1. “Development of integrated rice-azolla-duck-
fish farming systems with SRI methods
for rice production in the Mekong River
region, Vietnam”
Nghia Nguyen
Soil Biology Laboratory, Department of Soil Science, College of Agriculture &
Applied Biology, Cantho University, Cantho City, Vietnam
Cornell University, 07/01/2015
This project is funded by The Toyota Foundation, Japan
from 05/2015 to 05/2017

2. 1. Introduction
• Allocated in Southeastern
Vietnam.
• Extends 4.0 million ha, is
the heart of the rice
producing region of the
country where water, boats,
houses and markets coexist
to produce a generous
harvest of rice.

3. 1. Introduction
♦ Four main farming systems in this
area:
1. Rice
2. Aquaculture
3. Cash crops & fruit trees
4. Animals
♦ Rice & Aquaculture constitute a
major part of diet and livelihood and
for export.

4. 1. Introduction
+ 3 crops/year (mono and
intensive cultivation)
+ Continuous flooding
+ Preferably inorganic fertilizers
and overdose application rate
+ Excess or improper use of agro-
chemicals for plant protection
♦ Rice cultivation practices in the Mekong Delta, Vietnam:
+ Poor soil health and loss of soil
biodiversity
+ Increase GHG emission
+ Severse contamination of soil,
surface water and ground water
with inorganic fertilizers and
pesticides

5. 1. Introduction
♦ The need for more sustainable approach:
+ Increases productivity and resilience
+ Improves soil health
+ Reduces the GHGs emission (climate change)
+ Enhances national food security and development goals
+ Saves the fresh water for other uses
+ Produces safe and organic products from agriculture for sustainable
development
+ Beings friendly to environment and reduces the environmental
contamination
+ Improves community health
+ Improves livelihood

6. A integrated Rice-Azolla-Duck-Fish farming system?
1. Introduction

7. 2) Integrating fish and azolla into in rice-duck farming system in Asia
(Cagauan et al., 2000) in Philippine
1. Introduction

8. 1. Introduction
1. Complex agro-ecosystems
for food security in a changing
climate (Uma et al., 2012) in
Indonesia

9. ♦ Affect of integrated rice-azolla-duck-fish system on soil health, soil
microorganisms and green house gas emissions should be studied
more and intensively.
♦ Integrated rice-azolla-duck-fish system has been established in other
countries, but not yet been in the MD.
♦ Integrated rice-azolla-duck-fish system with SRI has not been yet
studied in the MD of Vietnam.
Study objectives:
1. Introduction
To evaluate the potential of the integrated rice-azolla-duck-fish practice
as a sustainable approach to cope with climate change.

10. 1. Introduction
Research questions:
♦ What is performance of a integrated R-A-D-F practice
production?
♦ To what extend does a integrated R-A-D-F practice contribute to
soil health, soil microorganisms, green house gas emission
mitigation to the climate change?

11. 2. Methodology
1. Experiment 1: “Efficacy comparison of Azolla with and without SRI on
growth, rice yield and soil chemical and biological properties under
green house conditions”
♦ Study objective: To compare the effect of Azolla on rice and soil properties
under 2 farming practices: with and without SRI methods.
♦ Seven treatments in total are included with 4 times of repetition in the green
house; rice variety: OM5451 seed application rare: 40 kg/ha for SRI and 80 kg/ha
for non SRI. Three continuous crops will be established.
T1. Control
T2: 90N-60P-30K (recommended rate for MD, inorganic fertilizer)
T3: Azolla green manure 10 tons/ha (basal application) + fresh Azolla 2 tons/ha
T4: Azolla green manure 10 tons/ha + fresh Azolla 2 tons/ha + 45N-30P-15K
T5: Cow dung manure 10 tons/ha +fresh Azolla 2 tons/ha
T6: Fresh organic mixture 10 tons/ha + fresh Azolla 2 tons/ha
T7: Fresh Azolla 2 tons/ha
* Fresh organic mixture including Azolla, spent coffee ground, milled eggshells, cow dung,

12. 2. Methodology
♦ Water management:
1. Conventional method: 7 days after seeding application, water will be introduced
continuously flooding with 20 cm above ground level thoroughly the experimental time,
and draining the paddy 2-3 weeks before harvest.
2. SRI method: 7 day after seeding application, a 1-2 cm layer of water is
introduced into the paddy, followed by alternate wetting and drying (during the
vegetative growth period). During flowering a thin layer of water (1-2 cm) is maintained,
followed by alternate wetting and drying in the grain filling period, draining the paddy 2-3
weeks before harvest.
PCV tube for water management in the SRI method

13. 2. Methodology
♦ Collected parameters:
1. Agronomic parameter for rice: Weekly measurements of plant height of rice, number
and diameter of tillers, and number of leaves. Other agronomic parameters determined include,
the grain yield, grain size, leaf length and width, panicle length, flowering and maturity days.
2. Weed: Recording weed constituents in each treatment, fresh and dry weed weight/m2
and
consuming time for manually weed control//m2
/each time.
3. Soil chemical parameters: pH, EC, OM, C/N ratio, N-Total , P-Total, K- Total, CaO,
MgO, Fe, Cu, Zn, Si at T-0 and T-End.
4. Soil and leave microbiological parameters: Total bacteria/fungi cells, number of free
nitrogen fixing bacteria, phosphate solubilizing bacteria and the number of endophyte bacteria in
rice roots and leaves at day 0, 10, 20, 30, 50, 70 and 90 will be determined. While soil microbial
diversity (DGGE), methane oxidizing gene (pmoA) and methane producing gene (mcrA) will be
detected at T-0 and T-End.

14. 2. Methodology
2. Experiment 2: “Efficacy comparison of Rice-Azolla-Duck-Fish system
with and without SRI on growth, rice yield and soil chemical and
biological properties under field conditions”
♦ Study objective: To compare the effect of Rice-Azolla-Duck-Fish system on rice
and soil properties under 2 farming practices: with and without SRI methods.
♦ Three treatments in total are included with 3 times of repetition in the field; rice
variety: OM5451. Experimental site: Allocated at My Loc Village, Tam Binh
District, Vinh Long Province. Three continuous crops will be established.
T1. Conventional method
T2: Conventional method with Rice-Azolla-Duck-Fish system
T3: SRI method with Rice-Azolla-Duck-Fish system

15. ♦ Seed application rate: 40 kg/ha for SRI and 80 kg/ha for conventional method.
♦ Fertilizer application rate: 90N-60P-30K, inorganic fertilizer for conventional
method and organic fertilizer which would show the best performance of rice’s yield from
the green house experiment will be used as organic fertilizer for the SRI method.
♦ Water management:
1. Conventional method: 7 days after seedling application, water will be kept
continuously flooding with 20 cm above ground level thoroughly the experimental time,
and draining the paddy 2-3 weeks before harvest.
2. SRI method: after 7 day after seedling application, a 1-2 cm layer of water is
introduced into the paddy, followed by alternate wetting and drying (during the vegetative
growth period). During flowering a thin layer of water (1-2 cm) is maintained, followed by
alternate wetting and drying in the grain filling period, draining the paddy 2-3 weeks
before harvest.
2. Methodology

16. 2. Methodology
PCV tube for water management in the SRI method

17. ♦ Collected parameters:
1. Agronomic parameter for rice: Weekly measurements of plant height of rice, number
and diameter of tillers of tillers and number of leaves. Other agronomic parameters determined
include, the grain yield, grain size, leaf length and width, panicle length, flowering and maturity
days.
2. Weed: Recording weed constituents in each treatment, fresh and dry weed weight/m2
and
consuming time for manually weed control//m2
/each time.
3. Soil physical properties: Soil bulk density, soil porosity and soil aggregates.
4. Soil chemical parameters: pH, EC, OM, C/N ratio, N-Total , P-Total, K- Total, CaO,
MgO, Fe, Cu, Zn, Si at T-0 and T-End.
5. Soil and leave microbiological parameters: Total bacteria/fungi cells, number of free
nitrogen fixing bacteria, phosphate solubilizing bacteria and the number of endophyte bacteria in
rice roots and leaves at day 0, 10, 20, 30, 50, 70 and 90 will be determined. While soil microbial
diversity (DGGE), methane oxidizing gene (pmoA) and methane producing gene (mcrA) will be
detected at T-0 and T-End.
2. Methodology

18. 6. Green house gas emission: CH4, CO2, N2O will be collected at each growth period
of rice (2 times in vegetative growth period; 1 time at flowering period, 1 time at grain
filling period and 1 time at maturating period).
2. Methodology

19. 3. Expected results and future perspectives
1. In both green house and field experiments the SRI method will give a better results
than the conventional method in improvement of plant growth and yield and as well
as soil physical, chemical and microbiological properties.
2. There will be more methane oxidizing bacteria and less green house gases emit
from soil in the SRI method than these in the conventional method.
Any Question? Suggestion? Comments?

20. Acknowledgement
Prof. Uphoff Norman and others from
Cornell University

21. Thanks you very much!