in southwestern Goiás. The experiment was conducted in a completely randomized design and consisted of areas subjected to five land use and management systems [native Cerrado vegetation (Brazilian Savanna), pasture under intensive grazing, pasture under extensive grazing, soybean and maize rotation, and eucalyptus]. Soil samples were collected at the 0-0.1 and 0.1-0.2 m layers. The land use and management systems affected the carbon stocks and quality. In the 0-0.2 m layer, the carbon stocks ranged between 15.9 and 29.2 Mg ha⁻¹. The areas with eucalyptus and under intensive grazing promoted increases in the carbon stocks that ranged between 72 and 84 %, when compared to the areas with Cerrado vegetation and soybean and maize rotation. The carbon contents in the F1, F2 and F4 fractions were higher in the areas with eucalyptus and under intensive grazing. In the 0-0.1 m soil layer, the areas with eucalyptus and under intensive grazing had an increase in the carbon management index by 33 and 36 %, respectively, when compared to the reference area with native Cerrado vegetation.

KEYWORDS:
Matéria orgânica do solo; qualidade de carbono; índice de manejo de carbono

pH	OM	P	K	Ca	Mg	Al	H + Al	SB	CEC	BS
CaCl₂	g dm⁻³	________mg dm⁻³________		_______________________________________cmol_c dm⁻³_______________________________________						%
4.0	18.7	1.02	22	0.76	0.25	0.56	2.47	1.07	3.54	30.2

Treatment	Description
Cerrado vegetation	Area with natural Cerrado vegetation without anthropogenic interference.
Soybean and maize rotation	Area of 80 ha used for extensive grazing until 2004. In 2005, it was converted to cropping area, with limestone application to increase the base saturation to 50 %. A rotation of summer soybean and second-crop maize was used. In subsequent years, liming was applied to avoid the base saturation to decrease to 40 %; thus, limestone was applied to increase the base saturation to 60 %. Applications of 80 to 90 kg ha⁻¹ of P₂O₅ and K₂O were carried out for both crops. Approximately 100 kg ha⁻¹ of N were applied using urea for the second crop maize, in addition to fertilizers containing P and K.
Degraded pasture	Area of 10 ha used for beef cattle grazing in extensive system for at least 15 years, without fertilization and soil acidity correction. The species used was Paspalum notatum Fluegge.
Pasture under intensive grazing	Area of 5 ha used for rotational grazing, cultivated with Mombasa grass. Dolomitic limestone (3 Mg ha⁻¹) and turkey litter (10 Mg ha⁻¹) were applied in early December 2010. The grass was planted in mid-2011. Turkey litter (10 Mg ha⁻¹) was applied in October 2011 and poultry litter (6 Mg ha⁻¹ year⁻¹) in October, from 2012 to 2014. Poultry litter (4 Mg ha⁻¹ year⁻¹) was applied between 2015 and 2017 and dolomitic limestone (2 Mg ha⁻¹) in 2015. No chemical or organic fertilizers were applied between 2018 and 2020. Fertilizers and limestone were applied to the soil surface, without incorporation. The average stocking rate was 6 to 7 animal units (450 kg) per hectare from 2011 to 2016, and 3 animal units (450 kg) per hectare from 2017 to 2020. In addition to poultry waste, 100 kg ha⁻¹ of N fertilizer were applied using urea, in all years.
Eucalyptus plantation	Area of approximately 4 ha with eucalyptus (Eucalyptus grandis) plantations, implemented in December 2008.

Treatments	F1	F2	F3	F4
Treatments	________________________________________________________g kg⁻¹________________________________________________________
	0.0-0.1 m
Cerrado vegetation	3.79 b*	2.26 bc	0.88^ns	4.48 b
Eucalyptus	5.35 a	3.75 a	1.04	9.45 a
Intensive grazing	5.37 a	3.55 a	0.85	8.46 a
Extensive grazing	3.53 b	1.76 c	0.73	4.72 b
Soybean-maize	4.72 a	3.11 ab	0.84	4.15 b
	0.1-0.2 m
Cerrado vegetation	3.90^ns	2.23^ns	0.62^ns	4.23 b
Eucalyptus	4.04	2.20	0.60	8.61 a
Intensive grazing	4.24	2.46	0.63	5.55 ab
Extensive grazing	4.04	2.48	0.85	5.08 ab
Soybean-maize	3.77	2.11	0.69	3.89 b

Escola de Agronomia/UFG Caixa Postal 131 - Campus II, 74001-970 Goiânia-GO / Brasil, 55 62 3521-1552 - Goiânia - GO - Brazil
E-mail: revistapat.agro@ufg.br

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[TFN1] OM: organic matter; SB: sum of bases; CEC: cation exchange capacity; BS: base saturation.