Quantity-intensity ratio of potassium in gypsiferous soils in Iraq

Al-Jumaily, Mijbil Mohammad; Al-Hamandi, Hudhaifa Maan; Al-Obaidi, Mohammed Ali; Al-Zidan, Radhwan Rafid

doi:10.1590/1983-40632022v5271620

Acessibilidade / Reportar erro

Brasil

Pesquisa Agropecuária Tropical

Español English

Brasil

Español English

sumário « anterior atual seguinte »

Sumário

Research Article • Pesqui. Agropecu. Trop. 52 • 2022 • https://doi.org/10.1590/1983-40632022v5271620 copy

Quantity-intensity ratio of potassium in gypsiferous soils in Iraq

Relação quantidade-intensidade de potássio em solos gipsíferos no Iraque

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

In gypsiferous soils, potassium (K) undergoes leaching, precipitation and other reactions that reduce its availability. This study aimed to evaluate the physicochemical behavior of K in gypsiferous soils of the Salahaddin province (Iraq), in twelve locations chosen according to the variation in their soil physical and chemical properties. The K adsorption phenomenon was described by using thermodynamic parameters according to the quantity-intensity ratio (Q/I), with the following results: equilibrium activity ratio of 16 to 48 x 10⁻⁵ (mol L⁻¹ )^1/2, total labile K of 19 to 80 x 10⁻³ cmol_c kg⁻¹, potential buffering capacity of 22 to 42 cmol_c kg⁻¹ (mol L⁻¹)^−1/2, free energy of exchange of -1.237 to -1.086 kJ mol⁻¹ and Gapon selectivity coefficient of 3.86 to 5.45 (L mol⁻¹)^1/2. All the investigated soils are characterized by good potassium reserves, but low in release.

KEYWORDS:
Exchangeable-K; buffering capacity; labile potassium; Gapon selectivity

Sample number	Soil location	Latitude (N)	Longitude (E)
1	Shirqat 1	35°32′25.84″	43°13′50.38″
2	Shirqat 2	35°32′23.27″	43°15′07.41″
3	Makhool	35°08′20.13″	43°27′44.04″
4	Makhool 2	34°57′23.43″	43°26′02.88″
5	Baje 1	34°55′46.52″	43°31′22.54″
6	Baje 2	34°50′19.44″	43°32′51.23″
7	Tikrit 1	43°43′49.66″	34°46′28.55″
8	Tikrit 2	43°39′17.16″	34°43′29.39″
9	Dour 1	43°51′30.46″	34°31′07.55″
10	Dour 2	43°49′19.91″	34°29′17.65″
11	Tuz 1	44°24′59.48″	34°40′51.09″
12	Tuz 2	44°28′21.34″	34°53′20.66″

Sample number	Location	PSD (g kg⁻¹)				pH	E_C (S m⁻¹ at 25 °C)	CEC (cmol_c kg⁻¹)	OM	CaSO₄	CaCO₃
Sample number	Location	Sand	Silt	Clay	Texture	pH	E_C (S m⁻¹ at 25 °C)	CEC (cmol_c kg⁻¹)	gk g⁻¹
1	Shirqat	540	230	230	SCL	7.50	1.50	10.0	12.0	20	300
2	Shirqat	505	285	210	L	7.40	2.30	11.0	14.0	35	330
3	Makhool	498	314	188	L	7.25	2.70	9.2	10.0	50	240
4	Makhool	484	348	168	L	7.50	2.00	8.9	10.0	62	270
5	Baje	500	349	151	L	7.50	2.80	8.3	8.0	83	350
6	Baje	600	256	144	SL	7.00	2.50	8.7	9.5	103	300
7	Tikrit	510	355	135	L	7.70	3.00	7.4	8.0	121	200
8	Tikrit	533	342	125	SL	7.30	2.20	6.6	6.5	150	240
9	Dour	526	359	115	SL	7.60	2.70	6.6	6.0	172	300
10	Dour	582	308	110	SL	7.40	2.90	5.5	4.0	196	325
11	Tuz	600	305	95	SL	7.10	3.74	7.0	7.5	205	296
12	Tuz	630	280	90	SL	7.50	3.52	4.8	3.3	220	210

Sample number	AR^K_e (mol L⁻¹)^½ x 10⁻⁵	L_K cmol_c kg⁻¹ x 10⁻³	PBC_K cmol_c kg⁻¹ (mol L⁻¹)^−½	−ΔG kJ mol⁻¹	k_G (L mol⁻¹)^½
1	43	79	41	-1.097	4.10
2	48	80	42	-1.082	3.82
3	36	70	38	-1.123	4.13
4	45	66	36	-1.091	4.04
5	32	68	37	-1.139	4.46
6	29	54	34	-1.153	3.91
7	33	48	33	-1.135	4.46
8	23	40	28	-1.186	4.24
9	24	50	29	-1.180	4.39
10	19	26	30	-1.213	5.45
11	16	27	27	-1.237	3.86
12	18	19	22	-1.221	4.58

Sample number	—————— K-forms (cmol_c kg⁻¹) ——————				—————— Mineral contents (%) ——————
Sample number	Soluble	Exchangeable	Non-exchangeable	Total	Smectite	Illite	Kaolinite	Palygoriskite	Chlorid
1	0.014	0.11	0.31	22.3	++++	+++	+++	++	+
2	0.014	0.11	0.21	21.5	+++	+++	+++	++	++
3	0.013	0.10	0.20	20.8	+++	+++	+++	+++	+
4	0.012	0.09	0.19	20.1	+++	++++	++	+	+
5	0.011	0.10	0.20	19.7	+++	+++	++	+	++
6	0.012	0.08	0.18	19.3	+++	++	++	++	++
7	0.011	0.07	0.17	18.6	+++	+++	+++	++	++
8	0.011	0.06	0.16	18.2	+++	++	+++	++	++
9	0.010	0.07	0.17	17.7	++++	+++	++	+++	+
10	0.008	0.04	0.14	17.4	++++	++++	+++	++	+
11	0.006	0.04	0.14	16.8	+++	++	+	+	++
12	0.004	0.03	0.13	16.5	+++	++	+	+	+

Parameters	Soil properties
Parameters	Ec	CEC	OM	CaSO₄	CaCO₃
AR^K_e	0.9873**	0.8359**	0.9986**	0.8923**	0.8511**
L_K	0.2930	0.1022	0.3325	0.1082	0.1004
PBC_K	0.6090*	0.8567**	0.4507	0.8086**	0.8526**
-ΔG	0.9923**	0.8927**	0.9841**	0.9094**	0.8979**
k_G	0.3970	0.6767*	0.3330	0.6236*	0.6781*

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

Acompanhe os números deste periódico no seu leitor de RSS

[TFN1] SCL: sandy clay loam; L: loam; SL: sandy loam; PSD: particle size distribution; E_c: electrical conductivity; CEC: cation exchange capacity; OM: organic matter