Rice-based Systems Research: Regional Technical Workshop June 2012 Australian Centre for International Agricultural Research (ACIAR)

1. Rice water use productivity in Cambodia
ACIAR project LWR2009/46
Dr Evan Christen (CSIRO) & Dr Seng Vang (CARDI)
in collaboration with:
HE Pich Veasna & Mr Prum Kanthel (TSC MOWRAM)
Mdme Men Nareth & Dr Oeurng Chantha (ITC)
Dr Philip Charlesworth (IDE)

2. Improved irrigation water management to
increase rice productivity in Cambodia
Background
• Rice is staple food and yields are low (2.4t/ha), much poverty that could be
alleviated by increased agricultural output
• Rice irrigation water management has been identified as a key constraint to
increasing farmer incomes and Cambodian production of rice for
consumption and export
• Compared to neighbouring countries rice yields in Cambodia are low.
Problems
• flooding in rainy season, limited/variable water supply in dry season, poor
irrigation, infrastructure, small plots, low inputs
Objectives
• Develop an improved understanding of farm-level water management
constraints and opportunities;
• Research and develop adapted water management and agronomic
interventions at a farm and district level to increase productivity;
• Support CAVAC extension efforts by providing timely, practical on-farm
water management information especially in the areas of canal
rehabilitation by CAVAC in Takeo and Kampot.

3. The project
Partners:
• Cambodian Agricultural Research and Development Institute (CARDI)
• Ministry of Water Resources& Meteorology (MoWRM) – Technical
Services Centre (TSC)
• Institute of Technology Cambodia (ITC)
• International Development Enterprises (IDE)
The Project:
• 4 years, start 2011 – still in first year
• ACIAR funding $1.06M, total funding $1.7M
• Work with CAVAC in providing readily adoptable interventions
• Target lowland rice where some control over irrigation & drainage
• Target rice crops with supplemental or full irrigation

4. Methods
• Surveys of communes (Takeo province)
1. Socio-economic of communes - to understand irrigation and
agronomic practices and constraints.
2. Infrastructure and topographical survey of same communes
Link the two above to identify links between irrigation/drainage
infrastructure and rice productivity
Identification of improved water management approaches -
participatory process, identification of “case studies of success”, which
will then be tested in field trials.

5. Methods
• Laser levelling tested/demonstrated with farmers (CARDI) and when
irrigation areas are redeveloped (MoWRAM).
• Field studies to measure rice water and fertiliser use under the current
management practices identified in the initial surveys and under the
options for improved water and fertiliser management.
• Analysis of groundwater quality and suitability for irrigation
• Weather data for agricultural management
1. Compiling of historical weather data
2. Installation of Automatic Weather Stations
• Bring together the field studies and data gathering for water balance
and crop growth modelling - leading to the development of improved
agronomic practices for increased productivity.

6. Results – farming system analysis
• Rice farming systems, Takeo (analysis of CAVAC data 2009)
• Rice yields show a lot of variation – reasons?
• Best wet season yields are higher than worst dry season and early wet
season – much work to be done increasing yields of all seasons.

7. Results – farming system analysis
• Rice farming systems, Takeo (analysis of CAVAC data 2009)
• Wet season and early wet season - area per farmer < 2 ha
• Dry season half farmers < 2 ha, but some quite large areas grown

8. Results – farming system analysis
• Rice farming systems, Takeo (analysis of CAVAC data 2009)
• Total area of dry season rice nearly twice wet season rice – economic
importance?

9. Results – surveys of communes (CARDI)
Objectives
•Understand the irrigation practices for rice production, and differences
between districts.
•Assess groundwater use and any problems with water qualities reported by
farmers
•Identify key farmers to work with demonstration on land leveling, water and
fertilizer management.
Location
•Takeo province: Angkor Borei, Koh Andeth, and Kirivong districts.
•Villages selected to include partially irrigated rice, fully irrigated rice and
surface and groundwater used for irrigation

10. Results – surveys of communes (CARDI),
continued
Methods
• Farmer workshops, farmer individual interviews, and key informants
interviews such as local authority leaders, service providers, and farmer water
user community (FWUC) leader.
• 7-10 farmers in each workshop with a total of 85 farmers in 9 villages.
• 80 households in-depth interviews.
• GPS point coordinates were recorded - mapping of farmer field and irrigation
infrastructure survey (by MoWRAM TSC team)
Linking socio-economics with the paddy field condition and irrigation
infrastructure, survey by TSC of:
• Paddy field size
• Paddy field levelness
• Irrigation infrastructure condition
• Water availability

11. Results – Laser levelling demonstration
• Laser levelling demonstration - Kandal Stung Model site (3/4/12) and
Kpok Trabek (Upper Slaku) on 4/4/12 , Angkor Borei (19/3/12)
1. SURVEY 2. PLOUGH
Explaining laser
levelling to the farmers
3. LEVELLING 4. CHECK LEVEL
Conducted as a
collaboration between
CARDI and TSC

12. Results – rice water use monitoring at research
station
Lysimeters used for measuring water balance components
Energy balance instrumentation used for directly measuring rice crop
evapotranspiration
Total water applied to rice paddy
Conducted as a collaboration between
CARDI, ITC and TSC

13. Results – Rice evapotranspiration by lysimeters
800
700
600 ET1 ET2 ETm
ET (mm)
500
400
300
200
100
0
2
2
2
12
12
12
2
2
2
12
12
12
-1
-1
n-1
n-1
n-1
r-1
ar-
ar-
ar-
pr-
pr-
pr-
eb
eb
Ma
-Ja
-Ja
-Ja
-M
-M
-M
-A
-A
-A
-F
-F
1-
11
21
31
10
20
30
10
20
11
21
31
Date (day)
Crop yielded 3.8t/ha at 19% moisture

14. Results – Rice evapotranspiration by Bowen
Ratio equipment
Bowen ratio data Full season crop factor = 1.07, ETcrop 535 mm (99 days)
This does not include percolation losses, these were 250- 500mm (not finalised)

15. Results – Groundwater sampling
Preliminary sampling of groundwater undertaken in Angkor Borei – to test
methods – sampling methods, Temp, salinity, pH and field kits (alkalinity, Fe)

16. Results – Groundwater sampling
Some salinities quite high and one elevated Iron (Fe) level
Date Location Village T (oC) EC pH Alkalinity Fe
(dS m-1) (mg L-1 (mg L-1)
CaCO3)
18/3/20 11‟02‟11 44”N, Toul Sangkor 30 0.935 6.52 230 nd
12 104‟57‟07‟95E
11‟02‟06 32”N, Toul Sangkhor 31.1 0.959 6.75 240 nd
104‟56‟55‟72”E
**11‟01‟35 Toul Sangkhor** 31.2 0.488 6.6 250 0.11
76”N,
104‟56‟55‟72”E
11‟01‟31. 41”N, Toul Sangkhor 30.6 0.777 6.75 268 0.01
104‟57‟26.58”E
19/3/20 11‟02‟34. 00”N, Ta Ei 31.1 1.31 6.7 157 0.0
12 104‟58‟17.53”E
11‟02‟26. 56”N, Ta Ei 31.4 1.36 6.71 162 0.01
104‟58‟16.98”E
11‟02‟29. 53”N, Ta Ei 31.2 1.31 6.7 161 0.0
104‟58‟23.39”E
11‟02‟52. 67”N, Ta Ei 30.7 1.09 6.72 238 0.0
104‟56‟36.19”E
** Domestic well used for washing and drinking not irrigation. NB elevated iron.

17. Results – Groundwater analysis
Laboratory capability and methods used at CARDI need to be improved:
-Water supply, use of filters and reagents
- lab protocols for Na, K, Ca and Mg and nutrients in agricultural water
samples are required
Dr Wendy Quayle (CSIRO) with Mrs
Saosrey Touch (CARDI laboratory
technician) in the CARDI laboratory

18. Results – Cambodian weather data
• Established 3 automatic weather
stations – Takeo, Kampot, Kampong
Thom (new station of CARDI)
• Developed web based data storage
and access
• Collated all historic weather data
Website for the weather data
from the automatic weather
stations
PDWRAM staff Mr. Yuk Narin at
Automatic weather station in Takeo
http://weather.irrigateway.net/cambodia/

19. Results – „Case studies of success‟
An Example is farmer Chhim Son who presented a poster at the Angkor
Borei laser levelling demonstration explaining that he wanted to use
laser levelling on his farm to increase yields and so be able to send
his children to a better school
Website for the weather data
from the automatic weather
stations

20. Conclusions
• The project is just gaining momentum, 1st year
• Much room for improvement in rice yields across all seasons
• Wide distribution of rice yields, 2 fold in wet season and 4 fold in dry season – learn
from the best farmers
• Laser land levelling is ready for adoption in Cambodia – filling the gaps in business
models required (CAVAC collaboration)
• Getting MOWRAM engaged in on-farm results is critical to improving returns from
government investment in irrigation infrastructure
• Rice water requirement for evapotranspiration (dry season) is about 5mm/day,
percolation, lateral leakage and any draining of paddies will increase this.
• Need to understand „leakiness‟ of soils better to understand total water requirements
for rice in any particular region
• Linking irrigation infrastructure and paddy field condition with socio-economics is
unique exercise and should be very informative

21. THANK YOU