Farmers preference for improvement of rice straw management in mekong delta, vietnam

2.1.2 Field Incorporation of Rice Straw 9 2.1.3 Economic Uses of Rice Straw in Vietnam 10 2.2 Rice Straw Management in the Mekong Delta 11 2.3 Air Pollutant Emissions from Open Rice Stra

UNIVERSITY OF THE PHILIPPINES LOS BAÑOS Doctor of Philosophy in Agricultural Economics

ONG QUOC CUONG

FARMERS’ PREFERENCE FOR IMPROVEMENT OF

RICE STRAW MANAGEMENT IN MEKONG DELTA, VIETNAM

MATTY DEMONT, Ph.D ISABELITA M PABUAYON, Ph.D Co-Adviser Adviser

Date: DECEMBER 2019

This dissertation can be accessed only after consultation with the author and

ONG QUOC CUONG

SUBMITTED TO THE FACULTY OF THE GRADUATE SCHOOL

UNIVERSITY OF THE PHILIPPINES LOS BAÑOS

IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE

DEGREE OF

DOCTOR OF PHILOSOPHY (Agricultural Economics)

DECEMBER 2019

This dissertation attached hereto, entitled “FARMERS’ PREFERENCE FOR

IMPROVEMENT OF RICE STRAW MANAGEMENT IN MEKONG DELTA, VIETNAM” prepared and submitted by ONG QUOC CUONG in partial fulfillment of

the requirements for the degree of DOCTOR OF PHILOSOPHY (AGRICULTURAL

ECONOMICS) is hereby accepted

AGHAM C CUEVAS

Member, Advisory Committee

Date signed

DINAH PURA T DEPOSITARIO

Member, Advisory Committee

Accepted in partial fulfillment of the requirements for the degree of DOCTOR OF

PHILOSOPHY (AGRICULTURAL ECONOMICS)

ANTONIO JESUS A QUILLOY

Chair, Department of Agricultural and Applied Economics

College of Economics and Management

Date signed

JOSE V CAMACHO JR

Dean, Graduate School University of the Philippines Los Baños

Date signed

BIOGRAPHICAL SKETCH

The author was born on September 08, 1989, in Ninh Kieu District, Can Tho City,

Vietnam He is the second child of Mr Ong Duc Phat and Mrs Dang Thi Bich Hang

He obtained his elementary education from Le Quy Don Primary School in 2000,

secondary education from Luong The Vinh Junior High School in 2004, and high school

education from Chau Van Liem High School in 2007 He graduated with a Bachelor of

Science degree in Business Administration from Can Tho University in 2011 He has

been working as a lecturer in the Department of Business Administration, College of

Economics, Can Tho University from November 2011 He graduated with a Master of

Science degree in Business Administration from Can Tho University in 2013 He is

happily married to Ms Nguyen Ngoc Ha since December 2015

In June 2016, the German Academic Exchange Service and Southeast Asian

Regional Center for Graduate Study and Research in Agriculture (DAAD-SEARCA)

granted him a three-year scholarship for a Doctoral Degree in Agricultural Economics,

with a cognate in Business Management at the University of the Philippines Los Baños

(UPLB)

ONG QUOC CUONG

ACKNOWLEDGMENT

I wish to express my sincere gratitude and heartfelt appreciation to the people and

institutions that contributed to the completion of my Ph.D degree:

I am most grateful to Dr Isabelita M Pabuayon, Chair of my Advisory

Committee and Dr Matty Demont, Co-Chair of my Advisory Committee for their

intellectual insights, valuable advice, constant encouragement, and hospitality My thanks

to the members of my advisory committee: Dr Agham C Cuevas, and Dr Dinah Pura T

Depositario for their valuable comments, sincere concern, and understanding

I am grateful to the German Academic Exchange Service and the Southeast Asian

Regional Center for Graduate Study and Research in Agriculture (DAAD-SEARCA) for

granting me financial support I also thank Dr Maria Cristeta N Cuaresma, Program

Head, Graduate Education and Institutional Development Department (GEIDD), and all

the staff of the GEIDD for responding to all my requests so graciously

My thanks also go to the administrative staff of the Department of Agricultural

and Applied Economics, CEM, and the Faculty of Graduate School of UPLB for their

great support in helping me meet all requirements and the Vietnamese Student

Association at UPLB for their encouragements during my study

I am forever grateful to my parents, my elder sister, especially, my wife, Nguyen

Ngoc Ha, for their love, understanding, and spiritual support

2.1.2 Field Incorporation of Rice Straw 9 2.1.3 Economic Uses of Rice Straw in Vietnam 10 2.2 Rice Straw Management in the Mekong Delta 11 2.3 Air Pollutant Emissions from Open Rice Straw Burning 12 2.4 Farmers’ Perception About Rice Straw Management

2.6.1 Agricultural Production Practices 20

4.4.1 Magnitude of Rice Straw and Potential Pollutant Emissions

5.1 Socio-demographic Characteristics of Farmers 87

5.3 Magnitude of Rice Straw and Potential Pollutant Emissions 104

5.3.1 Quantity of Rice Straw Subject to Open Burning 104

CHAPTER PAGE

5.3.3 Environmental Cost due to Greenhouse Gas Emission from Rice Straw Burning

109

5.4 Rice Straw Management Practices and Their Determinants 113

5.4.3 Field Incorporation of Rice Straw 131

5.4.5 Factors Affecting Farmers’ Choices of Rice Straw Management

143

5.5 Farmers’ Perception about Rice Straw Managment 175

5.5.1 Benefits and Disadvantages of Burning Rice Straw

5.6 Farmers’ Preference for Designing Possible Improvement

in Rice Straw Management

LIST OF TABLES

3 Rice planted area, yield and production by province, Mekong

4 Sample size by province, Mekong Delta, Vietnam, 2019 55

5 Summary of EFs specific to rice straw open burning 58

6 Direct Global Warming Potential relative to carbon dioxide 59

7 Description of explanatory variables used in multinomial logit

9 Attributes and levels for designing possible improvement in rice

14 Profiles with attribute assigned and sorted into three blocks 75

21 Definition of variables used in choice experiment 85

22 Actual sample size by province and commune, 543

23 Socio-demographic characteristics, 543 farmer-respondents,

24 Cropping season by province, 543 farmer-respondents, Mekong

25 Rice variety in the Summer-Autumn 2018 by province, 543

26 Rice variety in the Autumn-Winter 2018 by province, 435 93

TABLE PAGE

27 Rice variety in the Winter-Spring 2018-2019 by province, 543

28 Rice production, costs and net income by season, 543

29 Participation in “Small Farmers, Large Field” program, 543

30 Rice cultivation practices by province, 543 farmer-respondents,

34 Type of buyers of paddy rice by province, 543

35 Quantity of rice straw subject to open burning, Mekong Delta,

36 Estimated air pollutant emissions from rice straw burning,

37 Amount of emissions in carbon dioxide equivalent from rice

38 Environmental cost due to greenhouse gas emission from rice

39 Rice straw management practices by cropping season, 543

40 Rice straw management practices by province, 543

41 Difficulties in rice straw management practices by province, 543

42 Quality of rice straw by province, 543 farmer-respondents,

43 Rice straw management and contact with agricultural extension,

44 Rice straw management and agricultural training, 543

TABLE PAGE

45 Rice straw management and access to credit, 543

46 Rice straw management and production contract, 543

47 Burning of rice straw by province, 543 farmer-respondents,

48 Reasons for burning rice straw in the field, 483

49 With or without cost in burning rice straw by season, 483

50 Cost of burning of rice straw (1,000 VND/ha) by season, 483

51 Field incorporation of rice straw by province, 543

52 Reasons for field incorporation of rice straw, 367

53 Use of machinery and spraying Trichoderma for faster

decomposition, 367 farmer-respondents, Mekong Delta, 2019 134

54 Cost of field incorporation of rice straw (1,000 VND/ha) by

season, 367 farmer-respondents, Mekong Delta, 2019 135

55 Removal of rice straw by province, 543 farmer-respondents,

56 Purpose of removal of rice straw by season, 93

57 Advantages of removal of rice straw, 93 farmer-respondents,

58 Methods of collecting rice straw, 93 farmer-respondents,

59 Buyers of rice straw by season and province, 93

60 Price of rice straw (1,000 VND/ha) by province, 83

61 Methods of storing rice straw collected from the field, 10

62 Cost of removal of rice straw from the field (1,000 VND/ha) by

season, 10 farmer-respondents, Mekong Delta, 2019 142

TABLE PAGE

63 Rice straw management practices, 534 farmer-respondents,

64 Likelihood-ratio test for independent variables 145

65 The Wald test for combining dependent categories 146

66 Multinomial logistic model in the Summer-Autumn season 147

67 Marginal effects of factors affecting burning of loose straw and

68 Marginal effects of factors affecting the removal of loose straw

and incorporation of stubbles in the Summer-Autumn 152

69 Marginal effects of factors affecting incorporation of loose straw

70 Likelihood-ratio test for independent variables 155

71 The Wald test for combining dependent categories 156

72 Multinomial logistic model in the Autumn-Winter season 157

73 Marginal effects of factors affecting burning of loose straw and

74 Marginal effects of factors affecting the removal of loose straw

and incorporation of stubbles in the Autumn-Winter 162

75 Marginal effects of factors affecting incorporation of loose straw

76 Likelihood-ratio test for independent variables 165

77 The Wald test for combining dependent categories 166

78 Multinomial logistic model in the Winter-Spring season 167

79 Marginal effects of factors affecting burning of loose straw and

80 Marginal effects of factors affecting the removal of loose straw

and incorporation of stubbles in the Winter-Spring 173

81 Marginal effects of factors affecting incorporation of loose straw

82

Likert scores on the farmers’ perception of benefits and disadvantages of burning rice straw, 543 farmer-respondents, Mekong Delta, 2019

176

83

Likert scores on the farmers’ perception of benefits and disadvantages of field incorporation of rice straw, 543 farmer-respondents, Mekong Delta, 2019

179

TABLE PAGE

84

Likert scores on the farmers’ perception of benefits and disadvantages of removal of rice straw, 543 farmer-respondents, Mekong Delta, 2019

182

85 Likert scores on the farmers’ perception of use of rice straw, 543

86 Distribution by block and province, 543 farmer-respondents,

87 Distribution by block, alternatives per block and province, 543

88 The estimated results of mixed logit model for choice experiment 189

89

Estimates of marginal willingness to accept subsidy (1,000 VND/ha) for improvement of rice straw management, Mekong Delta

190

90 Environmental cost of burning rice straw and private cost of

LIST OF FIGURES

2 Conceptual framework for determining alternatives for

improvement of rice straw management, Mekong Delta, Vietnam 50

LIST OF APPENDICES

1 Chi-square test between actual rice varieties in the

2 Chi-square test between actual rice varieties in the

3 Chi-square test between actual rice varieties in the

4 Rice production, costs and net income in Summer-Autumn by

7 Rice production, costs and net income in Summer-Autumn by

participation in “Small Farmers, Large Field” program 221

8 Rice production, costs and net income in Autumn-Winter by

participation in “Small Farmers, Large Field” program 222

9 Rice production, costs and net income in Winter-Spring by

participation in “Small Farmers, Large Field” program 223

10 Chi-square test between rice cultivation practice and province 224

11 Rice production, costs and net income in Summer-Autumn by

12 Rice production, costs and net income in Autumn-Winter by

13 Rice production, costs and net income in Winter-Spring by rice

14 Chi-square test between type of contract and province 228

15 Rice production, costs and net income in Summer-Autumn by

16 Rice production, costs and net income in Autumn-Winter by

17 Rice production, costs and net income in Winter-Spring by rice

18 Chi-square test between the type of buyer and province 232

19 Chi-square test between spraying Trichoderma into the

20 Multinomial logistic model in Summer-Autumn season 234

21 Multinomial logistic model in Autumn-Winter season 237

22 Multinomial logistic model in Winter-Spring season 240

APPENDIX PAGE

of rice straw, partial removal, and complete removal), medium and high availability of machinery for these practices, farmers’ organization and local government as mechanism for implementing the rice straw management program, and government subsidy to farmers to encourage them to adopt sustainable rice straw management These findings are useful in designing possible improvements in rice straw management in order to achieve proper utilization of rice straw and thus minimize pollution from the prevailing practice of burning rice straw

CHAPTER I

INTRODUCTION

1.1 Background of the Study

Vietnam is the 4th rice producer and ranks as the 2nd largest global exporter,

selling approximately 8 million tons (Mt) of milled rice (2014), which is one-fifth of the

global trade volume (US$4 billion in rice export) (Tivet and Boulakia, 2017) There are

six major rice straw producing regions These are Mekong river delta in the South, Red

river delta in the North, Northern Central and Central Coast, Northern highland and

mountain areas, South-East region and the Central highland region Mekong river delta

has the biggest rice straw yield in Vietnam (ESCAP-CSAM, 2018)

The Mekong Delta, which is located in the South of Vietnam, is the biggest rice

granary of the country Annually, it produces up to 50% of the total rice output and

comprises more than 95% of the total milled rice export of Vietnam (ESCAP-CSAM,

2018) The Mekong Delta has played a central role in sustaining Vietnam’s high level of

rice production (Tivet and Boulakia, 2017) It has three major cropping seasons, namely,

spring or early season, autumn or midseason, and winter, a long-duration wet-season

crop The largest rice area is cropped during the autumn season followed by a spring

crop; only a small area is cropped in winter (GRiSP, 2013) The Mekong Delta produces

21 Mt of rough rice and an estimated 24 Mt of straw (dry weight) annually (Arai et al.,

2015)

2

Rice straw is a rice by-product produced when harvesting paddy Each kg of

milled rice results in roughly 0.7-1.4 kg of rice straw depending on variety, cutting-height

of the stubbles, and moisture content during harvest Rice straw is separated from the

grains after the plants are threshed either manually, using stationary threshers or, more

recently, using combine harvester (IRRI Rice Knowledge Bank)

Rice cropping system intensification with a shorter turnaround time between

crops and higher yields means that large amounts of straw can be produced in a relatively

short period of time The rapid introduction of combine harvester is a game changer in

these systems, as these machines leave the straw spread over the field (Hung et al., 2016)

The use of combine harvester increases drastically to offset the scarcity of labor force

This technology has a direct impact on rice straw management and thus greenhouse gas

emissions (Tivet and Boulakia, 2017)

1.2 Statement of the Problem

Emission from field burning of crop residue, a common practice in many parts of

the world today, has potential effects on air quality, atmosphere and climate (Oanh et al.,

2011) Although rice production practices vary from one country to another, open

burning of rice straw is a common practice in India, Thailand, and the Philippines (Gadde

et al., 2009) Open burning of rice straw is a serious problem in Thailand, especially in

dry season (Kanokkanjana and Garivait, 2013)

In Vietnam, approximately 6.1 Mt of crop residue is burned annually on-field

which is the sixth largest amount in Asia (Streets et al., 2003) Approximately one fourth

of the straw is burned on the field, which is a common practice in intensive rice

cultivation systems in the Mekong Delta This is because there is limited time to prepare

the field for the next crop The spread of intensive rice production in the Mekong Delta

may increase the total biomass of burning crop residues, significantly contributing to

greenhouse gas (GHG) emissions in Vietnam (Hong Van et al., 2014; Arai et al., 2015)

In the winter-spring cropping season, almost all of straw harvested in the Mekong Delta

is burned (Hong Van et al., 2014; Nam et al., 2014)

Burning causes atmospheric pollution and results in nutrient loss, but it is a

cost-effective method of straw disposal and also helps reduce pest and disease populations that

may occur due to reinfection in the straw biomass (Dobermann and Fairhurst, 2002)

Burning of rice straw clears the land quickly before the next crop is established, thus

facilitating seed germination and establishment (Mandal et al., 2004) Rice straw burning

has advantages in terms of farm operations but has also disadvantages from an

environmental perspective (Romasanta et al., 2017) Straw disposal by incineration

directly in the field is often adopted by farmers for convenience However, this method

leads to loss of organic carbon and nitrogen and also has a great effect on civil safety and

the rural eco-environment (Xionghui et al., 2012)

Open field burning is an uncontrolled combustion process during which gases

such as CO2, nitrous oxide (N2O), CH4, CO, non-methane hydrocarbons (NMHC), NOx,

SO2, particulate matter (PM) and few others are being emitted Among those, the

greenhouse gases (GHGs) of importance are N2O and CH4 which contribute to global

warming and climate change (Gadde et al., 2009) Rice straw burning in the field causes

4

greenhouse gas (GHG) emissions, including 0.7-4.1 g of CH4 and 0.019-0.057 g of N2O

per kg of dry rice straw, and emission of other gaseous pollutants such as SO2, NOx, HCL

and, to some extent, dioxins and furans (Oanh et al., 2011; Jenkins et al., 2003) Rice

straw burning also causes significant air pollution and killing of beneficial soil insects

and microorganisms (Mandal et al., 2004)

Straw burning is hard to manage, which will not only result in ecological

environment pollution, but also increasing security risks These discarded crop straws

were burnt by farmers after harvesting or before planting due to lack of appropriate

methods and machines, shortage of rural labour, and weak environmental awareness

(ESCAP-CSAM, 2018)

To reduce air pollution from impact of burning rice straw in Vietnam, it is

suggested that modern technology practices such as incorporation, mushroom cultivation,

compost, and biochar be adopted instead of the traditional use of straw (Duong and

Yoshiro, 2015) Incorporation, mushroom production, cattle feed, and biogas production

should be promoted in order to return organic matters to the soil (Hien, 2017)

Increasing straw utilization efficiency and reducing straw burning and waste will

not only improve the agricultural ecological environment, but also develop rural

economy, increase farmers’ income and promote sustainable development of agricultural

production (ESCAP-CSAM, 2018)

Several studies about rice straw have already been conducted in Vietnam Truc et

al (2012) conducted a study of famers’ awareness and factors affecting adoption of rapid

composting in the Mekong Delta In a study undertaken by Truc et al (2013), logit model

was applied to determine factors affecting farmer’s acceptance to grow straw mushroom

in Mekong Delta Hong Van et al (2014) studied rice straw management by farmers in a

triple rice production system in Can Tho, located in the centre of the Mekong Delta Nam

et al (2014) estimated the quantity of rice straw and its use in different provinces (An

Giang, Dong Thap, Kien Giang, and Can Tho) in the Mekong Delta Arai et al (2015)

investigated greenhouse gas emissions from rice straw burning and straw-mushroom

cultivation in a triple rice cropping system in the Mekong Delta Hien (2017) reviewed

the utilization of rice straw in the world and in Vietnam, including the production and

properties of straw, different equipment for gathering and processing of straw, and

various methods of using straw However, there is no study that analyzes the preference

of farmers for designing possible improvements in rice straw management in the Mekong

Delta using choice experiment approach

The study provides an important and highly interesting topic towards farmers’

preference for improvement of rice straw management in the context of an important rice

producing country in Asia The study will generate new knowledge about designing

possible improvements in rice straw management in order to achieve proper utilization of

rice straw and thus minimize pollution from the prevailing practice of burning rice straw

6

1.3 Objectives of the Study

The main purpose of this study is to determine farmers’ preference for designing

possible improvement in rice straw management in the Mekong Delta

Specifically, the study aims to:

1 To analyze the current situation of rice straw management practices in terms of

quantity of rice straw subject to open burning and potential quantity of air

pollutant emissions in the Mekong Delta;

2 To determine the actual rice straw management practices and their

determinants;

3 To analyze the farmers’ perception about rice straw management;

4 To determine farmers’ preference for alternative designs of improving rice

straw management and their willingness to accept subsidy for improvement;

5 To provide policy recommendations for improvement in the rice straw

management in the Mekong Delta

1.4 Significance of the Study

The study will provide information about the magnitude of rice straw in the

Mekong Delta subject to open burning and their potential pollution effects, as well as the

actual rice straw management practices adopted by rice farmers Likewise, the study will

provide an understanding of the perceptions of the farmers on rice straw management

There is no study that analyzes the preference of farmers for designing possible

approach The study will generate new knowledge about designing possible improvement

in rice straw management in order to achieve proper utilization of rice straw and thus

minimize pollution from the prevailing practice of burning rice straw This study will be

the first to apply choice experiment in the analysis of rice straw management Thus, the

findings will contribute valuable insights in determining options for sustainable rice straw

management, as well as to the knowledge base for the economic literature

Farmers in the study area will gain from this research since they will know the

possibilities for better use of their rice straws that will benefit them and the community

Policy-makers will be properly guided and have sufficient basis in the formulation of

alternative designs for improving rice straw management in the study area

8

CHAPTER II

REVIEW OF LITERATURE

2.1 Rice Straw Management

Rice straw is a rice by-product produced when harvesting paddy Each kg of

milled rice produce results in roughly 0.7-1.4 kg of rice straw depending on varieties,

cutting-height of the stubbles, and moisture content during harvest Rice straw is

separated from the grains after the plants are threshed either manually, using stationary

threshers or, more recently, using combine harvester (IRRI Rice Knowledge Bank)

Straw is the only organic material available in significant quantities to most rice farmers

About 40 percent of the nitrogen (N), 30 to 35 percent of the phosphorus (P), 80 to 85

percent of the potassium (K), and 40 to 50 percent of the sulfur (S) taken up by rice

remains in vegetative plant parts at crop maturity (Dobermann and Fairhurst, 2002)

Rice straw utilization can be divided into use in the field (burning or

incorporation), or use out of the field (baling and collection) by various types of

equipment It can also be classified as destruction of straw organic matters (field burning,

combustion for power generation), and preservation of organic matters (incorporation,

mushroom production, cattle feed, biogas production) (Hien, 2017)

2.1.1 Burning of Rice Straw

Field burning is a process of uncontrolled combustion during which carbon

dioxide (CO2), the principal product of the combustion, is emitted into the atmosphere

with carbon monoxide (CO), and un-burnt carbon (as well as traces of methane, i.e.,

CH4), nitrogen oxides (NOx) and comparatively less amount of sulphur dioxide (SO2)

(Gadde et al., 2009)

Rice straw burning in the field causes greenhouse gas (GHG) emissions, including

0.7-4.1 g of CH4 and 0.019-0.057 g of N2O per kg of dry rice straw, and emission of

other gaseous pollutants such as SO2, NOx, HCL and, to some extent, dioxins and furans

(Oanh et al., 2011; Jenkins et al., 2003) Burning causes almost complete N loss, P losses

of about 25 percent, K losses of 5 to 60 percent The amount of nutrient lost depends on

the method used to burn the straw (Dobermann and Fairhurst, 2002)

2.1.2 Field Incorporation of Rice Straw

Incorporation of the remaining stubble and straw into the soil returns most of the

nutrients and helps to conserve soil nutrient reserves in the long-term (Dobermann and

Fairhurst, 2002) Results drawn from many studies revealed that incorporation of straw

into the soil improves remarkably soil organic matter, soil porosity, availability of N, Zn,

Fe, Mn, and enzymes (ESCAP-CSAM, 2018)

Incorporation of large amounts of fresh straw is either labor-intensive or requires

suitable machinery for land preparation and may result in the build up of disease

problems Transplanting should be carried out two to three weeks after straw

10

incorporation (Dobermann and Fairhurst, 2002) Slow decomposition is often the reason

why farmers do not want to incorporate crop residues (Hung et al 2016)

Straw incorporation costs 5-18 times compared to field burning However, it

brings several advantages such as improving the soil fertility and stabilizing the rice yield

in spite of continuous rice cultivation, thus compensates for the added costs (Hien, 2017)

Although careful management of rice straw incorporation can help sustain and improve

soil fertility in rice production, increasing the organic matter in irrigated rice soils can

result in increased GHG emissions (Hung et al 2016)

2.1.3 Economic Uses of Rice Straw in Vietnam

Straw can be used for livestock feed, mushroom production, and biogas

production, among others (Hien, 2017) Straw can be used as fuel for cooking, ruminant

fodder, and stable bedding or as a raw material in industrial processes The effect of straw

removal on long-term soil fertility is much greater for K than for P (Dobermann and

Fairhurst, 2002)

Rice straw is usually used as an important part of nutritional requirements for

ruminant animals like buffaloes, cattle beef, cows, sheep and goats in most of rice

producing countries Traditionally, ruminant animals can eat rice straw directly in the

fields after harvesting seasons or within the farms (ESCAP-CSAM, 2018)

Mushroom can be grown anywhere with conditions suitable to its growing

Mushroom could be grown traditionally in open fields, semi-open fields, in-door spaces

or under automatic controlled conditions The traditional method which is growing

mushroom in the open fields, is still the most popular method in straw mushroom

growing in Southeast Asia countries In addition, in-door mushroom growing methods

can improve significantly quality as well as market prices of the mushroom compared

with the traditional mushroom growing in the open fields (ESCAP-CSAM, 2018)

2.2 Rice Straw Management in the Mekong Delta

Hong Van et al (2014) conducted the study of rice straw management in Tan Loi

2 Hamlet, Thot Not District, Can Tho City Interview surveys of 50 household farmers on

their use of straw in 2007-2011 and 35 household farmers on their use of straw and yields

of rice grain and straw from September 2011 to November 2012 were conducted The

result showed that all of the straw harvested from the winter-spring cropping season was

burned The straw was sold primarily to other mushroom farmers (45.3% in the

spring-summer season and 51% in the spring-summer-autumn season), transferred free to the other

mushroom farmers (15.9% in the spring-summer season and 13.5% in the

summer-autumn season), and used as the mushroom beds for the straw-harvesting farmers (7.3%

in the spring-summer season and 6.9% in the summer-autumn season) Most of the

harvested straw that was not burned was removed from the paddies and used as compost

for mushroom straw-cultivation (69% in the spring-summer and 71% in the

summer-autumn)

Nam et al (2014) conducted the study of rice straw use in different provinces (An

Giang, Dong Thap, Kien Giang, and Can Tho) The result showed that the usage of rice

straw varied seasonally Straw burning was the most common activity (98.2%) in the

12

winter-spring season The proportion of straw burning decreased to 89.7% while burying

accounted for 6.65% in the summer-autumn In the autumn-winter season, straw burning

has the lowest level (54.1%) while the proportion of straw burying was quite high

(26.1%), followed by mushroom cultivation (8.1%)

2.3 Air Pollutant Emissions from Open Rice Straw Burning

Gadde et al (2009) estimated the quantity of rice straw subject to open field

burning, and air pollutant emissions from rice straw burning in India, Thailand, and the

Philippines The quantity of rice straw subject to open field burning was estimated using

data on rough rice production, straw to grain ratio (0.75), and proportion of rice straw

subject to open field burning The quantity of air pollutant emissions from rice straw

open field burning was estimated based on the quantity of rice straw subject to open field

burning, emission factor of pollutant species, and combustion factor (0.80) Results

showed that the annual quantities of rice straw residues in India, Thailand, and the

Philippines were 13.92 Tg, 10.45 Tg, and 10.15 Tg, respectively Emissions of pollutant

species such as CO2, nitrous oxide (N2O), CH4, CO, non-methane hydrocarbons

(NMHC), NOx, SO2, particulate matter (PM) were estimated Among those, the

greenhouse gases (GHGs) of importance are N2O and CH4 which contributed to global

warming and climate change The emissions of CO2 in India, Thailand, and the

Philippines were 16,253,012, 12,206,603, and 11,850,034 Mg, respectively The

emissions of CH4 in India, Thailand, and the Philippines were 13,359, 10,033, and 9,740

Mg while N O pollutant emissions were 779, 585, and 568 Mg

Dung et al (2012) estimated air pollutant emissions from open rice straw burning

in the Red River Delta This study applied the formula of Gadde et al (2009) in order to

estimate the quantity of rice straw subject to open field burning, and quantity of air

pollutant emissions Results revealed that the quantity of rice straw subject to open field

burning was in the range of 1,019.4 – 4,077.8 thousand tons based on the proportion of

rice straw subject to open field burning from 20% to 80% The emission of CO2 was the

largest, between 1.2 – 4.7 million tons The emission of CH4 was in the range of 1.0 – 3.9

thousand tons per year while CO pollutant emission was 28.3 – 113.2 thousand tons per

year

Nam et al (2014) estimated the quantity of rice straw subject to open field

burning and the amount of greenhouse gas emitted from burning rice straw in the

Mekong Delta in 2011 This study applied the formula of Gadde et al (2009) in order to

estimate the quantity of rice straw subject to open field burning, and quantity of air

pollutant emissions However, the straw to grain ratio was estimated based on dry weight

of straw, and paddy weight Thus, the average straw to grain ratio in autumn-winter, and

winter-spring were 1,16±0,08, and 1,11±0,01 The quantities of rice straw subject to open

field burning in Kien Giang, Dong Thap, Can Tho, An Giang, and the Mekong Delta

were 1.96, 3.05, 1.2, 4.63, and 20.93 million tons, respectively This led to an

accumulated release approximately 17.95 million tons of CO2, 485.58 thousand tons of

CO, and 10.38 thousand tons of NOx in the atmosphere

14

2.4 Farmers’ Perception About Rice Straw Management Practices

Launio et al (2013) used the Likert scale to evaluate perceptions, awareness, and

attitudes of farmers in Philippines towards rice straw management and environmental

consequences Expected changes owing to incorporation of rice straw in soil, awareness

of environmental issues in rice farming, awareness of environmental regulations,

responsibility for environmental problems, priority for environmental issues, obedience

to environmental laws/ordinances were used as criteria for evaluation The results showed

that around 90% of farmers believed in the expected benefits of incorporating rice straw

in the soil such as its effect on soil conditions and fertility, and yields in general More

then 80% of farmers were aware of the impact of open-field burning on air pollution and

ozone layer destruction

Ahmed and Ahmad (2013) used questions to evaluate farmers’ opinion in Punjab,

Pakistan about the impact of residue burning on yield, soil, and the environment In terms

of impacts on soil quality, 54 percent of farmers thought that burning of residue improves

the physical properties of the soil and 42 percent of farmers reported no impact on the

physical properties of soil due to burning of residue In terms of impact on environment,

48 percent of farmers felt that the burning of rice residue had a negative impact on the

environment, while 30 percent of farmers had no opinion on the effect of burning on the

environment

2.5 Factors Affecting Farmers’ Choices of Rice Straw Management Practices

Gupta (2012) applied the probit model and linear probability model to identify the

determinants of emissions from open-field burning of rice residue in Punjab The use of

combine-harvester was the most important determinant of the decision to burn rice

residue Residue on plots on which farmers harvested a rice crop using a

combine-harvester was 80% more likely to be burnt on average than residue on plots on which

farmers harvested the rice plant using farm labor Farm location was another factor

influencing the decision to burn the residue In addition, number of person equal to or

above 15 years of age in the household had negative effect on the rice residue burning

decision

Truc et al (2012) used logit model to determine the factors affecting adoption of

rapid composting in Mekong Delta, Vietnam and Central Luzon, Philippines The results

showed that household income and perceptions about rapid composting were significant

factors affecting the acceptability of using Trichoderma for rapid composting both in

Mekong Delta and Central Luzon The signs of the household income coefficients

differed between Mekong Delta and Central Luzon In Mekong Delta, households with

higher income were less likely to adopt Trichoderma because they can afford to buy

inorganic fertilizers This may also be due to their perception of longer decomposition

period compared to the time needed for them to start the next crop Households with

greater income in Central Luzon were more likely to adopt Trichoderma because they can

afford to buy the activator and pay for labor requirement for rice straw rapid composting

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Farm size was another significant factor in Central Luzon Households with bigger farm

sizes were less likely to accept the technology than those with smaller farm sizes because

applying the technology in bigger farms would entail additional labor and input cost

In the study conducted by Truc et al (2013), logit model was applied to determine

the factors affecting farmer’s acceptance to grow straw mushroom in Mekong Delta,

Vietnam and Central Luzon, Philippines In Mekong Delta, lower income and smaller

households were more likely to grow mushroom than those with higher income and

bigger households Bigger households tended to send their children to work or study

outside the communes They might have to take care of their children, so they have no

more vacant time for straw mushroom growing However, households with higher

income and smaller farm size were more receptive to grow straw mushroom in Central

Luzon Growing straw mushroom was considered a small business in Central Luzon

rather than a livelihood, as opposed to the culture in Mekong Delta wherein poor farmers

engaged in mushroom production to augment their household income In addition,

households with smaller farm size were more likely to accept the technology since they

would want to earn more to compensate for the small income they get from producing

rice within their small farm areas

Supaporn et al (2013) applied the logit regression model to determine the factors

affecting farmers’ decisions on utilization of rice straw compost in Khon Kaen Province

in Northeastern Thailand Results of the study showed that the farmers’ education,

number of rice straw compost training, insufficiency of labor, lack of knowledge about

technology, and difficulty in making rice straw compost had a significant impact on the

farmers’ decisions to use rice straw compost

Haider (2013) conducted a study on the determinants of rice residue burning in

the southwest region of Bangladesh The logit regression model was used to assess the

reasons for the rice residue burning The random-effect logit model, fixed-effect logit

model, and linear probability were estimated to check the robustness of the findings The

results showed that straw length, low-elevation land and distance to the plot from the

farmers’ homestead positively and significantly influenced the rice residue burning

decision in the field while residue price negatively influenced the residue burning

decision of farmers

In the study of rice straw management in the Philippines, Launio et al (2014)

applied multinomial logit model to understand why farmers choose to burn, incorporate

or remove rice straw in the field Farm type, number of household members with older

than 13 years, livestock ownership, the distance from farm to house, perceptions on

negative impacts of open-field burning, awareness of environmental regulations, attitudes

toward incentives/market were the significant factors that influence farmers’ decisions to

either incorporate or remove straw from the field for other uses instead of burning

Income from non-rice farming, total area cultivated, and tenure status were factors that

significantly influence the decision to remove straw from the field, while attendance at

rice production training, and perceptions on the positive and negative effects of straw

incorporation were factors that significantly influence the decision to incorporate rice

straw in the soil

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Ahmed et al (2015) conducted the study of examining farmers’ choices of rice

residue management practices in Punjab, Pakistan Farmers followed five practices for

managing crop residues These included removal of rice crop residue (full removal),

removal of pural and burning of the lower parts of the rice stem (partial burn), burning of

pural and lower parts of the rice stem (full burn), removal of pural and incorporation of

the lower parts of the rice stem (partial incorporation), and complete incorporation of rice

residue (full incorporation) They used two approaches to model the adoption of rice

residue management, namely, seemingly unrelated regression (SUR) and seemingly

unrelated Tobit regression (SUTR) Geographic location of the farm, convenience in use

of farm machinery due to burning of residue, negative impact of burning on environment,

Rajput caste, and reduction in turn-around time between the harvesting of rice and the

sowing of wheat crop were significant in the allocation of rice acreage to various rice

residue management practices

Chendrashekhar et al (2018) conducted the study of factors influencing the

adoption of paddy straw management practices by farmers of Karnataka (India) There

were four methods of residue management practices These were removal of loose straw

and burning of stubbles, burning of loose straw and stubbles, removal of loose straw and

incorporation of stubbles, and incorporation of loose straw and stubbles The

socioeconomic factors influencing the different residue management practices were

analyzed by using multinomial logit model The area under paddy cultivation and the

number of animals had a significant influence on the removal of loose straw and burning

of stubbles method of residue management Education had negative and significant

influence on the burning of loose straw and stubbles method In case of the removal of

loose straw and incorporation of stubbles method, farming experience, number of

animals, and training programmes had positive influence In addition, farming

experience, farm implements, and training programmes had positive and significant

influence on incorporation of loose straw and stubbles method

Roy et al (2018) applied the binary logistic regression to find out the factors

affecting farmers’ decision on paddy straw burning in Punjab The results showed that

farmers’ land holding, extension contact, and innovativeness were the significant factors

contributing to their decision to burn the paddy straw Socio-personal and psychological

variables (Z-test) such as annual income, extension contact, mass media exposure,

innovativeness, and ecological consciousness were significantly different among the

farmers managing paddy straw and those using alternative techniques other than burning

In the previous studies, the logit model, probit model, and multinomial logit

model were applied to examine farmers’ choices This study applied multinomial logit

model to determine factors affecting the actual rice straw management practices in the

Mekong Delta The dependent variable is the rice straw management practices classified

into five categories These included removal of loose straw and burning of stubbles

(partial burning), burning of loose straw and stubbles (full burning), removal of loose

straw and incorporation of stubbles (partial incorporation), incorporation of loose straw

and stubbles (full incorporation), and removal of loose straw and stubbles (full removal)

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2.6 Applications of Choice Experiments

The choice experiment approach has been applied in many studies involving

agricultural production practices, conservation agriculture, agri-environmental schemes

Generally, the choice experiment approach is a form of choice modeling in which

respondents are presented with a series of alternatives and asked to choose their most

preferred (Bateman at al., 2002) The concept and application of choice experiment is

further explained in the succeding sections

2.6.1 Agricultural Production Practices

Jaeck and Lifran (2014) conducted the study of farmers’ preferences for both

cropping and management practices in the Rhone River Delta Based on expert and

pretest interviews, six credible and relevant attributes associated with cropping practices

were identified Three attributes were related to agro-ecological practices, namely,

varietal choice, weed control practice, and type of crop rotation Two others concerned

agricultural outcomes; these were average yield over five years and yield variability over

five years The last attribute related to the Common Agricultural Policy (CAP) single

payment scheme It was a form of financial support for rice production, similar to

payment received under the CAP The results showed a strong case for differentiating

incentives to encourage environmentally friendly practices and identified the diversity of

values attached to the main components of rice cropping technology Implicit prices

indicated that most rice growers could be persuaded to adopt environmentally friendly

Coffie et al (2016) applied an advanced discrete choice experiment to evaluate

farmers’ preferences for rice production practices in Ghana Based on expert interviews,

focus group discussions and relevant attributes established in the literature, they

described a rice production technology using seven attributes Four of these attributes

were quantitative (yield, gross margin, labor, and risk) while three were qualitative

(cultivar choice, weed control technology and cropping pattern) They generated

willingness to pay (WTP) estimates using willingness to pay space (WS) and compared

with values from the indirect or preference space (PS) method

2.6.2 Conservation Agriculture

Duke et al (2012) used choice experiments to estimate the benefits of agricultural

land preservation and three conservation management practices Sustainable management

was conceptualized with three illustrative practices that impact water quality, carbon

sequestration, and soil erosion The preservation contract, the management contract

(pelletized broiler litter fertilizer, increased riparian buffers, and no-till cropping), and

yearly increase in taxes and fees were identified as attributes of this study The results

identified substantial benefits for land preservation, the use of broiler litter, and riparian

buffers but not for conservation tillage

Vaiknoras et al (2015) conducted the study of farmers’ preferences for attributes

of conservation agriculture in Uganda These attributes included yield, soil erosion, labor

requirements for land preparation, and input costs A mixed logit model was applied to

determine how reductions in erosion, reductions in labor requirements for land

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preparation, increases in yield, and increases in input costs influence farmers’ choices of

production methods The results also showed that preferences for these attributes varied

by district, gender, and prior farming practices

Ward et al (2016) used discrete choice experiments to study farmers’ preferences

for different conservation agriculture (CA) practices in Malawi and assessed willingness

to adopt conservation agriculture These attributes included program implementer,

intercropping requirement, zero tillage requirement, percentage residue-mulching

requirement, and subsidy level The results indicated that current farm level practices

largely influenced willingness to adopt the full conservation agriculture package

Providing subsidies can increase likely adoption of a full conservation agriculture

package, but may generate some perverse incentives that can result in subsequent

disadoption

Barrowclough and Alwang (2017) conducted the study of conservation

agriculture in Ecuador’s highlands The six important attributes to the adoption decision

were identified such as on-year yield, four-year yield, planting labor days, weeding labor

days, soil erosion, and cost This study used discrete choice experiment to determine the

relative importance of conservation agriculture attributes, and measured expected welfare

changes associated with conservation agriculture adoption The results showed that

producers are most concerned with future yields, planting labor, and overall costs

2.6.3 Agri-environmental Schemes

Ruto and Garrod (2009) used a choice experiment approach to investigate

farmers’ preferences for the design of agri-environment schemes This study collected

choice data in 10 case study area across the EU and used both mixed logit and latent class

models These attributes included minimum length of agreement, flexibility over what

areas of the farm are entered into the scheme, flexibility over undertaking some of the

measures required under the scheme, average time spent on paperwork/administration,

and additional payment per ha The results showed that farmers were found to require

greater financial incentives to join schemes with longer contracts or that offer less

flexibility or higher levels of paperwork

In the study conducted by Espinosa-Goded et al (2010), an error component

random parameter logit model was employed to investigate farmers’ preferences for

different options in a specific agri-environment schemes aimed at encouraging nitrogen

fixing crops in marginal dry-land areas in Spain These attributes included flexibility over

the amount of land to be enrolled in the agri-environment schemes, flexibility over

grazing in the land under agri-environment schemes, availability of a compulsory and

free of charge technical training and advisory service, fixed premium, and premium level

(payment level per ha and year) The results showed that farmers displayed a strong

preference for maintaining their current management strategies, and significant savings in

cost or increased participation can be obtained by modifying some agri-environment

schemes attributes