Survey of
Rice Cropping Systems in Kampong Chhnang Province, Cambodia
Volker Kleinhenz1, Sophon Chea1, Ngin Hun2
(1 Deutsche
Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH, #17, Street 306,
P.O. Box 81, Phnom Penh, Cambodia;
2 Provincial Department of Agriculture (PDA) Kampong Chhnang, Sangkat
Ksam, Kampong Chhnang City, Kampong Chhnang Province, Cambodia; *
Present address: TH Herbals Joint Stock Company, 8th Floor, BAC A
Building, No. 9, Dao Duy Anh Street, Dong Da District, Hanoi, Vietnam)
ABSTRACT: Although Cambodia might have achieved self-sufficiency and
an exported surplus in rice production, its rice-based farming systems are
widely associated with low productivity, low farmer income and rural poverty. The study is based on
a questionnaire village survey in 14 communes containing 97 villages of Kampong
Chhnang Province from March to June, 2011. It analyzes the prevailing rice-based cropping
systems and evaluates options for their improvement. Differences in cropping
systems depend on the distance from the Tonle Sap water bodies. At distances
greater than 10
km, transplanted wet-season rice cropping system with low productivity of
about 1.6 t/hm2 prevails. This deficiency can be primarily attributed to soils
with high coarse sand fractions and low pH (< 4.0), use of ‘late’ cultivars, and
exclusive use of self-propagated seeds. To improve this cropping system, commercial ‘medium’ cultivars help
prevent crop failure by shortening the cultivation period by one month and complementation of wet-season rice with
non-rice crops should be expanded. Areas adjacent (≤ 1
km) to the water bodies become inundated for up to seven months between July
until January of each year. In this area,
soils contain more fine sand, silt and clay, and their pH is higher (> 4.0).
Farmers predominantly cultivate dry-season recession rice between
January and April. Seventy-nine percent of the area is sown directly and harvested by combines. Adoption ratio of
commercial rice seeds is 59% and yields average 3.2 t/hm2.
Introduction of the second dry-season rice between April and July may
double annual yields in this rice cropping system. Besides upgrading other
cultivation technologies, using seeds from commercial sources will improve
yield and rice quality. Along with rice, farmers grow non-rice crops at different intensities ranging from single annual crops to intensive
sequences at low yields.
Keywords: rice cropping system; wet-season rice; dry-season rice; rice-based
cropping system; Cambodia; Kampong Chhnang
While
annual growth of the world’s population between 2009 and 2015 is estimated 1.1%
(World Bank, 2011), annual growth of the world’s rice production is about 4.5%
(FAO, 2011). The latter growth is due to the expansion in rice-cultivation area and the increase in productivity.
There are, however, large differences in productivity among rice-growing
nations and particularly in mainland Southeast Asia which is home to Thailand
and Vietnam as the world’s two prominent rice-exporting nations. While the
world’s paddy rice yield in 2009 averaged 4.3 t/hm2 and that of
Vietnam 5.2 t/hm2, average yield in Cambodia reached only 2.8 t/hm2
(FAO, 2011),
which
is one of
the reason
why
export
of milled rice (4
299
t in 2008) in
Cambodia
is only a fraction (0.05% and 0.09%) of that in Thailand and Vietnam.
Although the land endowment predestines Cambodia to exporting
rice (Dawe, 2004),
the predominant
rice cropping system
in Cambodia
is the wet-season crop, which accounts for over 86% of the total rice area, and 90% of this area is
rainfed (USDA, 2010). Some researchers have
highlighted innovations in Cambodia for rainfed rice cultivation (Mak, 2001), however, others have
pointed to the relationship between human poverty and such rainfed cropping
systems (Fujisaka, 1991). In addition to the wet-season crops, Cambodia produces dry-season rice which includes irrigated dry-season rice and ‘recession rice’ (USDA, 2010). Recession rice
is
planted into receding floodwaters from Cambodia’s major water bodies that comprise the Tonle
Sap Lake, the Tonle Sap River and the Mekong River, which merge in Phnom Penh to become the Tonle Bassac River.
Low productivity is symptomatic for Cambodia’s production of non-rice crops as well. For example, the total production
of vegetables in
Cambodia in 2009 was only
21% of that in Thailand
and 11% of that in Vietnam. Yields for these crops averaged 37% below yields in Thailand and 48% below those
in Vietnam (FAO, 2011). The primary objective of the study is to provide an overview of
existing rice cropping systems in selected communes in Kampong Chhnang Province, Cambodia.
The
study also
classifies these cropping systems by identifying the main factors which
determine their prevalence and evaluates solutions for improving these
rice cropping systems within Kampong Chhnang Province, Cambodia.
Materials and Methods
Study area
Cambodia comprises 24
provinces which are divided into 185
districts, 1 621 communes and 14 073 villages
(NIS, 2008). Our study area encompasses 14
communes within three districts of Kampong Chhnang Province (Fig. 1).
Their total population of 87 400 represents 19%
of the province’s and 0.6% of Cambodia’s populace. Communes were
selected on rural-development indicators including population density, poverty
and human-development index (ADB, 2007). In
comparison to Cambodia’s national average, the region is characterized
by high population density and above-average percentage of households living
below the poverty line (NCDD, 2009).
Fig. 1. Survey locations (source:
adapted from MIC, 2010 and NordNordWest, 2009).
Kampong Chhnang Province is
located in the basin of the Tonle Sap Lake and the Tonle Sap River. The Tonle
Sap Lake is the largest freshwater lake in Southeast Asia, covering an area of
about 3
000 km2 in the dry season
(November to April) and about 16 000
km2 in the wet season
(May
to October).
The difference in the
area
between seasons is primarily due to the Tonle Sap River which drains the lake
during the dry season and replenishes it when the waters of the Mekong
River cause the reverse flow
into the lake during the wet season. The seasonally inundated area up to 13 000 km2 is usually
referred to as ‘floodplain’.
Table 1 presents an overview of our
study area and the extent of seasonal flooding within the communes covered in
this study. The average distance of each commune from the Tonle Sap River
or the
Tonle
Sap
Lake
was calculated as the mean of the geographical distance of each commune’s village to the closest water body. For
this, GPS data was recorded using a mobile phone and ‘My BB GPS’ software
version
1.6.0.
|
Table
1.
Selected
characteristics of surveyed communes.
|
|
Commune
|
District
|
Population
|
Area
(hm2)
|
Population
density
(km-2)
|
Ratio of agricutual. area
(%)
|
Farm size
(hm2)
|
Distance from
Tonle Sap
a
(km)
|
Flooding b
(months)
|
Ratio of
flooding area b
(%)
|
|
Anhchanh Rung
|
Baribour
|
5269
|
6954
|
76
|
67
|
4.0
|
11.5
|
0
|
0
|
|
Khon Rang
|
Baribour
|
7288
|
4207
|
173
|
43
|
1.3
|
2.5
|
6
|
24
|
|
Kampong Preah Kokir
|
Baribour
|
1983
|
3000
|
66
|
41
|
2.9
|
0.0
|
5
|
100
|
|
Melum
|
Baribour
|
3916
|
5300
|
74
|
38
|
2.0
|
3.5
|
3
|
2
|
|
Dar
|
Kampong Laeng
|
6759
|
8500
|
80
|
36
|
2.2
|
1.0
|
5
|
13
|
|
Kampong Hau
|
Kampong Laeng
|
8078
|
4803
|
168
|
23
|
0.6
|
0.5
|
6
|
100
|
|
Pou
|
Kampong Laeng
|
5249
|
9350
|
56
|
25
|
1.5
|
2.5
|
0
|
0
|
|
Samraong Saen
|
Kampong Laeng
|
1555
|
4454
|
35
|
7
|
0.8
|
0.0
|
7
|
100
|
|
Trangel
|
Kampong Laeng
|
6226
|
10910
|
57
|
24
|
2.1
|
2.5
|
0
|
0
|
|
Ampil Tuek
|
Kampong Tralach
|
12530
|
4518
|
277
|
68
|
1.3
|
0.0
|
5
|
100
|
|
Chouk Sa
|
Kampong Tralach
|
9083
|
3753
|
242
|
62
|
1.1
|
10.5
|
0
|
0
|
|
Kampong Tralach
|
Kampong Tralach
|
6519
|
1599
|
408
|
63
|
0.8
|
0.0
|
3
|
63
|
|
Peani
|
Kampong Tralach
|
7723
|
1798
|
430
|
39
|
0.4
|
11.5
|
5
|
2
|
|
Thma Edth
|
Kampong Tralach
|
5222
|
3648
|
143
|
34
|
1.1
|
11.5
|
0
|
0
|
|
Mean
|
|
6243
|
5200
|
163
|
41
|
1.6
|
|
|
|
|
Total
|
|
87400
|
72794
|
|
|
|
|
|
|
|
a Average
distance from Tonle Sap River or Tonle Sap Lake; b Period
during the wet season when waters from the Tonle Sap Lake or Tonle Sap River
floods the area between ca. July and December.
|
Fine and coarse sands are the prominent
soil fraction across the study area (data not shown). In communes at distances
greater than 10
km from the Tonle Sap soils with high coarse sand fractions and low pH
(particle size: 1.6% clay, 2.6% silt, 28.7% fine sand, 67.1% coarse sand; EC:
0.01 dS/m; pH 3.8;
exchangeable Al: 0.14 cmol/kg) prevail, whereas soils in areas adjacent (≤ 1
km) to the water bodies are higher in fine sand, silt and clay fractions with
higher pH (2.7% clay, 5.8% silt, 37.1% fine sand, 54.3% coarse sand; EC: 0.02
dS/m; pH 4.3;
exchangeable Al: 0.07 cmol/kg).
Surveys
The
study was designed as a village survey in a total of 97 villages (2–14 villages
per commune, data not shown). It encompassed interviewing key informants such
as the Commune Councilor, the Commune Council Assistant, other Commune Council
members, and a varying number of Village Chiefs and farmers between March to
June, 2011.
The survey questionnaire contained two sections
focused on rice cropping. Section one covered socio-economic indicators including household size and farm area, and section two
focused on on-farm activities associated with rice production.
The commune-based interviews of key
informants were conducted following the Delphi method (Linstone and Turoff, 1975) and divided into a maximum of three
rounds. During the first round of interviews, the representatives of communes
were asked to answer the questionnaire. These answers were reviewed and
summarized by the interviewers for encouraging the informants to revise their
earlier answers considering the answers of the other commune representatives.
After such discussion, consent was
usually reached in the second round.
Statistical analysis
Basic
statistics including sums, means and standard deviations (SD), and analysis of variance
(ANOVA) and multivariate analysis (cluster analysis) were calculated with SAS software
version 9.2 (SAS Institute Inc., Cary). Differences among districts,
clusters and groups of geographical distance were analyzed with one-factorial
ANOVA and means separated with the Duncan test (α = 0.05).
Results
Basic characteristics of the study area
The
study area covers a total of 72 794 hm2, 41% of which is for
agricultural use on average
(Table 1). While the ratio exceeds 20% in 13 communes, only 7% of the total
area of Samraong Saen commune is used for agricultural purposes. This can be
attributed to a flooding period of approximately seven months (July to January) during
which the area is totally inundated. The total population of this area is 87 400. The population
density ranges between 35 and 430
km-2 and averages 163
km-2. With 18 193 households
in total, the average household size is 4.7. Farm size averages 1.6 hm2, ranging from
0.4 hm2
in densely populated Peani commune to 4.0
in Anhchanh Rung commune.
Flooding by waters from the Tonle Sap
Lake and Tonle Sap River
Fig.
1 and Table 1 illustrate that only four of the 14 communes, i.e., Anhchanh
Rung, Chouk Sa, Peani and Thma Edth, are more than 10
km away from the Tonle Sap Lake and/or the Tonle Sap River, and
almost do not become flooded during the wet season. Other
communes become inundated when the waters of the Mekong River flow into the
Tonle Sap River and Lake during the season,
except Pou and Trangel. Communes in close
proximity to the water bodies including Kampong Preah Kokir, Melum, Kampong Hau, Dar, Samraong Saen,
Ampil Tuek and Kampong Tralach experience 3–7 months of
flooding during the wet-season months mostly from the end of July until the
end of December (Samraong Saen: from the middle of July until the beginning of
February). The wet-season flooding does not only affect these communes for a
longer period of time but also affects a greater percentage of their area
(Table 1).
Rice cropping systems
About
34% of the
total area of the 14 communes is used for rice production, which
corresponds to 83% of the arable land (Tables 1 and 2). Rice cropping systems can be divided into wet-season
(about 69% of the
total
rice cultivation area) and dry-season production (31%). Except Kampong Tralach
and Khon Rang communes where 30 hm2 and 360 hm2 are
double-cropped,
respectively,
all
the
other areas in the study are single-cropped,
i.e. one rice crop per year. Only in Pou and Trangel communes, some areas (13% and 5% of the total arable
area,
respectively)
are currently not
used for rice cultivation. Farmers singled out lack of labor as a primary
reason.
|
Table
2.
Characteristics
of rice cultivation in surveyed communes in Kampong Chhnang Province, Cambodia.
hm2
|
|
Commune
|
Area
|
Wet season
|
|
Dry season
|
Directly sown a
|
Transplanted b
|
|
Medium cultivar
(June–October)
|
Late cultivar
(June–November)
|
First crop
(January–April)
|
Second crop
(May–July)
|
|
Anhchanh Rung
|
4 646
|
2 323
|
2 323
|
0
|
0
|
0
|
4 646
|
|
Khon Rang
|
1 700
|
1 020
|
680
|
360 c
|
0
|
0
|
1 700
|
|
Kampong Preah Kokir
|
700
|
0
|
0
|
700
|
0
|
0
|
700
|
|
Melum
|
2 000
|
540
|
1 260
|
200
|
0
|
1 880
|
120
|
|
Dar
|
2 480
|
1 990
|
0
|
490
|
0
|
240
|
2 240
|
|
Kampong Hau
|
992
|
0
|
0
|
992
|
0
|
592
|
400
|
|
Pou
|
1 690 d
|
860
|
0
|
610
|
0
|
0
|
1 690
|
|
Samraong Saen
|
118
|
0
|
0
|
118
|
0
|
0
|
118
|
|
Trangel
|
2
582 d
|
1 974
|
0
|
480
|
0
|
0
|
2 582
|
|
Ampil Tuek
|
2 937
|
0
|
0
|
2 937
|
0
|
2 937
|
0
|
|
Chouk Sa
|
2 015
|
1 411
|
604
|
0
|
0
|
0
|
2 015
|
|
Kampong Tralach
|
993
|
115
|
115
|
733
|
30
|
993
|
0
|
|
Peani
|
710
|
213
|
497
|
0
|
0
|
0
|
710
|
|
Thma Edth
|
1 225
|
858
|
367
|
0
|
0
|
0
|
1 225
|
|
Total
|
24 788
|
11 304
|
5 846
|
7 620
|
30
|
6 642
|
18 146
|
|
a Sown directly
in the field and harvested with combine harvesters; b Transplanted:
seedlings raised in a nursery, transplanted into the field and harvested by
hand;
c
Transplanted
into areas with a subsequent wet season rice crop; d Not all arable
area currently used for cultivation.
|
In areas which are comparably distant
from the Tonle Sap Lake or the Tonle Sap River (Anhchanh Rung, Chouk Sa, Peani
and Thma Edth), farmers
exclusively cultivate wet-season rice. While late cultivars mature within 5-6
months between June and November/December, medium cultivars require only 4-5
months between June and September/October. Farmers plant late rice cultivars for about 34% and medium
cultivars for about 66% of the total
area. This distribution does not only apply to the total area but also to the
area on individual farms, i.e., a majority of farmers
cultivate late and medium cultivars on different fields of their farms.
Although some farmers plant floating
rice (Khon Rang, 380 hm2; Dar, 140 hm2; Pou, 220 hm2; Trangel, 128 hm2), the
predominant cropping system in areas which become flooded between July and December
(Kampong Preah Kokir, Kampong Hau, Samraong Saen and Ampil Tuek) is
a first dry-season rice crop. The seeds of this crop are sown in January immediately after the floodwater from the Tonle
Sap recedes from the fields
(‘recession’ rice) and
harvested during April. This cropping system offers the opportunity of
cultivating another (the
second)
crop from April/May until the onset of flooding in late July. Currently,
however, only about 30 hm2
in Kampong Tralach commune have been planted this crop and only since 2010.
Although most of the production areas are only meters away from the waters of
the Tonle Sap River/Lake, lack of irrigation equipment was singled out as the
major hindrance to growing the second dry-season crop.
In communes geographically located
between wet-season or dry-season rice areas (Khon Rang, Melum, Dar, Pou,
Trangel and Kampong Tralach), farmers cultivate both crops. Depending on the
natural water supply, these crops are
grown on different fields within individual farms.
The cropping system determines the mode
of cultivation. In contrast to wet-season crops which are traditionally
pre-nursed, transplanted and harvested by hand, dry-season rice is usually directly
sown
and
harvested by combines. While 60% of
the dry-season cultivation area of 992 hm2
in Kampong Hau commune
is directly sown, the total dry-season cultivation area of 2 937 hm2
in Ampil Tuek commune is cultivated using these practices. In Kampong Tralach, farmers have extended
direct-sowing practices beyond the dry-season crop: not only 733 hm2 of dry-season rice but also 115 hm2 of wet-season
rice are seeded directly and harvested by combine harvester (Table 2).
A feature across rice cropping systems
is the use of self-propagated seeds. Exceptions from this practice include
Ampil Tuek (2
937
hm2) and Kampong
Tralach (993 hm2) where seeds
for the dry-season crops are typically acquired from private seed companies.
Seed rates exceed the
recommended
rates (directly sown in the dry season, 60–70
kg/hm2; directly sown
in the wet season, 80–120
kg/hm2; transplanted
in both seasons, 20–30
kg/hm2) up to
five-fold: The overall seed rate in the study area is 115
kg/hm2, for wet-season
transplanted rice 105
kg/hm2 and for
dry-season directly-sown rice 122
kg/hm2. The highest
seeding rates were
recorded for Kampong Hau commune (195
kg/hm2 for the first
directly-sown dry-season rice crop) and Ampil Tuek commune (180
kg/hm2 for the first
and the second directly-sown dry-season crop).
Compared to the world’s average
paddy-rice yield of 4.3 t/hm2
in 2009 (FAO, 2011), the
average
productivity of rice in the surveyed communes is significantly lower (2.5 t/hm2,
Table 3). Only yields in Kampong Tralach (3.5 t/hm2), Ampil Tuek (4.0 t/hm2), Kampong Preah
Kokir (4.5 t/hm2) and Kampong Hau (4.8 t/hm2) approach or
exceed the world’s average. The factors
influencing productivity include geographic
location, season, cultivation mode and source of seeds. All communes with
above-average rice productivity are located in close proximity to the Tonle
Sap River where dry-season rice is the predominant cropping system, crops are
almost exclusively sown directly, and commercial cultivars are cultivated in 59% (Ampil
Tuek and Kampong Tralach) of the total area. On average, dry-season rice yields
(3.2 t/hm2) exceed those of wet-season rice (1.6 t/hm2)
by 100% (Table 3). Low productivity of rice prevails in communes at distances
from the Tonle Sap exceeding 10
km: rice yields in Anhchanh Rung, Thma Edth, Chouk Sa and Peani communes were only 0.9, 1.4, 1.8 and 2.3 t/hm2, respectively. Farmers grow
no dry-season crops in these communes and
crops are exclusively transplanted.
While rice cultivation covers a total
area of 24
788
hm2
in the study area (Table 2), other crops occupy 2 699
hm2 which
corresponds to 11% of the paddy area, 9% of the agricultural area and 4% of the
total area. This non-rice crop production is restricted to areas adjacent to
the Tonle Sap Lake/River.
|
Table
3. Productivity of rice
cultivation in surveyed communes in Kampong Chhnang
Province, Cambodia. t/hm2
|
|
Commune
|
Wet
season
|
|
Dry
season
|
Mean
|
|
Medium
cultivar
(June–October)
|
Late
cultivar
(June–November)
|
Mean
|
First
crop
(January–April)
|
Second
crop
(May–July)
|
Mean
|
|
Anhchanh Rung
|
0.8
|
1.0
|
0.9
|
|
|
|
0.9
|
|
Khon Rang
|
1.3
|
1.3
|
1.3
|
1.3
|
|
1.3
|
1.3
|
|
Kampong Preah Kokir
|
|
|
|
4.5
|
|
4.5
|
4.5
|
|
Melum
|
1.5
|
1.8
|
1.6
|
2.0
|
|
2.0
|
1.8
|
|
Dar
|
1.6
|
|
1.6
|
1.2
|
|
1.2
|
1.4
|
|
Kampong Hau
|
|
|
|
4.8
|
|
4.8
|
4.8
|
|
Pou
|
1.2
|
|
1.2
|
3.2
|
|
3.2
|
2.2
|
|
Samraong Saen
|
|
|
|
2.5
|
|
2.5
|
2.5
|
|
Trangel
|
2.0
|
|
2.0
|
3.5
|
|
3.5
|
2.8
|
|
Ampil Tuek
|
|
|
|
4.0
|
|
4.0
|
4.0
|
|
Chouk Sa
|
1.5
|
2.0
|
1.8
|
|
|
|
1.8
|
|
Kampong Tralach
|
2.5
|
2.5
|
2.5
|
4.5
|
4.5
|
4.5
|
3.5
|
|
Peani
|
1.8
|
2.5
|
2.2
|
|
|
|
2.2
|
|
Thma Edth
|
1.3
|
1.5
|
1.4
|
|
|
|
1.4
|
|
Mean
|
1.6
|
1.8
|
1.6
|
3.2
|
4.5
|
3.2
|
2.5
|
While rice cultivation covers a total
area of 24
788
hm2
in the study area (Table 2), other crops occupy 2 699
hm2 which
corresponds to 11% of the paddy area, 9% of the agricultural area and 4% of the
total area. This non-rice crop production is restricted to areas adjacent to
the Tonle Sap Lake/River.
Categorization of cropping systems
The first approach of explaining differences in cropping systems between
surveyed communes is categorizing
communes into districts (data not shown). This clustering explains only that
the average geographical area of communes between districts is statistically
significantly different, i.e., communes in Kampong Laeng district are larger
than those in Kampong Tralach district and that the reverse is true for
population density and the ratio of agricultural area to the total area.
The second approach is a multivariate analysis based on the
parameters distance to Tonle Sap Lake/River, the total area,
total agricultural area, rice agricultural area, non-rice agricultural area,
flooding period, flooding area, wet-season rice area, dry-season rice area,
transplanted rice area, directly-sown rice area, rice yield and rice seed rate.
This analysis results in three clusters (data not shown). Cluster 1 contains
only Anhchanh Rung commune in Baribour district, cluster 2 comprises Dar, Pou
and Trangel communes which all belong to Kampong Leaeng district, and cluster 3
is composed of the ten remaining communes across the districts. The
results of this analysis are primarily based on highly significant (P < 0.001)
differences in total area, agricultural
area, wet-season rice area and transplanted rice area between clusters.
Anhchanh Rung commune with a total area of 6 954 hm2 (Table 1), of which 4 646 hm2 (Table 2) are exclusively used for transplanted wet-season rice, is classified in a different cluster from all other communes. Cluster 2 comprises the three
communes with large total area but more diversified rice production (wet-season
and dry-season cultivation) whereas cluster 3 combines the communes of smaller
individual area.
The third approach of differentiating
cropping systems in the study is categorizing communes according to their distance
from the Tonle Sap Lake or Tonle Sap River (Table 1). Among the 27 parameters
subjected to analysis of variance, ten parameters revealed significant
differences among the groups of
communes
based on the distance from the Tonle Sap Lake/River: (1) within 1
km (five communes including Kampong Preah Kokir, Kampong
Hau, Samraong Saen, Ampil Tuek and Kampong
Tralach); (2) between 1 and 10 km (five communes
including Khon Rang, Melum, Dar, Pou and Trangel); and (3) beyond 10
km (four communes
including Anhchanh Rung, Chouk Sa, Peani and Thma Edth) (Tables 1 and 4). While the
average period and area during which waters of the Tonle Sap Lake and Tonle Sap
River inundate parts of the surveyed communes decrease with distance from the
water bodies, the share of dry-season rice area decreases and that of
wet-season rice area increases. Since nearly all of the wet-season rice is transplanted,
the area of transplanted rice increases and that of directly-sown rice
decreases (not
significantly)
with distance from the lake/river. Due to this, there is a highly significant
inverse relationship between the rates of dry-season rice area and wet-season rice
area to total commune
area. Since yields are higher for dry-season
rice and the share of dry-season rice decreases with distance from the Tonle
Sap
Lake/River,
average rice yields are more than double (3.6 t/hm2) in communes close to the Tonle Sap Lake/River compared to communes at distances beyond 10
km from the Tonle Sap
Lake/River
(1.5 t/hm2).
|
Table
4. Selected
agricultural indicators by distance from Tonle Sap
Lake/River.
|
|
Agricultural
indicator
|
0–1
km
|
1–10
km
|
> 10 km
|
Mean
|
P a
|
|
Population
(commune-1)
|
5 647
|
6 253
|
6 824
|
6 243
|
ns
|
|
Population
density (km-2)
|
197
|
101
|
223
|
163
|
ns
|
|
Household size
(household-1)
|
4.9
|
4.8
|
4.5
|
4.7
|
ns
|
|
Total area (hm2/commune)
|
3 393
|
7 178
|
4 038
|
5 200
|
ns
|
|
Agricultural
area (hm2/commune)
|
1 404
|
2 164
|
2 223
|
1 963
|
ns
|
|
Rate of agricultural
area to total area (%)
|
45
|
32
|
50
|
41
|
ns
|
|
Farm size (hm2)
|
1.5
|
1.7
|
1.7
|
1.6
|
ns
|
|
Rice
cultivation area (hm2/commune)
|
1 180
|
1 907
|
2 149
|
1 768
|
ns
|
|
Non-rice
cultivation area (hm2/commune)
|
217
|
256
|
74
|
193
|
ns
|
|
Rate of non-rice area to agricultural
area (%)
|
28
|
11
|
3
|
14
|
ns
|
|
Rate of non-rice area to rice area (%)
|
59 a
|
14
b
|
4
b
|
24
|
0.05
|
|
Flooding period
(month)
|
5 a
|
3 ab
|
1
b
|
3
|
0.05
|
|
Flooding area
(hm2/commune)
|
3 243 a
|
1 162 b
|
8
c
|
1 427
|
0.01
|
|
Rate of flooding area to total area (%)
|
91 a
|
23
ab
|
<1 b
|
36
|
0.01
|
|
Rice area (hm2/commune)
|
1 187
|
1 909
|
2 149
|
1 771
|
ns
|
|
Dry-season rice
area (hm2/commune)
|
1 130 a
|
522
ab
|
0
b
|
546
|
0.04
|
|
Wet-season rice
area (hm2/commune)
|
58 b
|
1
387 ab
|
2
149 a
|
1 225
|
0.02
|
|
Transplanted
rice area (hm2/commune)
|
205 b
|
1
455 ab
|
2
149 a
|
1 296
|
0.04
|
|
Directly-sown
rice area (hm2/commune)
|
983
|
452
|
0
|
474
|
ns
|
|
Rate of dry-season rice
area
to total
area (%)
|
94 a
|
35
b
|
0
c
|
42
|
0.00
|
|
Rate of wet-season rice
area
to
total area (%)
|
6
c
|
65
b
|
100
a
|
58
|
0.00
|
|
Dry-season rice
seed rate (kg/hm2)
|
116
|
127
|
|
122
|
ns
|
|
Wet-season rice
seed rate (kg/hm2)
|
100
|
110
|
101
|
105
|
ns
|
|
Average rice
seed rate (kg/hm2)
|
116
|
123
|
101
|
115
|
ns
|
|
Dry-season rice
yield (t/hm2)
|
3.9
|
2.7
|
|
3.2
|
ns
|
|
Wet-season rice
yield (t/hm2)
|
2.5
|
1.6
|
1.5
|
1.6
|
ns
|
|
Average rice
yield (t/hm2)
|
3.6
a
|
2.4
ab
|
1.5
b
|
2.5
|
0.01
|
|
a
Significance group effect (ANOVA).
Data followed by
different lowercase letters differ
significantly-DUNCAN (0.05), within row comparison.
|
While the average period and area during
which waters of the Tonle Sap Lake and Tonle Sap River inundate parts of the
surveyed communes decreases with distance from the water bodies, the share of
dry-season rice area decreases and that of wet-season rice area increases.
Since nearly all of the wet-season rice crops are transplanted, the area of
transplanted rice increases and that of directly-sown rice decreases (n.s.)
with distance from the lake/river. Due to this, there is a highly significant
inverse relationship between dry-season rice area and wet-season rice area per
total commune area. Since yields are better for dry-season rice crops and the
share of dry-season rice decreases with distance from the Tonle Sap, average
rice yields are more than double (3.6 t/hm2) in communes close to
the Tonle Sap compared to communes at distances beyond 10 km from the Tonle Sap
(1.5 t/hm2).
Table 5 summarizes the typical
cropping systems prevailing in the study area of Kampong Chhnang Province in Cambodia throughout a
year. While intensification of land use is restricted by seasonal flooding in
close proximity (0–1
km) to the Tonle Sap
Lake/River,
cultivation of the second
dry-season rice can be expanded beyond Kampong Tralach commune (System 1). The
least extensive cropping system prevails at greater distance to the water
bodies (>
10 km; System 1) where
farmers typically cultivate only a single wet-season rice crop during a year.
|
Table
5.
Typical
cropping systems (land use) by distance from Tonle Sap.
|
|
|
0–1 km
|
|
1–10 km
|
|
>10 km
|
|
|
|
System 1
|
System 2
|
System 3
|
System 1
|
System 2
|
System 3
|
System 1
|
System 2 a
|
|
|
January
|
DSR1
|
VEG1 c
|
Flooded
|
Flooded
|
DSR1
|
VEG1
|
|
VEG1
|
|
|
February
|
DSR1
|
VEG1
|
VEG1
|
VEG1
|
DSR1
|
VEG1
|
|
VEG1
|
|
|
March
|
DSR1
|
VEG1
|
VEG1
|
VEG1
|
DSR1
|
VEG1
|
|
|
|
|
April
|
DSR1
|
VEG1
|
VEG1
|
VEG1-VEG2
|
DSR1-VEG1
|
VEG1
|
|
VEG2
|
|
|
May
|
DSR2 b
|
VEG1
|
VEG2
|
VEG1-VEG2
|
VEG1-VEG2
|
VEG1
|
|
VEG2
|
|
|
June
|
DSR2
|
VEG1
|
VEG2
|
VEG2
|
VEG2
|
WSR e
|
WSR
|
VEG2
|
|
|
July
|
DSR2
|
VEG1
|
VEG2
|
VEG2
|
VEG2-VEG3
|
WSR
|
WSR
|
VEG2
|
|
|
August
|
Flooded
|
Flooded
|
VEG3
|
WSR
|
WSR
|
|
|
|
September
|
Flooded
|
Flooded
|
VEG3
|
WSR
|
WSR
|
VEG3
|
|
|
October
|
Flooded
|
Flooded
|
Flooded
|
WSR
|
WSR
|
VEG3
|
|
|
November
|
Flooded
|
Flooded
|
Flooded
|
WSR c
|
WSR c
|
VEG3
|
|
|
December
|
Flooded
|
Flooded
|
Flooded
|
|
|
VEG1
|
|
|
a Chouk Sa
commune.
b
Kampong Tralach commune; c Late cultivar.
DSR, Dry season rice crop (directly
sown);
VEG, Vegetable
crop;
WSR, Wet
season rice crop (transplanted)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Discussion
Study area in the context of Cambodian and
Southeast Asian agriculture
Approximately
83% of arable land
in the study
is used for rice cultivation. As such, the study area within Kampong
Chhnang Province represents the structure of rice
production in Cambodia and ‘monsoon’ mainland Southeast Asia
(Masumoto, 2005). While
the household size of 4.7 (Table 4) equals the average of Cambodia (NIS,
2008), farm size (1.6 hm2) is 33% greater
than the national average of 1.2 hm2 per household (USDA,
2010). Mean population density (163 km-2) in the study area is,
however, approximately
double that of Kampong Chhnang Province (85 km-2) and Cambodia
(75 km-2) (NIS, 2008). The
highest population density prevails in Kampong Tralach (408 km-2) and Peani (430
km-2). In comparison,
population density of Southeast Asia is 126 km-2 including the Philippines
(288 km-2), Vietnam
(254 km-2), Thailand
(127 km-2) and Laos
(26 km-2). The study area
can, thus, be characterized as a region with high population density but
relatively low population pressure on farmland (Chhetry, 2001).
Cropping systems in Southeast Asia
are defined by distinct wet and dry seasons (Huke and Huke, 1997; Lau and Yang,
1997). In contrast to Thailand (25%) and particularly Vietnam
(53%), however, only 16% of rice area is irrigated in Cambodia
(Jamora, 2010). Largely because of this, rainfed wet-season rice dominates its
cropping systems, which accounts for over 90% of its total wet-season crop area
(USDA, 2010). Three of the 14 communes included in the study (Anhchanh
Rung, Peani and Thma Edth) represent this traditional cropping system with a
single wet-season rice crop cultivated without supplemental irrigation. While
these communes are at least 10
km away from the waters of the Tonle Sap Lake and Tonle Sap River, the predominant rice cropping system
changes with decreasing distance from the water bodies. In communes located at
1–10
km distance to the Tonle Sap Lake/River (Khon Rang, Melum, Dar, Pou, Trangel
and Kampong Tralach), farmers grow both wet-season and dry-season rice which
makes them less vulnerable to shocks like crop failure in either season.
Communes in direct proximity to the river (0–1
km distance to the Tonle Sap Lake/River) have no option to cultivate a
wet-season crop since they get inundated by the waters of the Tonle Sap during
this season. Farmers in these communes (Kampong Preah Kokir, Kampong Hau,
Samraong Saen and Ampil Tuek), hence, exclusively grow dry-season crops. Since
the natural environments close to the Tonle Sap Lake/River provide a source for irrigation during the dry
season, farmers in these communes compliment rice crops with extensive to very
intensive cultivation of non-rice crops. While 100% of communes at a distance
of up to 1 km from the Tonle
Sap cultivate non-rice crops, this percentage drops to 80% for communes at
distances between 1–10
km and 25% for communes at distances greater than 10
km from the Tonle Sap
Lake/River.
Wet-season rice cropping systems
Although
some farmers plant floating rice in communes close to the Tonle Sap (Khon Rang, 380 hm2; Dar, 140 hm2; Pou, 220 hm2; Trangel, 128 hm2) during the wet
season, the rice planting area is rapidly
declining, e.g., from 900 to 140 hm2
in Dar commune during the past three years. Reasons for this decline include
the long cultivation period (8 months between June and January) and low yield
(about 1.2 t/hm2).
In areas at greater distance to the
Tonle Sap
Lake/River,
particularly in Anhchanh Rung, Chouk Sa, Peani and Thma Edth communes, the
traditional crop is the late wet-season crop with a cultivation period of 5–6
months. This crop is increasingly being replaced by medium crops with a
cultivation period of 4–5 months. Farmers have already cultivated the medium
crops
on 66% of the total wet-season rice production area of 17 150 hm2 and usually
plant both types on different fields of their farms to alleviate the risk of
crop failure. The advantage of medium cultivars is that they are less affected
by drought during grain filling and ripening
(Fukai, 2006). In Anhchanh Rung and Peani communes, farmers
estimate the risk of losing the whole (late) crop due to drought during the end of
the cultivation period at 40%. While this risk is circumvented by medium rice cultivars, the disadvantage of the late cultivars is that their
harvest during the end of the wet season may be hindered by submerged field
conditions and/or localized flash floods during that time. The high rate of
adoption of medium rice
cultivars,
however, illustrates the success of their promotion by the local authorities
including the Provincial Department of Agriculture.
Farmers exclusively propagate seeds for
their wet-season rice by themselves. In Trangel commune, farmers grow a
wet-season cultivar introduced in 1979. During the past 32 years, they consequently
used part (7%) of their annual harvest for sowing the crop in the subsequent
season. It can be presumed that the poor quality of the seeds particularly in
terms of genetic consistency contributes to the low yield of 1.6 t/hm2, which is 63%
below the world’s average paddy rice yield of 4.3 t/hm2 (FAO, 2011).
Poor germination might be one of the reasons for high seed rate of 105
kg/hm2
which highly
exceeds the recommended
rates for transplanted rice (20–30 kg/hm2).
Local authorities have just initiated a program of distributing seeds of
commercial cultivars under the
precondition that farmers do not propagate them for longer than three seasons.
The most significant contributor to low
yields, however, appears to be prevalence of sandy acid soils at the southern
end of the Tonle Sap Lake (Hin, 2010). Low water-holding capacity and low
fertility of these soils are singled out
as the predominant factors negatively affecting yields in this zone. Although
the introduction of improved (medium) rice cultivars has lowered the risk of
crop failure in some locations, they have not significantly improved the yield levels. Experiences with inorganic fertilizers including urea and diammonium phosphate have apparently not
appreciably improved the productivity either. This might presumably be
related to inappropriate scheduling of applications
and/or leaching. Development of permanent irrigation, i.e., switching from
rainfed to irrigated cultivation may have a significant impact on improving
productivity in this area albeit with low water-use efficiency. Another reason
for limited use of inorganic fertilizers is their cost (about 0.60 US$/kg for urea and
0.80 US$/kg for diammonium
phosphate) since they are exclusively
imported (legally or illegally) from Thailand or Vietnam.
It can only be speculated if additions of organic sources of fertilizers
including compost might be able to improve the water-use efficiency and the productivity by
increasing the water-holding capacity of soils (Leu et al, 2010). Such
practices are, however, currently practiced only on a very limited scale.
Wet-season rice is entirely
pre-nursed, transplanted and harvested by hand, with one exception in Kampong
Tralach commune. In line with 763 hm2 of dry-season
area, farmers sow
an area of
230 hm2 directly with wet-season rice
and use combines for their harvest. Although this figure is currently marginal
(1.3%) for the total wet-season rice area of 17 150 hm2
in the study, it may be expected that the share of directly sown rice in the
wet-season cropping systems will increase in the future (De Datta, 1986).
Dry-season rice cropping systems
Due
to seasonal flooding, communes less than 1 km away from the
Tonle Sap Lake/River
(particularly
Kampong Preah Kokir, Kampong Hau, Samraong Saen, Ampil Tuek and Kampong
Tralach) have no agricultural area available to cultivate a rainy-season crop.
The total area affected by seasonal flooding in these communes is 20 039 hm2 (92% of their
total agricultural area) and the number of affected people 36 653. Since this
land becomes completely inundated for 3–7 months of each year (between the
end of July and December), people can farm their land for only 5–9 months of
each year and resort to fishing activities during the flooding period. Despite
this apparent disadvantage, this area is comparably highly populated with up to 408 people/km2. People in the
area have adopted their livelihoods to the prevailing natural conditions by
modifying their cropping systems so that these do not resemble the typical
rice-cultivation system in the greater part of Cambodia.
Dry-season flood-recession rice is the
major land use in the area which Fox and Ledgerwood (1999) called an extremely
productive and sustainable ‘ancient land-use system’. The share of
dry-season rice cropping systems in this area is 95%. The first dry-season rice
is cultivated from the beginning of January when the floodwaters of the Tonle
Sap Lake/River recede from the
fields. During the 3-month cultivation period until April, this crop may be
additionally irrigated. Since natural soil water reserves only lasts for a few
months, farmers in this agro-ecological zone require short-season rice
cultivars. Seeds for dry-season
rice
are not as readily available as for the wet-season rice, consequently, a
greater percentage of those seeds (59%) are acquired from commercial sources.
Rice yields for the first dry-season
average 3.2 t/hm2, which doubles the yield level of the wet-season rice
(1.6 t/hm2). Yields in Kampong Preah Kokir (4.5 t/hm2)
and in Kampong Hau (4.8 t/hm2) even exceed the world’s average paddy rice yield of 4.3 t/hm2 (FAO,
2011). Availability of water and soils with greater water-holding capacity ease
soil water management in this area while fertile silt which deposits during the
annual floods (Fox and Ledgerwood, 1999) contributes to soil fertility. Both
conditions improve the
rice productivity
in this area.
A distinguishing feature of the
dry-season cropping systems compared to the wet-season cropping systems is the
use of direct-sowing and combine-harvesting practices.
Commune members singled out two primary reasons for this very recent
development. The first reason is limited availability of labor for nursing,
transplanting and harvesting rice crops by hand, and the second reason is the
unpredictability of the exact time when the
receding floodwater allow the establish- ment of the crop. The first reason appears questionable since household
size in the communes close to the Tonle Sap Lake/River is not significantly different from that of communes more distant from the
waterway. The second argument may be more significant: if the floodwater
recedes too early,
seedlings are too young to be transplanted. In contrast, if the floodwaters
recede just one or two weeks after the anticipated date, rice seedlings in the
nursery may become over-mature since they should be transplanted within a short
period of three weeks
after sowing. The other disadvantage of nursing seedlings in this area is that
seedlings need to be raised in elevated nurseries or fields which are not
submerged beyond a few centimeters during that time. To avoid the risk of
raising seedlings and to save cultivation time in the fields, some farmers
sow germinated seeds, a cultural practice between sowing seeds and
transplanting seedlings.
Both commune council and farmers have
singled out cultivation of the second dry-season rice as the primary development
goal in the area. This crop can be cultivated after the harvest of the first
dry-season crop in April until the onset of flooding during late July.
Currently, the
planting area of the second dry-season rice is only 30 hm2
in Kampong Tralach commune and only since 2010. Communes with the greatest
potential of introducing and expanding cultivation of the second dry-season
crop include Kampong Preah Kokir (700 hm2), Kampong Hau
(992 hm2), Samraong Saen
(118 hm2), Ampil Tuek (2 937 hm2) and Kampong
Tralach (703 hm2). Communes with
less potential comprise Khon Rang (360 hm2), Melum (200 hm2), Pou (610 hm2) and Trangel
(480 hm2). If only 50%
(3 500 hm2) of these 5 450–7 100 hm2 are used for rice cultivation
with
an average yield of 3.2 t/hm2, it will result in an extra rice production of 11 200 t. This
extra quantity almost doubles the total rice production (23 914 t) within
the communes Kampong Preah Kokir, Kampong Hau, Samraong Saen, Ampil Tuek and
Kampong Tralach, and increases the total rice production within the study area (53 219 t) by 21%. At a producer price of 199 US$/t
in Cambodia in 2008 (FAO, 2011), this production has a total value of US$2.2
million.
The most significant prerequisite for
cultivating the second dry-season rice crop is irrigation. Farmers indicate
that appropriate irrigation pumps cost around US$250 and require about 120
L/hm2 of fuel. While this is a significant investment for many or
most farmers in the study area, farmers spent 75 US$/hm2 for harvesting
the first directly-sown crop by combine. If the yield of 3.2 t/hm2
is completely sold at a producer price of 199 US$/t, a farmer will receive a return
of 637 US$/hm2 or US$828 for
the average farm size of 1.3 hm2
in these communes. In other words, farmers have to sell the production of about 0.4 hm2 to offset the
costs of a newly-acquired pump and about 0.7 hm2 to offset those
for a new pump and fuel (1.5 US$/L). If only fuel costs are taken into
consideration, these costs can be offset by selling the harvest of only 0.3 hm2, i.e., 1 t of
rice. The fuel requirements can be reduced by saving irrigation through raising
rice seedlings and transplanting the second dry-season crop. This technique
does not incur the risks prevailing for the first dry-season crops, but farmers
might be reluctant or unable to switch back to this labor-intensive form of
rice cultivation.
Much similar to the wet-season cropping
systems, seed rates for directly-sown dry-season rice exceed twice of the recommended
rates: while 60–70
kg/hm2 are
recommended, farmers on average use 122
kg/hm2, with 195
kg/hm2
in Kampong Hau and 180
kg/hm2
in Ampil Tuek communes.
Since not all seeds are self-propagated as in the wet-season rice cropping
systems, these practices waste farmers’ agricultural, nutritional as well as
financial resources. To improve these as well
as other cultivation practices, the
commune council members in this area call for better training of farmers
preferably by way of demonstration fields.
ConclusionS
The
high percentage of 83% of the arable land in the study
used
for cultivation of rice predisposes the area to producing rice in excess of the requirements of its own population. It can potentially contribute to Cambodia redeeming its traditional role as a rice-exporting nation. The study highlights
that there is no single solution for improving rice production not even within
the geographically localized region covered by this survey. While two
approaches of clustering cropping systems failed, the approach of categorizing
them by the
distance
from the Tonle Sap Lake/River was successful and pointed towards routes for
improving productivity. Establishing irrigation infrastructure is a
prerequisite for expanding production of rice and non-rice crops. In areas
distant to the Tonle Sap Lake/ River, introducing high-yielding medium maturing
cultivars in the
wet-season rice cropping system has already proven its potential for leveraging
the risk of crop failure caused by occasional drought during the grain ripening
stage at the beginning of the dry season in November. In the prevailing
dry-season cropping system of communes adjacent to the Tonle Sap Lake/River, introduction
of a second dry-season rice crop between April and July can possibly double
annual yields and contribute to Cambodia’s efforts to expand production of
export-quality rice crops. Complementation of rice with non-rice crops should
be promoted in these cropping systems, and the low yields call for improved cultivation
technologies for these crops as
well.
ACKNOWLEDGEMENTS
The
authors thank the members of councils, villages and the farm households of the
communes of Anhchanh Rung, Khon Rang, Kampong Preah Kokir, Melum, Dar, Kampong
Hau, Pou, Samraong Saen, Trangel, Ampil Tuek, Chouk Sa, Kampong Tralach, Peani
and Thma Edth in Kampong Chhnang Province, Cambodia who actively
supported our survey visits and provided invaluable input on which this paper
is based. We thank the Asian Development Bank (ADB) for financial support (Loan No. 2376 CAM/Grant No. 0092 CAM).
We also thank Deutsche Gesellschaft für Technische Zusammenarbeit (GIZ) for
their funding of project personnel and the Management of the Tonle Sap Lowlands
Rural Development Project (TS-LRDP) for their support. The views expressed in
this paper are those
of the
authors and do not necessarily reflect the views of the donor or the authors’
institutions.
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