Effect of Gluconacetobacter diazotrophicus inoculation and reduced nitrogen fertilizer on yield and growth parameters of rice varieties Journal of Seed Science

Abstract

This study aimed to investigate effects of nitrogen (N) fertilizer rates and inoculation of rice seeds with N-fixing bacterium Gluconacetobacter diazotrophicus on the growth parameters and yield of OM5451 and OM6976 rice varieties in the Vietnamese Mekong Delta region. Nitrogen fertilizer rates of 50 kg N.ha-1 and 100 kg N.ha-1 were used, with latter reflecting farmer practice. Three rice seed inoculation methods were also employed: Seeds soaked in water for 24 hours and allowed to stand for 30 hours (control) (B0); Seeds soaked in water for 24 hours and inoculated with G. diazotrophicus for 30 hours (B1); Seeds soaked with G. diazotrophicus in water for 24 hours and allowed to stand for 30 hours. Applying 50 kg N.ha-1 without combining with NFB bacterium in this experiment generally resulted in less tillers, shorter plants, a lower SPAD index, and lower grain yield. Combining G. diazotrophicus bacterium with reduced N fertilizer of 50 kg N.ha-1 demonstrated rice growth and yield may be maintained in both varieties compared to 100 kg N.ha-1. These results providing a firm foundation for future research of adding NFB to paddy soils to decrease the N fertilizer requirement.

Full text

Eect of Gluconacetobacter diazotrophicus inoculaon and
reduced nitrogen ferlizer on yield and growth parameters
of rice variees
Tran Van Dung1 iD , Do Ba Tan1 iD , Tran Huynh Khanh1 iD , David Gale2 iD ,
Vu Van Long3* iD
*Correspondig autor
E-mail: vvlong@vnkgu.edu.vn
Received: 06/13/2021.
Accepted: 09/23/2021.
1 Soil Science Department, College
of Agriculture, Can Tho University,
Can Tho, 94100, Vietnam.
2 Graham Centre for Agricultural
Innovaon, Wagga Wagga, NSW
2650, Australia.
3 Faculty of Natural Resources-
Environment, Kien Giang University,
Kien Giang, 91752, Vietnam.
ABSTRACT: This study aimed to invesgate eects of nitrogen (N) ferlizer rates and
inoculaon of rice seeds with N-xing bacterium Gluconacetobacter diazotrophicus on the
growth parameters and yield of OM5451 and OM6976 rice variees in the Vietnamese
Mekong Delta region. Nitrogen ferlizer rates of 50 kg N.ha–1 and 100 kg N.ha–1 were
used, with laer reecng farmer pracce. Three rice seed inoculaon methods were
also employed: Seeds soaked in water for 24 hours and allowed to stand for 30 hours
(control) (B0); Seeds soaked in water for 24 hours and inoculated with G. diazotrophicus
for 30 hours (B1); Seeds soaked with G. diazotrophicus in water for 24 hours and allowed
to stand for 30 hours. Applying 50 kg N.ha–1 without combining with NFB bacterium in this
experiment generally resulted in less llers, shorter plants, a lower SPAD index, and lower
grain yield. Combining G. diazotrophicus bacterium with reduced N ferlizer of 50 kg N.ha–1
demonstrated rice growth and yield may be maintained in both variees compared to 100
kg N.ha-1. These results providing a rm foundaon for future research of adding NFB to
paddy soils to decrease the N ferlizer requirement.
Index terms: alluvial soils, nitrogen-xing bacterium, paddy soil, seed, Vietnam.
RESUMO: Este estudo teve como objevo invesgar os efeitos das doses de nitrogênio
(N) do ferlizante e da inoculação de sementes de arroz com a bactéria xadora de
nitrogênio Gluconacetobacter diazotrophicus sobre os parâmetros de crescimento e
produvidade das variedades de arroz OM5451 e OM6976 na região do Delta do Mekong
Vietnamita. Foram ulizadas doses de nitrogênio ferlizantes de 50 kg N.ha–1 e 100 kg
N.ha–1, sendo que a úlma reete a práca do agricultor. Três métodos de inoculação de
sementes de arroz também foram empregados: sementes embebidas em água por 24
horas e deixadas em repouso por 30 horas (controle) (B0); Sementes embebidas em água
por 24 horas e inoculadas com G. diazotrophicus por 30 horas (B1); Sementes embebidas
com G. diazotrophicus em água por 24 horas e deixadas em repouso por 30 horas (B2).
A aplicação de 50 kg N.ha–1 sem combinação com a bactéria NFB neste experimento
geralmente resultou em menos perlhos, plantas mais curtas, índice SPAD mais baixo e
menor rendimento de grãos. A combinação da bactéria G. diazotrophicus com ferlizante
de N reduzido de 50 kg N.ha–1 demonstrou que o crescimento e produvidade do arroz
podem ser mandos em ambas as variedades em comparação com 100 kg N.ha–1. Esses
resultados fornecem uma base sólida para pesquisas futuras de adição de NFB aos solos
de arroz para diminuir a necessidade de ferlizante N.
Termos para indexação: solos aluviais, bactéria xadora de nitrogênio, solo de arroz,
sementes, Vietnã.
Journal of Seed Science, v.43, e202143029, 2021
ARTICLE
Journal of Seed Science, v.43,
e202143029, 2021
hp://dx.doi.org/10.1590/
2317-1545v43253229
Journal of
Seed Science
ISSN 2317-1545
www.abrates.org.br/revista

INTRODUCTION
The Vietnamese Mekong Delta (VMD) region is the largest rice culvaon area in Vietnam (GRISP, 2013). It accounts
for more than half of domesc rice producon and approximately 90% of rice is exported (Pandey et al., 2010;
Wassmann et al., 2010). In the intensicaon of culvaon of rice, farmers have tradionally applied more ferlizer to
increase rice yield. In parallel with this the risk of loss of ferlizer through runo, leaching, and evaporaon due to the
excessive ferlizers has become major problem in agricultural producon systems (Can, 2002). According to Ha and Bo
(2013), about 40–60% of applied ferlizers is lost from improper applicaon leading to acidicaon, eutrophicaon,
and greenhouse gas emissions.
Nitrogen (N) is an essenal element for rice growth by promong root development, owering, as well as the
uptake of other nutrients (Weil and Brady, 2017). A large amount of chemical N ferlizers have therefore oen been
applied to gain high-crop yield (Galloway et al., 2004). However, losses of excess N can result in many problems in
the rice producon system, including high input cost and environmental polluon with N2O and NH3 gas emission
(Wulf et al., 2002). Recently, some studies showed that the applicaon of Neb26 compounds belonging to the
group of urea inhibitor products (Giang et al., 2017) or combining N ferlizer with green manure (Ding et al., 2018)
could slightly increase N use eciency. However, these methods have not been completely eecve in improving
N use eciency, growth, and rice yield. Giang et al. (2017) reported that the rice yield in the treatment with a
25% reducon in Neb26 N ferlizer (5.3 tons.ha–1) was not signicantly dierent to the treatment receiving 100%
inorganic N ferlizer (5.3 tons.ha–1). The rice yield was, however, lower in the treatment to which 50% Neb26 N
ferlizer (5.0 tons.ha–1) was applied compared with the control treatment (Giang et al., 2017).
A biological nitrogen source should therefore be considered as an alternave approach to this problem. Nitrogen-
xing bacterium (NFB) are the most important microorganisms contribung to natural processes to x N2 from
the atmosphere into the inorganic N compounds usable by plants (Kennedy and Islam, 2001). Gluconacetobacter
diazotrophicus is the NFB and member of the family Acetobacteraceae (Mehnaz and Lazarovits, 2017). This bacterium
was originally isolated in sugarcane (Chawla et al., 2014), but it has also been found in natural endophyc associaon
with potatoes (Luna et al., 2012), rice (Jha et al., 2009), and other host plants (Chawla et al., 2014). As an endophyc
bacterium G. diazotrophicus needs to enter the seeds to be eecve. Soaking seeds in the bacterium is the preferred
method of applicaon of NFB in rice. There has been no other reported use of G. diazotrophicus on rice seeds in
invesgang the growth of paddy rice.
The underlying hypothesis of this study is that the applicaon G. diazotrophicus bacterium to rice seed will create a
symbioc relaonship within the host plants enabling it to obtain N via a biological process in xing the N2 gas from the
air to the soil as a substute for chemical N ferlizer. The aims of this study were to evaluate the dierence in the llers,
plant height, SPAD index, biomass, and yield under dierent N ferlizer rates and G. diazotrophicus addion compared
to standard treatments on alluvial soil in Vinh Long province of Vietnam.
MATERIAL AND METHODS
Experimental site and soil characteriscs
The experiment was conducted in the paddy soil of a rice with the mono-rice farming system which is connuously
cropped three mes per year at Tra On district, Vinh Long province, which is in the VMD region (9°57ʹ13ʺ N, 105°56ʹ54ʺ
E). The soil was classied as Mollic Gleysols, it was slightly acidic (pH 5.7), soil organic carbon (26.8 kg C.ha–1), and total N
(1.00 kg N.ha–1) were considered very low level for the paddy eld. The soil was rich in total P (2.36 kg P.ha–1) and available
soil-P (13.0 mg.kg–1) was considered average.
Journal of Seed Science, v.43, e202143029, 2021
2T.V. Dung et al.

Experimental design and treatments
The eld trial was laid out in a split-plot design with four replicates. To the main plots N ferlizer was applied at
two rates: 50 kg N.ha–1 (N50) and 100 kg N.ha–1 (N100) with the laer reecng the recommended rate for rice. To the
sub-plots three seed inoculaon methods were applied: Seeds soaked in water for 24 hours and allowed to stand for 30
hours (control) (B0); seeds soaked in water for 24 hours, mixed with G. diazotrophicus and allowed to stand for 30 hours
(B1); Seeds soaked with G. diazotrophicus in water for 24 hours and allowed to stand for 30 hours (B2). A germinaon
test of coated rice seeds was implemented at 25 °C under laboratory condions. The content of G. diazotrophicus in
the treatments was 1.0 × 109 CFU.g–1.
Field Management
Each experimental plot had an area of 42 m2 (6 m × 7 m), separated by the bunds (30 cm wide × 30 cm high). Bunds
were covered with a plasc sheet installed to a depth of 50 cm below the soil surface to minimize seepage between
adjacent plots and from the surrounding eld. Rice culvars used for this experiment were OM5451 and OM6976 with
the dominant characteriscs being high-yield and short-duraon growth period of 90–97 days.
Ferlizer was applied to the trial at a rate of 50 or 100 kg N.ha–1, 30 kg P2O5.ha–1, and 30 kg K2O.ha–1 as recommended
by the Cuu Long Rice Research Instute, Vietnam. This applicaon was in the form of urea, superphosphate, and
potassium chloride. All phosphorus ferlizer was applied at sowing me. Nitrogen was applied 10, 20, and 40 days aer
sowing (DAS) 20%, 40%, and 40% of the total rate, respecvely. Potassium ferlizer was split into two equal applicaon
20 and 40 DAS.
Measured crop parameters
Measurements of the number of llers, plant height, leaf chlorophyll content (SPAD index), and grain yield were
collected at various growth stages of the crop. The number of llers and rice height were measured at ller iniaon
(20 DAS), acve llering (30 DAS), and panicle iniaon (45 DAS). These parameters were determined from samples
collected in an area of 0.25 m2 (0.5 m × 0.5 m) within the experimental plot. SPAD index was recorded at 30 DAS, 60
DAS, and 75 DAS.
For determinaon of grain yield, rice was harvested from an area of 5 m2 of each plot. Grain was separated, air-
dried, and then weighed. The nal grain yield measured at 14% moisture.
Germinaon was calculated according to the following equaon (Mori et al., 2012):
Germination (%)=Number of seeds germinated after innoculation
Number of seeds tested × 100
Stascal analysis
The data collected from the experiment were stascally analyzed with Genstat using a general analysis of variance.
A P-value < 0.05 was considered a stascally signicant dierence.
RESULTS AND DISCUSSION
The percentage of seed germinaon of variees OM5451 and OM6976 under the various treatments are shown
in Figure 1. Seedling emergence, which is a complex process in rice culvaon system, is controlled by many factors
including water, light, temperature and phytohormones (Huang et al., 2018). In this study, the seed inoculaon was
implemented under laboratory condions meaning that seed emergence was mainly depended on rice variety (Ju et al., 2000). The
germinaon of rice seeds could be used to evaluate seedling growth and grain yield (He and Yang, 2013). On average,
there were no signicant dierences in the germinaon rate between treatments (P > 0.05). The germinaon rate was
Journal of Seed Science, v.43, e202143029, 2021
3
Gluconacetobacter diazotrophicus combined nitrogen ferlizer

consistently above 93.0% in both variees. The result of this study indicates that applying NFB to coat the seeds did not
aect the germinaon of rice seed.
The number of llers is an important factor inuencing rice yield. Under normal condions the number of llers is
inuenced by agricultural pracces and the environment (Huang et al., 2013). A recent study reported that the applicaon
of N ferlizer results increased the number of llers in rice culvaon (Zhong et al., 2003). Another study, however,
indicated that reducing N ferlizer did not aect rice llers (Sathiya and Ramesh, 2009). For the variety OM5451 at 30
DAS in the current experiment, treatments with 50 kg N.ha–1 and 100 kg N.ha–1 and no bacterium had less llers than the
respecve treatments with the bacterium (Table 1). These results may support the hypothesis that when G. diazotrophicus
is applied to the seed a 50% reducon N may be possible whist maintaining the number of llers. This trend did not carry
through to 45 DAS, however, with no signicant dierences between N50 × B0 and N50 × B2, or between any of the 100 kg
N.ha–1 treatments. The interacon of N ferlizer rate and seed treatment methods (N × B) also resulted in a signicant
eect on the number of OM6976 llers at 30 DAS (Table 1). The results show that the number of llers was highest in N50
B0: Rice seeds soaked in water for 24 hours, incubated 30 hours; B1: Rice seeds soaked with water for 24 hours, incubated with NFB for 30
hours; B2: Rice seeds soaked with NFB for 24 hours, incubated for 30 hours
Figure 1. The seedling emergence of OM5451 and OM6976 variees under dierent seeds incubaon treatments.
Table 1. The number of llers (llers per m2) over N rates and seed treatment methods of two rice variees.
Treatments OM5451 OM6976
20 DAS 30 DAS 45 DAS 20 DAS 30 DAS 45 DAS
N50 × B0421 a 726 a581 a427 b 526 a498 a
N50 × B1 489 ab 895 b654 b373 b 653 bc 551 abc
N50 × B2 454 ab 964 c600 a417 b 728 c 593 bcd
N100 × B0 455 ab 888 b722 c334 b 517 a 526 ab
N100 × B1500 b 1031 cd 719 c388 b735 c642 d
N100 × B2522 b1080 d723 c562 a 578 ab 626 d
F-test * * * * * *
LSD 72.4 95.7 53.2 73.7 101 90.6
CV (%) 11.1 13.8 14.9 21.6 17.5 12.9
Means in a column for each rice variety followed by the same leer are not signicantly dierent. In the analysis of variance, * means P <0.05; N
and B treatments are explained in the text.
OM6976
OM5451
Journal of Seed Science, v.43, e202143029, 2021
4T.V. Dung et al.

× B2 and N100 × B1 treatments at 30 DAS (728 and 735 llers, respecvely), although these were not signicantly dierent
from each other or from N50 × B1, again providing support for the hypothesis that when G. diazotrophicus is applied to the
seed a 50% reducon N may be possible whist maintaining the number of llers. It is also of note in this context that at 45
DAS N50 × B2, N100 × B1 and N100 × B2 were not signicantly dierent from each other.
Plant height is another important indicator of yield, and some signicant dierences were observed with respect
to the variety OM5451 (Table 2). At 20 DAS, N50 × B0 was signicantly lower than N50 × B1 and N100 × B2 which were not
dierent from each other. The corresponding pairs of N50 and N100 treatments at 30 DAS were dierent from each other,
with the N100 treatments producing a consistently taller plant (Table 2). The same trend was observed at 45 DAS with the
N50 treatments not dierent from each other, but dierent from the N100 treatments which were also not dierent from
each other. The results of this experiment showed no signicant dierences between any of the OM6976 treatments
at any number of DAS (Table 2).
Soil Plant Analysis Development (SPAD) is another important index which reects the chlorophyll content of leaves
with a higher chlorophyll content leading to beer photosynthec assimilaon and plant performance (Ghosh et al.,
2020) and rice yield (Nawaz et al., 2017). The SPAD value is therefore considered a reliable parameter for predicng
the N status of rice, as aected by various natural or anthropogenic factors (Yuan et al., 2016). This ability of the
bacterium to supply the host plant with xed N (Hala, 2020) without the formaon of nodules, could promote plant
growth in terms of increased ller number, chlorophyll content (SPAD), and yield (Chawla et al., 2014). Our results
showed that N50 treatments with the inclusion of G. diazotrophicus bacterium were not stascally dierent, and in
one case beer, than the equivalent N100 treatments in both OM5451 and OM6976 variees (Table 3). For OM5451, at
30 DAS, the results showed that SPAD in the N50 × B0 was signicantly lower than the N100 × B0, B1, and B2 treatments
(Table 3). However, SPAD in the treatment which combined 50 kg N.ha–1 with G. diazotrophicus did not dier signicant
compared with the treatment received 100 kg N.ha–1 B0 and B2. Similar results were observed at 60 DAS with N50 × B1
and B2 not signicant dierent from N100 × B1 and B2 (Table 3). At 70 DAS, however, N50 × B2 had a signicantly higher
SPAD than any of the N100 treatments. There were no signicant interacons between N applicaon rates and seed
treatment with G. diazotrophicus on the SPAD index at 30 DAS in OM6976 (Table 3) and at 60 DAS N50 × B0 and B1 were
not signicantly dierent from all of the N100 treatments which may suggest that OM6976 is a less N responsive variety.
The combinaon eect of N ferlizer and rice seed treatment using NFB on OM6976 signicantly increased rice leaf
SPAD at 70 DAS. The applicaon 50 kg N.ha–1 without G. diazotrophicus resulted in a signicantly lower SPAD than
the treatment received 100 kg N.ha–1 without G. diazotrophicus, as expected. The combinaon of N50 and the B2 seed
Table 2. Rice height (cm) over N rates and seed treatment methods of two rice variees.
Treatments OM5451 OM6976
20 DAS 30 DAS 45 DAS 20 DAS 30 DAS 45 DAS
N50 × B025.7 a 39.5 ab 49.0 a28.2 45.2 59.0
N50 × B127.6 b 39.8 abc 50.0 a29.0 45.3 57.5
N50 × B2 26.4 ab 38.4 a50.4 a28.6 44.0 58.4
N100 × B0 26.7 ab 41.2 cd 55.2 b30.3 45.3 60.7
N100 × B1 26.8 ab 41.8 d54.4 b29.4 43.8 59.0
N100 × B227.7 b 40.8 bcd 53.8 b28.7 43.2 60.5
F-test * * * ns ns ns
LSD 1.31 1.61 2.25 2.41 4.15 4.93
CV (%) 3.95 3.75 5.39 5.88 6.19 11.1
Means in a column for each rice variety followed by the same leer are not signicantly dierent. In the analysis of variance, ns means P >0.05,
* means P <0.05; N and B treatments are explained in the text.
Journal of Seed Science, v.43, e202143029, 2021
5
Gluconacetobacter diazotrophicus combined nitrogen ferlizer

treatment method produced a signicantly larger SPAD than N50 × B0 and was not dierent from N100 × B0, a result which
supports the hypothesis but which needs to be considered in the context of N50 × B0, N50 × B2 and N100 × B0 not being
dierent from N50 × B1, N100 × B1 and N100 × B2 (Table 3). The results are therefore inconclusive with respect to the benet
to SPAD from the addion of G. diazotrophicus although they do suggest that further invesgaon is warranted as the
50% reducon in N ferlizer is not detrimental to SPAD as may be naturally expected.
Nitrogen—a macronutrient for rice and other host plants—is closely related to grain yield in rice (Esfahani et al.,
2008). Biological N xaon that is process converts the inert dinitrogen gas of the air (N2) to reacve N that becomes
available to forms of the plant is probably the most important biochemical reacon in the Earth (Weil and Brady, 2017).
The G. diazotrophicus bacterium is the rice growth-promong rhizobacteria, and the amount of N xed in the root
environment in the agricultural system applying NFB range in 20–30 kg N.ha–1 per year (Weil and Brady, 2017). In our study,
G. diazotrophicus bacterium was applied in seeds incubaon stage to increase the N xaon capacity with the N xed
enabling a 50% reducon in N ferlizer. This study hypothesized that 50 kg N.ha-1 with the addion of G. diazotrophicus
bacterium would maintain rice yield compared with applying 100 kg N.ha–1 for the rice variees OM5451 and OM6976.
Table 3. SPAD index over N rates and seed treatment methods of two rice variees.
Treatments OM5451 OM6976
30 DAS 60 DAS 70 DAS 30 DAS 60 DAS 70 DAS
N50 × B028.1 a31.7 a 31.9 bc 34.0 35.1 ab 33.4 a
N50 × B1 28.8 ab 31.8 ab 31.9 bc 34.2 35.0 ab 34.8 ab
N50 × B2 29.2 ab 31.3 ab 33.4 c34.8 32.5 a37.1 b
N100 × B0 30.8 bc 34.5 c28.1 a35.3 36.9 b37.4 b
N100 × B133.2 c 32.7 ab 30.5 b35.8 36.2 ab 35.9 ab
N100 × B2 30.9 bc 33.5 ab 30.4 b36.7 38.4 b 35.9 ab
F-test * * * ns * *
LSD 2.48 2.90 1.64 3.36 4.08 3.18
CV (%) 7.30 6.09 6.39 6.12 8.55 7.63
Means in a column for each rice variety followed by the same leer are not signicantly dierent. In the analysis of variance, ns means P >0.05;
* means P <0.05; N and B treatments are explained in the text.
Table 4. Rice yield (tons.ha–1) over N rates and seed treatment methods of two rice variees.
Treatments OM5451 OM6976
N50 × B05.70 5.38 a
N50 × B15.61 5.33 a
N50 × B25.93 5.44 ab
N100 × B05.98 5.64 ab
N100 × B16.19 6.04 b
N100 × B26.34 5.71 ab
F-test ns *
LSD 0.78 0.68
CV (%) 8.53 8.32
Means in a column for each rice variety followed by the same leer are not signicantly dierent. In the analysis of variance, ns means P > 0.05;
* means P <0.05; N and B treatments are explained in the text.
Journal of Seed Science, v.43, e202143029, 2021
6T.V. Dung et al.

There were, however, no signicant dierences in yield between the two N ferlizer rates and three seeds inoculaon
methods for the variety OM5451 (Table 4). In OM6976, the applicaon of 50 kg N.ha–1 with G. diazotrophicus according
to the B2 treatment method resulted a yield which was not signicantly dierent from the 100 kg N.ha-1 treatments
(Table 4). Treatments N50 × B0 and N50 × B1 were signicantly dierent from N100 × B1 but not dierent from other
treatments. From the observed results it is not possible to say that NFB when combined with N ferlizer at 50 kg N.ha–1
is the reason for sustained yield in the OM6976 rice variety compared to 100 kg N.ha-1 (Table 4) but the results indicate
that further invesgaon is jused.
CONCLUSIONS
Rice seeds coated G. diazotrophicus forming a symbioc relaonship in the root environment and could supplied
amount of N xed for rice demand. The applicaon 50 kg N.ha–1 without combine with NFB bacterium resulted in
reduce the number of llers, plant height, SPAD index, and grain yield. Combining G. diazotrophicus bacterium with
reduced nitrogen ferlizer of 50 kg N.ha–1 demonstrated the maintaining rice growth and rice yield in both OM5451 and
OM6976 variees. The applicaon of 50 kg N.ha–1 combined G. diazotrophicus bacterium can save 50% amount of N
ferlizer. More eld experiments with G. diazotrophicus should be carried in dierent soil types and cropping seasons
to fully esmate the eect of this bacterium on the rice growth in the VMD region.
REFERENCES
CAN, N. D. Development of agricultural systems in the Mekong Delta of Vietnam: current rice culvaon and problems involved.
Proceeding of Internaonal Workshop on GMS Water Environment, organized by Alliance for global sustainability and GMS academic
and research network. Bangkok, August 22nd, 2002. hps://crd.ctu.edu.vn/images/upload/anpham/Can/2002_development-of-
agrarian-systems-in-the-mekong-delta.pdf
CHAWLA, N.; PHOUR, M.; SUNEJA, S.; SANGWAAN, S.; GOYAL, S. Gluconacetobacter diazotrophicus: An overview. Research in
Environment and Life Sciences, v.7, p.1-10, 2014. hps://www.researchgate.net/publicaon/320224539_Gluconacetobacter_
diazotrophicus_An_overview
DING, W.; XU, X.; HE, P.; ULLAH, S.; ZHANG, J.; CUI, Z.; ZHOU, W. Improving yield and nitrogen use eciency through alternave
ferlizaon opons for rice in China: A meta-analysis. Field Crops Research, v.227, p.11-18, 2018. hps://doi.org/10.1016/j.
fcr.2018.08.001
ESFAHANI, M.; ALIABBASI, H. R.; RABIEI, B.; KAVOUSI, M. Improvement of nitrogen management in rice paddy elds using chlorophyll
meter (SPAD). Paddy Water Environment, v.6, p.181-188, 2008. hps://doi.org/10.1007/s10333-007-0094-6
GALLOWAY, J. N.; DENTENER, F. J.; CAPONE, D. G.; BOYER, E. W.; HOWARTH, R. W.; SEITZINGER, S. P.; ASNER, G. P.; CLEVELAND, C.
C.; GREEN, P.; HOLLAND, E. A. Nitrogen cycles: past, present, and future. Biogeochemistry, v.70, n.2, p.153-226, 2004. hps://doi.
org/10.1007/s10533-004-0370-0
GHOSH, M.; SWAIN, D. K.; JHA, M. K.; TEWARI, V. K.; BOHRA, A. Opmizing chlorophyll meter (SPAD) reading to allow ecient
nitrogen use in rice and wheat under rice-wheat cropping system in Eastern India. Plant Producon Science, p.1-16, 2020. hps://
doi.org/10.1080/1343943X.2020.1717970
GIANG, N.D.C.; DUNG, T.V.; DONG, N.M. Eects of reducing nitrogen ferlizer plus nBPT, Neb26 on rice growth and yield, and
nitrogen use eciency in rice soil at Tam Binh district-Vinh Long province. Can Tho University Journal of Science, v.51, p.39-45,
2017. hps://doi.org/10.22144/ctu.jvn.2017.077
GRISP. Rice Almanac. 4th edion. Los Baños (Philippines): Internaonal Rice Research Instute. 2013. 283 p. hp://books.irri.
org/9789712203008_content.pdf
HA, P.Q.; BO, N.V. Ferlizers used in relaon to food producon, environmental protecon and migaon of greenhouse gas
emission. Vietnam Journal of Agriculture and Rural Development, v.3, p.1-12, 2013.
Journal of Seed Science, v.43, e202143029, 2021
7
Gluconacetobacter diazotrophicus combined nitrogen ferlizer

HALA, Y. The eect of nitrogen-xing bacteria towards upland rice plant growth and nitrogen content. IOP Conference Series: Earth
and Environmental Science, v.484, 012086. 2020. hps://doi.org/10.1088/1755-1315/484/1/012086
HE, D.; YANG, P. Proteomics of rice seed germinaon. Froners in Plant Science, v.4, p.1-9, 2013. hps://doi.org/10.3389/
fpls.2013.00246.
HUANG, L.; JIA, J.; ZHAO, X.; ZHANG, M.; HUANG, X.; JI, E.; NI, L.; JIANG, M. The ascorbate peroxidase APX1 is a direct target of
a zinc nger transcripon factor ZFP36 and a late embryogenesis abundant protein OsLEA5 interacts with ZFP36 to co-regulate
OsAPX1 in seed germinaon in rice. Biochemical and Biophysical Research Communicaons, v.495, n.1, p.339-345, 2018. hps://
doi.org/10.1016/j.bbrc.2017.10.128
HUANG, M.; YANG, C.; JI, Q.; JIANG, L.; TAN, J.; LI, Y. Tillering responses of rice to plant density and nitrogen rate in a subtropical
environment of southern China. Field Crops Research, v.149, p.187-192, 2013. hps://doi.org/10.1016/j.fcr.2013.04.029
JHA, B.; THAKUR, M. C.; GONTIA, I.; ALBRECHT, V.; STOFFELS, M.; SCHMID, M.; HARTMANN, A. Isolaon, paral idencaon and
applicaon of diazotrophic rhizobacteria from tradional Indian rice culvars. European Journal of Soil Biology, v.45, n.1, p.62-72,
2009. hps://doi.org/10.1016/j.ejsobi.2008.06.007
JU, Y. C.; HAN, S. W.; CHO, Y. C.; PARK, K. Y. Eects of submerged condion, temperature, and ripening stages on viviparous
germinaon of rice. Korean Journal of Crop Science, v. 45, n.1, p.20-25, 2000. hps://www.koreascience.or.kr/arcle/
JAKO200011922227252.page
KENNEDY, I.; ISLAM, N. The current and potenal contribuon of asymbioc nitrogen xaon to nitrogen requirements on farms: a
review. Australian Journal of Experimental Agriculture, v.41, n.3, p.447-457, 2001. hps://doi.org/10.1071/EA00081
LUNA, M. F.; APREA, J.; CRESPO, J. M.; BOIARDI, J. L. Colonizaon and yield promoon of tomato by Gluconacetobacter diazotrophicus.
Applied Soil Ecology, v.61, p.225-229, 2012. hps://doi.org/10.1016/j.apsoil.2011.09.002
MEHNAZ, S.; LAZAROVITS, G. Gluconacetobacter azotocaptans: A Plant Growth-Promong Bacteria. In: MEHNAZ S. (Ed.).
Rhizotrophs: Plant Growth Promoon to Bioremediaon. Microorganisms for Sustainability, Springer, Singapore, p. 1-14, 2017.
hps://doi.org/10.1007/978-981-10-4862-3
MORI, S.; FUJIMOTO, H.; WATANABE, S.; ISHIOKA, G.; OKABE, A.; KAMEI, M.; YAMAUCHI, M. Physiological performance of iron-
coated primed rice seeds under submerged condions and the smulaon of coleople elongaon in primed rice seeds under
anoxia. Soil Science and Plant Nutrion, v.58, n.4, p.469-478, 2012. hps://doi.org/10.1080/00380768.2012.708906
NAWAZ, M. A.; WANG, L.; JIAO, Y.; CHEN, C.; ZHAO, L.; MEI, M.; YU, Y.; BIE, Z.; HUANG, Y. Pumpkin rootstock improves nitrogen use
eciency of watermelon scion by enhancing nutrient uptake, cytokinin content, and expression of nitrate reductase genes. Plant
Growth Regulaon, v.82, n.2, p.233-246, 2017. hps://doi.org/10.1007/s10725-017-0254-7
PANDEY, S.; PARIS, T.; BHANDARI, H. Household income dynamics and changes in gender roles in rice farming. In: PANDEY, S.;
BYERLEE, D.; DAWE, D.; DOBERMANN, A.; MOHANTY, S.; ROZELLE, S.; HARDY, B. (Eds.). Rice in the global economy: Strategic
research and policy issues for food security, p.93-111, 2010.
SATHIYA, K.; RAMESH, T. Eect of split applicaon of nitrogen on growth and yield of aerobic rice. Asian Journal of Experimental
Sciences, v.23, n.1, p.303-306, 2009. hp://ajesjournal.com/PDFs/09-1/45.%20Eect%20of%20Split%20Applicaon.pdf
WASSMANN, R.; NELSON, G. C.; PENG, S.; SUMFLETH, K.; JAGADISH, S.; HOSEN, Y.; ROSEGRANT, M. Rice and global climate change.
In: PANDEY, S.; BYERLEE, D.; DAWE, D.; DOBERMANN, A.; MOHANTY, S.; ROZELLE, S.; HARDY, B. (Eds.). Rice in the global economy:
Strategic research and policy issues for food security. p.411-433, 2010.
WEIL, R.; BRADY, N.C. The nature and properes of soils, 15th ed. Pearson Educaon Limited: Edinburgh Gate, Harlow, Essex CM20
2JE, England, 2017. 1104 p.
WULF, S.; VANDRÉ, R.; CLEMENS, J. Migaon opons for CH4, N2O and NH3 emissions from slurry management. In: VAN HAM,
J.; BAEDE, A.P.M.; GUICHERIT, R.; WILLIAMS-JACOBSE, J.G.F.M. (Eds.). Non-CO2 greenhouse gases: scienc understanding,
control opons and policy aspects. Proceedings of the Third Internaonal Symposium, Maastricht, Netherlands, 21-23, Millpress,
Roerdam. p.487-492, 2002. hps://www.researchgate.net/publicaon/312992679_Migaon_opons_for_CH4_N2O_and_
ammonia_NH3_emissions_from_slurry_management
Journal of Seed Science, v.43, e202143029, 2021
8T.V. Dung et al.

YUAN, Z.; ATA-UL-KARIM, S. T.; CAO, Q.; LU, Z.; CAO, W.; ZHU, Y.; LIU, X. Indicators for diagnosing nitrogen status of rice based on
chlorophyll meter readings. Field Crops Research, v.185, p.12-20, 2016. hp://dx.doi.org/10.1016/j.fcr.2015.10.003
ZHONG, X.; PENG, S.; SANICO, A. L.; LIU, H. Quanfying the interacve eect of leaf nitrogen and leaf area on llering of rice.
Journal of Plant Nutrion, v.26, n.6, p.1203-1222, 2003. hps://doi.org/10.1081/PLN-120020365
Journal of Seed Science, v.43, e202143029, 2021
9
Gluconacetobacter diazotrophicus combined nitrogen ferlizer
This is an Open Access arcle distributed under the terms of the Creave Commons Aribuon License, which permits unrestricted
use, distribuon, and reproducon in any medium, provided the original work is properly cited.