Soil management and ionic strength on selenite retention in oxidic soils

Araujo, Anderson Mendes; Lessa, Josimar Henrique de Lima; Ferreira, Liniker André; Guilherme, Luiz Roberto Guimarães; Lopes, Guilherme

doi:10.1590/1413-70542018424007318

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Sumário

Agricultural Sciences • Ciênc. agrotec. 42 (4) • Jul-Aug 2018 • https://doi.org/10.1590/1413-70542018424007318 copy

Soil management and ionic strength on selenite retention in oxidic soils

Manejo do solo e força iônica na retenção de selenato em solos oxídicos

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

Sorption of selenium (Se) on soils may be influenced by factors that are changed though agricultural practices usually performed for crop production, such as soil pH, competing anion and organic matter contents, among others. This study aimed to evaluate the influence of soil management and ionic strength (IS) on Se retention in Brazilian soils, which is important to predict Se availability in both systems, native and cultivated soils. For that, adsorption and desorption reactions of Se were evaluated in 16 soil samples (eight from cultivated soils and eight from native soils), using solutions containing 100 and 500 µg L^-1 Se in the form of sodium selenate and in two IS, 15 and 150 mM. Se adsorption varied as a function of IS for most soils, which may indicate that the adsorption mechanism by outer-sphere complex is important for selenate retention in the studied soils, but future studies involving other techniques, such as spectroscopic studies, are needed to more clearly confirm the adsorption mechanism. In general, adsorption varied in relation to soil characteristics, and native soils adsorbed larger Se amounts than the cultivated soils. In terms of desorption, soils which had larger Se adsorbed amounts also presented larger desorbed amounts. Finally, IS and soil management influenced the availability of selenate in the studied soils.

Index terms:
Adsorption/desorption reactions; brazilian soils; competitive anion; soil cultivation; retention/mobility.

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[1] ^*Corresponding author: guilherme.lopes@dcs.ufla.br

Soil	State	Geographic coordinates		pH	PZSE	P	S	CEC	Al_AO	Fe_AO	Al_DCB	Fe_DCB	P₂O₅	Al₂O₃	Fe₂O₃	SOM	Clay	Sand
Soil	State	Latitude	Longitude			-- mg dm^-3--		cmol_c dm^-3	------------ g dm^-3------------				-------------------------- % -------------------------
Cultivated soils
1	MT	15°26’29.6” S	55°37’16.8” W	5.5	5.4	12.5	12.6	7.3	4.3	1.6	21.5	41.4	0.049	32.0	12.4	3.3	44	18
2	MT	13°03’09.6” S	55°20’44.5” W	5.4	4.6	31.9	17.4	7.8	5.4	3.2	16.0	33.6	0.014	14.3	5.2	2.9	36	61
3	MT	13°14’43.3” S	54°39’06.2” W	5.5	5.7	18.3	2.9	5.7	5.7	4.8	14.3	32.2	0.003	5.4	1.5	2.6	14	85
4	MT	14°42’13.8” S	54°04’21.3” W	6.5	7.9	21.1	4.0	4.0	5.3	3.7	17.1	41.6	0.003	3.1	1.7	1.3	8	92
5	GO	15°09’55.4” S	54°04’43.2” W	5.5	5.4	22.3	4.0	5.7	4.4	4.3	11.7	38.3	0.006	6.7	4.1	1.6	22	74
6	MG	18°01’46.1” S	46°26’59.6” W	4.7	4.7	42.5	48.6	9.2	3.7	3.0	10.4	41.9	0.035	18.2	9.8	2.9	51	42
7	MG	19°15’42.0” S	46°13’57.8” W	5.7	5.5	4.3	7.9	9.6	3.8	2.2	22.5	51.5	0.063	34.7	15.3	4.4	59	8
8	MG	19°26’17.8” S	46°11’20.8” W	5.6	5.4	91.8	24.2	8.2	5.0	2.1	17.3	47.0	0.486	38.4	15.3	3.4	56	22
Native soils
1	MT	15°26’32.0” S	55°37’13.4” W	5.4	4.3	0.8	7.0	6.1	3.4	1.6	11.5	39.1	0.017	15.6	5.8	2.7	65	14
2	MT	13°28’41.0” S	54°43’55.7” W	5.4	3.7	2.0	4.0	6.2	4.1	2.4	9.1	36.3	0.006	9.8	3.9	2.9	49	44
3	MT	13°14’41.7” S	54°39’01.5” W	4.7	4.2	2.3	5.4	12.9	6.2	3.4	17.3	27.8	0.002	1.4	0.6	2.1	15	81
4	MT	14°42’26.5” S	54°04’25.4” W	5.7	5.5	1.4	3.3	3.7	6.4	5.8	21.4	37.3	0.006	3.7	2.3	1.3	4	96
5	GO	15°52’50.0” S	51°40’56.6” W	5.1	4.2	2.6	5.4	6.1	5.0	2.6	11.3	39.5	0.047	10.7	6.2	2.1	20	75
6	MG	18°01’48.4” S	46°27’00.2” W	5.1	4.6	3.5	4.7	8.3	4.6	3.2	11.5	46.4	0.064	10.4	4.9	3.4	47	40
7	MG	19°15’44.9” S	46°13’56.1” W	4.8	3.9	1.4	6.2	13.7	3.1	1.6	26.7	50.0	0.005	39.2	14.4	4.6	79	6
8	MG	19°25’50.8” S	46°11’13.3” W	5.5	4.4	1.4	7.0	6.1	5.5	2.2	18.3	45.7	0.006	36.9	13.1	4.4	53	9

Soils	Kaolinite	Gibbsite	Goethite	Hematite
	--------------------------- % ---------------------------
1	14.8	11.5	3.6	0.3
2	16.6	3.8	2.3	1.4
3	2.8	0.3	2.8	0.0
4	9.9	0.0	3.7	0.0
5	18.3	4.1	2.6	1.4
6	8.6	8.2	3.8	0.8
7	11.6	40.8	4.8	0.2
8	8.8	39.3	4.5	0.1
Minimum	2.8	0.0	2.3	0.0
Mean	11.4	13.5	3.5	0.5
Maximum	18.3	40.8	4.8	1.4

Soil property	Cultivated soils				Native soils
	100 μg L^-1 de Se		500 μg L^-1 de Se		100 μg L^-1 de Se		500 μg L^-1 de Se
	IS 15	IS 150	IS 15	IS 150	IS 15	IS 150	IS 15	IS 150
Clay	0.80**	0.81**	0.87**	0.73**	0.57**	-0.028ns	0.49*	0.82**
S	0.61**	0.64**	0.57**	0.44*	0.12ns	-0.36ns	0.01ns	0.40ns
P	0.55**	0.31ns	0.51**	0.37ns	-0.25ns	0.33ns	-0.072ns	-0.46*
SOM	0.64**	0.72**	0.78**	0.61**	0.152ns	-0.11ns	0.33ns	0.43*
PZSE	-0.27ns	-0.53**	-0.49*	-0.14ns	-0.64**	-0.47*	-0.65**	-0.54**
Fe_AO	-0.81**	-0.79**	-0.69**	-0.81**	-0.59**	-0.12ns	-0.43*	-0.70**
Al_AO	-0.40*	-0.47*	-0.44*	-0.47*	-0.74**	-0.07ns	-0.56**	-0.93**
Fe_DCB	0.63**	0.41*	0.61**	0.71**	0.06ns	-0.40ns	0.45*	0.54**
Al_DCB	0.33ns	0.31ns	0.27ns	0.45*	-0.44*	-0.65**	-0.10ns	0.03ns
Al₂O₃	0.82**	0.78**	0.84**	0.80**	0.33ns	-0.30ns	0.54**	0.76**
Fe₂O₃	0.83**	0.77**	0.85**	0.81**	0.30ns	-0.28ns	0.50*	0.70**
TiO₂	0.71**	0.62**	0.83**	0.71**	0.14ns	-0.30ns	0.47*	0.57**
pH	-0.27ns	-0.53**	-0.42*	-0.13ns	0.01	0.05ns	-0.42*	-0.16ns
CEC	0.69**	0.60**	0.77**	0.69**	-0.06ns	-0.42*	0.38ns	0.20ns