Efficiency analysis of edible canna farms in Bac Kan Province Vietnam

Efficiency analysis of edible canna farms in Bac Kan Province Vietnam Efficiency analysis of edible canna farms in Bac Kan Province Vietnam Efficiency analysis of edible canna farms in Bac Kan Province Vietnam luận văn tốt nghiệp,luận văn thạc sĩ, luận văn cao học, luận văn đại học, luận án tiến sĩ, đồ án tốt nghiệp luận văn tốt nghiệp,luận văn thạc sĩ, luận văn cao học, luận văn đại học, luận án tiến sĩ, đồ án tốt nghiệp

國立屏東科技大學熱帶農業暨國際合作系 Department of Tropical Agriculture and International Cooperation National Pingtung University of Science and Technology

博士學位論文 Ph.D Dissertation

越南北干省食用美人蕉農場效率分析之研究

Efficiency analysis of edible canna farms in Backan Province, Vietnam

指導教授 Advisor: 彭克仲 博士 (Ke-Chung Peng, Ph.D.)

研究生 Student: 武氏姮 (Vu Thi Hien)

中華民國 109 年 7 月 10 日

July 10, 2020

論文摘要內容：

在越南食用美人蕉被視為是重要的糧食作物，且創造收入並減少貧困率，但近年來北干省食用美人蕉的生產面臨許多挑戰，如新鮮塊莖產量不穩定，產品質量低劣，產品價格不穩定等，故提高食用美人蕉生產效率將有助於越南北部山區的農民增加收入並維持其生計。不過，在越南關於衡量農業效率的研究非常有限，其中至今尚無分析越南食用美人蕉之生產效率相關研究。因此，本研究目的是使用資料包絡分析（DEA

）和隨機邊界分析（SFA）來評估北干省食用美人蕉農場之生產效率。研究結果顯示，三波縣農場的效率（技術、規模、分配與經濟效率）高於納里縣，表示納里縣的食用美人蕉農場可以透過採用合適的技術和有效地利用投入來提高效率。其中，有 92.38%的納里縣農場和 83.06%的三波縣農場經營處於規模報酬遞增階段，表示北干省的農場可以透過擴大規模以降低生產成本，從而提高種植效率。另，食用美人蕉農場的平均環境效率較低，納里縣與三波縣分別為 0.57 與 0.58，表示納里縣與三波縣的農場在不改變當前產出和投入水準下，能分別減少 43%和 42%不良投入量的使用。本研究還發現，納里縣農場比三波縣農場具有更高的能源指標（能源比、能源生產率、淨能源），代表納里縣農場可以減少能源投入，並略高於三波縣（分別為 54.54%與 53.61%）。另，食用美人蕉

農場的技術、經濟和環境效率受到教育和農業推廣接觸等相關因素的影響。因此，本研究建議農業政策應著重於發展北干省的推廣體系，為農民提供培訓與技術轉讓，以幫助農民提高在食用美人蕉的生產效率。 關鍵字：技術效率、資料包絡分析、隨機邊界分析、食用美人蕉農場、

越南

Abstract

Student ID: P10522021

Title of Dissertation: Efficiency analysis of edible canna farms in Backan

Province, Vietnam Total Pages: 142 Pages

Name of Institution: Department of Tropical Agricultural and International

Cooperation, National Pingtung University of Science and Technology

Graduate Date: July 10,2020 Degree Conferred: Doctoral Degree Name of Student: Vu Thi Hien Advisor: Ke-Chung Peng, Ph.D The content of abstract in this dissertation:

Edible canna is considered an important food crop that can contribute to create income and reduce the poverty rate in Vietnam In fact, the edible canna production in Backan province is recently facing many challenges such as unstable fresh tuber yield, low-quality products, unstable of output price, etc Thus, improving the efficiency of edible canna production helps farmers in the Northern mountainous regions of Vietnam increase income and guarantee their livelihood sustainably However, the research on measuring efficiency in agriculture is very limited in Vietnam It is the reason why, to date, there is no study which is related to analyzing the efficiency of edible canna production in Vietnam Therefore, the aims of this study were to evaluate the efficiency of edible canna farms in Backan province using data envelopment analaysis (DEA) and stochastic frontier analysis (SFA) approaches The findings indicated that the efficiency (technical, scale, allocative and economic) of farms

in Babe district found to be higher than in Nari district, implying that edible canna farms in Nari district can improve their efficiency scores by adopting the

suitable technology and using inputs efficiently In addition, 92.38% of total farms in Nari district and 83.06% of total farms in Babe district were being operated under increasing returns to scale, indicating that farms in Backan province could improve their efficiency in edible canna cultivation by increasing their scale to reduce the cost in production The results also showed that the average environmental efficiency of edible canna farms was low, of 0.57 and 0.58 for Nari and Babe districts, respectively, indicating that farms in Nari district and Babe district could have the potential to reduce 43% and 42%, respectively, of bad inputs usage without changing the current output and conventional input level Moreover, findings indicated that edible canna farms

in Nari district had high energy indicators (energy ratio, energy productivity, net energy) as compared to other farms in Babe district, implying that farms in Nari district had opportunities to reduce energy input with slightly higher than that in Babe district (54.54% and 53.61%, respectively) The results of this study also revealed that the technical, economic and environmental efficiency

of edible canna farms were affected by factors related to education and extension contact Therefore, this study suggested that agricultural policies should focus on developing the extension system in Backan province to provide training and facilitate technology transfer for farmers which can help farmers

to improve their efficiency scores in edible canna production

Keywords: technical efficiency, data envelopment analysis, stochastic frontier

analysis, edible canna farm, Vietnam

Acknowledgements

My study was conducted in the Department of Tropical Agriculture and International Cooperation (DTAIC), National Pingtung University of Science and Technology (NPUST) during the period from 2017 to 2020 During this period, I would like to express my appreciation and sincere thanks to my supervisor, Dr Ke-Chung Peng, for all his support and invaluable guidance on

my research His intellectual instruction with meaningful suggestions and comments help me to find the right method to complete my Ph.D research program on time I also would like to express my sincere thanks to Dr Rebecca

H Chung for her assistance and kindness to revise and give valuable suggestions for my papers

I would like to express my appreciation and thanks to advisory committee members: Dr.Feng-Jui Lin, Dr Chien-Feng Tai, Dr Biing-Wen Huang, and Dr Meng-Long Shih for their meaningful suggestions and comments for the successful accomplishment of my research work

I am grateful to Vietnamese and Taiwan government for financial support for my Ph.D study program in Taiwan I would also like to express my thanks

to the staffs of NPUST and DTAIC for their invaluable assistance for me to complete my doctoral program I would like to thank Thainguyen University of Agriculture and Forestry for supporting and encouragements during the period

of my study in Taiwan

I would like to express sincere thanks to Dr Ha Quang Trung, the head of Department of Economics and Rural development, Thainguyen University of Agriculture and Forestry, for his kind and meaningful suggestions and encouragement during the conduction of the survey and collection data in Vietnam I also would like to thanks to the staffs, all edible canna farms of both districts, Nari and Babe, in Backan province for their great assistance in

providing secondary data and information about edible canna production for

my research

Finally, I am extremely grateful to my parents and my husband who encouraged and supported me throughout my study period in Taiwan Especially, I am grateful to my daughter who motivated me to successfully complete my research program Many thanks to my relatives, colleagues, students, and Vietnamese friends in NPUST for their encouragement, helps during the time for studying and living in Taiwan

Table of Contents

摘要 I

Acknowledgements V Table of Contents VII List of Tables XI List of Figures XIV List of Abbreviation XV

Chapter 1Introduction 1

1.1 Research Background 1

1.2 State of the Problem 2

1.3 Objectives of the Study 3

1.4 Research Questions 4

1.5 Contribution of the Study 5

1.6 Structure of the Study 5

Chapter 2Literature Review 8

2.1 Scientific Characteristics of Edible Canna 8

2.1.1 Origin and Distribution of Edible Canna 8

2.1.2 Scientific Classification of Edible Canna 8

2.1.3 Some Characteristics of Edible Canna 9

2.1.4 The Nutritional Value and Pharmaceutical Activities of Edible Canna 11

2.1.5 Economic Benefits of Edible Canna 12

2.1.6 Summary of Studies about Edible Canna 13

2.1.7 Edible Canna Production in Backan Province 14

2.2 Efficiency Measurement Concept and Efficiency Analysis Methods 16

2.2.1 Efficiency Measurement Concept 16

2.2.2 Efficiency Analysis Methods 18

2.2.2.1 Data Envelopment Analysis (DEA) 18

2.2.2.2 Applications of the DEA in Agricultural Studies 18

2.2.2.3 Stochastic Frontier Analysis 27

2.2.2.4 Applications of SFA Approach in Measuring the Efficiency of Agricultural Production 27

Chapter 3Research Methodology 32

3.1 Study area 32

3.1.1 Natural Conditions of Study area 32

3.1.2 Socio - economic Conditions of Backan Province 33

3.2 Sampling methods and Data collection 34

3.2.1 Sampling Design 34

3.2.2 Data Collection 36

3.3 Theoretical and Data Analysis Framework 37

3.3.1 Study I: Analyze the Efficiency of Edible Canna Production Farms using

Two-stage Data Envelopment Analysis Approach 37

3.3.2 Study II: Evaluation of Environmental and Technical Efficiency of Edible Canna Farms using SFA Approach 41

3.3.3 Study III: Evaluation of Energy Efficiency of Edible Canna Farms using DEA Approach 47

3.3.4 Conceptual Framework of the Study 50

3.4 The Specific Variables used in this Study 52

3.4.1 Variable Specifications used in Measuring the Efficiency of Farms 52

3.4.2 Variable Specifications used in Measuring the Environmental and Energy Efficiency of Edible Canna Farms 55

Chapter 4Results and Discussion 58

4.1 Study I: Evaluation of Technical, Scale, Economic and Allocative Efficiency of Edible Canna Farms using Two-stage Data Evelopment Analysis (DEA) 58

4.1.1 Descriptive statistic 58

4.1.2 The Efficiency level of Edible Canna Production in Backan Province 60

4.1.3 Factors Influence on the Efficiency of Edible Canna Farms in Backan Province 63

4.1.4 Estimates Yield loss of Edible Canna Production in Backan Province by Regions 67

4.1.5 Summary of Study I 70

4.2 Study II: Evaluation of Environmental Efficiency and Its Determinants of

Edible Canna Production using Translog Frontier Production Function Model 71

4.2.1 Descriptive Analysis 71

4.2.2 Technical Efficiency of Edible Canna Farms and Determinants 75

4.2.3 Environmental Efficiency of Edible Canna Farms and Determinants 79

4.2.4 Factors Influencing on Environmental Efficiency of Edible Canna Farms in Backan Province 81

4.2.5 Summary Study II 82

4.3 Study III: Evaluation of Energy Efficiency and Optimum Energy Requirement for Edible Canna Farms using DEA Approach 84

4.3.1 Energy Efficiency of Edible Canna Farms in Backan Province 85

4.3.2 Energy Efficiency of Edible Canna Farms under Different Farm size 91

Chapter 5Conclusion and Policy Recommendations 99

5.1 Conclusions 99

5.2 Policy Recommendations 100

5.3 Limitations of this Study 101

5.4 Recommendations for Future Study 102

References 103

Appendices 119

Bio-Sketch of Author 139

List of TablesTable 2.1 Area and productivity of edible canna production in Backan province

during 2016-2018 15

Table 2.2 Summary of empirical studies used two-stage DEA on analyzing the

efficiency in agricultural production 22

Table 2.3 Summary of empirical studies on energy efficiency in agricultural

production using DEA approach 25

Table 2.4 Summary of some studies on evaluation the environmental

efficiency in agricultural sector using SFA approach 30 Table 3.1 The sample size of the study 35

Table 3.2 The description of variables were used to analyze the efficiency of

edible canna farms 56 Table 4.1 Descriptive statistic of production and socioeconomic variables of

edible canna farms 59

Table 4.2 The Frequency distribution of efficiency scores of edible canna

farms in Backan province 61

Table 4.3 The efficiency scores of edible canna farms in Backan province by

region 62 Table 4.4 Summary of returns to scale of edible canna farms 63 Table 4.5 Factors influencing efficiency scores of edible canna farms 66 Table 4.6: Estimated yield loss of edible canna production in Backan province

by regions 68

Table 4.7 Descriptive statistics of socioeconomic variables of the sample 72

Table 4.8 Descriptive statistics of production activity variables of the

sample 74

Table 4.9 Maximum likelihood estimates for parameter of translog production

function 77 Table 4.10 The output elasticity with respect to input variables 78

Table 4.11 The distribution of technical efficiency (TE) levels of edible canna

farms in Backan province 79

Table 4.12 The distribution of environmental efficiency of edible canna farms

in Backan province 80

Table 4.13 Truncated regression estimates for factors influencing on EE of

edible canna farms 81 Table 4.14 Energy equivalents of input and output variables 85 Table 4.15 Input and output energy used in edible canna production 86 Table 4.16 The ratio of energy input and energy output in edible canna

production (by regions) 87

Table 4.17 The frequency distribution of efficiency scores of edible canna

farms (by regions) 88

Table 4.18 The energy input target and saving energy for edible canna

production in Backan province, Vietnam 90 Table 4.19 The amount of energy inputs and output used in edible canna

production by different farm size 92 Table 4.20 The ratio of energy inputs and output in edible canna production

under different farm size 93

Table 4.21 Frequency distribution of efficiency scores of edible canna farms

under different farm size 94 Table 4.22 The energy target and saving energy for edible canna production in

different farm size 96

List of Figures

Figure 1 Flowchart of research 6

Figure 2 Adventitious roots which generate in pairs (right) from the rhizome

and a part of root (left) 11 Figure 3 Edible canna production in Backan province, 2014-2018 16 Figure 4 The map of Backan province with two study districts 32

Figure 5 The structure of economic sectors of Backan province from 2016 to

2018 34 Figure 6 Conceptual framework of the study 51

List of Abbreviation

AE: Allocative efficiency

BDARD: Backan Department of Agriculture and Rural development

BKSO: Backan of Statistic office

CRS: Constant returns to scale

DEA: Data envelopment analysis

DMUs: Decision making units

EVE: Environmental efficiency

GSO: General statistic office

PTE: Pure technical efficiency

SFA: Stochastic frontier analysis

TE: Technical efficiency

VRS: Variable returns to scale

Chapter 1 Introduction

1.1 Research Background

Edible canna (Canna edulis Ker) is considered to be one of the food crops

that plays an important role in the agriculture of Vietnam as well as many countries in the world It belongs to the genus Canna (Cannceae), which is widely planted in the tropical regions or subtropical highlands, including South America, Thailand, China, and Vietnam (Imai, 2008; Zhang and Wang, 2013) The acreage grown by edible canna was reported to be 200,000 to 300,000 ha all over the world with the average productivity of 30 tons per ha and rhizome production of 150,000-258,4000 tons per year (Hue and Loc, 2005;

Piyachomkwan et al., 2002) In Vietnam, edible canna is found in both

mountainous and delta areas and is the most popularly grown in the northern mountainous regions The cultivated areas of edible canna in Vietnam were

reported to be from 20,000 to 30,000 ha (Hermann et al., 1997; Hung and

Morita, 2005) Backan has many favorable conditions for agriculture development, in which edible canna is one of the crops with significant advantages This plant is easy to grow and relatively tolerant to drought Brück

et al (2001) and Hermann et al (1997) stated that there are advantages of

production edible canna includes use resources efficiency, high yields, shadowing tolerance, good drought tolerance, water-use efficiency, less pest and disease, and replant problems It is also known as species can be grown under tree canopies or in marginal lands which has low nutrient demand at

altitudes from 1000 to 2500m (Huang et al., 2013) Therefore, edible canna is

consider a suitable to optimize agricultural land uses

With a population of approximately 319,000, Backan is known as one of the poorest mountainous provinces of Vietnam with a poverty rate of 15.8% in

2016 (GSO, 2017) In addition, the majority of the population of Backan

province are minor ethnic people with three main groups, namely Tay, Dao, and Kinh Edible canna production is considered as an important means of livelihood for these minor ethnic people in Backan province as well as other provinces in the North of Vietnam, especially the minor ethnic people who live and cultivate in the highlands area such as Tay and Dao (Trædal and Vedeld, 2018) Furthermore, according to the survey conducted by Backan province, in

2017, the cultivated area of edible canna was 907 ha with an average yield of

70 tons/ha (BDARD, 2017) The edible canna starch is mostly used for preparing transparent starch noodles, which is one of the conventional food of

Vietnamese people (Kasemwong et al., 2008) Especially, the noodle made

from edible canna starch in Backan is very famous with high tensile strength and good for losing weight because it contains high amylose and soluble dietary fiber content (Hung and Morita, 2005; Zhang and Wang, 2013) Therefore, the development of edible canna production in a sustainable manner plays a vital role in meeting domestic demands, creating income opportunities, and more importantly, contributing to poverty reduction for the local community

Recently, although edible canna is considered a potential crop, the research

on evaluating efficiency of edible canna is limited in Vietnam, and the recent studies regarding edible canna mainly focused on analyzing physiological characteristics, molecular structure, and quality of starch from it

(Thitipraphunkul et al., 2003; Wandee et al., 2015) Therefore, studying on

efficiency analysis of edible canna production is very necessary to fill up the gap in literature

1.2 State of the Problem

The edible canna production in Backan province has been facing many challenges recently First, the edible canna production is mainly based on experience and traditional cultivation technique in upland fields As a consequence, the quality of produce is poor and fresh tuber yield is unstable as well Second, it is difficult to introduce canna products to new markets, i.e., the

demand is low and stagnant, which results in the low and unstable domestic prices Third, the production scale is small due to the lack of productive resources such as capital, labor, fertilizer, machine, etc Moreover, the farm households are economically poor with low education level, which barricades them from accessing better and more advanced technique as well as being granted for credits

From the challenges stated above, the question is whether edible canna production in Backan can bring economic, technical, environmental benefits to farmers? What solutions can be applied to address these problems? In addition, the assessment of environmental and energy efficiency has become an important measure in agricultural production in the world as well as Vietnam However, the research on environmental and energy efficiency in agriculture is limited in Vietnam It is the reason why, to date, there is no study which related

to analyzing the technical, scale, allocative, economic, environmental and energy efficiency of edible canna production in Vietnam

From the research gaps are shown above, it is very necessary to have a comprehensive study to estimate the efficiency levels of edible canna farms in Backan province and to suggest some solutions for policy intervention designed

to improve the efficiency of edible canna production, and in hope to improve the livelihood of local community by adopting sustainable production of edible canna To the author’s knowledge, studies analyzing the technical, scale, allocative, economic, environmental and energy efficiency of edible canna production in Vietnam have not been explored As such, the present study would fill the gap in the literature

1.3 Objectives of the Study

The main goals of this study were to analyze the efficiency and determinants of efficiency for edible canna farms, and to suggest solutions for policy-makers to improve the efficiency of edible canna production sustainably

in Backan province The specific objectives of this study included:

(i) To evaluate the technical, scale, allocative and economic

efficiency and to determine the factors affecting the efficient levels of edible canna farms in the study areas;

(ii) To measure the environmental efficiency and its determinants in

edible canna production in Backan province;

(iii) To evaluate the energy efficiency and the energy saving potential

for edible canna farms in the study areas;

(iv) To make policy recommendations for policy-designers and

farmers to improve the efficiency of edible canna production in the study areas as well as in the Northern mountainous region of Vietnam

1.4 Research Questions

This study attempted to answer the following research questions:

i What were the technical, scale, allocative and economic efficiency levels of edible canna farms in Backan province?

ii What were the important factors influencing the efficiency of edible canna farms?

iii How was the environmental efficiency level of edible canna farms in the study area?

iv What were the factors impacting the environmental efficiency level of farms?

v How about the energy efficiency and optimum energy requirement for edible canna production in Backan province?

vi What solutions and policy guidelines could be applied to contribute to improving the efficiency level of edible canna farms in Backan province?

1.5 Contribution of the Study

It was the first study on efficiency analysis of edible canna production Hence, the findings of this research showed the efficiency levels and gave evidences to indicate the negative effects of edible canna farms on the natural environment, but also determine factors that influence inefficiency of edible canna production in Backan province

This study suggested some important solutions for policy-makers to improve the efficiency of edible canna production, increase income, and contribute to developing rural economy, and reducing the poverty sustainably

in Backan province

1.6 Structure of the Study

The study was structured by five chapters and it was conducted following the flowchart as Figure 1 below:

Figure 1 could be summarized as below:

Chapter 1 Introduction: This chapter represented background information about edible canna production in the world, including Vietnam It also defined research problems, objectives and significant of the study

Chapter 2 Literature review: This chapter showed theoretical about efficiency concept, efficiency analysis and review results of previous studies about efficiency analysis and edible canna

Chapter 3 Research methodology: This chapter introduced the information about the study area and provided the detail about sampling size, data collection and data analysis methods

Figure 1 Flowchart of research

Chapter 1 Introduction

Define problem

Objectives and research questions

Significant of the study

Chapter 2: Literature review

Literature about efficiency concept, review

previous about efficiency analysis and

edible canna production

Suggest solutions and policy guidelines to improve the efficiency of edible canna

farms, to increase productivity, to contribute to protecting the environment and

sustainable development

Chapter 3: Research Methodology

Summary information about study area

Research methodologies

Chapter 5: Conclusions and Policy recommendations

Chapter 4: Results and discussion

4.1 Evaluation of technical, scale, economic and allocative efficiency of edible canna farms using two-stage DEA;

4.2 Evaluation of environmental efficiency and its determinants of edible canna production using translog frontier production function model;

4.3 Evaluation of energy efficiency and optimum energy requirement for edible canna farms using DEA approach

Efficiency analysis of edible canna farms in Backan province, Vietnam

Chapter 4 reported the result about efficiency analysis and identified factors influence on edible canna production farms in Backan province Based on the findings, suggestions and policy recommendations would be provided to use resources efficiently, increase productivity, to protect the natural environment and ensure sustainable development

Chapter 5 Conclusions and policy recommendations: This chapter summarized the main results of the research as well as provided recommendations for future study

Chapter 2 Literature Review

2.1 Scientific Characteristics of Edible Canna (Canna edulis Ker)

2.1.1 Origin and Distribution of Edible Canna

Edible canna, belonging to genus canna (Cannceae), is cultivated largely

in South America, Vietnam, Thailand and China (Puncha-arnon et al., 2007)

Edible canna originated in Peru, South America Today, edible canna is widely grown in tropical and subtropical countries around the world South America is a diverse center of canna, but Asia, Australia and Africa are the

largest growers and users (Hermann et al., 1997) There are two types of edible

canna which include ‘green’ and ‘purple’ (Kay, 1987)

This crop is typically cultivated in subtropical highland, at an altitude of 1,000-2,500m, mainly in China and Vietnam, with the variable rhizome production (150,000-2,584,000 tonnes of rhizomes per year) (Piyachomkwan

et al., 2002)

2.1.2 Scientific Classification of Edible Canna

Edible canna (Canna edulis Ker-Gawl)

Class: Liliopsida

Order: Zingiberales

Family: Cannaceae

Gennus: Canna L

About genus of edible canna: Edible canna has two types which includes

diploid (2n = 18) and triploid (2n = 27) with a number of chromosomes is 9 (Kubitzki, 1998) According to Imai (2008) and Hermann et al (1997), the

edible canna cultivated in Vietnam and other Southeast Asia countries is a triploid species and it is closest to Columbian triploid based on the result of DNA analysis

2.1.3 Some Characteristics of Edible Canna

Edible canna is cultivated in a small scale in subtropical and tropical regions of the world without intensive improvement It is probably one of the first plants to have been domesticated in the Andean region It has been suggested that the wild type was domesticated in mountainous areas from Columbia to Ecuador and rapidly transmitted through the Andean region into the west coast and northern Chili (Imai, 2008)

Edible canna can grows up to 3m at the late growth stage Edible canna has

a flower cluster (compound inflorescence) above the terminal leaf As for floral differentiation, Roth and Lindorf (2013) described that the genus canna is neutral to day length The leaves are large and thick with a layer of water storage cells (hypodermal cells) beneath the adaxial and abaxial epidermal cells These cells are thought to be adapted to savanna conditions (Gade, 1966) and in fact, edible canna is relatively drought tolerant caused by hypodermal cells to shrink under a low soil-water level (10% water holding capacity)

(Brück et al., 2001)

Edible canna is grown in all mountainous provinces and also in some lying areas According to official estimates, some 20,000ha of canna are cropped in northern Vietnam In the northern Vietnam, canna is cropped principally in the highlands (300-1,200m) Canna's season requirement is very strict, beginning at the onset of rains and lasting for 10-12 months Propagation

low-is by apical rhizome sections that are either immediately replanted or stored for

2-3 months to allow for staggered harvesting (Hermann et al., 1997)

The botanical characteristics of edible canna

Edible canna is a standing plant, 1.2 to 1.5m high, purple Body underground bulge bulb, contains more starch The bulb lies just below the ground Leaves oblong, 50-60cm long, 25-30cm wide with large midribs Duration growth of edible canna is from 10-12 months: the first month (when the tree is growing) is the period of seedlings; the next 5 months are the full tillers of leafy foliage; the last 4 to 5 months is the bulb period, accumulation

of starch After 12 months, when the bulbs are germinated, the starch contents

in the main bulbs will decrease

The Stem: The stem of the edible canna is erect with height about 300cm

or more at flowering stage and branched underground The single leaves are attached to the stem with a short petiole Edible canna has a flower cluster (compound inflorescence) above the terminal leaf

The leaf: Leaves of edible canna include leaf blade and petiole with leaf

margin at the base, leaf of canna longitudinal line, top surface of leaves are green or green-purple, green or purple underparts Leaves are about 35-60cm long and 22-25cm wide Around the edge of the leaf is bordered by a thin line

of purple red or white in color; leaf blade has a large midrib, parallel tendon, green or red-purple; the petiole leaves are about 8-15cm long

Roots and rhizomes: Edible canna has fibrous roots which are typical to

monocotyledons The root system is comprised of thick adventitious roots and thinner primary and secondary lateral roots The adventitious roots generate in pairs simultaneously near the nodes of rhizomes The ‘horizontal roots’ running shallow underground and the ‘vertical roots’ growing deep in the soil are clearly distinguished The roots generated from the basal and apical side of the nodes of the rhizomes tend to develop into ‘vertical roots’ and ‘horizontal roots’, respectively The ‘vertical roots’, especially those near the rhizome, have superior tissue structure and physical characteristics compared with the

‘horizontal roots’

Figure 2 Adventitious roots which generate in pairs (right) from the rhizome and a

part of root (left) (Imai, 2008)

Flower: The flower length of edible canna is about 7 to 9cm, with 3

calyxes, 3 lanceolate petals, 3 staminodia and 1 anther Staminodia are coloured bright red or orange, with the anther pale yellow and 1cm in length, shedding many pollen grains when it ruptures There is one pistil with a broad, flat yellow style and stigma connected with an inferior ovary at the bottom The ovary wall is dotted, pale green, with 3 loculi containing many ovules and axile placentation Single flowers bear a membranous bract, waxed on the surface In the case of two flowers, the first flower (with longer pedicel is bractless), and the second flower (with short pedicel) has two bracts Flowering within a raceme will begin from the basal one and continuing acropetal When two flowers are present together, the first flower will also open first The flower

is highly sterile, and as the result, no fertile seed can be obtained (Lai and Tsai, 1989)

2.1.4 The Nutritional Value and Pharmaceutical Activities of Edible Canna

As a statement of Zhang and Wang (2013), the dry rhizome of edible canna contained the starches of 70 to 80% and it found to be more digestible than other kinds of starches In addition, the phytochemical analysis of edible canna revealed that it contained many different nutritional components such as: crude

protein: 6.34 ± 0.21g/100g, crude lipid: 4.31 ± 0.11g/100g, crude fiber: 5.78 ± 0.08 g/100g, and calorific value: 1611.54 kJ100g-1DM (Al-Snafi, 2015; Mohan and Kalidass, 2010) With a high amount of fiber in the by-product of edible canna, it was considered as a good source for the production of soluble dietary fiber of obesity, diabetes, cardiovascular patients (Zhang and Wang, 2013)

Moreover, in Vietnam, edible canna is used in traditional Vietnamese medicine: leaf was used to clear ulcers and rheumatism and as a diuretic Rhizome was used as a diuretic and demulcent, and treatment of heart-related disease and acute hepatitis Canna edulis rhizome extracts have been viewed to

be a source of natural antioxidants as it contains a high amount of polyphenolic

compounds (Mishra et al., 2011) In another study, DPPH radical scavenging

activity has been determined with IC50 of 658µg/ml fresh weight basis, and maximum NO scavenging activity and hydroxyl radical inhibition activity were

observed in bioactive diethyl ether: ethyl acetate (1:1) fraction (Mishra et al.,

2012) Lignin isolated from Canna edulis Ker residue exhibited strong inhibition on α-D-glucosidate than acarbose with IC50 of 5.3±0.3 µM, which provides evidence that edible canna can be used for treactivitiesatment of type

2 diabetes (Xie et al., 2017)

2.1.5 Economic Benefits of Edible Canna

Edible canna is an easy-to-cultivate crop and high yield It is mostly cropped in Backan province, Vietnam The growing areas in this province were estimated to be 1.040 ha with production over 71.000 tons, edible canna starch noodle production over 20.000 tons 1 kg of edible canna starch noodle traded from 3 US$ (normal quality) to 5 US$ (best quality) Therefore, edible canna

is of commercial value and can provide an applicable cash income to small and poor villagers (Tanaka, 1998) Although edible canna is considered as an agriculture food crop to reduce poverty and ensure food security, it also is facing many difficulties and challenges, especially the management of product

quality and branding

2.1.6 Summary of Studies about Edible Canna

Although edible canna rhizomes were considered as a source of commercial starch, the researches about it have not received much attention from the scientist (Tanaka, 2004) The research about edible canna are mainly focused on analyzing characteristics, molecular structure and conducted by

many authors According to Piyachomkwan et al (2002), edible canna as an

alternative starch source was evaluated on the basis of genetic characteristics, agronomic and starch properties The finding of this research also revealed that starch yields of edible canna were lower than cassava However, edible canna provides starches with very attractive properties and totally different from cassava and it was also considered as a new starch source to alternate cassava starch

Thitipraphunkul et al (2003) studied about the starch from different edible

canna The results indicated that the absolute amylose content ranged from 19

to 25% and the amylopectin of edible canna starches contained high amount of organic phosphorus, from 391 to 420 ppm

However, Using starch from the fresh tuber of edible canna to produce

ethanol was conducted by Huang et al (2013) The findings revealed that

edible canna contained reasonable P, K+, Ca2+, and Mg2+ content and a nitrogen source containing organic and inorganic nitrogen in the fresh tuber of edible canna was widely used to ameliorate nitrogen deficiencies in ethanol fermentation

Starch of edible canna is mostly used for traditional food in the Southeast

Asia regions (Wandee et al., 2015) The study of Wandee et al (2015) about

the quality of edible canna noodles showed the potential of using canna starch and its derivatives to improve the qualities of rice noodles

Hermann (1996) denoted that canna noodles in Vietnam have excellent eating quality, much superior to extrusion noodles made experimentally from

sweet potato and cassava starches which are widely available in Southeast Asia The high amylose content (25% to 30%) of edible canna starches as compared with other root starches Moreover, the findings of this study showed that canna processing in Vietnam can provide employment to many thousands

of people in rural communities with as little as 500m2 of arable land per capita and improve income for local people in mountainous

Furthermore, Tanaka (1998) showed the economic botanical notes of edible canna in the South of Vietnam The results indicated that edible canna production had a vital role in the life of local people The local people used it for traditional food and starch extracted from rhizomes of edible canna was used to produce noodle which was sold in the market

2.1.7 Edible Canna Production in Backan Province

In Vietnam, edible canna is being planted in many regions such as Caobang, Backan, Tuyenquang, Hagiang, Quangninh, Sonla,…, and it is considered as economic crop of local people in the North of Vietnam The average area planted

by edible canna is around 30,000 ha per year and annual output is about 1.8 million tons of fresh bulbs (Son, 2013)

Edible canna is a plant suitable for local conditions and bring high economic efficiency for local people in Backan In recent years, Backan province has focused on strategies to promote the edible canna production to increase income, economic development and poverty reduction The strategy of Backan was shown

in Decision No.2094, date issued 21/12/2016 about production, processing and consumption edible canna during 2015-2025 and toward to 2030 (BK, 2016) The area and productivity of edible canna in Backan were presented in the Table 2.1

Table 2.1 Area and productivity of edible canna production in Backan

province during 2016-2018

Source: Statistical data (BKSO, 2019; GSO, 2018)

Table 2.1 showed that edible canna cultivation in Backan province remains small size and disperse During the period from 2016-2018, the area and productivity of edible canna were the highest in mountainous Nari district (with

500 ha and approximately 36.89 thous tons in 2018) It was followed by Babe (with 366 ha and 24.70 thous.tons), Bachthong (4.83 thous tons) and Chomoi (2.70 thous tons) in 2018 (BKSO, 2019) In contrast, other districts such as Nganson, Pacnam, Chodon and Backan city, the area and productivity of edible canna are quite low

It is clearly that there is an increasing trend in both productivity and yield of edible canna in Backan province in the period from 2014 to 2018 Edible canna production increased from 51.573 thousand tons in 2014 to 72.88 thousand tons

in 2018, and the edible canna yield increased from 68.04 tons/ha (2014) to 70.04 tons/ha (2018) (BKSO, 2019; GSO, 2018)

The growth of edible canna production and edible canna yield over the 5 years period was represented in Figure 3 as follows:

Figure 3 Edible canna production in Backan province, 2014-2018

Source: Statistic data (BKSO, 2019; GSO, 2018)

2.2 Efficiency Measurement Concept and Efficiency Analysis Methods 2.2.1 Efficiency Measurement Concept

Efficiency is defined as the same maximum of ratios of weighted outputs

to weighted inputs subject to the condition that similar ratios for every decision

making unit (DMU) is less than or equal to unity (Cooper et al., 2011)

Efficiency deals with the difference between the distance of observed input-output combinations and the best practice frontier attainable from each

input level (Coelli et al., 2005) According to Farrell (1957), the efficiency of

a farm includes three main component such as technical efficiency, allocative efficiency and economic efficiency The technical efficiency (TE) measures the ability of the farms to use the inputs in optimal proportion to obtain the maximum outputs (Farrell, 1957) The allocative efficiency (AE) measures the ability of farms to use inputs in the optimal proportions with their prices and

56.00 58.00 60.00 62.00 64.00 66.00 68.00 70.00 72.00

production technology Coelli et al (2005) stated that the combination of

technical efficiency and allocative efficiency provides a measure of total economic efficiency Economic efficiency refers to the ability to yield a given

of outputs at minimum cost, or utilize a given of input to maximum profit, or allocating inputs and outputs to maximize revenue

In addition, recent years, assessing environmental efficiency in agricultural production has become an urgent issue and concerned by many countries around the world with the aim of sustainable development Hence, there were emerging number of studies that were conducted to investigate the environmental efficiency for a wide range of agricultural production either at

the farm or national level (for example, Reinhard et al (2000) investigated the

environmental efficiency level of dairy farms in the Netherlands by incorporating the detrimental variables into the analysis; Zhang and Xue (2005) applied SFA to analyze environmental efficiency in vegetable production in China; Kouser and Mushtaq (2010) assessed the environmental efficiency of

rice farms in Pakistan; and Vo Hong et al (2015) evaluated and compared the

environmental efficiency level for both the ecological and the normal rice farms

in Vietnam)

Moreover, increasing food consumption in the world leads to the growth

of energy consumption as well as natural resources in agricultural sector Therefore, the effective energy use issue is becoming one of the most priority problems of sustainable agricultural production in many countries including Vietnam The energy efficiency evaluates the ability of the farms to use energy inputs in optimal proportion to achieve the maximum energy output

To measure the efficiency of the farm, there are two popular methods which include parametric (Stochastic frontier analysis-SFA) and non-parametric (Data envelopment analysis-DEA) Both of these methodologies have highly correlated results However, in comparison with SFA, the results

of the DEA method found to be more sensitive because of the lack of

determining the random variables which have an impact on the efficient levels

(Toma et al., 2017; Vu, 2016)

2.2.2 Efficiency Analysis Methods

2.2.2.1 Data Envelopment Analysis (DEA)

DEA is a non-parametric method that was applied first by Charnes et al

(1978) with the aim to evaluate the relative efficiency of the decision-making units (DMUs) These DMUs use multiple inputs to produce multiple outputs

According to Tipi et al (2009), there were two major advantages of DEA

Firstly, a production function form was not required to show the correlation between multiple inputs and outputs in DEA Secondly, the distributional assumption related to the inefficiency term did not require showing in DEA Thus, the DEA method was widely applied in various fields of both private and public sectors

Besides these advantages, DEA methods existed some weak points One of the disadvantages was that the results of the DEA approach were very sensitive due to lack of measurement errors and noises of data (Olson and Vu, 2009) In addition, it is difficult to conduct the tests of statistical hypothesis with non-parametric technique

Furthermore, the DEA has two basic models The first model assumes

constant returns to scale (CRS) which is developed by Charnes et al (1978)

This model is found to be appropriate to use when all DMUs are operating at

an optimal scale The second model is variable returns to scale (VRS) This model is propriate to use when all DMUs are not operating at an optimal scale (Huguenin, 2012)

2.2.2.2 Applications of the DEA in Agricultural Studies

With the strong points in comparison to other methods, DEA is considered

a popular technique in evaluating the technical, scale, allocative, economic, and

energy use efficiency Recently, DEA has been adopted by many reseachers to analyzed the efficiency on various crops in agricultural sectors

In vegetable production, Haji (2008) employed DEA approach to analyze economic efficiency and marketing performance of vegetable production in the Eastern and Central parts of Ethiopia The findings indicated that the economic efficiency of farms were not high in both regions of Ethiopia To improve efficiency at the farm level, policy-makers should focus on developing extension services, training activities, and supporting credit loans for farms instead of only pay attention to introducing new technologies

The input-oriented DEA method was also applied by Shrestha et al (2016)

to measure the efficiency level of 502 small vegetable farms in Nepal The results of this study revealed that average efficient scores of farms were very low, with 0.85 for scale efficiency, 0.62 for technical efficiency, 0.50 for allocative efficiency and 0.30 for economic efficiency

Hussaini and Abayomi (2010) adopted DEA technique to investigate the technical and scale efficiency of 192 vegetable farms in the North Central of Nigeria The findings illustrated that the mean technical and scale efficiency were 0.93 and 0.82, respectively

Bournaris et al (2019) analyzed the efficiency of 98 vegetable producers

The study reported that average efficient scores of farmers were 0.87, with the highest scores for eggplant production and the lowest efficient level for tomato crop

In maize production, Karimov et al (2014) estimated production and scale

efficiency by applying the DEA model The results indicated that some economic factors such as education, extension contact, and credit access had a

socio-positive effect on technical efficiency of farms Koc et al (2011) employed

DEA approach to measure the technical efficiency of maize growing farmers

in Turkey The findings revealed that the technical of maize farms in the East

Mediterranean region of Turkey was 0.80 In other words, the technical efficiency of maize farms in Turkey could be improved by reducing 19% of inputs while the output quantity was constant

With rice production, the DEA method applied by various authors to evaluate the efficiency of rice production in many countries in the world

Ogunniyi et al (2015) estimated the efficiency of 120 rice farms in Kwara State

of Nigeria by using CRS and VRS- DEA model The estimated results were 0.548 for technical efficiency under CRS, 0.681 for pure technical efficiency, and 0.844 for scale efficiency The findings showed that the majority of rice farms in Kwara State (82.5%) operated their farms at increasing returns to scale, implying that these farms could improve their efficiency by increasing their farm size

In addition, Zheng et al (2018) used data of rice production in China

during the period of 1995-2017 to evaluate the production efficiency by applying the DEA model The study illustrated that both scale and pure technical efficiency had an impact on the overall efficiency of rice production Therefore, to improve the production efficiency of rice farms, the solutions should focus on changing their farm size

Watkins et al (2014) employed DEA to analyze the efficiency of 158 rice

fields in Arkansas during the period from 2005 to 2012 The findings of the study revealed that average scale efficiency was the highest (0.920), followed

by 0.803 for overall technical efficiency, 0.711 for allocative efficiency, and the lowest score for economic efficiency (0.622) Moreover, the rice fields which were operated at increasing returns to scale made a majority (48.7%)

Wardana et al (2018) analyzed the technical efficiency of small rice farms

in Indonesia by using the DEA approach With 7 inputs and one output were used, the study indicated that the estimated efficiency of small rice farms was not high (0.41, 0.63, and 0.61 for overall technical efficiency, pure technical efficiency, and scale efficiency, respectively) The study showed that

inefficient management and scale were the reason of inefficiency in rice production of small farms in Indonesia

In Vietnam, Tung (2013) adopted the DEA model to analyze the technical and scale efficiency of rice production in the Mekong delta of Vietnam during the period of 1998-2010 The results indicated that there was an increasing trend in the technical efficiency of rice farms in Mekong delta from 0.48 (1998) to 0.61 (2010)

However, other than the SFA approach, the factors influencing the efficiency were not shown in the first when the DEA methodology was applied Thus, to determine the factors affecting the efficiency level, the Tobit regression model was used in the second stage because efficiency scores were bounded between 0 and 1 The summary of empirical studies on analysis the efficiency in agricultural production using DEA and Tobit regression model are presented in Table 2.2

Table 2.2 Summary of empirical studies used two-stage DEA on analyzing the efficiency in agricultural production

Table 2.2 Continue…

Futhermore, using DEA approach to investigate the efficiency of energy use in agricultural production was applied by several authors in various crops

in many countries around the world Wakil et al (2018) adopted DEA model

to evaluate the energy efficiency in Nigeria by using cross-section data of 130 rice farmers The study indicated that the energy saving of rice farms was computed by 8.02% compared to total actual energy inputs usage In addition, the results showed that rice producers could be saved 2711.21 MJ ha-1 of energy inputs in their production while the output level was constant

Kordkheili et al (2014) estimated the energy efficiency of 86 orange farms

by applying DEA approach The findings revealed that the computed SE was the highest (0.97) compared to 0.96 and 0.92 for TE, PTE, respectively Besides, the study also indicated that in total saving energy, the energy saving

of diesel fuel was the highest contribution, followed by chemical fertilizer and water energy inputs

Khoshroo et al (2013) employed the DEA method to estimate the energy

efficiency of grape production in Iran The estimated results indicated that there was a large difference between efficient and inefficient grape farms in using energy inputs such as chemicals, diesel fuel, and water for irrigation In addition, the education level of farmers had a positive effect on energy-efficient

of grape production farms

Masuda (2018) used data from 2005 to 2011 to evaluate the energy efficiency of rice production in Japan using the DEA approach The study revealed that the energy-efficient scores of larger farms found to be higher than that of the small ones, 0.988 and 0.732, respectively The results suggested that increasing the farm size was a good way to improve energy efficiency because

it was easy to adapt to high technology in rice production in Japan

The summary of some empirical studies on analysis the energy efficiency

of other crops was illustrated in Table 2.3