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International Journal of Sustainable Development &World Ecology

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Policy-driven rubber plantation and its drivingfactors: a case of smallholders in northeastThailand

Kanda Sakayarote & Rajendra P. Shrestha

To cite this article: Kanda Sakayarote & Rajendra P. Shrestha (2016): Policy-driven rubberplantation and its driving factors: a case of smallholders in northeast Thailand, InternationalJournal of Sustainable Development & World Ecology, DOI: 10.1080/13504509.2016.1143410

To link to this article: http://dx.doi.org/10.1080/13504509.2016.1143410

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Policy-driven rubber plantation and its driving factors: a case of smallholdersin northeast ThailandKanda Sakayarote and Rajendra P. Shrestha

Natural Resources Management Field of Study, School of Environmental, Resources and Development, Asian Institute of Technology,Pathumthani, Thailand

ABSTRACTGovernment-promoted rubber plantation has led to widespread land conversion to mono-culture rubber cultivation in northeast Thailand. To understand what household character-istics influence the decision for land conversion from traditional rice and upland cropscultivation and its impacts on sustainability, the study was conducted in Nong Khai andBueng Kan provinces of northeast Thailand by analyzing land-use changes between 2002 and2013. Majority of conversion to rubber took place in paddy-growing areas and the economicreturns from rubber along with institutional support from the government played a key rolein encouraging farmers to convert to rubber. Other household characteristics, such as farmers’experiences, age of household head, land security, size of paddy area owned, and off-farmincome were important factors influencing the conversion. The reduction of paddy fields maybe associated with an increased risk of food insecurity of smallholders. Spatial analysisshowed that 76% of new rubber plantations currently are in environmentally unsuitablemarginal areas, which are otherwise important for biodiversity conservation, watershedfunction, and environmental protection. The study findings will help to clarify the influencingfactors on land conversion to rubber plantation and to highlight some of the environmentalissues for developing sustainable extension strategies to ensure food security, reduce povertyand protect the environment from rubber plantation.

ARTICLE HISTORYReceived 27 September 2015Accepted 10 January 2016

KEYWORDSPolicy; socioeconomic;land-use; rubber; paddy;northeast Thailand

1. Introduction

Land-use change is driven by a combination of thecauses, broadly identified as proximate or direct andunderlying or indirect causes (Lambin et al. 2003). Ingeneral, proximate causes perform at the local level,such as individual farms, and households or commu-nities. The proximate causes of land-use changeinvolve local actions particularly human activities,such as infrastructure extension, agricultural expan-sion, that explain different processes of land-usechange, and ecosystem processes (Geist & Lambin2002). Underlying causes define the broader contextand fundamental forces supporting these local actions(Veldkamp & Lambin 2001). For instance, commodityprices, proximity to roads, wages, level of off-farmemployment, agricultural input price, householdincome, and tenure security affect land-use change(Irwin & Geoghegan 2001). Land-use conversion deci-sions are also influenced by the personal traits, laboravailability, land-use preferences, socioeconomic,institutional and political settings, and local environ-ment conditions in which the land units areembedded (Briassoulis 2000; Evans et al. 2011).

Country’s policy directly influences the land-useconversion through the changing market

opportunities and price guarantee as experienced inThailand. In the past three decades, the price of riceremained relatively low, and because of the high-timeand labor requirement, its cultivation was reduced.Maize for the market was planted instead because ofits attractive producer prices and increasing cash-earning opportunities in northeast Thailand (Cho2005). Thai’s national policies influencing land-usechange are often to support domestic demand. Forinstance, the recent expansion of agro-fuels is a resultof the Thai government’s advocacy for the use ofbiofuels as renewable energy for replacing non-renewable energy. Increasing demand of biofuelshas directly related to the expansion of land beingused for the production of agro-fuels, such as cassava,sugarcane, soybean, etc. (Taotawin & Taotawin 2015).

Rubber has been considered a new commercialcrop replacing traditional crops and the main featureof major land-use changes in Thailand (Li & Fox 2011).The export value of Thai natural rubber between 2010and 2013 averaged US$ 9.3 billion a year, comparedwith rice at an average export value of US$ 5.3 billiona year (OAE 2013). To meet the rubber demand ofworld market, Thai government announced an impor-tant scheme ‘Rubber Cultivation for Raising the

CONTACT Kanda Sakayarote kanda839@hotmail.com

INTERNATIONAL JOURNAL OF SUSTAINABLE DEVELOPMENT & WORLD ECOLOGY, 2016http://dx.doi.org/10.1080/13504509.2016.1143410

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Sustainable Income to Farmers in the New PlantingArea Phase 1 (2004–2006)’ to promote rubber cultiva-tion among the farmers who have never owned arubber plantation. The program target was to haverubber cultivation in 112,000 ha in the northeastThailand (Fox & Castella 2013). The first projectinvolved plantations in Nong Khai (including BuengKan province), Surin, and Burirum province. Nong Khaihas the largest area of rubber plantation in the north-east region assisting smallholders. Through politicallymotivated government intervention in the form ofrubber promotion project, rapid land use, and landcover change has taken place in most of its territoryand now rubber plantation can be found all overnortheast Thailand from the highland areas down tothe low-lying plains.

Over the past a decade, these areas have witnesseda major shift from predominantly subsistence agricul-ture to the expansion of rubber plantation due to lackof proper land-use planning. Farmers have perma-nently converted a large area under paddy and foodcrops, such as maize, sugarcane, and cassava, to rub-ber plantations (Trisurat et al. 2010). While agriculturalareas have also been lost to other non-agriculturalareas, it has caused increased competition for arableland availability leading to serious consequences onfood adequacy and the environment.

The competition for the land area can be identifiedas a factor driving the establishment of new rubberplanting in major crop areas due to limited landresources (Wang et al. 2012). Although rubber haspositively contributed the livelihoods of farmers byincreasing their income in comparison to other

agricultural products (Kroeksakul et al. 2011), thiscan limit the production of food crops due to shrink-ing land and eventually food security, and evenhousehold income as the rubber price is highly fluc-tuating (Viswanathan 2008). Besides, it also dis-courages multiple or mixed cropping because rubbercultivation was efficient and socially profitable underthe smallholder monoculture (Rodgers et al. 2010).

In order to identify sustainable land-use thatmatches productivity expectations with socioeco-nomic and environmental concerns, it is importantto understand the conditions and driving forces ofland-use change to rubber. It is important to under-stand how different factors interact and interplay ininfluencing farmers’ land-use decisions and subse-quent impacts of those decisions on the economic,social, and environmental domain. This studyattempted to quantify land-use change by assessingthe nature and magnitude of change in areas underrubber plantation over the past decade and investi-gate the driving factors of land conversion to rubberby smallholder farmers.

2. Study area

Situated along the Mekong River and covering morethan 700 km2, the study area comprised of Nong Khaiand Bueng Kan provinces, where the largest tract ofrubber plantation can be found in the northeastThailand (Figure 1). Average annual temperatures inthe area range from 11.07 to 40.93°C and an annualprecipitation is 1569 mm. Paddy, as the staple food, isthe major crop in the area. The agriculture is

Figure 1. Location map of study area showing major land uses.

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subsistence and farmers depend on small-scale farm-ing as a primary source of livelihood (Ekasingh et al.2007).

3. Method

This section presents data collection procedure, dataanalysis, and preliminary findings of spatial data ana-lysis on land-use change and land suitability.

3.1. Land cover data

Land-use data of 2002, 2006, 2009, 2012, and rubbersuitability zoning maps were obtained from the LandDevelopment Department (LDD). GIS-based land-usechange study for three periods (2002–2006, 2006–2009, and 2009–2012) was carried out to locate theareas where the land conversion to rubber hasoccurred. Paddy fields were the largest area to beconverted to the rubber plantation. The total area ofrubber in the study area was around 79,850 ha in2002. By the end of 2012, rubber area was157,164 ha which is 20% of the study area (Table 1).

3.2. Socioeconomic data

Socioeconomic data was collected through the house-hold surveys by interviewing the household heads inMarch–April of 2013. A household head makes all theland-use management decisions. A two-stage sam-pling procedure was used to select sample house-holds. Out of total 17 districts in the study area, 10were selected purposively. These 10 districts arelocated in and around the area where major rubberplantation is found. In the second stage, 211 respon-dents were interviewed randomly from these districtsbased on land allocation for rubber cultivation athousehold level of each district. Data were collectedby administering structured and unstructured ques-tions. The survey included specific questions onhousehold characteristics, farming practices, incomeand expenditure, and government support.

3.3. Data analysis

In this study, both descriptive statistics and econo-metric analysis were used to assess the relationship

between explanatory and dependent variables.Descriptive statistics involving mean, percentage,and standard deviations were analyzed to assess thesocioeconomic characteristics of the sample house-holds of rubber farmers in the study area. t-Test wasalso employed to assess the difference between thedifferent farming households. For the econometricanalysis, the tobit model was used to analyze factorsaffecting the farmers’ decision to allocate their landfor rubber plantations, whereas logistic regressionmethod was used to analyze factor affecting the farm-er’s decision to convert paddy field to rubber planta-tion (Iqbal SMM, Ireland CR, Rodrigo VHL 2006). Theeffect of the socioeconomic and institutional factorswere analyzed using the tobit regression method todetermine the extent of land conversion to rubberplantation. The censored tobit regression was usedto determine the effects of the independent variableson the adoption of rubber among the smallholderfarmers. The tobit model to estimate the factor affect-ing the land allocation was defined as

yi ¼ Xiβþ εi (1)

yi ¼ y�i if y�i <yu εi � n yu; σ2ð Þyu if y�i � yu yu ¼ 100ð Þ

�

where yi is the land size allocated for rubber cultiva-tion at a given level of Xi; n is the number of observa-tions; Xi is the vector of explanatory variables; β is thevector of unknown coefficients; and ɛi is the vector ofthe error terms that are distributed normally with amean of zero and constant variance σ2; yu is the 100%of total land holding. If yi is assumed to normally bedistributed, then consistent estimates are obtained byperforming a tobit estimation using and iterative max-imum likelihood algorithm (Chiputwa et al. 2011).

The binary logistic model was used to predict theprobability of adoption of rubber in paddy field. Inthis study, the independent variable was assessedwithin two populations with distinct and definedcharacteristics: (a) ‘Conversion’ mean householdshave full or partial conversion of paddy field to rubbercultivation, which included 100 households; (b) ‘non-conversion’ mean households who have not con-verted the paddy field to rubber cultivations, whilstthey change the other land-use types to rubber,which included 111 households. ‘Conversion’ as a

Table 1. Land-use change and land conversion to rubber in 2002–2012.

Land-use type

Area (ha) Converted to rubber (ha)

2002 2006 2009 2012 2002–2006 2006–2009 2009–2012

Paddy 399,828 316,935 291,141 281,431 51,229 23,114 9927Other field crops 53,185 50,504 43,620 31,592 8623 13,405 855Forest to rubber 71,155 78,401 66,372 66,952 5433 2246 652Rubber 79,850 115,282 136,223 157,164 37,679 86,589 138,846Other land use 120,572 163,468 187,234 187,451 12,318 10,869 6884

Total study area = 724,590 ha.Source: Estimated from land-use map in 2002–2012, LDD.

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dependent variable was defined taking binary values,namely, ‘conversion’ = one and ‘non-conver-sion’ = zero. The evaluation of the relative contribu-tion of significant variables in a logistic analysis waspresented by developing a predictive model withsimple indicators as suggested by (Iqbal SMM,Ireland CR, Rodrigo VHL 2006). The probability, Pi, ofa smallholder adopting a rubber replacing paddy fieldis given by

Pi ¼ expzi

1þ expzi; (2)

where zi is the random variable that predicts theprobability of the ith farmer adopting to changefrom paddy field to rubber. Therefore, for an indivi-dual farmer:

lnPi

1� Pið Þ� �

¼ β0 þ β1X1i þ β2X2i þ � � � þ βkiXki (3)

where i is the ith observation in the sample;P = probability of the outcome; β0 = intercept; β1,β2,. . ., βk is the coefficients associated with each expla-natory variable X1, X2,. . ., Xk.

The socioeconomic variables, such as age ofhousehold head, farming experience, householdlabor, and off-farm income, etc., were consideredto estimate the tobit and logistic regression mod-els. The independent variables that were expectedto affect the dependent variable with their unit ofmeasurement and expected sign are present inTable 2. STATA 11.2 software (STATA Corp.,College Station, Texas, USA) was used for statisticalanalysis.

3.4. Comparing land suitability for rubber andexisting rubber cultivation

As the Ministry of Agriculture and Cooperatives ofThailand is promoting extension of rubber cultivation

in the dry zone, particularly in the Northeast region ofthe country, which is relatively poor in agriculturalproductivity compared to other parts of Thailand.The expansion of rubber cultivation has occurredwithout considering the suitability of area of rubber.It is important to discuss the subject of land evalua-tion and selection for rubber. Land evaluation is anassessment of land for specified use, which identifiesland area of suitable and not suitable category forthat use. FAO framework of land evaluation (FAO1983) describes this procedure in detail. In thisstudy, land suitability for rubber was conducted byderiving land qualities for rubber (water availability,oxygen availability, nutrient availability index, waterretention, rooting condition, erosion hazard, andtopography), each of which was classified andassigned factor ratings.

The ‘Rubber suitability classes’ map included fourclasses of suitability: highly suitable (S1), moderatelysuitable (S2), marginally suitable (S3), and unsuitable(N) areas. For rubber in case of Thailand has beenadjusted by LDD (1996). Class S1 refers to land hav-ing no significant limitations to sustain application ofa given use for rubber, or only minor limitations thatwill not significantly reduce productivity or benefits.Class S2, less suitable than S1, is defined in terms ofland having limitations, which in aggregate are mod-erately severe limitations for sustained application ofthe given land utilization type; the limitations willreduce productivity or benefits and increase requiredinputs to the extent that the overall advantage to begained from the use, although still attractive. ClassS3, less suitable than S2, refers to land having limita-tions, which in aggregate are severe for sustainedapplication of a given use and will so reduce pro-ductivity or benefits of rubber. Land suitability mapfor rubber was overlaid with existing land use toidentify the areas which are not suitable for rubbercultivation but are under rubber currently.

Table 2. Socioeconomic characteristics of farm households.Householdcharacteristics Unit of measurement Mean Min Max

Age of householdhead

Year 48.46 25 77

Farmingexperience

Year of experience working with farm family 26.32 7 48

Farm householdlabor

Number of working age member 3 1 5

Off-farm income Baht/year 3.02E4 0.36E4 18.43E4Land-holding size Hectare 3.65 0.48 6.72Land security Household land ownership (ha) 3.49 0.48 6.56Paddy area owned Percent of paddy area of total land holding 57.61 8.57 100

Hectare 2.07 0.08 4.8Income sources Number of Income sources: (1) self-employment in agriculture (crop income, livestock income,

fishing), (2) self-employment in non-agriculture (rent, enterprise profits), (3) agricultural wage laborincome, (4) non-agricultural wage labor income)

2 1 4

Institutionalsupport

1. Seedling/financialsupport

Rubber area under government seedling/financial support (ha) 0.97 0 3.84

2. Extensionadvice

1 = accessible, 0 = inaccessible 0.42 0 1

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4. Results

4.1. Household socioeconomic characteristics

Majority of household heads who were also therespondents are of middle age (average of 48 years),and likely to be receptive to new rubber cultivation intheir farmland (Table 2). Majority of the respondentsare literate and have primary education (grade 1–6).This high-literacy level can have a positive effect inrespondents’ ability to cultivate rubber as well asmaking farmers to be more responsive to acceptanceof rubber plantation. The average farming experienceof 26.32 years of the respondents also indicates a vastexperience in traditional cultivation and farm man-agement practices. The study area has small-scalefarms per household with an average farm size of3.65 ha, and hence, there is tendency to increasemaximum return from their land. Rubber had rela-tively better prices and since it was initiated by thegovernment through providing incentives, farmerswere attracted to convert their farmland for rubbercultivation.

Majority of respondents owned the farmland theycultivated. The average number of labor availabilitywas three persons per farm household. The laborrequirement for farming activities is met usually byfamily labor. They are also involved in off-farm activ-ities as the opportunity arises. The mean paddy areaowned by a household was 2.07 ha indicating thatmost of them have paddy field over 57% of total theirfarmlands. Majority of respondents had incomesources from at least two sources indicating that therespondents may have low-risk investments with highexpansion of rubber. The average area under govern-ment support with seedlings and finance was 0.97 ha,which was about one-fourth of farm size. Forty twopercent respondents obtained advices from extensionworkers and thus have contact with extension agentsbefore carrying out any rubber cultivation indicatingthe role of extension agents in adoption of rubbercultivation by the farmers.

4.2. Determinants of land-use allocation forrubber cultivation

For identifying the determinants of land-use alloca-tion for rubber cultivation, the ‘amount of the landconverted (% of total land holding)’ to rubber cultiva-tion after rubber programs were established in thenortheast was considered as dependent variable inwhile employing the tobit model (Table 3). Modelresults showed that among the four variablesincluded in the model, age of household head andinstitutional support, government subsidy for seed-lings, and financial support in particular, had positiveinfluence on land conversion to rubber plantation.

The analysis yielded highly significant coefficientvalues between land conversion and age of house-hold head (0.207) at P < 0.01. The institutional supportvariable (3.997 at P < 0.05) also had a positive influ-ence on the land conversion to rubber plantation(Table 3). The land-holding size (−2.496) and incomediversity (−13.105) have negative effect on the landconversion to rubber plantation at P < 0.01.

4.3. Determinants of land conversion from paddyarea to rubber cultivation

The specific influence of the socioeconomic factors onthe conversion of paddy field to rubber plantationspecifically in non-traditional rubber growing regionwas examined using logit analysis. The descriptivestatistics of 10 selected socioeconomic characteristics,as continuous variables, of sampled farmer house-holds are presented in Table 4. The model resultsshowed seven factors to be significantly related toland-use conversion from paddy filed to rubber culti-vation. Four variables, namely age of household head,off-farm income, land security (size of land holdingwith tenure security), and paddy area owned werepositively and significantly related to the percentageof paddy field conversion to rubber plantation. t-Values computed for all continuous variables forland allocation of rubber cultivation was found thatfour variables, such as age of household head, land-holding size, income sources, and seedling/financialsupport (institutional support) of conversion groupand non-conversion group were statistically signifi-cant (P < 0.05). This also implies that variables weresignificantly different between conversion and non-conversion households of rubber cultivation in paddyfield. It was found that seven variables such as age ofhousehold head, farming experience, farm householdlabor, off-farm income, land security, paddy area

Table 3. Tobit regression model for the conversion to rubbercultivation.

Variables CoefficientMarginaleffect

Averagemarginal effect

Age of householdhead (year)

0.207**(0.08) 0.171 0.165

Land-holding size(ha)

−2.496**(1.16) −2.137 −2.465

Seedling/financialsupport (ha)

3.997*(2.06) 3.438 3.965

Income sources(number)

−13.105**(2.51) −12.282 −13.012

Constant 92.892 (10.25)Left-censored 0Right-censored +InfinityLikelihood ratiostatistic

−381.54

LR test 129.68**

*Significant P < 0.05; **significant at P < 0.01; marginal effect = (βkf(X̅β));average marginal effect = βk 1=kð ÞPk

k¼1 Xi;Kβ� �� �

; figure in parenth-eses are standard errors.

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owned, and income sources of conversion and non-conversion households of rubber cultivation in paddyfield is significantly different at 5% level of significant.However, institutional support (seedling/financial sup-port and extension advice) is not significant differencebetween conversion and non-conversion households.In other words, government support on financialincentives, rubber seedlings, and extension serviceshave not really have differential impact on thosetwo categories of farmers.

It was found that the coefficients were positivebetween land conversion and age of householdhead (0.114), land security (0.039), off-farm income(2.08E − 05), at P < 0.01, and paddy area owned(0.267 at P < 0.05). The potential for increased rubberplantation in paddy field is smaller for younger house-holds and larger for older households. This stands incontrast is between conversion and non-conversiongroup to the farming experience (−0.086 at P < 0.01)of the farmers in the villages, as it shows a negativerelation with amount of paddy area conversion torubber.

Farm household labor (−0.613 at P < 0.05) wasfound negatively related to the conversion of land-use from paddy field to rubber, implying theincreased availability of farm labor leads to havingenough labor to be able to cultivate both paddyand rubber. Farm labors are their main occupationon smallholder farmers where they usually take partin rice production. Labor is allocated to the utility ofland-use activities based on the availability of house-hold and wage labor. Nonetheless, total land holdingof household was not significant between conversionand non-conversion households of rubber in paddyfield but paddy area owned was significant betweenconversion and non-conversion households. Decreasein owned paddy area may be associated with othervariables, especially farm household labor. Householdmembers carry out majority of paddy field activities,for example, field preparation, transplanting, and har-vesting. Hence, larger paddy area of the householdwould require more labor for farm operations and as a

result, households with higher family labor may haveless conversion of paddy area to rubber cultivationthan households with lower family labor.

Land security to the land under household’s dispo-sal with land titles (title deeds) issued by theDepartment of Lands. Other land titles include ‘NorSor 3 Kor’ and ‘Sor Por Kor 4–10’ issued by theAgricultural Land Reform Office. Insecure land tenurerefers to ownership of land without recognized docu-ments or with only a document showing tax pay-ments made to the local authority (‘Por Bor Thor 5’).This variation is titles gives different level of use andsecurity rights to the land holders. The relationbetween land security and paddy area conversion torubber was positive, that is, for each additional per-centage of land security the household possesses, itwas found that the conversion of paddy to rubberareas increased.

Income sources are defined as activities that acti-vate crop cultivations, such as fisheries, poultry opera-tions, and livestock. A negative relationship (−1.706 atP < 0.01) between income sources and land-use sharein terms of rubber areas was observed. Householdswith more income sources showed lower conversionrates than households with less income sources.However, the off-farm income was found to be posi-tively related with land-use change from paddy torubber. The amount of off-farm income was signifi-cant (P < 0.01), thus suggesting that farm investmentcan be supported by off-farm household incomes.

4.4. Land suitability for rubber versus existingrubber cultivation

Land-use change is influenced by not only economicand institutional factors but also many others, such asbiophysical, technological, and social factors. Theexploratory land quality, such as soil quality, moistureavailability, and erosion resistance influenced the suit-ability level of rubber cultivation. In Table 5, expan-sion of rubber cultivation has been in marginallysuitable land for rubber as can be seen that

Table 4. Socioeconomic characteristics and a logit model estimates on decision for rubber plantation in paddy field.

Variable

Conversion (change ofpaddy to rubber)

(n = 100)Non-conversion (nochange) (n = 111)

t-Valuea

Logit model

Coefficient standard error Standard errorMean SD Mean SD

Age of household head (years) 50.04 11.19 47.05 10.80 * 0.114** 0.029Farming experience (years) 25.48 12.63 27.08 12.23 * −0.086** 0.026Farm household labor (number) 3.59 0.91 4.45 1.02 * −0.613* 0.280Off-farm income (baht/year) 4.66E4 3.84E4 4.21E4 3.51E4 * 2.08E − 05** 0.76E − 05Land-holding size (ha) 3.42 1.89 3.88 1.67 – – –Land security (ha) 2.23 1.59 1.49 1.03 ** 0.039** 0.009Paddy area owned (% of total land holding) 45.45 1.72 71.09 2.92 ** 0.267* 0.186Income sources (number) 2.02 0.77 2.34 0.81 ** −1.706** 0.390Seedling/financial support (ha) 1.07 0.79 0.95 0.82Extension advice (0/1) 0.44 0.22 0.41 0.19 – – –Constant −1.227 1.156

at-Test for mean difference between conversion and non-conversion groups. *Significant P < 0.05; **significant at P < 0.01; 1 US$ = approx. 35 Thai baht.

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64,623 ha in 2002 increased to 119,868 ha in 2012.Nearly 10% of rubber is grown even in unsuitableareas, although there is declining trend. This declinewas due to damage by droughts and severe floods. Inaddition, some farmers have destroyed their rubberplots because the rubber planted in unsuitable landdid not give good production. Due to limited avail-ability of land and the huge demand for rubber, farm-ers attempt new marginal land for rubber plantation.However, factors other than economic return of rub-ber and government policy were also involved inland-use decision-making since the government pro-vided all supports from planting to marketing of rub-ber in the study area. Rural communities often rely onexperience and determination of land resource eva-luation in their traditional land management systemsinstead of standard land suitability evaluation thatleads to rubber cultivation in not so suitable areas. Anumber of factors related to land-use decisions inother contexts, such as credit, population, and infra-structure were not included (e.g., credit, population,and infrastructure) in this study which may requirefurther consideration with a more quantitativeapproach.

5. Discussion

With the ready promotion of government project onrubber cultivation in almost every province of theregion, the northeast region is expected to be thelargest natural rubber production base in the country.The area under paddy cultivation significantlydecreased in the study area as they were replacedby the rubber and hence areas under rubber cultiva-tion significantly increased due to both high prices ofrubber in the global market and government supportto rubber growing farmers. The attractive economicreturns and the agricultural extension interventionsare the most important driving forces in land-usechange to rubber plantations. The hope to have agreater and more secure income is the main incentivefor smallholders to plant rubber. The higher profit-ability and government support for rubber plantationexplain why paddy fields and field crops are beingconverted to rubber.

In the past before 2003, farmers did not practicecultivating rubber in the lack of market for rubberlocally where they could sell their products (Evanset al. 2011). Farmers also lacked basic know-how ofrubber cultivation. After government promotion onrubber cultivation, those constraints were eased andthe farming community in the study area preferredrubber cultivation instead of annual crops, such asrice, maize, sugarcane, and cassava, as there was nolucrative price of these commodities despite relativelyhigh investment. Farmers often lose their incomefrom their produces when the prices of the commod-ity go down in the lack of stable or even high-com-modity price unlike for some other commodities, likerubber, which has attractive economic returns sup-ported by government policy.

5.1. Land-use change and driving forces

Institutional factors increased the probability of land-use change to rubber. Since 2003, the Office ofRubber Replanting Aid Fund (ORRAF) has been sup-porting smallholders in various ways, from helping inplot preparation, providing seedlings or other materi-als of production, to providing technical knowledgeand marketing skills. During the earlier period, farmershad to learn from the peers who had already adoptedand had seen the benefits of rubber plantation. As aresult of government-supported funds and extensionservices, farmers were encouraged to increase rubbercultivation in their land. While the net income frompaddy has been steady over the years and low, thenet income from rubber was much higher by some 8–12 times than net income from paddy between 2006and 2009 (Figure 2), which however is due to rapidlyincreasing demand of rubber in global market. Paddy-field area continuously decreased whereas rubberarea gradually increased between 2003 and 2009.The Royal Thai Government through ORRAF endea-vored to achieve a target of new planting of112,000 ha in northeast region of the countrybetween 2003 and 2013. Cloned seedlings havebegun sprouting in almost every province of thenortheast region, replacing short-term cash cropssince the government project announcement.Lucrative prices for rubber products as well as policyinterventions to promote rubber cultivation is themajor driving factor why farmers have started con-verting their paddy and field crop areas into rubberplantation. Policy on commodity price and subsidiza-tion of agricultural inputs are major factors affectingland-use decision-making of smallholder farmers inthe area as small holders’ land use is affected bymarket incentive and policy (Wannasai & Shrestha2008).

It is well accepted that land-use change dependson different socioeconomic, demographic and

Table 5. Rubber cultivation in different land suitability levelfor rubber.

Land suitability forrubber

Area(ha)

Area occupied by rubber (ha)

2002 2006 2009 2012

Highly suitable 31,666 1669 3735 4356 6019Moderately suitable 49,068 6484 14,825 21,456 26,497Marginally suitable 353,072 64,623 87,246 106,691 119,868Unsuitable 290,785 7075 9476 3720 4778Total 724,590 79,850 115,282 136,223 157,164

Source: Analysis from land-use maps and a rubber suitability-zoning mapof LDD.

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institutional factors. As reported in earlier section, ageof household head, land-holding size, income sources,and seedling/financial support were the major signifi-cant factors in this study. Similar result that age ofhousehold head influenced the land-use decision isreported by Bosselmann (2012) in case of coffee plan-tation in Costa Rica. This implies that household witholder household head increases the level of land con-version to rubber cultivation, because older farmerhave more farming experience and influence theland-use decision-making. Many of them were foundto have experience of growing rubber when theyworked as farm labors in the southern region ofThailand, which is the main pocket for rubber growingin Thailand for long. Older household heads also tendto increase rubber areas while younger householdheads had a greater share of land for both rubberand other crops. Paddy fields are more likely to bechanged to rubber plantations by elder farmers asmost of them have high-financial assets and tenuresecurity of the land they own. In addition, some ofthem were pioneers, as early adopters, to converttheir land areas to rubber, who were followed byyounger rubber farmers later.

ORRAF, a rubber promotion scheme, providedfinancial incentives to farmers who have land titledeeds and certificates. They limit to grow rubberonly on the land suitable for rubber so that goodproduction or rubber can be ensured without furtherdegrading land. Such support policy resulted in aspecific pattern of rubber expansion in the studyarea. Farmers with paddy areas may face difficulty inreceiving the support from the government for rubbercultivation as the rice areas are biophysically

unsuitable for rubber. Therefore, institutional supportwas not included in the logit model of adoption ofrubber into paddy field but it affected the land con-version decision for rubber by increasing the prob-ability of land conversion of total land holding of thehousehold.

An increase of land-holding size decreases theprobability of land conversion for rubber.Households with larger land-holding size tend to allo-cate the land to other crops too to reduce risk ofrubber price fluctuations, which has been occurringin recent years. Larger farms still realize better finan-cial returns, and they are able to make more intensiveland use with range of choices for land management.They usually allocated the land under rice and rubberconsidering the available family labor. Smaller landholders mostly dedicated a large proportion of theirholdings for rubber anticipating its higher profit.While some small farm households put all the landthey have for rubber cultivation and rented land fromthe neighbors for rice cultivation, some farmers pre-ferred rubber and kept producing rice or other cropsbecause they had enough land to do both, providinga more diversified option for income generation.

The source of income was a vital variable thatdescribed negative effects on the land conversionfor adopting rubber plantation in paddy fields. Morenumber of income sources can reduce the effects ofsome important key risks, such as inflation, longevity,and market volatility and can further increase foodsecurity (Mutoko et al. 2014). In the study area,farms functioned through their family labor. Suyantoet al. (2001) reported that labor use per cultivatedarea was higher for paddy cultivation than for rubber

Figure 2. Net income and cultivated area of rubber and paddy in the study area (2002–2012) 1 US$ = approx. 35 Thai baht\r\nSource: Office of Agricultural Economics and Land Development Department, Thailand.\r\n.

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plantations on account of the long fallow period ofpaddy field. Further, households with high-farmlabors were found to prefer to keep their paddy fieldsfor household consumption. Similarly, tenure securityplays a critical role in the land-use change, whichinfluenced land conversion to rubber. The increasedpercentage of plots with an ownership certificate hasa positive relation with land conversion to rubberplantation. A higher land-tenure security leads togreater incentives for long-term investment on per-ennial crops, encouraging farmers to continue to usethe land (Wannasai & Shrestha 2008). The large por-tion of paddy areas under tenure security would havea high rate of conversion of paddy to rubber planta-tion. It was also observed that the households withhigher off-farm income have higher paddy to rubberconversion than households with lower off-farmincome. This probably is due to the capacity of thehouseholds to invest in long-term commodity, such asrubber, as they have relatively more income than thefellow farmers who have relatively less off-farmincome and thus cannot afford investing in rubber.

As expected the farming experience negativelyaffected cultivation of rubber in the paddy fields.The farming experience in the villages was relevantto the support of local land-use plans as farmers haveto pay attention to the knowledge and information onhow to cultivate rubber appropriately in their com-munities. The farmers with less experience in thecommunities tend to grow rubber on the basis ofmarket prices rather than considering the land char-acteristics and quality suitable to specific crop typeresulting into paddy areas being converted to rubbercultivation.

5.2. Socioeconomic impact of rubber cultivationunder the new planting scheme

Nearly 25% of the original paddy areas have beenconverted to rubber land use, with a considerableloss of food-production area. There were significantdifferences in rice supply between conversion andnon-conversion household. One can notice thatbetween 2002 and 2012, the paddy area was higherthan at present (Table 6). Paddy areas in 2012 ofconversion households were lower than non-conver-sion households. Rice purchase was found signifi-cantly higher in conversion households (1.02 t/household/year) than in non-conversion households(0.015 t/household/year) due to the fact that riceproduction was significantly lower in conversionhouseholds compared to non-conversion households.However, net income did not show any significantdifferences between two groups of households.Therefore, replacing paddy fields with rubber canbring about negative impacts on smallholders’

livelihood (Salisbury & Schmink 2007) and futurefood production at the national and household level.

In the past, most smallholder farmers in the studyarea depended on rice production for household con-sumption, and food was almost sufficient in amountfor the whole the year. Now that the farmers havechanged paddy fields to rubber, if their holdings weretoo small to produce sufficient rice for home con-sumption, the resources are being diverted fromfood consumption to market crop production result-ing in lower food availability from farm productionand a greater dependence on local markets in suchinstances of land-use change (Isvilanonda & Bunyasiri2009). Hence, the reduction of paddy fields may beassociated with an increased risk of food insecuritythat can increase marginal supply costs within thefood sector to raise long-run price of the land andfood, although rubber increases income (Kroeksakulet al. 2011) as long as the price is stable which is notso in recent years in the study area and many otherplaces. This is however difficult to collect data on theprecise effects of food prices on household foodsecurity as they are more delicate.

The cultivation of rubber trees led people to relyon the economic system, market mechanism in parti-cular (Joseph & George 2010). Rural households in thestudy area could not survive by relying on any oneparticular activity. This may be considered as part ofthe economic diversification of the smallholderhouseholds. In the long run, policy initiatives enablediversification of the sources of income and ensuresustainability of rubber cultivation. Economic diversi-fication has thus become one of the most importantlivelihood strategies because smallholder farmers donot have control over the market price of their pro-duces, and then they usually grow a few cash crops toreduce the risks. They are also involved in many non-agricultural activities, as work migrants in urban areas.Some have also started their own business in thevillage, such as running grocery shops, food shops,

Table 6. Area, production and purchase of rice by householdcategory.

Variable

Conversion(change of paddy

to rubber)(n = 100)

Non-conversion(no change)(n = 111)

Paddy area in 2002 (% oftotal farm size)

72.80** (3.14) 46.58 (2.32)

Paddy area in 2012 (% oftotal farm size)

21.03** (2.47) 45.16 (1.67)

Rice production (t/household/year)

1.83** (0.27) 4.54 (0.37)

Rice purchase for householdconsumption (t/household/year)

1.02** (0.79) 0.015 (0.013)

Net income (Baht/year) 3.11E5 (1.63E5) 3.12E5 (1.71E5)

*Significant at P < 0.05; **significant at P < 0.01. Figure in parenthesesare standard deviation; 1 US$ = approx. 35 Thai baht at the time ofsurvey.

Source: Field survey (2013).

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and fertilizer and agro-chemicals shops to diversityrisk and income sources in addition to keep growingpaddy as main staple food.

5.3. Environmental effects in new rubberplantation area

The price of natural rubber escalated continuously,which prompted smallholder rubber farmers to growrubber even on unsuitable lands. The unrestrictedexpansion of rubber plantations in the marginallysuitable land and non-suitable land of the study areacould have devastating environmental effects.According to Ahrends et al. (2015), the area of landdedicated to such rubber farming could increasemore than double or triple – vastly reducing biodiver-sity and potentially having severe consequences onwater resources in the new rubber areas of the main-land Southeast Asia.

In the study area, a large amount of paddy areashas been cultivated in flood plains and poorly drainedlands that are unsuitable for rubber plantation. Somefarmers, especially in Rattanawapi district of NongKhai province, have dug large drainage in lowlandareas, rice fields in particular, for draining excesswater, and constructing ridges to plant rubber on it.The major problem is the risk of plantation failure inmarginal environments. The remaining rubber areasare distributed on high slopes or low land where soilerosion or waterlogging problems may be encoun-tered. These areas also pose high risk of long-termdegradation due to top-soil erosion, disruption ofnatural stream flows, and greater risk of landslides.

Additionally, rubber farming is mostly monocultureas it creates shades and not suitable to grow othercrops in rubber fields and also mixed cropping mayaffect yield of both rubber and other crops. ORRAFemphasizes only monoculture and has pushed small-holders to use more chemical fertilizers and herbicidefor better production. The production of concentratedlatex, the usual method applied in the study area toprevent premature coagulation, contributes to severalenvironmental problems such as malodorous pro-blems from odor of chemicals, and rubber, waterpollution from acidic wastewater, and toxicity fromthe use of chemicals (such as ammonia, sodium sul-phite, and formalin). Moreover, the potential for nega-tive environmental impacts from monoculture rubbermay cause loss of biodiversity, reduce watershed func-tion, and environmental pollution (Li et al. 2007). Therequirement of information on sustainable productionhas been becoming inevitable for exporting to theinternational market (Jawjit et al. 2013). It has beenchallenging for Thai policy maker and rubber entre-preneurs to seek for appropriate measures to produceenvironment-friendly rubber products. Therefore,there is a necessity for more research on sustainable

production or a life cycle assessment in the nearfuture.

Although the Ministry of Agriculture andCooperatives of Thailand has identified and declaredthe land zoning for rubber plantation in 2013, the aimof this plan was only to improve the productivity andincome of farmers. There was no clear policy or man-agement system for handling the amount producedin the zoning areas, or even the lower priced output.Integrated land management policies and conserva-tion of paddy fields to restrict the conversion need tobe promoted as an important strategy in the contextof the growing food security concerns. The policychallenge should be to find a balance between envir-onmental conservation and economic opportunitiesof developing areas.

6. Conclusion

The government’s deliberate attempt to grow morerubber in the northeast region of Thailand has attractedsmallholder farmers to make investments, which other-wise were previously the exclusive domain for the capi-talists. The objective of this study is to analyzehousehold characteristics that may influence the deci-sion for rice conversion to rubber cultivation and itsimpacts on sustainability. The results indicate that thelarge number of smallholder farmers in the study areahave fully accepted rubber plantations into their farm-ing systems. Paddy fields were the largest areas con-verted to rubber cultivation, although the areascurrently under rubber cultivation are not necessarilysuitable for rubber growing. The major factors, likeeconomic returns and institutional support from thegovernment influenced land-use changes in the studyarea, resulting in an increase of rubber cultivation. Thefact that institutional supports affect the land allocationfor rubber positively and significantly implies theimportant role of the extension service in order topersuade farmers’ incentives for the benefit and credit.Some socioeconomic factors, such as the age of house-hold head, land-holding size, institutional supports andincome sources have a significant effect on the landconversion to rubber plantation. Evidently, the socio-economic factors, such as declining land-holding size,non-availability of farm labor, increasing age of farmers,and land-tenure security improvement had acted asimportant constraints in land conversion from paddyfields to rubber plantations. The uncontrolled expan-sion of rubber cultivation has potentially a number ofunexpected consequences including risk of food inse-curity and environmental pollution. The householdincome of rubber growers is entirely dependent onthe rubber price determined by the external factorsand given that there is strikingly low rubber price forconsecutive years in the recent past. The governmentpolicy should be revisited and emphasis should be to

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encourage a sustainable land management options formaintaining land quality and ecological integrity whileproviding adequate livelihood opportunities to thesmall holders of the fragile landscape like northeast ofThailand.

Acknowledgments

The Land Development Department (LDD), Office ofAgricultural Economics (OAE), Office of the RubberReplanting Aid Fund (ORRAF), and Nong Khai RubberResearch Center (NRRC) of Thailand who helped in facilita-tion during data collection are also acknowledged. Sincereappreciation is extended to smallholder farmers for theirunreserved support. Constructive comments and sugges-tions of anonymous referees are also highly acknowledged.

Disclosure statement

No potential conflict of interest was reported by theauthors.

Funding

The authors greatly acknowledge the financial support andassistance provided by the Asian Institute of Technology(AIT) and Agricultural Land Reform Office of Ministry ofAgriculture and Cooperatives, Thailand.

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