The impact of alternative wetting and drying technique adoption on technical efficiency empirical evidence from rice production in mekong river delta, vietnam

UNIVERSITY OF ECONOMICS
HO CHI MINH CITY
VIETNAM

ERASMUS UNVERSITY ROTTERDAM
INSTITUTE OF SOCIAL STUDIES
THE NETHERLANDS

VIETNAM – THE NETHERLANDS
PROGRAMME FOR M.A IN DEVELOPMENT ECONOMICS

THE IMPACT OF ALTERNATIVE WETTING AND DRYING
TECHNIQUE ADOPTION ON TECHNICAL EFFICIENCY: EMPIRICAL
EVIDENCE FROM RICE PRODUCTION IN MEKONG RIVER DELTA,
VIETNAM

BY
HUYNH NGOC SONG MINH

MASTER OF ARTS IN DEVELOPMENT ECONOMICS

HO CHI MINH CITY, DECEMBER 2017


UNIVERSITY OF ECONOMICS

INSTITUTE OF SOCIAL STUDIES

HO CHI MINH CITY

THE HAGUE

VIETNAM

THE NETHERLANDS

VIETNAM - NETHERLANDS
PROGRAMME FOR M.A IN DEVELOPMENT ECONOMICS

THE IMPACT OF ALTERNATIVE WETTING AND DRYING
TECHNIQUE ADOPTION ON TECHNICAL EFFICIENCY: EMPIRICAL
EVIDENCE FROM RICE PRODUCTION IN MEKONG RIVER DELTA,
VIETNAM

A thesis submitted in partial fulfilment of the requirements for the degree of
MASTER OF ARTS IN DEVELOPMENT ECONOMICS

By
HUYNH NGOC SONG MINH

Academic Supervisor:
DR. LE THANH LOAN

HO CHI MINH CITY, DECEMBER 2017


DECLARATION
I hereby declare that this thesis entitled “The impact of alternative wetting and
drying technique adoption on technical efficiency: empirical evidence from rice
production in Mekong River Delta, Vietnam” has been completely written by
myself. The study is the result of my own work combined with supervision and

guidance from Dr. Le Thanh Loan of University of Economics, Ho Chi Minh
city, Vietnam. I guarantee that the results with all suggestions in this study are
fully based on my personal work and knowledge which are strictly followed the
disciplines of Vietnam Netherlands Programme. This study, or any related
documents of this dissertation, has certainly not been submitted for any previous
qualifications or any other institutions and resources. I am also responsible for all
the contents in this research.
Date: 07 December 2017
Signature: _______________

Full name: Huynh Ngoc Song Minh

i


ACKNOWLEDGEMENT
The past two year with Vietnam – the Netherlands programme has been such a
memorable and special experience in my life. I feel truly thankful for all of the
knowledge and skills that I have the chance to learn which are extremely
important for me to complete this thesis successfully.
First and foremost, I would like to express the deep gratitude to my
supervisor, Dr. Le Thanh Loan. It has been an honor to be her only master
student in Vietnam and the Netherlands programme 22nd course. She has been
sharing with me the integrant researching experience from collecting data to
completing thesis. I appreciated all of her contributions of time, ideas, dedicated
guidance and support during my thesis process. The enthusiasm that she has for
this project was extremely motivational for me, even during tough times in this
master journey. I am also thankful for the excellent example she has provided as
a successful woman economist and professor.
Secondly, I would like to thank the funding from FAO and CGIAR for the

project titled "Documenting Adoption of the AWD Water Management
Technique in Vietnam" in the MRD, Vietnam in 2016.
Furthermore, I also want express my appreciation to Prof. Dr. Nguyen Trong
Hoai, Dr. Pham Khanh Nam and all the lecturers as well as the entire associates
of Vietnam – the Netherlands Program for their dedication and willingness to
support all students in my class. Especially, I would like to thank Dr. Truong
Dang Thuy and Dr. Le Van Chon for their valuable suggestions which help me to
complete my thesis. In addition, I am extremely appreciative the valuable time
with my classmates in course 22, particularly, all of the members in my study
group, for their encouragement and cooperation during the course.
After all, I want to express how valuable it was to me for receiving the strongest
encouragement and support from my beloved family, especially my mom.
Because all of their sacrifices which generate the best conditions for me to finish
this program and this thesis.

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TABLE OF CONTENTS
DECLARATION .................................................................................................... i
ACKNOWLEDGEMENT ..................................................................................... ii
TABLE OF CONTENTS ...................................................................................... iii
LIST OF FIGURES................................................................................................ v
LIST OF TABLES ................................................................................................ vi
ABSTRACT ......................................................................................................... vii
ABBREVIATION ............................................................................................... viii
CHAPTER 1: INTRODUCTION .......................................................................... 1
1.1 Problem Statements ...................................................................................... 1
1.2 Research Objectives...................................................................................... 8
1.3 Scope of the study ......................................................................................... 9

1.4 Structure of the thesis ................................................................................. 10
CHAPTER 2: LITERATURE REVIEW ............................................................. 11
2.1 Overview about the AWD technique .......................................................... 11
2.1.1 AWD definition .................................................................................... 11
2.1.2 AWD guideline in Viet Nam ................................................................ 13
2.1.3 The AWD score .................................................................................... 15
2.1.4 The impact of adopting AWD .............................................................. 16
2.2 Overview about technical efficiency of production function ..................... 19
2.2.1 Theory of frontiers production technical efficiency............................. 19
2.2.2 Empirical Technical Efficiency Review .............................................. 21
2.2.3 Review of Determinants on Technical Efficiency ............................... 22
2.3 Summary ..................................................................................................... 23
CHAPTER 3: DATA AND METHODOLOGY ................................................. 25
3.1 Methodology ............................................................................................... 25
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3.1.1 Conducting the AWD Score ................................................................. 25
3.1.2 Analytical Framework .......................................................................... 28
3.1.3 Econometrics Model............................................................................. 31
3.2 Data ............................................................................................................. 34
CHAPTER 4: RESULTS AND DISCUSSION ................................................... 37
4.1 Descriptive Statistics .................................................................................. 37
4.1.1 Data Description ................................................................................... 37
4.1.2 Correlation Matrix ................................................................................ 40
4.2 Empirical Results ........................................................................................ 43
4.2.1 The AWD adoption degree and challenges for AWD adoption .......... 44
4.2.2 Results of average technical efficiency of rice production in the MRD
region ............................................................................................................. 47
4.2.3 Results of determinants on the technical inefficiency.......................... 48

4.3 Discussion ................................................................................................... 51
CHAPTER 5: CONCLUSION ............................................................................. 53
5.1 Main findings .............................................................................................. 53
5.2 Policy implications ..................................................................................... 54
5.3 Limitations .................................................................................................. 54
REFERENCES ..................................................................................................... 56
APPENDIX .......................................................................................................... 63

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LIST OF FIGURES
Figure 2.1: The isoquant for technical efficiency estimation from the inputoriented ................................................................................................................. 20
Figure 2.2: The frontier for technical efficiency estimation from the outputoriented ................................................................................................................. 20

v


LIST OF TABLES
Table 3.1: The synthesis of signals that farmers use to observed water level on
the field during irrigation process ........................................................................ 26
Table 4.1: Descriptive Statistics ........................................................................... 38
Table 4.2: Correlation Matrix .............................................................................. 41
Table 4.3: Variance inflation factor ..................................................................... 42
Table 4.4: Correlation Matrix .............................................................................. 43
Table 4.5: Percentage of different AWD adoption level ..................................... 44
Table 4.6: AWD adoption score by provinces ..................................................... 45
Table 4.7: Challenges of AWD adoption in MRD province ............................... 46
Table 4.8: Estimated Average Technical Efficiency ........................................... 47
Table 4.9: The technical inefficiency determinants model .................................. 48

Table 4.10: Akaike's information criterion and Bayesian information criterion . 50
Table A1: Comparison between estimated results between half-normal and
truncated distribution efficiency model ............................................................... 63

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ABSTRACT
One of the most serious issues that potentially lead to total rice yield losses
is climate change and its consequence, water scarcity. To counteract with this
problem, the International Rice Research Institute has developed and promoted
the alternate wetting and drying (AWD) water saving technique among rice
growing countries to save irrigation water as well as enhance productive
cropping. However, after widely adopted, farmers have adjusted the technique
differently in term of irrigating schedule and practice. These realities lead to a
problem in measuring the degree of AWD technique adoption at farm level and
investigating its impact on rice production. From the original AWD score, this
study suggests a modified AWD score including water drainage practice to
represent for the adoption degree of each farm, based on that AWD application
impact on the rice production technical efficiency is also evaluated. Using the
sample of 250 farms surveyed in Mekong River Delta provinces, the adjusted
AWD score is calculated for each farm. Subsequently, a Stochastic Frontiers
Cobb-Douglas production function is regressed using maximum log likelihood
method to measure the technical inefficiency, after which, a function of technical
inefficiency determinants is investigated, where AWD score was included as a
main factor. Results indicate that higher AWD application degree can improve
technical efficiency of the production. Thus, AWD technique should be
continually promoted on large scale adoption and strictly followed IRRI
instructions to improve rice production technical efficiency.
Key words: Alternative wetting and drying technique (AWD), Technical

efficiency, Mekong River Delta, Vietnam.
JEL: Q12, Q15

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ABBREVIATION
PH – Power of hydrogen
AWD – The Alternate Wetting and Drying Technique
IRRI – The International Rice Research Institute
CH4 – Methane
MRD – Mekong River Delta
1M5R – One must do and five reduction campaign
KPA – Kilopascal
KG – Kilogram
DAS – Days after sowing
FGDS – Focus groups discussions
KIIS – Key informant interviews
VIF – Variance inflation factor
BIC – Bayesian information criterion
AIC – Akaike information criterion
CM – Centimeters

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CHAPTER 1: INTRODUCTION
In this chapter, firstly, a brief overview of the problem setting is provided
and based on that, the research problem of this study is given. Also, the research
questions and main objectives are described together with a short introduction of

the data and methodology used for this study. Finally, the structure of the
research is included.

1.1 Problem Statements
According to the Food and Agriculture Organization of the United Nation,
nature provides us more than 50,000 edible plants, however, only three of them,
which are rice, maize and wheat are considered as the world leading staple food.
The main reason is because these three directly provide over 60% of energy and
42% of calories intake for the entire human population. Out of these three, rice is
of the most important role. Rice feeds almost half of the human being, especially
in low and middle – income countries. People depend mostly on rice in their
daily meals. As the world population is growing rapidly, it would lead to the
increasing food demand in the near future (Easter, Rosegrant et al. 1998). The
major supply for food comes from agricultural products, especially rice as
proved, and the total rice consumption, in the coming year, is also expected to
increase.
In fact, the Food and Agricultural Policy Research Institute has projected
that the global demand for rice consumption will arise from 439 million tons in
2010 to 496 million tons in 2020 and reach 555 million tons by 2035. The
predicted upward trend in the global rice consumption can be observed through
actual data around the world. Firstly, rice is mainly consumed in Asia. This
region accounted for 90% of the total world rice consumption. Although per
capita consumption in China and India declines continuously because of
increased income and a rapid urbanization, Asia also contributes 67% of the total
increase. The Asia rice consumption of 388 million tons in 2010 will level up to
465 million tons in 2035. Secondly, outside Asia, where rice has not become a
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staple food yet, per capita consumption shows the same increasing trend.

Particularly, in Africa, rice is the fastest growing food, both urban and rural
residents here used to eat rice only in their special occasion, but recently, rice has
become their daily food. As a consequence, an arising demand of 30 million tons
more will be needed by Africa. Rice consumption will surge 130% from 2010
and remain growing onwards. There is a gap between demand and supply of rice
in Africa, moreover, this continent accounted for 32% of global rice trade in
2015, importing 14.3 million tons of the total 44.6 million tons traded worldwide.
In the Americas, total rice consumption is also projected to rise by 33% over the
next 25 years as a result of steadily increasing incomes, as well as continued
population growth. Even in the Middle East and developed European Countries,
a significant increase of rice consumption was observed. This partly causes by
migrants from countries where rice is more often consumed, along with wider
globalization of food availability and tastes.
Generally, the demand for rice continues to rise, and for every one billion
people added to the world’s population, 100 million more tons of rice is needed
to be produced annually. While rice consumption is increasing around the world,
most of its production only centers in Asian countries. According to Food and
Agriculture Organization of the United Nation, the top 10 rice producing
countries in the world today are India, China, Indonesia, Bangladesh, Thailand,
Vietnam, Burma, the Philippines, Cambodia, and Pakistan. To meet the
increasing demand, global rice yields now must rise faster than the past to keep
the world market prices stable at affordable levels for the billions of rice
consumers. However, with the current state of slow productivity growth,
inefficiency production and unsustainable management of natural resources,
expansion of the rice production would be limited. Furthermore, the International
Food Policy Research Institute forecasts that by 2050 rice prices will increase
about 32% to 37% and the yield losses in rice could be 10% to 15% as a result of
climate change. Phenomenon as sea-level rise causing flooding, salinity, and
water scarcity will be negatively affected rice production.

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The first problem is the sea level. When the sea level rises as predicted, a
large area of low – lying lands, deltas and coastal areas in Asia will be
submerged, leading to salinity throughout the region and making rice production
become vulnerable. For instances, in all of the hydrology system of the Mekong
River Delta (MRD), one of the primary rice growing area in Vietnam will be
damaged, sediment discharge and shoreline gradient will change. Flooding is
also caused by rising sea-level, rice cannot survive if they are submerged under
water, and flooding makes it difficult for harvesting. Currently, about 20 million
hectares of the world’s rice growing areas is at risk of occasionally being
flooded, particularly in major rice growing area as India and Bangladesh.
Generally, risen in sea-level would mainly reduce quality, size of cultivated land,
and the amount of irrigated water.
The second major problem in rice production is water scarcity. Water is one
of the most important inputs for rice production, in fact, without water rice
cannot grow. Rice systems depend on their ecological resilience largely from
intensive water use in order to control weed, soil salinity, pH, and to avoid heat.
Water for agriculture uses around the world are becoming increasingly scarce
(Rijsberman 2006). Scarcity irrigated water source is mainly caused by reduction
of water resources and quality, malfunctioning of irrigation systems, and
increased water use competition from other sectors such as urban and industrial
users. In conclusion, one of the most important issues in rice production
nowadays is water scarcity.
Asia, the world biggest rice production region, has been experienced long
developing history of rice production, and for more three millennia, their
irrigation system presents sustainable condition. Nevertheless, recent rapid
population growth that leads to a declining share of land, water, labor, energy
resources and overuse of production inputs made more than 23 million hectares

of rice production areas in South and Southeast Asia facing water scarcity. Tuong
and Bouman (2003) estimated that by 2025, 2 million hectares of Asia's irrigated
dry season rice and 13 million hectares of its irrigated wetland rice may
experience “physical water scarcity” and the rest of the approximately 22 million
3


hectares of irrigated dry season rice in South and Southeast Asia may suffer from
“economic water scarcity”, which results from competing water uses and climate
change. Also, in northwestern India, declining groundwater levels will pose a
serious threat to one of the world’s largest grain basket. These challenges rise in
rice production together with the increase demand in rice consumption require
agriculturists to rethink about the current management paradigms and finding
new solutions to prevent and address water scarcity condition.
In order to alert this future scenario, numerous efforts are made to develop
new water saving technologies for rice production. Different new technology
suggestions are the alternate wetting and drying technique (AWD) (Bouman and
Tuong 2001), continuous soil saturation (Borrell, Garside et al. 1997), irrigation
at fixed soil moisture tensions varying from zero to 40 kPa (Sharma, Bhushan et
al. 2002, Singh, Choudhury et al. 2002), or irrigation at an interval of one to five
days after disappearance of standing water (Chaudhary 1997). These water
management practices are called partial aerobic rice systems. These techniques
not only bring hope for rice farmers suffered from water scarcity but also save
water from rice production for other economic or environmental purposes. The
Integrated Rice Research Consortium has recapitulated, researched, and
completed these water management practices, and launched these worldwide for
all of the rice producing countries.
Actually, keeping the farm non – continuously flooding practices have been
used for several decades as a water saving method, but in many cases, farmers
were following an uncontrolled or unplanned watering practice. After the

intervention of IRRI, from then, among all of the water saving techniques, the
alternate wetting and drying technique (AWD) is one of the most significantly
and widely adopted technique. The definition of AWD is introduced by IRRI as
follow, “Alternate Wetting and Drying (AWD) is a water-saving technology that
farmers can apply to reduce their irrigation water for rice fields without
decreasing its yield. In AWD, irrigation water is applied a few days after the
disappearance of the ponded water. Hence, the field gets alternately flooded and
non – flooded. The number of days of non-flooded soil between irrigations can
4


vary from one to more than 10 days depending on the number of factors such as
soil type, weather, and crop growth stage.”
At first, farmers practiced ‘forced’ AWD early in 2006 among the region of
Angat Maasim River Irrigation System. After that, some practices that keep nonflooded conditions in the rice field for short interval of growing days become
commonly for about 40% of rice farmers in China and more than 80% of rice
farmers in North Western India and Japan (Richards and Sander 2014). However,
nowadays farmers follow a ‘safe’ AWD in which they maintain the threshold of
15 centimeters subsurface water level for the next time they pump water and
flooding the field. (Lampayan, Palis et al. 2009). This method has also been
recommended method for rice areas which faced scared irrigation water status in
South and Southeast Asia. In Philippines, safe AWD is firstly adopted at the
Tarlac Province since 2002, with farmers who use deep – well pump irrigation
systems (Lampayan, Palis et al. 2009). Nowadays, the International Rice
Research Institute (IRRI) has been promoting alternate wetting and drying as a
smart water saving technology for rice cultivation through national agricultural
research and extension its adoption mainly in Bangladesh, the Philippines, and
Vietnam.
After years of adoption, IRRI has worked in partnership with national
research institutions to conduct researches studied about the impact of AWD in

order to develop this technique. Generally, in economical dimension, a vast
majority of study showed that, certainly, AWD can reduce the amount of water
input or water cost. However, the impacts of AWD on the yield across regions
and countries are inconsistent. In some cases, researches stated that AWD
technique adoption does not reduce the amount of total yield, while others
suggested that this technique increases the amount of total yield and the
remaining concluded that AWD technique can result in total yield losses. The
reason behind those vague impacts of adopting AWD technique on the yield is
mainly because the famers apply AWD differently. Nevertheless, under the new
and simple practices of “safe AWD” suggested by IRRI, researchers hope that in
general AWD could bring positive economic impacts for rice production.
5


Another influence of AWD technique in cultivation is on environmental
dimension, scientists reported that applying AWD could also reduce the
greenhouse gases emissions and saving the water for the environment. Overall,
AWD and safe AWD has been field tested and validated by rice farmers in
Bangladesh, Indonesia, Laos, Philippines, Myanmar and other countries. The
technique has also been proved to offer potential reducing yield gaps, increasing
rice production, protecting the environment which finally can generate positive
benefits for both rice farmers and society at large. Consequently, AWD technique
is now centered in many extension efforts by formal institutes and non –
governmental organizations across number of Southeast Asia countries. Materials
for training and extending purposes on AWD are also being widely added in
numerous agricultural colleges, universities and opened certification plans.
In Vietnam, Agriculture has always appeared as one of the key sector of the
economy. Over the past decade, Vietnam agriculture has significantly developed
which helps Vietnam became the world top exporters in rice, rubber, coffee,
pepper, cashew nuts and other agricultural products. According to the Vietnam

General Statistics Office, among all the agriculture products, paddy is the most
important crop in Vietnam, occupying for almost 40% of gross output of
agriculture sector. Vietnam is also one of the top rice productions, the second
biggest rice exporters worldwide only after Thailand. Although Vietnam’s
climate was said to be suitable for cultivation activities, the nation’s agricultural
products are judged as low quality in comparison with other countries, especially
Thailand. The main reason is because Vietnam agricultural development is
fundamentally based on exploiting the natural resources rather than based on
technology. The future perspective of rice production in Vietnam is not bright. In
the latest estimation of General Statistics Office Vietnam, the country’s total rice
yield in 2016 is 43,6 million milled tons, reduce 4% compared with the amount
of 2015, which are mainly due to water scarcity, high level of salinity, serious
storm and flooding. If agriculturalist in Vietnam and the government does not
making the best effort to improve this current state, Vietnam rice production will
face many obstacles in the near future.
6


The Mekong River Delta is one of the major rice production areas of
Vietnam. This area accounts for more than 50% of the total products during main
cultivation season (Winter – Spring). However, this area is also suffering under
the general threat of salinity and late, uncertain rainy season, which leads to
water scarcity and reduces productivity. In 2016, the water source cannot supply
enough for irrigation system and high level of salinity pose a significant 10%
reduction of the total rice output, making the productivity in main season falling
back to 6.4 tons per hectares and the trend is projected to remain downwards in
the following year. Reduction in total yield also leads to high level of rice price.
In order to address these problems in rice production for the whole country
including MRD area, the Vietnam Plant Protection Department of the Ministry of
Agriculture and Rural Development has partnered with the Irrigated Rice

Research Consortium to adopt new water saving technology and orient the new
strategy for rice production. Through this partnership, alternate wetting and
drying technique was introduced and implemented in Vietnam incorporated with
various campaigns. One of the most popular campaigns is “One Must Do, Five
Reductions” (1M5R) program launched since 2009. After years of applying, each
of these contents belonged to the program has been successfully promoted and
applied nationally to improve rice production including AWD water saving
technique. Recognizing the benefits that can be derived when AWD is widely
adopted, in 2011, Vietnam’s Ministry of Agriculture and Rural Development
again highlighted AWD as one of the improved cultivation techniques for rice
production to be implemented broadly through 3.2 million hectares of rice
cultivation areas by 2020. With this policy support, the adoption of AWD
continues to be mainstreamed in different programs of Vietnam’s Ministry of
Agriculture and Rural Development. However, the current state of AWD
adoption still contains three particular problems:
Firstly, there are no clear evidences about the impact of widely adopted
AWD technique on rice production in Vietnam to convince the famers and policy
makers in implementing this technique more resolutely. In fact, although, it has
been broadly applied and suggested from agricultural policy for years, Vietnam’s
7


rice production is still facing challenges of salinity and water scarcity, which
leads to declined and erratic trend in total output.
Secondly, there are many researches investigate the impact of AWD
technique around the world, but the major was experimental field tests or
descriptive studies instead of econometrical technique or model. In fact, both
experimental fields test and descriptive studies has some limitations. For
experimental field tests, scientists only study about the AWD impact under
strictly adopted conditions. While AWD in widely implement does not exactly

follow the instruction, Yamaguchi, Luu et al. (2016) observed that famers made
some modifications which indicate that they have adapted AWD for their local
farming conditions. In addition, as analyses from descriptive studies cannot be
that of persuasion compared to econometrical studies, then a regression model
for determining AWD technique impact on rice production is required.
Finally, AWD diversified adoption practices create the challenge in
determining the adoption degree in each farm compared to original AWD
instruction. IRRI has documented a measurement to address this issue which is
the AWD score suggest by Moya et al., 2004. Nevertheless, this measurement
has not considered water drainage which is an important cultivated practice
related to specified topography, hydrology characteristics in Vietnam.
Therefore, in the attempt to fill these gaps, initially, this thesis suggested a
modified score including water drainage effect to measure degree of AWD
technique adoption at farm level in Vietnam. After that, a regression model with
AWD score is suggested to determine the impact of AWD technique and provide
a clear evident to support agricultural policy that enhance AWD adoption on a
larger scale.

1.2 Research Objectives
This research would use the data of 2016 main crop season from 250
interviewed farms in MRD, Vietnam. The investigation center in answering the
question of how changing from traditional continuous flooding into alternative
wetting and drying irrigation would make contribution for rice producers in
8


MRD provinces economically. In details, this paper aims to address three main
objectives:
-

Firstly, to evaluates the degree of AWD adoption in each farm using the
modified AWD score and analyze the challenges for AWD adoption in
different provinces of the MRD.

-

Secondly, to measures the average technical efficiency of the rice
production in MRD provinces during main crop season in 2016 by using
the production function approach.

-

Finally, to estimate the impact of AWD adoption and other determinants
on technical efficiency of rice production in MRD provinces.

1.3 Scope of the study
Under the study topic of: “The impact of alternative wetting and drying
technique adoption on technical efficiency: Empirical evidence from rice
production in Mekong River Delta, Vietnam.” A cross-sectional survey dataset
from a group of 250 rice producers from four main provinces in the MRD,
Vietnam is analyzed to address the research problems. The dataset includes
information about the household characteristics, farming conditions, watering
practices, inputs and outputs of each farms during main seasons (Winter-Spring)
of 2016. Initially, an adjusted AWD score is conducted base on the original
AWD score by Moya et al., 2004, combined with AWD definition introduced by
IRRI and water withdrawing practice from the famer. This score reflects the
extent of adoption for each farmer in MRD, Vietnam. Subsequently, the Frontier
Production Functions approach is applied to measure the Technical Efficiency of
these farms. Finally, AWD score and other key factors are examined to see their
impact on rice farm’s technical inefficiency.

Overall, this study is the first research that determines the impact of
adopting AWD technique widely in Vietnam by using a econometrical model.
Moreover, an adjusted measurement for AWD technique which including water
withdrawing practice is newly contributed for the literature review. Finally, while
numerous studies about AWD impacts are generated, this is also the first time
that AWD adoption effect on rice production’s technical efficiency is evaluated.
9


The findings of this study states that adopting AWD technique in large scale can
improve the technique efficiency of rice production. In specific, this means after
applying the AWD technique, producing rice become more effective and with
each level of input, famers can generate higher level of yield as the output.

1.4 Structure of the thesis
The study is organized as following manners. Chapter 1 is the introduction
which provides general view of the study and suggests the main research
problem, research objectives, the importance and structure of the research.
Chapter 2 presents general knowledge about AWD technique, from its definition
review, to standard AWD practice guideline, and its impacts studies from
previous researches. Continuously, the theory of technical efficiency and some
empirical studies measures technical efficiency in agriculture sector are
introduced. After that, review of technical efficiency determinants is given with a
summary to suggest our study gaps. Chapter 3 briefly describes the dataset, data
collection process, the analytical framework and the final empirical estimation
model. Chapter 4 exhibits the estimation results and discussions. The last chapter
is the conclusion.

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CHAPTER 2: LITERATURE REVIEW
In this chapter, initially, the overview about the AWD technique including
the AWD definition, AWD standard guideline practices, AWD adoption
measurement and AWD impact is provided. The following part offered the
literature review of technical efficiency, the indicator that is used to analyze
AWD impact. Firstly, a review about the theory of the technical efficiency, is
mentioned and secondly, the estimation method, empirical studies and the
determinants of technical efficiency are described.

2.1 Overview about the AWD technique
2.1.1 AWD definition
Analyses of IRRI suggested that, rice required flooding condition to grow since
this type of plant absorbs more than twice of the water input amount compared to
other crops at field level. However, 60% to 80% of total water input for rice
production is actually unproductive, because through seepage and percolation,
the irrigated water can rejoin the groundwater or water downstream. Therefore,
reducing irrigation water to rice fields is reduction of unproductive seepage and
percolation water losses (Saleh and Bhuiyan 1995, Bouman and Tuong 2001, Li
and Li 2001, Tabbal, Bouman et al. 2002). Based on this insight, several water
management practices were created including the alternate wetting and drying
technique.
The alternate wetting and drying (AWD) technique for rice production is
one of the water management techniques that have been developed by IRRI over
years. The general idea behinds this technique is instead of keeping the field
continuously flooded as traditional cultivation, famers could wait for the soil to
dry out for one to several days after the disappearance of ponded water before it
is flooded again. In fact, this idea was originally developed from an Indian term
called “intermittent irrigation” (Sandhu, Khera et al. 1980). However, Stoop,
Uphoff et al. (2002) and Uphoff, Felske et al. (2001) suggested that a similar

11


discontinuous flooding irrigation method was included in the system of Rice
Intensification, an integrated farm management technique developed by the
Jesuit priest Father Henri de Laulanie in Madagascar since 1980. In detailed of
the system of Rice Intensification guideline, during the growing period, the field
should not be continually flooding, a moderate amount of water should be
regularly provided to maintain an integrated condition of aerobic and anaerobic
cultivation soil and before harvesting, lower level of pond water should be kept
on field surface.
Even though, initial concept of AWD appeared in other regions, recently,
AWD development has been centered in East and Southeast Asia. In fact, a
particular AWD guideline is conducted in each area, with a specific instruction
about schedule, duration, and frequency of non-flooded periods. For instance, Li
and Barker (2004) mentioned that since irrigation water became increasingly
scared in China as an effect of highly demand water for other uses, a form of
AWD is widely practice in some area very early. In this practice, water is refilled
in about a week for heavy soils and in about five days for light soils, the level of
irrigated water is about five to six centimeters above the field surface, during the
interval days between irrigations, water ponds disappear from field surface and
naturally dries through seepage and percolation. The implement instructions
might be slightly different between sites in term of the cultivation conditions,
habits, type of input (seed, water, land), and also the in term of expressions.
However, generally, these are usually very inflexible and complex, which is hard
for farmers to strictly adopt the technology, especially when they think of
potential yield loss. In order to simplified the recommendations, some
agriculturist express AWD definition as keeping the field non-flooded from one
to ten of days (Bouman, Humphreys et al. 2007). Other scientists suggest famers
to irrigate when the tension of the soil water in the root zone reached a threshold

value of 10 kPa (the index measured soil moisture level for the plant). Again, this
instruction was inconsequential for farmers as they do not have appropriate
equipment to soil measure level. In conclusion, obsession about potential yield
loss, unpractical and complicated instruction while the impact of water scarcity is
not physically or economically visible are obstacles for AWD broadly adoption.
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Understand the limited of adopting and promoting AWD broadly. In 2002,
IRRI developed simpler instruction of AWD include with a practical tool to
allow farmers to reduce irrigation water input while maintaining yield. The
definition of safe AWD suggested by IRRI is:
“Alternate Wetting and Drying (AWD) is an irrigation technique in which
water is applied to the field a number of days after the disappearance of ponded
water. This is in contrast to the traditional irrigation practice of continuous
flooding (meaning never let the ponded water disappear). This means that rice
fields are not kept continuously submerged but are allowed to dry intermittently
during the rice growing stage. The number of days in which the field is allowed
to be “non-flooded” before irrigation is applied can vary from 1 day to more than
10 days.”
The mentioned practical tool is a 30 centimeters length water pipe. Under
safe AWD adoption a maximum irrigated water level of five centimeters above
the field surface and a threshold of 15 centimeters water dropped level below the
surface is empathized.
2.1.2 AWD guideline in Viet Nam
In Vietnam the standard AWD technique, is introduced in a guide book
published by the Sub – Department of Plant Protection in 2011. Actually, this
book provide instruction for all components in “one must do and five reduction
(1M5R)” national agriculture campaign. In 1M5R program, famers practice “one
must” is to use certificated seeds instead of poor quality seeds and “five

reductions” are to reduce the amount of sowed seed, agrichemicals, fertilizers,
irrigation water, and postharvest loss. According to Dinh, Chung et al. (2013),
this program was an effort of policy makers to increase net returns by removing
inefficiencies in rice production. 1M5R campaign suggests famers applying
AWD technique, specific instructions were provided to explain how to
implement AWD in Vietnam. AWD standard guideline in Vietnam stated that
farmers control their irrigation water level at a height of five centimeters above
the field surface and wait until the water drop to maximum level of 15
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centimeters below the field surface for the next irrigation. In details, the
irrigation schedule to apply safe AWD for rice production is described as follow.
Firstly, farmers are recommended to use a water tube to observe the water
level and irrigate adequately. This water tube can be made of cheap and popular
material in Vietnam, for instance plastic water tube or bamboo. The water tube is
about 30 centimeters height with the diameter of around 10 to 15 centimeters so
that water level can be easily noticed from inside the tube. On the side of the
water tube, there are some 0.5 centimeters holes and scale marks. The farmers
can place more than four pipes over their fields to observe the water level.
Placement position should be careful while choosing to help the farmers
conveniently observed water level and control the irrigation. A recommendation
is that the position should be representative of the average water depth in the
field. Famer should put the pipe at the depth of 20 centimeters under the ground
then remove the soil inside it so water level can be observed. The water level
inside the pipe is the same as the level of water on the field.
Secondly, AWD technique’s implement schedule is instructed base on the
growing process of the rice. During the first seven days, the soil needs to be
moistened after sowing but also needs to avoid flooding. Fertilization should be
conducted at seven to ten days after sowing (DAS), the paddy should be flooded

to a depth of one to three centimeters of water level about the field in this period.
Water height should be continuously maintained at three to five centimeter level
during 10 to 20 DAS because flooded irrigation is necessary for rice growth
during this period and it also controls weeds. The second fertilization should be
conducted in 18 to 20 DAS. Rice is in vegetative growth during 25 to 40 DAS,
about 60% soil moisture is sufficient for prosperous growth. Thus, AWD should
be conducted during this period as in drying condition, the roots would go further
under the field surface to find water sources and the rice plants can grow stronger
with longer root which also help to avoid harvest losses. Additionally, rice is
prone to sheath blight disease during this period, shortening of the flooded
conditions by AWD restricts spreading of the pathogenic fungus (Rhizoctonia
solani). Third fertilization should be conducted during forty to forty – five DAS
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and the water depth should be maintained at one to three centimeters this time.
Nothing significant is noted during forty – five to sixty DAS. The period of sixty
to seventy – five DAS corresponds to the flowering stage; rice requires large
volumes of water in this stage, thus, water depth should be continuously kept at
five centimeters. Farmers should drain the water from the paddy fields ten to
fifteen days before harvest. Draining the water before harvesting promotes rice
ripening and facilitates the machine harvesting operation.
2.1.3 The AWD score
As the definition of AWD is relatively general while the practices of AWD
are differently conducted among rice producing areas, people could hardly define
AWD technique adoption. Furthermore, when AWD is widely adopted, local
famers also do not strictly follow the guidelines but adjust the practice differently
in their own ways. For instance, Satyanarayana, Thiyagarajan et al. (2007)
indicated that some farmers found it possible to applied alternate wetting and
drying irrigation for the whole cultivation season and this practice could even

generate some benefit. Consequently, a measurement of AWD adoption is
required to determine the degree of AWD adoption for each farm.
Among the previous studies, there are two approaches to proxy AWD
adoption. The first one is using a dummy variable which equals to zero when the
farmers apply continuous flooding irrigation and equals to one when the famer
use AWD irrigation (Rejesus et al., 2011). Nevertheless, it is hard to distinguish
between AWD non-adopters and AWD adopters. Additionally, a dummy variable
could not be able to reflect the diversified adoption level among famers. The
second appropriate is the AWD score which is originally introduced by Moya,
Hong et al. (2004). This score formulates AWD adoption mainly based on the
irrigation times and irrigation water level. AWD score has been documented by
IRRI as an approach to measure AWD adoption at farm level and also has been
used by several researchers to investigate the AWD impacts (Moya, Hong et al.
2004, Mushtaq, Dawe et al. 2006, Li and Li 2010).
However, the degree of AWD adoption might not only depend on water
irrigation but also on water drainage. First of all, drainage helps to save water
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