IJERD – International Journal of Environmental and Rural Development (2011) 2–1

Research article
erd

Effect of Land Use Change and Food Availability in
Phatthalung Watershed, Southern Thailand
ANISARA PENSUK
Thaksin University, Phatthalung, Thailand
Email: anisara.pensuk@gmail.com

RAJENDRA SHRESTHA
Asian Institute of Technology, Pathumthani, Thailand
Received 30 November 2010

Accepted 21 February 2011

Abstract During the past few decades, land use change has been taking place over the
Phatthalung watershed and the major change has been the replacement of paddy fields
with rubber plantations. Those changes cause the reduction of paddy field and crop landarea. Together with the population growth, urbanization and soil degradation, the foodavailability becomes a concerned issue. The food availability situation of Phatthalungwatershed under different possible scenarios has been investigated as the major objectiveof this study. The scenarios developed in this study included the biophysical factors, socioeconomic factors and policy factors. The projected food production of four scenarios
except the worst case exceeded the local consumption rate and the high surplus of rice wasfound in the best case scenario. The projected food production from the baseline and themoderate case scenarios was medium, whereas the projected food production from theworst case scenario was lower than the household requirement, which can be interpreted as
insufficient. These results from the four scenarios should be recognized in order to prevent
and avoid the local and national food, especially rice, insecurity in the future.
Keywords biophysical factor, food availability, land use change, Phatthalung watershed,socio-economic factor, policy factor

INTRODUCTION
Food security is currently becoming a global concern due to the rapidly increasing population, thedegradation of arable land and the conversion of food crop land into biofuel crop production whichis resulting in the depletion of the fertile land for food production. The recent agricultural
production data shows that the global cereal production is in decline (FAO, 2004). The assessmentof the availability of food helps understanding the situation of food supply and food security.
However, there are concerns that there are various factors besides land use which influences foodproduction, e.g. water availability, land quality, the adoption of technology, commodity prices,
population  and  its  growth  rate  as  well  as  the  country’s  policy  on  promoting  rubber  plantation  and  the biofuel crops.
In Phatthalung watershed, the conversion of food production areas (e.g. paddy fields) to rubber
plantation is the major land use change (Anisara and Shrestha, 2008). The increasing trend of
paddy area conversion to rubber plantation has resulted in the decline of rice growing area andproduction in the watershed. Among several types of food items consumed by the population of
Phatthalung watershed, rice is the major source of staple food. Thus, the decreasing rice production
area is a serious concern in terms of food availability.
It is useful to realize the future food availability condition as we are able to prepare for
uncertainty and ensure that local food production is sufficient for local people. Scenarios analysis,an environmental assessment tool, is useful to examine the future food availability. There areseveral scenarios related to food system including IPCC-SRES, GEO-3, Millennium Ecosystem
Assessment, Global Scenarios Group, IFPRI 2020 and FAO (Monika, 2006). In this study, the© ISERD

1

IJERD – International Journal of Environmental and Rural Development (2011) 2–1

likely change in future food availability was assessed under four different scenarios involving
variation in land uses, the quality of land and water, the commodity prices and the local andnational land policy.
MATERIALS AND METHODS
Factors influencing food availability
The availability of food can be influenced by various biophysical, economic, social or policy
factors. Fig. 1 presents various factors used in the study to simulate future food availability under
different scenarios.
The biophysical factors were the factors which have influences on the rice production systeme.g. land area, production rate, the technology input etc. The change in those factors can havepositive or negative effect on the food availability. Among various factors, the factors considered inthis study included rice production area, land quality and the availability of water. Major economic
factors included the import and export of rice and those factors can have effects on the quantity ofrice within the watershed, whereas commodity price of agricultural productions was anotherimportant economic   factor   which   can   have   influences   on   farmers’   land   use   decisions   on   crop  selection to grow in their land. For example, the price of rubber was much higher than that of rice
during the study period, hence farmers tended to convert their land to rubber plantation. Even
though, the commodity prices did not have a direct effect on the availability of food, it can affectthe production area. Population and population growth were the social factors considered in thisstudy, higher population growth can reduce the food availability and hence, consequence to foodinsecurity as insufficient food supply. Furthermore, the increasing population can also reduce theproduction area due to agricultural land conversion to urbanization. Policy factors can play
important roles indirectly via other factors which can have positive or negative effects on foodavailability. For example, policy can affect food availability via social factors by establishing the
population control policy thus reducing the food demand. Similarly, land use policy can influence
area dedicated for rice cultivation through commodity prices.

Fig. 1 Factors influencing food availability
Scenarios development
Scenarios are alternative possible outcomes in future, affected by different factors at different
levels. Scenario analysis helps make better decisions in the context of uncertainty, particularly
associated with future events. In this study, four potential scenarios were developed in order to© ISERD

2

IJERD – International Journal of Environmental and Rural Development (2011) 2–1

predict the availability of food in different situations. The influencing factors considered fordeveloping the scenarios included population and its growth rate, the agricultural commodity prices
and rice yield. The rice production area is influenced by agricultural commodity prices and thepolicy whereas the rice yield is influenced by land quality and water availability.
The availability of food assessed in this study was presented as quantity of rice per capita(kg/capita). There are four scenarios developed in this study, the criteria and assumptions for four
scenarios are given in Table 1.
1) Baseline scenario (BL): It assumes a business-as-usual scenario. It is assumed that thecurrent trend will continue in the future too. Hence, the assumptions are simply the extension of thepast trend of different factors to continue in the future in the study area.
2) Best case scenario (BC): It assumes the synergy of the factors for the highest level of foodavailability in the area. The population of this scenario is assumed unchanged and it is under theassumption that the birth rate and the immigration are assumed equal as the death rate and theoutmigration.
3) Moderate case scenario (MC): This scenario is less optimistic than best case scenario andassumes that policy intervention and technological development will be at the moderate level.
4) Worst case scenario (WC): This scenario assumes the worst possible condition with highrate of population growth and high decreasing rice production rate.
Table 1 Criteria and thresholds for assessing food availability under four scenarios
Scenario
Social factor
Population

Baseline(BL)

Best case(BC)

Moderate case(MC)

Worst case(WC)505,129505,129505,129505,129

0

+0.60

+1.09

+4.76

+2.10

-16.80+0.30+15.00

+0.15
+5.00

-0.30
-6.00

+4

+15

+30

+5% of riceproduction area

+3% of riceproduction area

-15% of riceproduction area

Population growth rate
+0.26(%/year)Biophysical factor
Rice production area changing
0
rate (%/year)aLand quality (%/year)-0.16
Water availability (%/year)-5.00
Economic factor
Commodity prices changing
0
rate (%/year)b
Policy factor (National/Provincial Plan)
Land related policy (%/year)
0
Note:

a
b

Present paddy field area = 72,826.4 ha
The average rubber price in 2006 = 61 Baht/kg

Food availability projection
The relationships of the influenced parameters mentioned in Table 1 have been constructed in the
STELLA environmental dynamic model in order to project the food availability in a 30-year timeframe.
RESULTS
Food availability under the baseline scenario
The baseline scenario was projected based on the real situation. The projected population is
showing the increasing trend with the moderate rate (Fig. 2). Even though, the area for riceproduction under this scenario is assumed unchanged (Fig. 3), the projected rice production shows
the declining trend (Fig. 4) resulting in the decline of food availability. The present rice production
is about 163,000 tons and it decreases to 130,000 tons in 2030. The decrease in rice production
under this scenario mainly results from the decreasing of the rice yield; the current rice yield is 2.24
© ISERD

3

IJERD – International Journal of Environmental and Rural Development (2011) 2–1

tons/ha/year and it became lower than 2 tons/ha/year in 2025 because the land and water resource isassumed to be left over without improvements.
The decline of rice production area resulting in the declining rice production and the increasein the population can lead to the declining of food availability (Fig. 5). The range of the projectedfood availability under baseline scenario was between 0.24 and 0.32 tons/capita/year with theaverage decreasing rate of 1% per year. The projected food availability is found slightly lower thanthe local rice consumption rate (336 kg/capita/year). Therefore, the Phatthalung watershed will befacing the problem of rice insufficiency in the near future under the current situation. There is theneed of having appropriate policy and plan, both local and national, to increase the area under riceproduction in order to avoid the food insecurity problem in the study area.
Food availability under the best case scenario
Fully aware of the global food insecurity problem and the fact that Thailand is one of the biggest
food exporters globally, the Thai government is establishing a policy of paddy area preservation inorder to produce more food especially rice for the global market. The growing rice export can also
contribute to the growth of national economy through agricultural development. Phatthalungwatershed is considered as one of the most suitable area for rice production. The rice production
area preservation policy is to turn the area which is suitable for rice but is being used to produce
other types of crops (e.g. rubber plantation, oil palm, shrimp farms etc) to rice production area.
As described earlier, this scenario assumes strong policy intervention on rice area preservation,and improvement in land quality and water availability. The rice production of this scenario isincreasing not only from the assumed enforcement of rice area preservation policy but also fromthe assumed very small rate of increase in the rubber prices, which in turn is expected to result in
low economic incentives to convert rice production areas into rubber plantations. Fig. 3 shows arapid increase of rice production area projected under this scenario; the increasing trend becomesstable in 2030 as it reaches the maximum suitable land area for rice production (at 150,000 ha).
Together with the improvement in land quality, the implementation of irrigation system, theprojected amount of rice production under this scenario was the highest. The maximum and theminimum of the projected food production are over 640,000 and about 167,000 tons respectively(Fig. 4).
The predicted food availability under the best case scenario was substantially higher than theother three scenarios, because of the increased area under rice production and the increase in rice
yield due to land and water improvement accompanied by decreasing of rice consumption due tothe population control policy. The predicted annual food availability per capita of the best casescenario ranged between 0.32-1.21 kg (Fig. 5) and it is about double of the household consumption
obtained from HH survey from the year 2023, implying sufficiency and surplus of food under this
scenario.
Food availability under the moderate case scenario
In this scenario, the population is assumed to increase with moderate rate. Similarly, the riceproduction area and rice yield are assumed to increase at moderate rate due to the area preservation
policy, with the smaller percent compared to the best case scenario, and ongoing land conversion
because of the stable increase of rubber prices. The quality of land and the availability of water
were assumed to slightly improve through fertilizer and irrigation water supply.
Similar to the best case scenario, the area for rice production was assumed to increase due tothe policy even though at lower rate. Also, the economic factor, i.e., rubber prices, has been
assumed to have lower influence in encouraging farmers to change the paddy field to rubber
plantation.
In terms of social factors, population and its growth rate of this scenario are assumed toincrease with the rate of 0.6% per year without population control policy (Fig. 2). The rice

© ISERD

4

IJERD – International Journal of Environmental and Rural Development (2011) 2–1

production area of this scenario is projected to increase with the rate at 2.1% per year, themaximum projection area is nearly 136,000 ha (Fig. 3).
The amount of rice production projected under this scenario is increasing at the rate of about
2.8% per year (Fig. 4). The minimum projected amount of rice production under this scenario is
about 163,000 tons and the maximum is nearly 379,000 tons (Fig. 4) due to the land and water isassumed to be improved under this scenario.
The projected annual food availability of this scenario ranged between 0.32-0.63 tons/capita.
The projected results for first few years (2010-2017) are less than the local consumption rate
obtained from the household survey but it rises afterwards (Fig. 5).
In this scenario, the food availability predicted under this scenario is showing sufficiency for
local consumption for the next 30 years of the projection period (until 2040) but it is under risk if
the population of this scenario keeps increasing without control, resulting in consumption of rice
higher than its production.
Food availability under the worst case scenario
The worst case scenario assumed a greater decrease in rice production area, deteriorating land
quality, water availability as well as the rice yield, along with the increase in the population and its
growth rate. In terms of economic factors, the rubber price was assumed to increase by about 30%
from the present one, which encourages farmers to convert rice paddies into rubber plantations.
The increasing population and the development of economic and industrial sectors are thedominant assumption of this scenario. Policy assumed in this scenario mainly focuses on economic
development and the growing industrial sector together with the increasing population. Therefore,
the paddy areas are encroached and replaced by human habitats and the infrastructures such as
roads, buildings, and factories.
The high population growth rate without control and the high increase in rubber price drive tothe worsening food availability. The projected population of this scenario shows a rapid increase(Fig. 2). On the other hand, the projected rice production and its area of this scenario are the lowest
with the rapidly decreasing rate (Fig. 3-4). The projected area for rice production is found less than
50,000 ha in 2013, the rice production area kept deceasing over the years and it can be completely
replaced by other types of land use within few decades. The area was rapidly decreasing to about
30,000 ha in 2015 (Fig. 3) which was the preserved area for rice production due to land properties
constraints.
The degradation of land quality and the water insufficiency assigned for this scenario causes
negative effects on the rice yield. The projected yield becomes lower with a high rate and it isfound lower than 1 ton/ha/year within a decade. The decrease of rice yield causes the decrease ofrice production amount and it is found nearly three times lower than the baseline scenario, only forthe first decade of the projection.
The results of food availability showed a rapid decline until 2013 with a decreasing rate ofabout nearly 20% annually; the results ranged between 0.08-0.32 tons/year (Fig. 5) and lower thanthe local consumption rate (0.33 tons/capita/year) obtained from household surveys. The minimum
amount of the projected results under this scenario is inadequate for people in terms of energy
requirement from carbohydrate because the general minimum energy requirement fromcarbohydrate or rice is at about 73 kg/year (Anchanee, 2005).
According to the projected results under this scenario, the situation of food availability of
Phatthalung watershed is in crisis as all rice production area can be completely replaced by othertypes of land use within the two decades.
The food availability of Phatthalung watershed will be insufficient and lead to malnutrition
problem if the food production keeps reducing. In this scenario, the declination is resulting fromthe decreasing production area with the increasing demand for food due to the high population.

© ISERD

5

IJERD – International Journal of Environmental and Rural Development (2011) 2–1

1: population BL
1:
2:
3:
4:

2: population BC

3: population MC

4: popuation WC

1: rice production area BL

700000

1:
2:
3:
4:

2: rice production area BC

3: rice production area MC 4: rice production area WC

160000
2

2

2

4

4

3
3

1:
2:
3:
4:

4

600000

2

1:
2:
3:
4:

3

94500

3

4

3
3

1

2

3

1

1

1

1

3
3

4

1:
2:
3:
4:

500000

1

2

3

1

0.00

1

1
2

2

6.00

1

2

12.00

18.00

Page 1

1:
2:
3:
4:

2

4

Y ears

0.00

6.00

12.00

2: rice production BC

4

24.00
30.00
9:50 PM Mon, Jan 11, 2010

Rice production (ha)Fig. 2 Projected population for all scenarios
1: rice production BL

4
18.00

Y earsPopulation

1:
2:
3:
4:

4

4

29000

24.00
30.00
9:50 PM Mon, Jan 11, 2010 Page 1

3: rice production MC

Fig. 3 Projected rice production area for all
scenarios

4: rice production WC

620000

1: rice per capita BL
1:
2:
3:
4:

2

2: rice per capita BC

3: rice per capita MC

4: rice per capita WC

2

2
2
2

2
1:
2:
3:
4:

1:
2:
3:
4:

3

335000
3

2

2
1
2

3
3

1
1:
2:
3:
4:

2

3

1
4

4

50000
0.00

6.00

Page 1

1

1

1
4

12.00

1
4

18.00
Y ears

4

1:
2:
3:
4:

24.00
30.00
9:50 PM Mon, Jan 11, 2010 Page 1

Rice production (tons)

2

3

1
4

1
4

3

3

3

3

1
4

1
4

4

0
0.00

6.00

12.00

18.00
Y ears

24.00
30.00
9:50 PM Mon, Jan 11, 2010

Food av ailability (ton/capita/y ear)Fig. 4 Projected rice production for all scenarios Fig. 5 Projected food availability for all
scenarios
CONCLUSION
There are numerous factors which can have influences on the availability of food. In this study,
population size, the area for rice production, rice yield, the condition of land and water resources,
which are important factors for crop productions, and the policy were considered as the key factors
affecting the food availability.
The 30 years projected food production of the four scenarios, except for the one worst casethat exceeds local consumption and the minimum human energy requirement. The high surplus ofrice was found in the best case scenario, whereas the projected production from the worst casescenario was the lowest and lower than the household requirement.
The promotion of rubber plantation can be good alternative sources of household income,since the economic return from cultivating rubber is higher than producing rice. However, it has to
be ensured that the remaining area is capable to produce sufficient food for the local population.
Otherwise local people have to purchase imported rice from neighboring countries which willaffect the majority of household expenditure in the future.
REFERENCES
Anchanee, U. (2005) Thai food to the world: Weight control Thai food. http://www.thaifoodtoworld.com/
home/recipediet.php?&language=TH&language=TH&language=EN.
Anisara, P. and Shreatha, R. (2008) Linking land use change and rural livelihoods: A study of Phatthalungwatershed in Southern Thailand. APJORD, 18(2), 143-164.
FAO (2004) FAO Global information and early warning system on food and agriculture world foodprogramme, Rome.
Monika, Z. (2006) A short review of global scenarios for food systems analysis. GECAFS, Rome.

© ISERD

6