Influence of some essential elements (P, K, Ca, Mg, Fe and Mn) on the efficiency of five BGA (blue-green algae) species and two fertilizers in the growth of rice

doi:10.15406/mojbb.2018.05.00088

MOJ

eISSN: 2573-2951

Bioequivalence & Bioavailability

Research Article Volume 5 Issue 2

Influence of some essential elements (P, K, Ca, Mg, Fe and Mn) on the efficiency of five BGA (blue-green algae) species and two fertilizers in the growth of rice

Md Didar-ul Alam

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Department of Soil, Water and Environment, University of Dhaka, Bangladesh

Correspondence: Md Didar-ul-Alam, Professor, Department of Soil, Water and Environment, University of Dhaka, Dhaka-1000, Bangladesh, Tel 01716058417

Received: June 24, 2017 | Published: March 26, 2018

Citation: Didar-ul-Alam M. Influence of some essential elements (P, K, Ca, Mg, Fe and Mn) on the efficiency of five BGA (blue-green algae) species and two fertilizers in the growth of rice. MOJ Bioequiv Availab. 2018;5(2):99-110. DOI: 10.15406/mojbb.2018.05.00088

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Abstract

The P-content values obtained at the second harvest were significantly lower than the 1st harvest; P-offtake by plants in pots inoculated with BGA was significantly lower than from pots receiving fertilizer in the 2nd harvest. Like K-content there are no clear differences between Ca-contents or Mg-contents although the values for pots inoculate with BGA were slightly but not significantly lower than for those receiving fertilizer. Fe content significantly higher in plants from pots receiving fertilizer than from those inoculated with BGA at both the 1st and 2nd harvests. In case of Mn there is a little variation at the highest but between harvest there is a significant increase in both % Mn-content and Mn offtake.

Keywords: nutrient elements, interaction, harvest

Introduction

Competition for space and resources has imposed on us the necessity to further optimize our exploitation of cultivated and wild lands. It has been revealed that agricultural production will have to increase by 60% on the next 20 years to sustain the world’s population after 2025. An important problem is not only to increase the yield per unit area, but also per unit input. We cannot rely on the application of chemical and organic fertilizers alone, we need to analyze the ecosystem economy. Elucidation of the essential elements inputs and outputs of the ecosystem, estimation of microbial transformations and internal essential elements turnover and extensive application of low-cost fertilizer are aspects of the major elements economy that still require study. So, water bloom algae mainly composed of microsyst can be utilized as a bio-fertilizer, because elements like carbon, nitrogen, phosphorus and potassium are liberated in forms available to growing plants after decomposition of alga bodies. The quantity of various essential elements released from decomposition of different blue-green algae to the growing crop is likely to vary with different soil conditions. Thus, the blue-green algae may act not only as a substitute for mineral fertilization, but as a supplement.¹ Flooding Paddy soils causes a number of electrochemical changes in that soil that, in general benefit the crop. Many nutrients like N, P, K, Ca, Mg, Fe, Mn etc. become more available to the crop and most nutrients toxicity’s and deficiencies associated with extreme soil pH.² An effort has been made to estimate to see the influence of various elements on the efficiency and five BGA species and two chemical fertilizers and compound them under green house condition.

Methods and material

The soil for the present experiment is highly productive known as Insch soil obtained from Murrials farm in aberdeenshire of Scotland UK. Chemically, the soil had pH 5.96, organic carbon 7.95 %, total nitrogen 0.28 %, cation exchange capacity 11.5meq 100-1 and sandy loam as texture. The rice variety ‘MRI’ of Malaysian agricultural development Institute were 1R22 collected from school of agriculture, Aberdeen University, UK. ‘MR1’was selected as indicator plant because of its high and stable yield that has poor eating quality but excellent plant type. After viability test (98.3 % germination was recorded), the 25 days old seedlings were transplanted to pots. The experiment was laid out in a split plot design. The experimental plots were divided into two blocks representing two replications. Each block was sub-divided into sub-blocks. Each sub-block was again divided into 21 unit plots upon which the treatment was superimposed randomly. The total number of unit plots (pots) was 84. There were three sources of nitrogen, namely urea (U), ammonium sulfate (As) and blue green algae (BGA) each at five rates. For the BGA each species was considered to be a rate (Table 1).

Rate	Fertilizers (mg N pot-1)	BGA
1	30	Anabaena variabilies
2	60	Anabaena cylindrica
3	90	Anabaena doliolum
4	120	Nostoc muscorum
5	150	Plectonema boryanum

Table 1 Five species of BGA

Two types of control were prepared provided in this design. One control receiving no nitrogen (0) and the second control was inoculated with five species of BGA in each sub block without growing rice plants. Thus there were 21 treatments; the total number of unit plots (pots) was 84. There were three sources of nitrogen, namely urea (U), ammonium sulfate (As) @ 30,60.90,120, & 150 (mg N pot-1) and all five blue green algae (BGA) as the five rates. For the BGA each species was considered to be a rate by the following way (Table 1).

84 plastic 21x17 cm round pots were numbered consecutively. Each pot was about 4-litre capacity and the drainage holes were closed with thick sticky tape. The pots were washed carefully and dried before use. 1800g air-dry soil was placed into each pot with capillary matting (Fyba mat) at the bottom. The air dry soil was mixed with 20ml of KH2PO4 solution in a Kenwood mixer for the basic fertilizer dose of p and K .The moist soil were transferred to the pots with light and even packing and 1500ml of water were added to each pot. This forms a 2cm depth of standing water over the soil surface. The pots were kept at constant temperature covering with polythene sheet. The pots were transformed after 5 days to the glass house and appropriate quantities of N fertilizer added and mixed. In case of BGA pots each inoculate was applied as a liquid suspension. Four days after transplanting, when the seedlings become fully established, the depth of standing water was raised to 4.5cm and maintained throughout the growing period. In the present study the temperature was optimum (25-300C) up to 56 days and then dropped in month November. In that month and especially on cloudy clays fluorescent lights were used to supply adequate light. The pots were weeded by hand from time to time when necessary the rice plants started tillaring within 2 weeks after transplanting. Six weeks after transplanting, pots numbering 1‒21 from block I and 43‒63 from block II and twelve weeks after transplanting (harvest) the plant samples were removed, washed, weighed, dried, reweigh and ground. The method of Bremner,³ was followed for nitrogen analysis.

Statistical analysis

It was necessary to calculate the standard error of differences of means (SED) for correct comparison among all treatments. The Genstat statistical computer package,⁴incorporates a split plot model consists of: N rates, N-rates X N-source interaction, Harvest X rates, harvest X sources, harvest X rate X source at two different harvest. The SED at p£0.001, p£0.01, p£0.05 levels were shown in each table. In comparing those results the superscript letter before the mean indicates weather within the columns are significantly different while those following the means provide information on the significance between columns.

Result and discussion

In (Table 2A) (Table 2B) as content and offtake of P K, Ca, Mg, Fe and Mn are expressed as percentage of dry matter (dm) in duplicate values at 1st and 2nd harvest. The statistical results of above all elements are presented in Table 3‒11.

Treatments	Dry matter yield(dm) g pot-1		P %		P offtake mg pot -1		K %		Ca %		Mg %		Fe µg g-1 dm*		Fe offtake µg pot-1		Mn µg-1 dm		Mn offtake mg pot -1
6	0.87	1.01	0.74	0.51	6.4	5.2	1.95	1.9	0.38	0.37	0.13	0.12	161	164	139.9	165.1	752	713	0.6	0.71
7	1.93	2.08	0.7	0.68	13.5	14.1	1.85	1.92	0.39	0.44	0.13	0.15	224	210	431.4	436.4	1043	977	2	2
8	1.79	1.87	0.72	0.71	12.9	13.3	1.95	1.65	0.4	0.4	0.13	0.13	224	224	400	400.2	1016	977	1.8	1.8
9	1.25	1.37	0.62	0.61	7.8	8.4	1.55	1.65	0.43	0.43	0.14	0.14	346	357	432.6	1779	937	871	1.2	1.8
10	1.56	1.66	0.55	0.53	8.6	8.8	1.85	1.75	0.4	0.42	0.13	0.14	229	237	357.1	686.4	1017	977	1.6	1.6
11	1.63	1.71	0.57	0.62	9.3	10.6	1.65	1.85	0.4	0.4	0.13	0.13	379	357	617.8	687.4	1109	1056	1.8	1.8
12	1.88	1.96	0.58	0.56	10.9	11	1.95	1.85	0.4	0.4	0.14	0.13	360	259	676.2	1127.7	977	951	1.8	1.8
13	1.96	2.01	0.5	0.51	9.8	10.3	1.85	1.75	0.4	0.43	0.15	0.14	253	253	496.7	669.4	898	977	1.8	2
14	1.7	1.76	0.61	0.6	10.4	10.6	1.95	1.98	0.43	0.43	0.14	0.14	270	382	458.6	1424.9	924	898	1.5	1.6
15	1.27	1.41	0.56	0.55	7.1	7.8	1.92	1.85	0.39	0.4	0.13	0.13	371	360	470.7	1155.7	1003	964	1.3	1.4
16	1.12	1.05	0.65	0.64	7.3	6.7	1.65	1.65	0.4	0.38	0.13	0.13	234	278	415.1	613.8	1030	924	1.2	1
17	1.5	1.45	0.66	0.64	9.9	9.3	1.95	1.65	0.4	0.39	0.13	0.13	333	346	351.5	1028.7	898	1096	1.3	1.6
18	1.96	1.83	0.54	0.53	10.6	9.7	1. 5	1.85	0.44	0.41	0.15	14	319	335	651.6	1200	950	845	1.9	1.5
19	1.53	1.62	0.58	0.61	8.9	9.9	1.83	1.8	0.39	0.39	0.13	0.13	319	335	487.8	718	1003	964	1.5	1.6
20	1.79	1.93	0.59	0.57	10.6	11	1.95	1.85	0.41	0.4	0.14	0.13	428	436	765.8	1165.7	977	1056	1.7	2
21	2.27	2.33	0.55	0.53	12.5	12.3	1.85	2.05	0.4	0.4	0.13	0.14	199	188	451.5	848	1201	1307	2.7	3

Table 2A Nutrient content (P, K, Ca, Mg, Fe and Mn) and offtake (P, Fe and Mn) by rice by following application of different rates of urea, ammonium sulphate and BGA species at 1st harvest
dm*, dry matter

Treatments	Dry matter yield(dm) g pot-1		P %		P offtake mg pot-1		K %			Ca %	Mg %		Fe µg g -1 dm*		Fe offtake µg pot-1		Mn µg-1 dm		Mn offtake mg pot-1
6	3.53	3.74	0.41	0.41	14.5	15.3	1 .35	1.38	0.66	0.62	0.2	0.21	128	134	454.5	499.4	1214	1175	4.3	4.4
7	5.9	5.73	0.43	0.43	25.4	24.6	1.45	1.55	0.68	0.66	0.22	0.2	169	155	996.8	889.9	1584	1478	9.3	8.5
8	5.15	5.42	0.39	0.38	20.1	20.6	1.68	1.65	0.66	0.66	0.21	0.21	174	166	898.2	900.9	1690	1690	8.7	9.2
9	5.74	5.58	0.38	0.39	21.8	21.8	1.65	1.65	0.63	0.66	0.23	0.21	305	319	1751.8	1779	1478	1439	8.5	8
10	4.39	4.58	0.32	0.33	14.5	15.1	1.65	1.75	0.69	0.66	0.21	0.21	134	150	586.2	686.4	1465	1426	6.4	6.05
11	4.57	4.76	0.35	0.35	16	16.7	1.65	1.55	0.66	0.67	0.21	0.22	134	144	610.2	687.4	1610	1571	7.4	7.5
12	4.36	4.45	0.4	0.4	17.4	17 .8	1.75	1 65	0.61	0.57	0.2	0.19	234	253	1021.8	1127.7	1795	1742	7.8	7.8
13	4.19	4.31	0.42	0.41	17.6	17.7	1.67	1.65	0.6	0.51	0.2	0.17	180	155	753.6	669.4	1452	1399	6.1	6
14	6.13	6.3	0.39	0.4	3.9	25.2	1. 70	1.55	0.63	0.57	0.21	0.19	245	226	1503.9	1424.9	1676	1637	10.3	10.3
15	6.24	6.33	0.4	0.4	24.9	25.3	1.52	1.55	0.63	0.61	0.21	0.2	199	183	1241.3	1155.7	1307	1280	8.2	8.1
16	3.99	4.25	0.42	0.36	16.8	15.3	1.55	1.45	0.57	0.56	0.19	0.19	169	144	674.1	613.8	1637	1571	6.5	6.7
17	5.89	5.72	0.41	0.34	24.1	19.4	1.57	1.85	0.66	0.6	0.21	0.2	164	180	963	1028.7	1452	13.73	8.6	7·9
18	6.32	5.97	0.4	0.38	25.3	22.7	1. 75	1.5	0.64	0.63	0.23	0.21	183.2	1153.8	1153.8	1200	1439	1386	9	8.3
19	4.06	4.25	0.38	0.38	15.4	16.1	1.35	1.45	0.59	0.6	0.19	0.2	138	169	641.7	718	1402	1412	6.6	6
20	5.97	6.2	0.38	0.38	2.7	23.6	1.55	1.55	0.63	0.62	0.21	0.2	177	188	1057.4	1165.7	1518	1492	9.1	9.2
21	4.89	5.02	0.39	0.39	19.1	9.6	1 .47	1.5	0.62	0.64	0.22	0.23	177	169	866	848	1610	1663	7.9	8.3

Table 2B Nutrient content (P, K, Ca, Mg, Fe and Mn) and offtake (P, Fe and Mn) by rice by following application of different rates of urea, ammonium sulphate and BGA species at 2nd harvest
dm*, dry matter

P content and P-offtake

A small difference was observed in %P-content of the plant material at the 1st harvest (Table 3) it being significantly higher with the addition of U which may be due to localized differences in soil/water pH in the early stages of growth as this differences disappeared by the 2nd harvest. The P-content values obtained at the 2nd harvest were significantly lower than for the first harvest because of the increase in dry matter yield. The P-offtake data presented in Table 4 show the same difference for the 1st harvest despite the difference in dry matter yield but by the second harvest offtake of P by plants in pots inoculated with BGA was significantly lower than from pots receiving fertilizer. This difference may be due to the competition between BGA and rice plants for P or it may be due to the lower dry matter yield where BGA was inoculated. Rice yield increased nearly five folds with the application of 150kg P2O5 ha-1 Compared to control treatments. For upland rice P deficiency is the most limiting factor among all essential plant nutrients. This is due to the low inherent P level of the soil (<2mg kg-1) and high fixation capacities.⁵

Treatment means 1st harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
0.673b 0.568a 0.555a 0.610a 0.571a					0.0243	P≤0.05
		a=n.s. & b=0.05
N-sources (S)	BGA	U	AS
	0.595b	0.629c	0.563a		0.0188	P≤0. 1
		b=0.1 c=0.1
N-Sources × Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	0.625	0.042	P≤0.05
1	c0.69a	a0.72a	a0.62a	a=n.s.
2	a0.54a	a0.60ba	a0.57a	a=n.s.
3	a0.51a	a0.61a	a0.56a	a=n.s.
4	a0.65a	a0.65b	a0.54a	b=0.05
5	a0.60a	a0.58a	a0.54a	a=n.s.
	a=n.s	a=n.s	a=n.s

Treatment means 2nd harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
0.400a 0.358b 0.403d 0.385c 0.383c					0.00953	P≤0.05
		b=0.05
N-sources (S)	BGA	U	AS
	0.388a	0.388a	0.388a		0.00738	P≤0.00 1
		a=n.s
N-Sources × Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	0.041	0.01651	P≤0.01
1	e0.430b	a0.385a	a0.385a	a=n.s.
				b=0.05
2	d0.325b	b0.350a	b0.400b	a=n.s.
				b=0.01
3	c0.415a	c0.395b	c0.400b	a=n.s.
4	b0.390a	d0.375c	b0.390b	a=n.s.
5	a0.380a	c0.380c	c0.390b	a=n.s.
	b=0.01	a=n.s.	a=n.s.

Table 3 % P content of rice as obtained by application of different species of BGA and rates of ammonium sulphate and urea at each of two harvests
+ abc means bearing the different superscripts differ significantly at P≤0.001, P≤0.01,and P≤0.05
+ All SED!s are against 15 df.

Treatment means 1st harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
11.67d 9.87b 9.30a 8.92a 10.87c					0.2828	P≤0.01
b=0.1 , c=0.01 & d=0.05
N-sources (S)	BGA	U	AS
	9.79a	10.77b	9.81a		0.2191	P≤0.001
		b=0.001
N-Sources × Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	5.8	0.4899	P≤0.001
1	c13.80b	b13.10b	a8.10a	b=0.001
2	b8.70a	a9.95b	b10.95c	b=0.05
				c=0.1
3	b10.05b	a10.40b	a7.45a	b=0.001
4	a7.06a	a9.60b	b10.15b	b=0.001
5	b9.40a	a10.80b	c12.40c	b=0.05
				c=0.01
	b=0.01	a=n.s.	a=n.s.
	c=0.001	b=0.001	b=0.001	c=0.01

Treatment means 2nd harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
22.38d 16.25a 22.43d 20.61c 19.42b					0.635	P≤0.001
b=0.001, c=0.01 & d=0.01
N-sources (S)	BGA	U	AS
	17.85a	21.23b	21.57b		0.491	P≤0.001
		b=0.001
N-Sources × Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	14.9	1.099	P≤0.001
1	b25.00b	b20.35a	b21.80a	b=0.01
2	a14.80a	b16.35a	a7.60a	a=n.s.
3	ca7.65b	b24.55a	c25.10a	b=0.00
4	a16.05a	b21.77b	c24.00c	b=0.001
				c=0.1
5	a15.75a	b23.15c	a9.35b	b=0.01
				c=0.01
	a=n.s.	b=0.01	a=n.s.
	b=0.001		b=0.01
			c=0.1

Table 4 P-offtake by rice (mg/pot-1) as obtained by application of different species of BGA and rates of ammonium sulphate and urea at each of two harvests
+ abc means bearing the different superscripts differ significantly at P≤0.001, P≤0.01, and P≤0.05
+All SED’s are against 15 df.

% K content

There are no obvious differences in % K content except that at both 1st and 2nd harvests (Table 5) values for plants from pots inoculated with BGA were marginally but not significantly lower. There was a significant reduction in values at the 2nd harvest because of increased dry matter yields.

Treatment means 1st harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
1.795a 1.817a 1.883a 1.767a 1.888a					0.0513	P=n.s.
a=n.s.
N-sources (S)	BGA	U	AS
	1.790a	1.863a	1.837a		0.0397	P=n.s.
		a=n.s.
N-Sources × Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	1.925	0.0888	P≤0.01
1	a1.89b	a1.90b	a1.60a	b=0.01
2	a1.80a	a1.75a	b1.90a	a=n.s.
3	a1.80a	a1.97a	b1.89a	a=n.s.
4	a1.65a	a1.80a	b1.85a	a=n.s.
5	a1.82a	a1.90a	b1.95a	a=n.s.
	a=n.s.	a=n.s.	b=0.05

Treatment means 2nd harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
1.605b 1.667b 1.607b 1.612b 1.478a					0.0502	P≤0.05
b=0.05
N-sources (S)	BGA	U	AS
	1.552a	1.630a	1.599a		0.0389	P=n.s.
		a=n.s.
N-Sources×Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	1.365	0.087	P≤0.1
1	a1.50a	a1.67b	a1.65b	b=0.1
2	b1.70a	a1.60a	a1.70a	a=n.s.
3	b1.66a	a1.63a	a1.54a	a=n.s.
4	a1.50a	a1.71a	a1.63a	a=n.s.
5	a1.40a	a1.55a	a1.49a	a=n.s.
	a=n.s.	a=n.s.	a=n.s.	b=0.1

Table 5 %K content of rice as obtained by application of different species of BGA and rates of ammonium sulphate and urea at each of two harvests
+ abc means bearing the different superscripts differ significantly at P≤0.001, P≤0.01,and P≤0.05
+ All SED!s are against 15 df.

% Ca and Mg content

Like K-content there is no clear difference between Ca-content (Table 6) and Mg-contents (Table 7) although the values for pots inoculated with BGA were slightly but not significantly lower than for those receiving fertilizer. However, for both elements values for % content at the 2nd harvest were significantly higher than at the first, which indicates increased demand or uptake for those elements in the later period of growth.

Treatment means 1st harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
0.415a 0.407a 0.413a 0.403a 0.402a					0.00833	P=n.s.
a=n.s.
N-sources (S)	BGA	U	AS
	0.404a	0.406a	10.414a		0.00645	P=n.s.
		a=n.s.
N-Sources × Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	0.375	0.01443	P≤0.1
1	a0.415a	a0.400a	a0.430a	a=n.s.
2	a0.410a	a0.400a	a0.410a	a=n.s.
3	a0.415a	a0.430a	a0.395a	a=n.s.
4	a0.390a	a0.395a	a0.425a	a=n.s.
				b=0.1
5	a0.390a	a0.405a	a0.410a	a=n.s.
	a=n.s.	a=n.s.	a=n.s.
		b=0.1

Treatment means 2nd harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
0.658b 0.643b 0.592a 0.617a 0.617a					0.0132	P≤0.1
b=0.1
N-sources (S)	BGA	U	AS
	0.612a	0.636a	0.624a		0.0102	P=n.s.
		a=n.s.
N-Sources × Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	0.64	0.0228	P≤0.01
1	b0.670a	a0.660a	a0.645a	a=n.s.
2	b0.675a	a0.665a	a0.590a	b=0.01
3	a0.555a	a0.600b	a0.620b	b=0.1
4	a0.565a	a0.630b	a0.635b	b=0.05
5	a0.595a	a0.625a	a0.630a	a=n.s.
	a=n.s.	a=n.s.	a=n.s.
	b=0.01

Table 6 % Ca content of rice as obtained by application of different species of BGA and rates of ammonium sulphate and urea at each of two harvests
+ abc means bearing the different superscripts differ significantly at P≤0.001, P≤0.01,and P≤0.05
+ All SED!s are against 15 df.

Treatment means 1st harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
0.137a 0.133a 0.138a 0.135a 0.133a					0.00349	P=n.s.
a=n.s.
N-sources (S)	BGA	U	AS
	0.136a	0.133a	0.137a		0.0027	P=n.s.
		a=n.s.
N-Sources × Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	0.125	0.00604	P≤0.05
1	a0.140b	a0.130a	a0.140a	b=0.1.
2	a0.135a	a0.130a	a0.135a	a=n.s.
3	a0.145b	a0.140b	a0.130a	a=n.s.
4	a0.130a	a0.130a	a0.145b	a=n.s.
				b=0.05
5	a0.130a	a0.135a	a0.135a	a=n.s.
	a=n.s	a=n.s	a=n.s

Treatment means 2nd harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
0.212a 0.207a 0.197a 0.206a 0.208a					0.00527	P=n.s.
a=n.s.
N-sources (S)	BGA	U	AS
	0.198a	0.206b	0.213b		0.00408	P≤0.1
		b=0.1
N-Sources × Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	0.205	0.00913	P≤0.05
1	a0.210a	a0.205a	a0.220a	a=n.s.
2	a0.210a	a0.215a	a0.195a	a=n.s.
3	a0.185a	a0.200b	a0.205b	b=0.1.
4	a0.190a	a0.205b	a0.220c	b=0.1
				c=0.1
5	a0.195a	a0.205a	b0.225b	b=0.05
	a=n.s	a=n.s.	a=n.s.
			b=0.1

Table 7 % Mg content of rice as obtained by application of different species of BGA and rates of ammonium sulphate and urea at each of two harvests
+ abc means bearing the different superscripts differ significantly at P≤0.001, P≤0.01, and P≤0.05
+ All SED’s are against 15 df.

% Fe content and Fe-offtake

Values for % Fe content are presented in Table 8 and showed significantly higher Fe content in plants from pots receiving fertilizer than those from inoculated with BGA at both the 1st and 2nd harvests, this difference which is more obvious in the Fe-offtake (Table 9) may be due to competitive uptake by the BGA. Fe- content and Fe up-take was highest in plants receiving AS fertilizer at both harvests. This may be due to localized higher acidity in the pots receiving AS compared to those receiving U. Off-take values increase with increasing amounts of N-applied which may due to increased dry matter yields.

Treatment means 1st harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
263.9a 317.9c 292.9b 320.2c 317.5c					6.96	P≤0.001
b=0.001 & c=n.s.-0.01
N-sources (S)	BGA	U	AS
	279.6a	308.2b	319.6c		5.39	P≤0.001
		b=0.001& c=0.1
N-Sources × Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	162.3	12.06	P≤0.001
1	a216.4a	a223.4a	b351.5b	a=n.s.
				b=0.001
2	a233.0a	c367.9b	b352.9b	b=0.001
3	b256.1a	b261.6a	b361.0b	a=n.s.
				b=0.001
4	d365.1c	b256.1a	b339.3b	b=0.01
				c=0.05
5	c327.0b	d431.9c	a193.5a	b=0.001
				c=0.001
	a=n.s	b=0.05	b=0.001
	b=0.1	c=0.001
	c=0.001	d=0.001
	d=0.01

Treatment means 2nd harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
274.9b 174.8a 204.7b 173.9a 173.0a					6.67	P≤0.001
a=n.s. & b=0.001
N-sources (S)	BGA	U	AS
	158.3a	183.9b	222.6c		5.17	P≤0.001
		b=0.001 & c=0.001
N-Sources × Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	130.8	11.56	P≤0.001
1	a162.1a	b170.5a	c312.0b	a=n.s.
				b=0.001
2	a141.1a	a139.0a	b243.8b	a=n.s.
				b=0.05
3	a167.6a	c255.7c	a190.7b	b=0.01
				c=0.00
4	a156.7a	b171.7a	a193.5b	a=n.s.
				b=0.001
5	a163.5a	b182.6a	a173.0a	a=n.s.
	a=n.s	b=0.05	a=n.s.
		c=0.001	b=0.001
			c=0.001

Table 8 Fe content of rice (g g-1 dry matter) as obtained by application of different species of BGA and rates of ammonium sulphate and urea at each of two harvests
+ abc means bearing the different superscripts differ significantly at P≤0.001, P≤0.01,and P≤0.05
+ All SED!s are against 15 df.

Treatment means 1st harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
434.4a 555.5c 487.5b 468.7b 587.9d					13.57	P≤0.001
b=0.05, c=0.001 & d=0.05
N-sources (S)	BGA	U	AS
	445.9a	530.7b	543.8b		10.51	P≤0.001
		b=0.001
N-Sources × Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	152.5	23.5	P≤0.001
1	a433.8a	a408.9a	a460.4a	a=n.s.
2	a375.3a	b613.9b	d677.3c	b=0.001
				c=0.05
3	b508.5b	a449.8a	b504.3b	b=0.05
4	a396.4a	a377.3a	c632.4b	a=n.s
				b=0.001
5	b515.4b	c803.6c	a444.8a	b=0.01
				c=0.001
	a=n.s	a=n.s	a=n.s
	b=0.001	b=0.001	b=0.1
		c=0.001	c=0.001
			d=0.1

Treatment means 2nd harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
1202.8e 786.7a 1124.7d 938.9c 882.8b					31.09	P≤0.001
b=0.001, d=0.001 & c=0.1 e=0.05
N-sources (S)	BGA	U	AS
	723.0a	1024b	1214.5c		24.08	P≤0.001
		b=0.001 &c=0.001
N-Sources × Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	477	53.85	P≤0.001
1	b943.4a	b899.5a	d1765.4b	a=n.s.
				b=0.001
2	a636.3a	a649.0a	b1074.7b	a=n.s.
				b=0.001
3	a711.4a	e1464.1c	c1198.5b	b=0.001
				c=0.00
4	a643.9a	c995.9b	c1177.0c	b=0.001
				c=0.001
5	a679.9a	d1111.6c	a857.1b	b=0.01
				c=0.001
	a=n.s	b=0.001	b=0.01
	b=0.001	c=0.1	c=0.1
		d=0.05	d=0.001
		e=0.001

Table 9 Fe offtake by rice (g pot-1) as obtained by application of different species of BGA and rates of ammonium sulphate and urea at each of two harvests
+ abc means bearing the different superscripts differ significantly at P≤0.001, P≤0.01,and P≤0.05
+ All SED!s are against 15 df.

% Mn content and Mn-offtake

These values are presented in Tables 10 & 11 respectively. There is little variation 1st harvest but between harvests there is a significant increase in both % Mn-content and Mn-offtake. As in the case of Ca and Mg this must represent increased demand and or uptake of the element in the later period of growth. Plant material obtained at the 2nd harvest showed significant differences in Mn-content. Values were highest in material from pots receiving U and lowest in material from pots inoculated with BGA. There was no obvious relationship with the rate of N-application. Mn-offtake at the 2nd harvest is significantly higher than for the 1st harvest and the values are highest for the fertilizer treated pots.

Treatment means 1st harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
970a 1014a 944a 957b 1085b					34	P≤0.05
a=n.s., & b=0.05
N-sources (S)	BGA	U	AS
	981a	1001a	1001a		26.3	P=n.s.
		b=0.001
N-Sources × Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	733	58.8	P≤0.001
1	a1010a	a997a	a904a	a=n.s.
2	a997a	a1082a	a964a	a=n.s.
3	a937a	a911a	a983a	a=n.s.
4	a977a	a997a	a898a	a=n.s
5	a983a	a1016a	b1254b	a=n.s.
				b=0.01
	a=n.s	a=n.s	a=n.s
			b=0.001

Treatment means 2nd harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
1560b 1602b 1459a 1543b 1531b					39.4	P≤0.1
b= n.s. –0.1
N-sources (S)	BGA	U	AS
	1492a	1611b	1514a		30.5	P≤0.1
		a=n.s.& b=0.01
N-Sources × Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	1195	68.3	P≤0.01
1	a1531a	a1690b	a1459a	a=n.s.
				b=0.05
2	a1445a	a1591b	c1769c	b=0.05
				c=0.05
3	a1426b	a1657e	a1294a	b=0.1
				c=0.01
4	a1604b	a1612b	a1412a	b=0.05
5	a1452a	a1505a	b1637b	a=n.s.
	a=n.s	a=n.s	a=n.s	b=0.1
			b=0.05
			c=0.1

Table 10 Mn content of rice (g g-1) as obtained by application of different species of BGA and rates of ammonium sulphate and urea at each of two harvests
+ abc means bearing the different superscripts differ significantly at P≤0.001, P≤0.01,and P≤0.05
+ All SED!s are against 15 df.

Treatment means 1st harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
1.773b 1.773b 1.617b 1.417a 2.083c					0.092	P≤0.001
b=0.05 & c=0.001
N-sources (S)	BGA	U	AS
	1.634a	1.70a	1.84b		0.071	P≤0.1
		b=0.1
N-Sources × Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	0.68	0.16	P≤0.001
1	c2.02b	a1.80b	a1.50a	b=0.1
2	b1.60a	a1.80a	a180a	a=n.s.
3	c1.90b	a1.60a	a1.35a	b=0.1
4	a1.10a	a1.45b	a1.70b	b=0.1
5	b1.55a	a1.85	b2.85c	a=n.s.
				c=0.001
	b=0.05	a=n.s	b=0.001
	c=0.1

Treatment means 2nd harvest
N-rates( R ) 1 2 3 4 5					SED	Significance of difference
8.70d 7.23a 8.17c 7.83b 7.85b					0.0502	P≤0.01
b=0.01 , c=0.1 & d=0.01
N-sources (S)	BGA	U	AS
	6.86a	8.82a	8.19b		0.129	P≤0.001
		b=0.001 & c=0.001
N-Sources × Rates (R×S)	BGA	U	AS
0 ( Cont)	-	-	-	4.35	0.288	P≤00.1
1	b8.90b	c8.95b	a8.25a	b=0.05
2	a6.45a	a7.45b	a7.80b	b=0.001
3	a6.05a	d10.30c	a8.15b	b=0.001
				c=0.001
4	a6.60a	b8.25b	a8.65b	b=0.001
5	a6.30a	c9.15c	a8.10b	b=0.001
				c=0.01
	b=0.001	b=0.05	a=n.s.
		c=0.05
		d=0.01

Table 11 Mn oftake by rice (mg pot-1) as obtained by application of different species of BGA and rates of ammonium sulphate and urea at each of two harvests
+ abc means bearing the different superscripts differ significantly at P≤0.001, P≤0.01,and P≤0.05
+ All SED!s are against 15 df.