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Rice vegetative response to different biological and chemical fertilizers.


Rice is an important food crop which is the main food for more than 40% of world population. Among different nutrients, nitrogen is of a high importance and directly affects plant growth. To ensure proper growth, large amount of chemical fertilizers are applied in different crops field but the problem is the loss of these chemical elements from the fields. This problem is more severe in rice paddies because high rate of runoff and leaching takes place which ends in soil and water contamination. This situation has encouraged researchers to study the non-chemical sources of nutrients to replace them with the currently used chemical ones. Some microorganisms live in symbiosis with plants root and improve their growth, which are generally called Plant Growth Promoting Rhizobacteria (PGPR) [13,16,17,18].

Azotobacter and azospirillum are free living (non-symbiosis), nitrogen fixing bacteria which live in rhizosphere and improve plant growth and yield under proper condition. These bacteria generally improve plant root development, water and nutrient absorption and fix air nitrogen into soil [7,10]. Singh et al. [14] studied the effect of biofertilizers on rice growth and development and concluded that inoculating rice transplants with azospirillum increases leaf area, plant height, panicle length and the number of grains/panicle. Kreem [6] also found that higher nitrogen application rate enhances the number of tillers and grains. In another research, El-Kalla et al., [4] represented that increasing the application of nitrogen up to 75 kg/ha increases plant height, flag leaf area and 1000 kernels weight. Finally, this experiment was conducted to study the ability of biofertilizers in meeting rice nutritional requirements.

Materials And Methods

This experiment was conducted in 2009 at the International Research institute of Rice, Gilan Province, Iran (37[degrees] 16' E, 49[degrees] 63' N, 7m below the sea level, 1320 mm average annual precipitation, silt clay loam soil type with the pH of 6.86 and organic matter content of 1.28%). The research was conducted in factorial experiment in the form of randomized complete block design (RCBD) with three replications and two factors:


At four levels including without, azospirillum, azotobacter and combined application of the two microorganisms. To inoculate rice roots with biofertilizers, transplant's roots were washed with water and then soaked in prepared inoculum for five seconds, right before transferring transplants to the paddy.

Chemical nitrogen fertilizer:

At three levels including 0, 45 and 90 kg/ha N. To add these amounts of N to soil, 0, 94 and 190 kg/ha urea was used, respectively. Chemical fertilizer was splited to two parts: 50% at the time of transplanting and 50% at the tillering stage.

The paddy, which had been under continuous rice cultivation, was prepared conventionally on May 22nd. Each plot was 3 x 3.5 m with 35 cm boundaries which were isolated by nylon to prevent water movement between plots. Finally, transplanting was carried out on May 26th, after inoculating roots with the biofertilizers.

On Aug. 30th, when rice plants were fully maturated, samples were taken and following traits were measured: plant height, flag leaf area, the total number of tillers, biomass, panicle weight and leaf weight. The following equation was used to calculate the flag leaf area:

Flag leaf area = the flag leaf length x the flag leaf width x 0.74

10 plants were harvested in each plot to count the total number of tillers. To measure the biomass and the weight of different plant parts such as leaves or panicle, 6 plants (0.125 [m.sup.2]) were harvested in each plot and oven dried at 75[degrees] for 48 hours. Finally, data were analyzed using MSTATC and means were compared according to Duncan's multiple range test.

Results And Discussion

Plant height:

Analysis of variances indicated the significant effect of N fertilizers on plant height, but the effect of biofertilizer and interaction of biofertilizer x N fertilizer was not significant (Table 1). The best N fertilizer application rate was 90 kg/ha which resulted in 136.2 cm plant height, and 0 kg/ha was the worst rate (Table 2). Aguilar and Guru (1990) represented that higher N application rates increase plant height.

Flag leaf area:

Flag leaf area was significantly affected by N fertilizer and the interaction of biofertilizer x N fertilizer (p[less than or equal to]0.01; Table 1). Mean comparison represented that the best value of flag leaf area (22.95 [cm.sup.2]) was occurred in 90 kg/ha N fertilizer. Ali Abbasi and Esfehani [1] concluded that nitrogen fertilizer significantly affected flag leaf area (p [less than or equal to] 0.01). Cechin [3] also reported that nitrogen fertilizer application increases flag leaf area. Mean comparison of the interaction of biofertilizer x N fertilizer showed that azotobacter x 90 kg/ha N was the best treatment (24.98 [cm.sup.2]; Table 2). Sadrzadeh [12] concluded that nitrogen fertilizer increases rice flag leaf area and 120 kg/ha nitrogen was the best treatment in their experiment (34.2 [cm.sup.2]). Flag leaf activity directly affects grains filling so has a vital role in yield production and nitrogen fertilizer increases photosynthesis and activity of flag leaf.

The number of tillers:

Results indicated that biofertilizer, N fertilizer and their interaction significantly affected the total number of tillers (p [less than or equal to] 0.01; Table 1). Mean comparison of N fertilizer application rates revealed that 90 kg/ha nitrogen was the best application rate and produced 11.79 tillers/[m.sup.2] (Table 2). Karimi [5] conducted an experiment on wheat and found that nitrogen increases the number of tillers. In another research, Mobasser et al. [8] represented that application of 50% of required nitrogen fertilizer at the beginning of tillering stage enhances the number of tillers. Mean comparison of the interaction of biofertilizer x N fertilizer indicated the highest (12.94) number of tillers in no biofertilizer x 90 kg/ha nitrogen (Table 2). Although Wada et al. [19] found that nitrogen increases the number of tillers, but Peng [11] represented that higher nitrogen application rates reduce the number of fertile tillers because it stimulates the vegetative growth.


Rice biomass production was significantly affected by N fertilizer and the interaction of biofertilizer x N fertilizer (p [less than or equal to] 0.01; Table 1), but the effect of biofertilizer was not significant. Mean comparison of N application rates indicated the highest biomass production in 90 kg/ha nitrogen (1251 g/[m.sup.2]) and the lowest in no N fertilizer (873.4 g/[m.sup.2]; Table 2). High nitrogen improves plant biomass production by elongating vegetative growth period and postponing flowering. On the contrary, low nitrogen content in soil shortens the vegetative growth period so plant biomass production decreases [9,15]. Mean comparison of the interaction of biofertilizer x N fertilizer represented that azotobacter x 90 kg/ha nitrogen was the best treatment (1410 g/[m.sup.2]) and azospirillum x no N fertilizer was the worst (804.5 g/[m.sup.2]; Table 2).

Panicle weight:

Panicle weight was only affected by N fertilizer (p [less than or equal to] 0.01); the effect of biofertilizer and the interaction of biofertilizer x N fertilizer was not significant (Table 1). According to the mean comparison, the highest panicle weight was observed in 90 kg/ha nitrogen (718 g/[m.sup.2]) and the lowest, in no N fertilizer (521.2 g/[m.sup.2]; Table 2). Although the interaction of biofertilizer x N fertilizer had no significant effect on this trait, but azotobacter x 90 kg/ha nitrogen was the best treatment with panicle weight of 677 g/[m.sup.2] (Table 2). Panicle weight is some part of biological yield and in plants inoculated with azotobacter, higher nitrogen absorption efficiency increases panicle weight.

Leaf weight:

Analysis of variances indicated that only N fertilizer significantly increased leaf weight (p [less than or equal to] 0.01) and the effect of biofertilizer and the interaction of biofertilizer x N fertilizer did not (Table 1). Mean comparison of the effect of nitrogen fertilizer application rates showed that 90 kg/ha N was the best treatment (69.95 g/[m.sup.2]). In high nitrogen application rates, plant vegetative growth increases and these are leaves which support such growth. In means that in high N content, leaves area and weigh increase in order to produce higher amount of assimilates to support the vegetative growth.


Azotobacter and azospirillum in combination with chemical nitrogen fertilizer significantly increased most of the measured traits, although the effect of biofertilizers was not significant in many cases. Results indicated that the best nitrogen application rate in this experiment was 90 kg/ha which significantly increased all measured traits.


[1.] Ali Abbasi, H.R. and M. Esfehani, 2007. The Effect of Nitrogen Fertilizer Application Rates and its Splitting on the Rate and Period of Grain Filling in Rice. Journal of Agricultural Science, 30(2): 25-38. (In Farsi).

[2.] Aguilar, M. and D. Guru, 1990. Effect of Applied before Seedling Nitrogen Fertilization on Rice Yield Components. Cahiers Options Mediterraneennes, 15: 53-64.

[3.] Cechin, I., 1997. Comparison of Growth and Gas Exchange in Two Hybrids of Sorghum in Relation to Nitrogen Supply. Revista Brasileira de Fisiologia Vegetal, 9(3): 151-156.

[4.] El-Kalla, S.E., A.T. El-Kassaby, A.A. Kandil, A.N. Attia and I.O. El-Sayed, 1988. Response of Rice Cultivar (IR50) to Nitrogen and Zinc Sulphate Application. Journal of Agricultural Sciences, 13(2): 629-634.

[5.] Karimi, H., 1992. Wheat. Iran University Press, Tehran, Iran. (In Farsi).

[6.] Kreem, M.K.E., 1993. Effect of Different Nitrogen Rates and Comp Nitrification Inhibitor on Growth and Yield of Rice. Journal of Agricultural Research, 19: 525-536.

[7.] Lin, W., Y. Okon and R.W.F. Hardy, 1983. Enhanced Mineral Uptake by Zea mays and Sorghum bicolor Roots Inoculated with Azospirillum brasilense. Applied Environmental Microbiology, 45: 1775-1779.

[8.] Mobasser, H., Gh. Nurmohammadi, V. Fallah, F. Darvish and E. Majidi, 2005. Effect of Application Rates and Splitting of Nitrogen on Grain Yield of Rice var. Tarom Hashemi. Journal of Agricultural Science, 11(3): 103-109. (In Farsi).

[9.] Ni, H., K. Moody, R.P. Robles, E.C. Paller Jr. and J.S. Lales, 2000. Oryza sativa Plant Traits Conferring Competitive Ability against Weeds. Weed Science, 48(2): 200-204.

[10.] Okon, Y. and R. Itzigsohn, 1995. The Development of Azospirillum as a Commercial Inoculant for improving Crop Yields. Biotechnology Advances, 13(3): 415-424.

[11.] Peng, S., 2000. Single-leaf and canopy photosynthesis of rice. In Redesigning rice photosynthesis to increase yield, Eds., Sheehy, J.E., P.L. Mitchell and B. Hardy. International Rice Research Institute, Losbanos, Philippines, pp: 213-228.

[12.] Sadrzadeh, M., 2002. Study of the effect of different rates of nitrogen and potassium on yield, yield components and growth indices of rice (var: Khazar), M. S. thesis, Gilan University, Iran. (In Farsi).

[13.] Salar Dini, A., 1992. Soil Fertilization. Tehran University Press, Tehran, Iran. (In Farsi).

[14.] Singh, A.L., P.K. Singh and P.L. Singh, 1988. Comparative Studies on the use of Green Manure and Azolla and Blue-Green Algae Biofertilizer to Rice. Journal of Agricultural Sciences, 2: 337-348.

[15.] Singh, M.P. and M. Singh, 1989. Effect of Nitrogen, Phosphorus and Potassium on Yield and Nutrient Uptake by Wheat and Rice in Wheat-Rice Cropping System. Annals of Agricultural Research, 10: 87-95.

[16.] Stacey, G., R.H. Burris and H.J. Evans, 1992. Biological Nitrogen Fixation. Chapman and Hall Publisher, US.

[17.] Vermerrin, H., A. Wellems, G. Schoofs, R. Demot, V. Keijers, W. Hai and J. Vander Leyden, 1999. The Rice Inoculant Strain Alcaligenes faecalis A15 is Nitrogen-Fixing Pseudomonas stutzeri. Applied Microbiology, 22: 215-225.

[18.] Violante, A., P.M. Huang, J.M. Bollag and L. Gianfreda, 2002. Soil Mineral-Organic Matter-Microorganism Interactions and Ecosystem Health. Elsevier, Netherlands.

[19.] Wada, G.D., V. Argones and R.C. Argones, 1998. Nitrogen Absorption Patina Pattern of Rice Plant in the Tropics Japan. Journal of Crop Science, 58: 225-221.

(1) Mohammad Javad Shakouri, (2) Ahmad Varasteh Vajargah, (1) Mehdi Ghasemi Gavabar, (3) Saeed Mafakheri and (3) Meisam Zargar

(1) Young Researchers Club, Roudsar and Amlash Branch, Islamic Azad University, Roudsar, Iran.

(2) Department of Agriculture, Lahijan Branch, Islamic Azad University, Lahijan, Iran.

(3) Young Researchers Club, Science and Research Branch, Islamic Azad University, Tehran, Iran.

Corresponding Author

Mohammad Javad Shakouri, Young Researchers Club, Roudsar and Amlash Branch, Islamic Azad University, Roudsar, Iran.

Table 1: Analysis of variances for measured traits.

                                     Mean Squares (MS)

                               Flag     of
                       Plant   leaf  tillers/           Panicle   Leaf
       SOV         df  height  area     m      Biomass  weight   weight

Biofertilizer (A)  3     ns     ns      **       ns       ns       ns
N fertilizer (B)   2     **     **      **       **       **       **
A x B              6     ns     **      **       **       ns       ns
CV (%)             --   4.55   4.90    9.70     8.09     13.61    3.10

ns, nonsignificant; **, significant
at 0.01; *, significant at 0.05.

Table 2: The effects of biofertilizer, N fertilizer application
rate and their interaction on the measured traits.

Treatments   Plant height   Flag leaf area       Number of
                 (cm)        ([cm.sup.2])    tillers/[m.sup.2]

B1             124/6 b         18/38 a            10/81 a
B2             131/1 a         18/29 a            10/81 a
B3             129/8 ab        18/99 a            10/35 a
B4              128 ab         18/23 a            11/13 a
N0             123/6 b         16/33 b            9/09 a
N45            125/4 b         16/10 b            11/44 a
N90            136/2 a         22/95 a            11/79 a
B1 x N0        116/8 d         17/36 d            9/1 def
B1 x N45       125/1 cd       16/47 def          10/39 cde
B1 x N90        132 bc         21/19 c            12/94 a
B2 x N0        128/8 bc       16/31 def           8/6 ef
B2 x N45       124/4 cd        15/40 ef          12/27 abc
B2 x N90       140/1 a         21/16 b           11/55 abc
B3 x N0        124/6 cd        14/86 f            8/16 f
B3 x N45       126/8 cd        17/13 d           12/44 ab
B3 x N90       138/1 ab        24/98 a          10/44 bcde
B4 x N0        124/3 cd        16/79 de         10/50 bcde
B4 x N45       125/3 cd        15/41 ef          10/66 bcd
B4 x N90      134/4 abc        22/47 bc          10/22 abc

Treatments      Biomass      Panicle weight    Leaf weight
             (g/[m.sup.2])   (g/[m.sup.2])    (g/[m.sup.2])

B1              1033 b          605/6 a          62/74 a
B2              1006 c          583/3 a         53/21 ab
B3              1073 a          601/1 a          66/05 a
B4              980/4 d         597/3 a          43/97 b
N0              873/4 c         521/2 b          46/30 b
N45             944/9 b         551/2 b          53/23 b
N90             1251 a           718 a           69/95 a
B1 x N0          823 h          493/3 e          51/44 b
B1 x N45        1008 e         574/5 cde        72/05 ab
B1 x N90        1269 b          748/9 ab        64/72 ab
B2 x N0         804/5 i         467/4 e          49/04 b
B2 x N45        979/5 f        604/7 cde         39/89 b
B2 x N90        1234 c         677/7 abc        70/69 ab
B3 x N0         842/1 g         509/8 e          42/80 b
B3 x N45        967/5 f          518 de          60/37 b
B3 x N90        1410 a          775/7 a          94/99 a
B4 x N0         1024 e         614/4 bcde        41/92 b
B4 x N45       824/6 gh         507/6 e          40/59 b
B4 x N90        1093 d         669/8 abcd        49/41 b

B1, no biofertilizer; B2, azospirillum, B3, azotobacter, B4,
combination of the two biofertilizers; N0, 0 kg/ha nitrogen; N45,
45 kg/ha nitrogen; N90, 90 kg/ha nitrogen.

Means in column followed by the same letter are not significantly
different at P [less than or equal to] 0.01.
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Article Details
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Title Annotation:Original Article
Author:Shakouri, Mohammad Javad; Vajargah, Ahmad Varasteh; Gavabar, Mehdi Ghasemi; Mafakheri, Saeed; Zargar
Publication:Advances in Environmental Biology
Article Type:Report
Geographic Code:7IRAN
Date:Feb 1, 2012
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