Application of nitrogen-fixing purple non-sulfur bacteria in improving nitrogen uptake, growth, and yield of rice grown on extremely saline soil under greenhouse conditions

Anh, Nguyen Hoang; Quang, Huynh Thanh; Huong, Bui Thi Thien; Quang, Le Thanh; Thu, Le Thi My; Trong, Nguyen Duc; Nguyen, Tran Trong Khoi; Xuan, Ly Ngoc Thanh; Phong, Ngo Thanh; Khuong, Nguyen Quoc

doi:10.1515/opag-2025-0425

Figures & Tables

Effect of nitrogen fertilizer supplemented with nitrogen-fixing PNSB on NH4
+ content of saline soil in My Xuyen district, Soc Trang province under greenhouse conditions. Note: Bars followed by different letters are statistically different at the 5% level (*). S01: Single strain of bacteria S01 added, S06: Single strain of bacteria S06 added, S01 + S06: Mixed addition of two strains of bacteria S01 and S06, 100%: 100% nitrogen fertilizer as recommended, 75%: 75% nitrogen fertilizer supplement as recommended, 50%: 50% nitrogen fertilizer supplement as recommended, and 0%: No nitrogen fertilizer. — Effect of nitrogen fertilizer supplemented with nitrogen-fixing PNSB on NH4 + content of saline soil in My Xuyen district, Soc Trang province under greenhouse conditions. Note: Bars followed by different letters are statistically different at the 5% level (*). S01: Single strain of bacteria S01 added, S06: Single strain of bacteria S06 added, S01 + S06: Mixed addition of two strains of bacteria S01 and S06, 100%: 100% nitrogen fertilizer as recommended, 75%: 75% nitrogen fertilizer supplement as recommended, 50%: 50% nitrogen fertilizer supplement as recommended, and 0%: No nitrogen fertilizer.

Effect of nitrogen fertilizer supplemented with nitrogen-fixing PNSB on total N uptake of rice grown on saline soil in My Xuyen district, Soc Trang province under greenhouse conditions. Note: Bars followed by different letters are statistically different at the 5% level (*). S01: Single strain of bacteria S01 added, S06: Single strain of bacteria S06 added, S01 + S06: mixed addition of two strains of bacteria S01 and S06, 100%: 100% nitrogen fertilizer as recommended, 75%: 75% nitrogen fertilizer supplement as recommended, 50%: 50% nitrogen fertilizer supplement as recommended, and 0%: No nitrogen fertilizer.

Effect of nitrogen fertilizer supplemented with nitrogen-fixing PNSB on rice yield grown on saline soil in My Xuyen district, Soc Trang province under greenhouse conditions. Note: Bars followed by different letters are statistically different at the 5% level (*). S01: Single strain of bacteria S01 added, S06: Single strain of bacteria S06 added, S01 + S06: Mixed addition of two strains of bacteria S01 and S06, 100%: 100% nitrogen fertilizer as recommended, 75%: 75% nitrogen fertilizer supplement as recommended, 50%: 50% nitrogen fertilizer supplement as recommended, 0%: No nitrogen fertilizer.

Characteristics of rice-shrimp soil in My Xuyen-Soc Trang

Indicator	Unit	Value	Status	Reference
pH_H₂O	—	6.59	—	—
pH_KCl	—	6.93	—	—
EC	mS cm⁻¹	6.80	High	[35]
N_total	%N	0.14	Low	[36]
NH₄ ⁺	mg NH₄ ⁺ kg⁻¹	59.2	—	—
P _total	%P₂O₅	0.055	Poor	—
P _soluble	mg kg⁻¹	23.2	Moderate	[35]
Al-P	mg kg⁻¹	31.7	—	—
Fe-P	mg kg⁻¹	84.9	—	—
Ca-P	mg kg⁻¹	107.9	—	—
CEC	meq 100 g⁻¹	14.4	Low	[37]
Na⁺	meq 100 g⁻¹	11.6	—	—
K⁺	meq 100 g⁻¹	1.47	High	[38]
Mg²⁺	meq 100 g⁻¹	8.58	Extremely high	[38]
Ca²⁺	meq 100 g⁻¹	0.624	Low	[38]

Effect of nitrogen fertilizer supplemented with nitrogen fixing PNSB on the fertility of saline soil of My Xuyen – Soc Trang under greenhouse conditions

		pH_KCl	pH_H₂O	EC	P_total	P_soluble	Fe-P	Al-P	Ca-P	N_total	NH₄ ⁺	CEC	Mg²⁺	Ca²⁺	K⁺	Na⁺
Factor				mS cm⁻¹	%P	mg kg⁻¹	mg kg⁻¹	mg kg⁻¹	mg kg⁻¹	%	mg kg⁻¹	meq 100 g⁻¹	meq 100 g⁻¹	meq 100 g⁻¹	meq 100 g⁻¹	meq 100 g⁻¹
The first season
Nitrogen	100%	6.85	7.23	1.74^b	0.054	22.8^bc	115.8	25.8	101.9	0.148	10.1	14.4	1.87	0.652	1.87^a	3.84
(A)	75%	6.86	7.11	1.95^a	0.053	23.4^b	116.3	26.8	100.0	0.156	10.5	14.8	1.81	0.641	1.81^ab	3.81
	50%	6.86	7.12	2.01^a	0.055	21.8^c	112.8	26.1	101.6	0.149	10.3	14.5	1.82	0.665	1.82^ab	3.74
	0%	6.84	7.18	2.03^a	0.056	25.0^a	112.1	26.8	98.8	0.151	10.5	14.6	1.72	0.668	1.72^b	3.77
Bacteria	No bacteria	6.88	7.01^b	2.25^a	0.053	19.3^d	119.6^a	29.2^a	114.2^a	0.150	7.38^d	15.1^a	6.69^b	0.634	1.61^c	4.26^a
(B)	S01	6.86	7.24^a	1.90^b	0.055	23.4^c	110.4^b	24.4^c	80.5^c	0.151	9.03^c	14.6^b	7.46^a	0.661	2.00^a	3.71^b
	S06	6.83	7.22^a	1.73^c	0.056	25.6^a	113.0^b	25.2^bc	103.4^b	0.147	10.1^b	14.3^b	7.58^a	0.663	1.83^b	3.60^b
	S01 + S06	6.83	7.17^a	1.85^bc	0.054	24.5^b	114.0^b	26.6^b	104.2^b	0.155	14.9^a	14.2^b	7.27^a	0.668	1.78^b	3.58^b
Significance (F _A)		ns	ns	**	ns	**	ns	ns	ns	ns	ns	ns	ns	ns	*	ns
Significance (F _B)		ns	**	**	ns	**	**	**	**	ns	**	**	**	ns	**	**
Significance (F _AxB)		ns	ns	**	*	**	**	ns	**	ns	**	Ns	ns	ns	**	**
CV (%)		1.53	2.07	10.2	6.93	6.49	5.28	10.0	5.48	20.9	9.49	4.06	8.49	8.35	8.42	2.36
The second season
	100%	6.47	7.37	2.25	0.180	13.9	432.9	141.6	101.2	0.156	118.4^a	13.0	8.21	0.702	0.528	3.40
Nitrogen (A)	75%	6.59	7.31	2.22	0.173	13.2	419.8	144.8	101.7	0.150	109.6^a	12.9	8.17	0.735	0.500	3.53
	50%	6.58	7.37	2.22	0.175	13.1	433.7	145.7	98.7	0.155	112.5^a	13.1	8.10	0.704	0.492	3.31
	0%	6.56	7.31	2.13	0.167	13.1	447.3	145.5	97.7	0.149	98.0^b	13.4	8.24	0.739	0.502	3.37
Bacteria	No bacteria	6.55	6.90^c	2.45^a	0.175	12.0^c	485.0^a	152.6^a	150.6^a	0.146	85.7^c	12.9	8.02^b	0.647^b	0.450^c	4.08^a
(B)	S01	6.60	7.55^a	2.22^b	0.168	13.3^b	426.7^b	140.5^b	100.0^b	0.158	115.3^ab	13.3	8.03^b	0.749^a	0.494^bc	3.39^b
	S06	6.56	7.50^a	2.16^b	0.175	13.4^b	427.8^b	143.8^b	76.2^c	0.144	111.9^b	13.0	8.41^a	0.760^a	0.557^a	3.12^bc
	S01 + S06	6.49	7.41^b	1.98^c	0.178	14.5^a	394.3^c	140.8^b	72.4^c	0.160	125.6^a	13.3	8.26^a	0.723^a	0.522^ab	3.03^c
Significance (F _A)		ns	ns	ns	ns	ns	ns	ns	ns	ns	**	Ns	ns	ns	ns	ns
Significance (F _B)		ns	**	**	ns	**	**	**	**	ns	**	Ns	**	**	**	**
Significance (F _A×B)		ns	**	ns	ns	ns	ns	**	**	ns	ns	Ns	ns	ns	ns	ns
CV (%)		2.05	1.72	11.1	18.2	9.01	6.73	6.05	6.23	20.8	13.3	6.10	3.26	12.4	15.3	12.5

Effect of nitrogen fertilizer supplemented with nitrogen fixing PNSB on the growth and yield of rice grown on saline soil of My Xuyen, Soc Trang under greenhouse conditions

		Plant height	Panicle length	Panicle number pot⁻¹	Seed number panicle⁻¹	Filled seed rate	1,000-seed weight	Yield
Factor		cm	cm	Panicles	Seeds	%	g pot⁻¹	g pot⁻¹
The first season
Nitrogen	100%	98.5^a	22.3^a	14.4^a	98.7^a	85.3^a	22.6	22.4^a
(A)	75%	95.2^b	21.3^b	12.6^b	88.5^b	82.0^b	22.9	22.2^a
	50%	89.2^c	20.8^c	10.8^c	80.6^c	81.6^c	23.4	22.2^a
	0%	69.1^d	17.7^d	6.50^d	45.6^d	79.2^d	22.7	21.2^b
Bacteria	No bacteria	83.6^c	19.5^b	10.4^b	71.5^c	72.9^c	23.0	20.6^c
(B)	S01	87.1^b	20.7^a	10.9^b	76.5^b	83.1^b	23.0	22.8^a
	S06	87.9^b	20.9^a	11.5^a	78.3^b	84.7^b	23.0	21.8^b
	S01 + S06	93.3^a	21.1^a	11.5^a	87.0^a	87.5^a	22.7	22.7^a
Significance (F _A)		**	**	**	**	**	ns	**
Significance (F _B)		**	**	**	**	**	ns	**
Significance (F _A×B)		**	ns	ns	ns	**	ns	**
CV (%)		2.59	5.55	6.65	7.28	3.20	5.60	4.41
The second season
Nitrogen (A)	100%	102.5^a	22.7^a	19.8^a	111.1^a	80.6^a	21.6	36.7^a
	75%	100.0^b	22.0^b	18.1^b	105.1^b	79.5^ab	20.7	30.2^b
	50%	93.0^c	20.9^c	15.3^c	97.2^c	77.4^b	20.9	21.3^c
	0%	69.2^d	17.0^d	7.00^d	53.5^d	62.6^c	20.9	5.05^d
Bacteria (B)	No bacteria	87.2^c	20.3	13.8^b	85.4^c	69.4^c	21.3	20.9^c
	S01	93.6^a	20.7	15.6^a	93.1^ab	78.3^a	20.9	23.5^b
	S06	93.1^a	21.1	15.2^a	96.8^a	78.0^a	20.7	24.8^a
	S01 + S06	90.7^b	21.1	15.7^a	91.6^b	74.4^b	21.2	24.0^ab
Significance (F _A)		**	**	**	**	**	ns	**
Significance (F _B)		**	ns	**	**	**	ns	**
Significance (F _A×B)		**	**	**	ns	**	ns	*
CV (%)		1.90	5.57	4.96	5.42	3.43	6.35	4.72

Effect of nitrogen fertilizer supplemented with nitrogen fixing PNSB on the Na and N uptake of rice grown on saline soil of My Xuyen, Soc Trang under greenhouse conditions

		N_total		Na_total		Biomass		N uptake		Na uptake		Total uptake
		Stem leaf	Seed	Stem leaf	Seed	Stem leaf	Seed	Stem leaf	Seed	Stem leaf	Seed	N	Na
Factor		%N		%		g pot⁻¹		mg pot⁻¹		mg pot⁻¹		mg pot⁻¹
The first season
Nitrogen	100%	0.684^a	1.247	0.810	0.339	20.3^a	22.8^a	140.3^a	285.0^a	163.7^a	75.8^a	425.3^a	239.5^a
(A)	75%	0.659^ab	1.243	0.818	0.353	15.9^b	18.5^b	105.8^b	231.5^b	129.5^b	65.9^b	337.2^b	195.4^b
	50%	0.602^c	1.243	0.857	0.354	13.6^c	14.6^c	82.0^c	182.4^c	115.4^b	51.0^c	264.4^c	166.4^c
	0%	0.613^bc	1.209	0.847	0.347	5.21^d	5.14^d	32.1^d	62.5^d	43.5^c	16.9^d	94.6^d	60.5^d
Bacteria	No bacteria	0.514^b	1.106^c	0.991^a	0.445^a	12.3^b	13.2^c	62.6^b	146.1^d	120.9^a	56.0^a	208.6^d	177.0^a
(B)	S01	0.695^a	1.323^a	0.853^b	0.352^b	14.3^a	15.4^b	99.9^a	205.4^b	119.9^a	56.3^a	305.3^b	176.2^a
	S06	0.690^a	1.217^b	0.830^b	0.306^c	14.3^a	15.4^b	95.8^a	188.5^c	117.3^a	48.1^b	284.3^c	165.4^a
	S01 + S06	0.659^a	1.293^a	0.658^c	0.290^c	14.2^a	17.1^a	101.9^a	221.4^a	93.9^b	49.3^b	323.2^a	143.2^b
Significance (F _A)		**	ns	ns	ns	**	**	**	**	**	**	**	**
Significance (F _B)		**	**	**	**	**	**	**	**	**	*	**	**
Significance (F _A×B)		**	**	ns	**	**	**	**	**	ns	**	**	ns
CV (%)		11.1	5.12	16.1	12.9	3.86	3.28	10.3	6.31	18.7	17.2	5.90	13.8
The second season
Nitrogen	100%	1.16	1.389^b	0.940	0.403^a	34.6^a	36.1^a	401.4^a	506.6^a	319.5^a	140.4^a	908.0^a	459.8^a
(A)	75%	1.18	1.385^b	0.925	0.377^b	31.2^b	28.5^b	371.8^b	397.3^b	285.9^b	100.2^b	769.1^b	386.1^b
	50%	1.12	1.374^b	0.955	0.285^c	21.2^c	19.5^c	240.4^c	269.3^c	200.8^c	54.6^c	509.7^b	255.4^c
	0%	1.17	1.584^a	0.916	0.262^d	5.86^d	3.51^d	68.6^d	56.0^d	53.3^d	8.6^d	124.6^c	61.9^d
Bacteria	No bacteria	0.916^c	1.230^c	1.09^a	0.543^a	20.5^d	18.6^d	186.6^c	210.7^c	231.1^a	118.0^a	397.3^d	349.2^a
(B)	S01	1.203^b	1.533^a	0.861^c	0.225^c	24.5^b	23.6^b	289.4^b	350.0^a	199.3^c	57.5^c	639.3^b	256.8^c
	S06	1.178^b	1.446^b	0.913^b	0.348^b	22.9^c	20.9^c	281.6^b	302.7^b	209.8^bc	72.6^b	584.2^c	282.4^b
	S01 + S06	1.332^a	1.524^a	0.867^c	0.212^c	25.0^a	24.6^a	324.6^a	365.9^a	219.3^b	55.7^c	690.5^a	274.9^b
Significance (F _A)		ns	**	ns	**	**	**	**	**	**	**	**	**
Significance (F _B)		**	**	**	**	**	**	**	**	**	**	**	**
Significance (F _A×B)		**	**	**	**	**	**	**	**	**	**	**	**
CV (%)		5.92	6.88	6.42	8.13	2.96	3.04	6.07	9.21	6.93	13.4	4.98	7.57

Effect of nitrogen fertilizer supplemented with nitrogen fixing PNSB on biochemical characteristics of rice grown on saline soil of My Xuyen, Soc Trang under greenhouse conditions

		SPAD				Chlorophyll			Proline
		21 DAS	28 DAS	35 DAS	42 DAS	a	b	a + b	µmol g⁻¹ DW
Factor		21 DAS	28 DAS	35 DAS	42 DAS	µg mL⁻¹
The first season
Nitrogen	100%	32.7^a	35.9^a	37.5^a	35.4^a	3.97^a	1.91^a	5.88^a	19.7^ab
(A)	75%	31.9^b	34.7^b	36.1^b	33.6^b	3.38^b	1.92^a	5.30^b	20.1^a
	50%	32.0^ab	34.2^b	35.3^c	31.4^c	2.80^c	1.66^b	4.46^c	19.2^b
	0%	29.5^c	29.4^c	26.9^d	24.6^d	2.60^c	1.59^b	4.19^c	16.0^c
Bacteria	No bacteria	30.5^c	32.5^b	32.6^b	30.5^b	2.84^d	1.98^a	4.82^b	23.9^a
(B)	S01	31.5^b	33.7^a	34.2^a	30.5^b	3.28^b	1.78^b	5.06^ab	16.6^c
	S06	31.8^ab	34.3^a	34.4^a	31.2^b	2.95^bc	1.67^b	4.62^b	16.4^c
	S01 + S06	32.4^a	33.6^a	34.5^a	32.9^a	3.68^a	1.65^b	5.33^a	18.1^b
Significance (F_A)		**	**	**	**	**	**	*	**
Significance (F_B)		**	**	**	**	**	**	**	**
Significance (F_AxB)		**	ns	*	ns	ns	ns	ns	**
CV (%)		3.20	3.37	2.51	4.22	17.0	11.9	13.3	6.58
The second season
	100%	35.1^a	35.5^a	35.0^a	34.0^b	2.96^a	0.938^a	3.90^a	5.31^b
Nitrogen (A)	75%	34.4^b	35.3^a	33.5^b	28.3^d	2.57^b	0.829^b	3.40^b	5.96^a
	50%	32.4^c	33.3^b	30.9^c	34.6^a	2.28^c	0.718^c	3.00^c	5.10^c
	0%	28.5^d	24.4^c	24.4^d	31.3^c	1.55^d	0.476^d	2.03^d	4.07^d
Bacteria	No bacteria	31.7^d	31.1^c	30.3^b	30.5^c	2.10^b	0.808^a	2.90^b	6.07^a
(B)	S01	32.9^b	33.0^a	31.2^a	34.8^a	2.46^a	0.729^b	3.19^a	4.20^d
	S06	33.6^a	32.3^b	31.2^a	31.2^b	2.48^a	0.758^ab	3.24^a	5.69^b
	S01 + S06	32.3^c	32.0^b	31.1^a	31.5^b	2.34^a	0.667^c	3.00^b	4.47^c
Significance (F _A)		**	**	**	**	**	**	**	**
Significance (F _B)		**	**	**	**	**	**	**	**
Significance (F _A×B)		**	**	**	**	**	**	**	**
CV (%)		1.56	2.19	2.29	2.15	8.50	10.2	6.68	4.66

Application of nitrogen-fixing purple non-sulfur bacteria in improving nitrogen uptake, growth, and yield of rice grown on extremely saline soil under greenhouse conditions

Figures & Tables

Figure 1

Figure 2

Figure 3

Characteristics of rice-shrimp soil in My Xuyen-Soc Trang

Effect of nitrogen fertilizer supplemented with nitrogen fixing PNSB on the fertility of saline soil of My Xuyen – Soc Trang under greenhouse conditions

Effect of nitrogen fertilizer supplemented with nitrogen fixing PNSB on the growth and yield of rice grown on saline soil of My Xuyen, Soc Trang under greenhouse conditions

Effect of nitrogen fertilizer supplemented with nitrogen fixing PNSB on the Na and N uptake of rice grown on saline soil of My Xuyen, Soc Trang under greenhouse conditions

Effect of nitrogen fertilizer supplemented with nitrogen fixing PNSB on biochemical characteristics of rice grown on saline soil of My Xuyen, Soc Trang under greenhouse conditions

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