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Effect of plant density and nitrogen rate on yield and yield components of wheat in wild oat-infested condition.


About 60% of cultivated land in the world is dedicated to cereal production which wheat and rye constitute 34% and barley and oat constitute 9-11% of this. Weeds are one the main limiting factor in Crop production [27 and 28]. According to Kumar and Singh [10] estimation weed cause considerable yield loss (9.8-13.1%) of wheat all around the world. Introducing modern varieties with less competitive ability and need to receive more fertilizer have been increasing these losses. Wild oat (Avena fatua) is one of the most interfering weed in cereal producing area and has been adapted with wide range of agroclimate conditions, and therefore consider as one of the main constrains in cereal production. Influence of certain weed on wheat depends on species, weed density, cultivar, rate and time of fertilizer consumption, planting date and time and other ecological and agricultural factors.

Fertilization management from view of time and rate of applied fertilizer is an important factor in optimize crop production and weed management. Despite fertilizers application can increase crop yield in weed free condition [29,30,31,32,33,34,35,36, 37,38], but at same time can increase weed biomass and density, which may increase seed production by weed [6,9,17,25,26] reported that ability of wild oat for nitrogen absorption is higher than wheat which can result in higher growth of this weed and therefore may reducing wheat yield at the higher rate. Ahmadvand et al., [1] showed that competitive effect of wild oat on wheat increase with increasing nitrogen rate, so in density of 80 plant/[m.sup.2] applying 50, 75 and 100 kg/ha N resulted in 37, 41.5 and 44.4% reduction in wheat biological yield, respectively. Rastgou et al., [21] evaluate the effect of rate and time of nitrogen application on economic threshold damage of wild mustard and concluded that densities of economic threshold damage of wild mustard in low, medium and high levels of nitrogen was 0.94, 0.79 and 0.14 plant/[m.sup.2] respectively. Base on this finding economic thrashed of wild mustard is less in higher rate of nitrogen and this means that wild mustard competitiveness increase with higher rate of nitrogen. Dhima, and Eleftherohorinos [3] reported that increasing nitrogen application in wheat in competing with wild oat resulted in increasing weed density and reducing crop yield. Iqbal and Whrigt [7] observed that with increasing soil nitrogen from 20 to 12 mg/kg wild mustard and lambsqurter biomass increased substantially and both of these weed respond to applied nitrogen more than wheat. Parchami and Behdadvand [18] reported that wheat grain and biological yield decrease significantly with increase wild oat density. Increase nitrogen rate in without competition situation increase wheat yield but, in competition situation economic loss of wild oat on wheat increase with increasing nitrogen rate. The maximum seed production for wild oat in low, medium and high rate of nitrogen was 38.69, 50.04 and 56.06 million seed/ha which indicate positive effects of nitrogen on wild oat seed production.

Competitive effects of weeds on crop have been affected by both of plants. Results of experiment indicated that with increasing wheat density its competitiveness increase against wild oat. Hasnzade Deloii, [5] evaluate the effects wheat densities of 300, 400 and 600 plants/[m.sup.2] in presence of 0, 20, 40, 60, 80 and 120 wild oat plants/[m.sup.2] and concluded that increasing wheat density reduced leaf area and biomass of wild oat while increase wheat yield and biomass. Martin et al., [13] showed that yield reduction in lower densities of wheat are more severe than higher densities so, in wheat density of 300 plant/[m.sup.2] presence of 5-6 wild oat plant reduced wheat yield by 20% while in wheat density of 700 plant/[m.sup.2] 38 wild oat required for reducing wheat yield by 20%.

Since optimum density and nitrogen requirement for wheat mostly determined in weed free condition and this finding can changed in presence of competition, this study evaluates the effects of wheat density and nitrogen application in situation of wild oat interference with wheat.

Material and Methods

The experiment was carried out in 2009 in southern Iran, in Pasargad city (1839 m above from sea level, 53[degrees] 08' altitude, 30[degrees] 01' latitude, average rainfall of 352.4 mm, min temperature of -4 and max of 36 [degrees]C). Physiochemical characteristic of experimental soil in 0-30 cm depth was shown in Table-1. Experiment was in Factorial using Randomized Blocks Design with four replications. Treatment consisted of 4 nitrogen level (0, 100, 150 and 200 kg ha) and three wheat densities (250, 400 and 550 plants per [m.sup.2]).

The experimental soil was fallow in previous year. In order to prepare the soil first plowed with a moldboard plow to a depth of 30 cm and then leveling the soil was frozen. Fertilizer application carried out in accordance with the soil test results. Prior to planting seeds were inoculating with Carboxy Tiraman fungicide. The experimental units were 3*4 m which wheat was hand seed according to desired densities. Wild oat seeds were sown in each with density of 80 seed per [m.sup.2]. Gibbrelic acid treatment was applied for breaking wild oat seed dormancy.

At physiological maturity wheat and wild oat plant were harvested at area of 1.5 [m.sup.2] by hand and below traits were measured. Wheat ear number in square meter, seed number per ear, grain yield, biological yield and harvest index and oat yield and yield components. All data were subjected to analysis of variance using SAS and mean were separated by Duncan multiple range test.

Results and Discussion

Yield Components:

Wheat density had significant effects on number of wheat tillers (Table 2). Number of tillers decrease by increasing density so, the highest tillers number (3.47 tiller/plant) observed in density of 250 plant/ [m.sup.2] and the lowest one (1.17 tillers/plant) observed in 550 (Table 3). In condition of competition nutrients, water and light availability limited and it can reduce number tiller per plant. In this situation some of tillers can not produce ear and therefore number of infertile tillers increased. The main mechanism of reducing tiller number in higher densities is reducing nitrate reductase enzyme activity. This enzyme contributes to nitrogen absorption by plant and therefore reduces plant nitrogen content. With reducing nitrogen absorption, root development and utilization of nutrient resource interrupt which resulted in lower tiller production [23]. Lemrel et al., [11] showed that tillers number is the most important yield component in wheat that reduced in competition with wild oat.

Increase nitrogen level resulted in higher tiller number production, so the highest tiller number (2.78 tiller/plant) obtained in treatment of 200 kg /ha nitrogen application while, no nitrogen application produced the lowest tiller. There is no significant difference between 150 and 200 kg N treatments (Table 4). With application sufficient N higher number of tillers can produce ear and number of fertile tiller increases.

Plant density, nitrogen application and density*nitrogen interaction had significant effect on wheat ear number (Table 2). The highest (650.39 ear/[m.sup.2]) and lowest (607.66 ear/[m.sup.2]) ear number observed in 550 and 250 plant /[m.sup.2] treatment, respectively (Table 3). Ear reduction in low densities is due lower plant per area unit. Although the number of tiller per plant increase in lower plant densities, lowering plant per area can not compensate with tiller number in these densities.

Ear number increase with increasing nitrogen application and the highest ear number (648.64) obtained from application of 200 kg/ha N while, lowest ear number obtained in no N treatment (Table 4). Increasing N availability in high N treatment may result in producing more ears from tillers and therefore increasing number of fertile ear. Khaliq et al., [8] showed that increasing N rate by 175 kg/ha increase ear number and grain yield of maize. In general yield increasing in situation of N application are mainly due to higher ear /area production.

Interaction effect of N*density showed that the highest ear number (667.8 ear/[m.sup.2]) were obtained in density of 550 plant/[m.sup.2] and application of 200 kg/ha, while the lowest ear number (511.8 ear/[m.sup.2]) belonged to 250 plant/[m.sup.2] density without nitrogen (Figure 1). Fallahi et al., [4] also reported that by increasing plant density number of ear /area increased significantly.

Number of seed per ear were significantly (p < 0.05) affected by density, N rate and interaction of these two treatment (Table 2). With increasing applied N, number of seed/ear increased significantly and the highest seed per ear (32.84) were observed in density of 250 plant/[m.sup.2]. The lowest seed/ear (29.17) observed in density of 550 plant/[m.sup.2] (table 3). Application of 200 kg/ha N produced the highest seed/ear among nitrogen treatment (table 4). Reddi and Patil [20] also showed that with increasing N rate number seed/ear increased which resulted in increasing grain yield in wheat.

Application of 200 kg N in density of 250 plant/[m.sup.2] produced the highest seed number/ear (35.85) among interaction treatments while, in density of 550 plant/[m.sup.2] without N the lowest seed number (28.35) were observed (Figure 2). Martin et al., [13] evaluated the effect of weed competition on growth and yield of spring barley and concluded that number of seed/ear are the most susceptible component which affected by competition. Blackshaw, [2] also showed that wheat yield reduction in competition with weed is related to reduction of seed number/ear.

Seed weight also significantly affected by plant density (table 2). Seed weight increased by increase density. The highest (37.35 g) and lowest (34.88 g) 1000 seed weight were observed in 250 and 550 plant/[m.sup.2], respectively(table 3). Among nitrogen treatment, applying 200 kg/ha N produced the highest (37.50g) 1000 seed weight (table 4). There different observation that showed seed weight may increase, decrease or remain unaffected by applying nitrogen.

Interaction effect of N*density showed significant effect on seed weight (table 2). The highest (38.76 g) were observed in 250 plant/[m.sup.2] density and 200 kg/ha N while the lowest (33.88 g) were observed in 550 plant/[m.sup.2] without N application (Figure 3). Poorazar and Ghadiri [19] showed that seed weight decrease by increasing plant density. Morshita and Thill, [16] concluded that seed weight in barley decrease 9-22% as affected by competition. [14] on the other hand reported that in presence of foxtail and Lolium number of wheat tiller decrease while, seed weight remain unaffected.





Grain Yield, Biological Yield and Harvest Index:

By increasing plant density grain yield and biological yield increased significantly while harvest index decreased (table 2). Density of 550 plant/[m.sup.2] produced the highest grain (8.68 t/ha) and biological yield (19.61) which showed 12 and 7% increased in comparison to 250 plant/[m.sup.2] treatment, respectively (table 3). The highest harvest index in contrast, were observed in 250 plant/[m.sup.2] treatment which showed 5% increase in comparison to 550 plant/[m.sup.2] treatment. This observation showed that by increasing plant density partitioning of assimilates to grain are more susceptible of vegetative parts. In fact in higher densities allocation pattern have changed. It has been shown that harvest index may increase in competition with other plant but, in some cases increase harvest index may be the main factor contributing in competition tolerance in crops [22]. Lindquist et al., [12] suggested that in competition situation assimilate allocation is more susceptible than dry matter acclimation.

Increase nitrogen rate increase by 200 kg/ha causes a significant increase in grain yield, biological yield and harvest index (table 4). The highest grain yield (9.00 t/ha) observed in 200 kg/ha N treatment which showed 12% increase in comparison with control (zero N) treatment. Mohajeri and Ghadiri [15] reported that in situation of wheat-wild mustard competition wheat grain yield increased by increase N rate by 100 kg/ha. Strong, [24] also observed that by increasing N rate under optimal level wheat growth and grain yield increased while, after this optimum level increase N rate only increase vegetative growth and grain yield remain unaffected. Henson and Jordan [6] in evaluation of wheat and wild oat competition for nitrogen absorption reported that increase N rate cause an increase in wheat dry matter accumulation and grain yield which reduced competition effects of wild oat, in fact nitrogen changes the competitiveness of plants. Biological yield increased from 17.9 t/ha in control N treatment to 19.5 t/ha in 200 kg/ha N treatment. There is no significant differences between 150 and 200 kg/ha N treatments. Harvest index also increased from 35.33 to 36.99% by increasing N rate from zero to 200 kg/ha(table 4). Interaction effect of N*density showed significant effect on grain yield (table 2). The highest grain yield (9.66 [t.ha.sup.-1]) were observed in 550 plant/[m.sup.2] density and 200 kg/ha N while the lowest (6.80 [t.ha.sup.-1]) were observed in 250 plant/[m.sup.2] without N application (Figure 4).


The overall results indicate, under wild oat infestation. Application of Nitrogen can increase competitive ability in winter wheat. increasing plant density reduces the biomass production of wild oat. wild oat through reducing the number of fertile tillers and that of the spikes per unit area also reduces the economic yield of wheat. We can reduce harmful effects of wild oat (if not controlled) by using high plant density or adequate utilization of nitrogen.


[1.] Ahmadvand, G., A. Koocheki and M. Nassiri Mahallati, 2002. Effect of nitrogen and plant density on competition interactions between winter wheat (T. aestivum) and wild oat(A. loduviciana).Presented in 12th EWRS Society symposium. Wageningen. 24-27 June.

[2.] Blackshaw, R.E., 1994. Differential competitive ability of winter wheat cultivars against downy brome. Agronomy Journal, 86: 648-654.

[3.] Carlson, H.L. and J.E. Hill, 1986. Wild oat (Avena fatua) competition with spring wheat: effects of nitrogen fertilization. Weed Science, 34: 29-33.

[4.] Dhima, K.V. and I.G. Eleftherohorinos, 2001. Influence of nitrogen on competition between winter cereals and sterile oat. Weed Science, 49:77-82.

[5.] Fallahi, H.A., A. Nasseri and A. Siadat, 2008. Wheat yield components are positively influenced by nitrogen application under moisture deficit environments. Int. J. Agric. Biol., 10: 673-676.

[6.] Hasnzade Deloii, M., 2002. Wheat Ideotype designing to compete with weeds. PhD thesis, Islamic Azad University. Science and Research Branch of Tehran. Page 125. (Abstract in English).

[7.] Henson, J.F. and S. Jordan, 1982. Wild oat (Avena fatua L.) compctition with wheat (Triticum aestivum and T. turgidium durum) for nitrate. Weed Science., 30: 197-300.

[8.] Iqbal, J. and D. Wright, 1997. Effects of nitrogen supply on competition between wheat and three annual weed species. Weed Research, 37: 391-400.

[9.] Khaliq, T.A. A. Ahmad, Hussain and M.A. Ali, 2009. Maize hybrids response to nitrogen rates at multiple locations in semiarid environment. Pakistan Journal Botany, 41: 207-224.

[10.] Kirkland, K.J. and H.J. Beckie, 1998. Contribution of nitrogen fertilizer placement to weed management in spring wheat (Triticum aestivum). Weed Technology., 12: 507-514.

[11.] Kumar, B.M. and K.N. Singh, 2003. Studies on the nitrogen, water regimes and weed control in upland direct seed rice. II. Nitrogen, its recovery and productive efficiency. Indian Journal of. Agronomy. 29(4): 453-458.

[12.] Lemerle, D., G.S. Gill, C.E. Murphy, S.R. Walker, R.D. Cousens, S. Mokhtari, S.J. Peltzer, R. Coleman and D.J. Luckett, 2001. Genetic improvement and agronomy for enhanced wheat competitiveness with weeds. Australian Journal Agricultural Research., 52: 527-548.

[13.] Lindquist, J.L., J.A. Dielman, D.A. Mortensen, G.A. Johnson and D.Y. Wyse-Pester, 1998. Economic importance of managing spatially heterogenous weed populations. Weed Technology., 12: 7-13.

[14.] Martin, M.P., L.D. Field and R.J. Field, 2001. Competition between plants of wild oat(Avena fatua) and wheat (Triticum astivum). Weed Research., 27: 119-124.

[15.] McMullan, P.M., J.K. Daun and D.R. Declercq, 1994. Effect of Wild Mustard (Brassica kaber) Competition on Yield and Quality of Triazine-tolerant and Triazinesusceptible Canola (Brassica napus and Brassica rapa). Canadian Journal Plant science., 74: 369-374.

[16.] Mohajeri, F. and H. Ghadiri, 2003. Competition of different densities of wild mustard(Brassica kaber)with winter wheat(Triticum aestivum)under different levels of nitrogen fertilizer application. Iranian Journal Agriculture Science., 34: 527-537.

[17.] Morishita, D.W. and D.C. Thill, 1988. Wild oat (Avena fatua) and spring barley growth and development in monoculture and mixed culture. Weed Science., 36: 43-48.

[18.] Naderi1, R. and H. Ghadiri, 2011. Competition of Wild Mustard (Sinapis arvense L.) Densities with Rapeseed (Brassica napus L.) under Different Levels of Nitrogen Fertilizer. Journal of Agricultural Science and Technology., 13: 45-51.

[19.] Parchami, P. and S. Behdadvand, 2009. competition between spring wheat and wild oat at different density and nitrogen amount. Plant physiology, 1(3): 81-88. (in Persian).

[20.] Pourreza, J., A. Bahrani and S. Karami, 2010. Effect of Nitrogen Fertilization Application on Simulating Wheat (Triticum aestivum) Yield Loss Caused by Wild Oat (Avena fatua) Interference. American-Eurasian Journal of Agricultural & Environmental Sci., 9(1): 55-61.

[21.] Reddi, S.G. and B.N. Patil, 2003. Influence of N-levels and Seed Rates on Growth, Yield, Protein Content and N-uptake in Wheat Genotypes. Karnataka Journal of Agricultural Science., 16(1): 31-34.

[22.] Rstgou, M., A. Ghanbari, M. Banayan awal and H. Rahimian, 2004. Effect of amount and timing of nitrogen application on economic threshold of Wild Mustard (Sinapis arvensis) in winter wheat. Agricultural Science and Technology., 18(2): 11-20.

[23.] Sarmadnia, G.H. and A. Kochaki, 1994. Crop physiology. Mashhad Jehad Daneshgahi press, 467p. (Translated in Persian).

[24.] Simmons, S.R., D.C. Ramusson. and J.V. Wiersma, 1982. Tillering in barley: Genotype. Row spacing and seeding rate effects. Crop Science., 22: 801-805.

[25.] Strong, W.M., 1974. Effect of late application of nitrogen on the yield and protein contact of wheat. Australian journal of experimental agriculture and animal husbandry., 22: 54-61.

[26.] Wagner, N.C., B.D. Maxwell, M.L. Taper and L.J. Rew., 2007. Developing an Empirical Yield-Prediction Model Based on Wheat and Wild Oat (Avena fatua) Density, Nitrogen and Herbicide Rate, and Growing-Season Precipitation. Weed Science, 55: 652-664.

[27.] Wilson, B.J., R. Cousens and K.J. Wright, 1990. The response of spring barley and winter wheat to Avena fatua population density. Ann Applied Biology., 116: 601-609.

[28.] Mohamed, R., PhD. Enan, 2009. Genotoxicity of the herbicide 2, 4-dichlorophenoxyacetic acid (2,4-D): Higher plants as monitoring systems, American-Eurasian Journal of Sustainable Agriculture., (3): 452-459.

[29.] E-Kivi, M.P. and S.J. E-Somarin, 2011. The Comparison Lentil Varieties in Competition with Weeds. Advances in Environmental Biology, 5(7): 1976-1978.

[30.] Khan, G.A. and and M.S. Amanullah, 2007. Response of Dhalia (Dhalia pinnata) to Different Levels of Nitrogen Alone and in Combinaiton with Constant Doses of Phosphorus and Potassium, American-Eurasian Journal of Sustainable Agriculture., 1(1): 25-31.

[31.] Ademiluyi, B.O. and S.O. Omotoso, 2007. Comparative Evaluation of Tithonia diversifolia and NPK Fertilizer for soil improvement in maize (Zea mays) production in Ado Ekiti, Southwestern Nigeria, American-Eurasian Journal of Sustainable Agriculture, 1(1): 32-36.

[32.] Lei, L., W. Jiao and Y.C. Yan, 2008. Evaluating Nitrogen Management of Farm Systems in the Steep-mountainaous KARST Region, American-Eurasian Journal of Sustainable Agriculture., 2(2): 180-186.

[33.] Onduru, D.D., A. De Jager, F.N. Muchena, G.N. Gachini and L. Gachimbi, 2008. Exploring Potentials of Rhizobium Inoculation in Enhancing Soil Fertility and Agro-economic Performance of Cowpeas in Sub-saharan Africa : A Case Study in Semi-arid Mbeere, Eastern Kenya, American-Eurasian Journal of Sustainable Agriculture, 2(3): 187-195.

[34.] Olaniyi, J.O., 2008. Comparative Effects of the Source and Level of Nitrogen on the Yield and Quality of Lettuce, American-Eurasian Journal of Sustainable Agriculture., 2(3): 225-228.

[35.] Olaniyi, J.O. and A.T. Ajibola, 2008. Growth and Yield Performance of Corchorus olitorius Varieties as Affected by Nitrogen and Phosphorus Fertilizers Application, American-Eurasian Journal of Sustainable Agriculture 2(3):235-241.

[36.] Olaniyi, J.O., 2008. Growth and Seed Yield Response of Egusi Melon to Nitrogen and Phosphorus Fertilizers Application, American-Eurasian Journal of Sustainable Agriculture., 2(3): 255-260.

[37.] Liasu, M.O., A.O. Ogundare, M.O. Ologunde, 2008. Effect of Soil Supplementation with Fortified Tithonia Mulch and Directly Applied Inorganic Fertilizer on Growth and Development of Potted Okra Plants, American-Eurasian Journal of Sustainable Agriculture., 2(3): 264-270.

[38.] Zarea, M.J., A. Ghalavand, E. Mohamadi Goltapeh, F. Rejali, Zahra Tabibzadeh Ghamsari, 2008. Green Manure, Mycorrhizas and Soil Fertility, American-Eurasian Journal of Sustainable Agriculture., 2(3): 294-299.

[39.] Ayeni, L.S., 2008. Integrated Application of Cocoa Pod Ash and NPK Fertilizer on Soil Chemical Properties and Yield of Tomato, American-Eurasian Journal of Sustainable Agriculture., 2(3): 333-337.

(1) Mohammd Armin, (2) Hassan gholami and (2) Hamidreaza Miri

(1) Department of agronomy, Sabzevar Branch, Islamic Azad University, Sabzevar, Iran.

(2) Department of agronomy, Arsanjan Branch, Islamic Azad University, Arsanjan, Iran.

Mohammd Armin, Hassan gholami and Hamidreaza Miri: Effect of Plant Density and Nitrogen Rate on Yield and Yield Components of Wheat in Wild oat-Infested Condition.

Corresponding Author

Mohammd Armin, Department of agronomy, Sabzevar Branch, Islamic Azad University, Sabzevar, Iran. Tel:+989155716747, Fax No:+985712647513

Table 1: Physico-chemical properties of soil.

Organic matter    Mg     Fe     Zn     Cu    Available P
     (%)                              Ppm

     1.02        23.94   9.8   0.64   1.74      18.5

Organic matter    Total N EC       pH     Sand   Silt   Clay
     (%)         ds.[m.sup.-1]                   (%)

     1.02         0. 14 1.35      7.26     20     40     30

Table 2: Analysis of variance table
for yield and yield components of wheat.

                                     ear          seed per
Source              df   tillers     number       ear

rep                 2    0.01 (ns)   76.45 (ns)   0.012 (ns)
nitrogen            3    9.07 **     9670.42 **   21.28 **
density             2    18.36 **    7083.56 **   75.77 **
nitrogen*density    6    0.11 **     2125.47 **   1.39 **
Error               22   0.006       23.87        0.01

                    Seed          yield             biological yield
Source              weight(g)     (t.[ha.sup.-1])   (t.[ha.sup.-1])

rep                 0.0001 (ns)   0.01 (ns)         0.0107 (ns)
nitrogen            9.07 **       4.34 **           3.98 **
density             18.34 **      3.49 **           7.06 **
nitrogen*density    0.11 **       0.02 **           0.006 **
Error               0.006         0.008             0.00681

Source              HI

rep                 0.01 (ns)
nitrogen            4.50 **
density             12.27 **
nitrogen*density    0.07 **
Error               0.007

ns: not significant; (*) and (**) represent
significant difference over control at
P < 0.05 and P < 0.01, respectively

Table 3: Effect of plant density on yield and yield components of

wheat density
plant/ [m.sup.2]   tillers   ear number   seed per ear   seed weight

250                3.47 a    607.66 b     33.08 a        37.35 a
400                2.47 b    609 b        31.31 b        36.23 b
550                1.17 c    650.39 a     28.12 c        34.88 c

wheat density      yield             biological
plant/ [m.sup.2]   (t.[ha.sup.-1])   yield (t.[ha.sup.-1])   HI

250                7.61 c            18.11 c                 37.09 a
400                8.19 b            18.58 b                 36.22 b
550                8.68 a            19.61 a                 35.07 c

Values followed by the same letter do
not differ significantly at p = 1% according to DMRT.

Table 4: Effect nitrogen yield on yield and yield components of

Nitrogen                          seed      seed
kg/ha      tillers   ear number   per ear   weight    yield

0          1.67 c    575.03 d     29.17 d   35.18d    7.36 d
100        2.22 b    626.86 b     30.30 c   35.65 c   7.91 c
150        2.67 a    638.87 c     31.03 b   36.27 b   8.37 b
200        2.78 a    648.64 d     32.84 a   37.50 a   9.01 a

Nitrogen   biological
kg/ha      yield        HI

0          17.98 d      35.33 d
100        18.50 c      35.83 c
150        19.04 b      36.34 b
200        19.52 a      36.99 a

Values followed by the same letter do
not differ significantly at
p = 1% according to DMRT.
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Title Annotation:Original Article
Author:Armin, Mohammd; Gholami, Hassan; Miri, Hamidreaza
Publication:Advances in Environmental Biology
Article Type:Report
Date:Sep 1, 2011
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