Water productivity of rice
in Africa
benchmarking and pathways for improvement
Sander Zwart
Africa Rice Center Cotonou, Benin
Petra Schmitter
International Water Management Institute Addis Ababa, Ethiopia
Introduction
• Rice in Africa
• Benchmarking water productivity
• Improving WP in rainfed rice systems
• …. and irrigated systems
• Landscape approach for water productivity
Rice in Africa
• Rice has an increasing importance for food security in Africa • Consumption increases due to population growth and
urbanization
• Consumption outpaces growth in production
• Higher dependency on international markets creates vulnerability to price shocks and loss of foreign currency
Rice in Africa
System Africa Asia
Irrigated rice 15% 90% Rainfed rice 85% 10% Production (t ha-1) Africa Asia Irrigated rice 2.2 5 Rainfed rice 1.2-1.9 1.5-2.5
Rice in Africa
• Worldwide competition of water resources
Rice in Africa
Low income results in low investments in new seasons, migration, low food
security, poverty
Low input rice production
rainfed, traditional varieties, little or no fertilizers/pesticides, weeds infestation
Rice systems that are vulnerable to environmental hazards
Rice in Africa
Smart investments are required targeting
stabilized increase of the efficient use of water resources for rice production in a sustainable manner.
Increase of water productivity by making use of available sources while not affecting other users in a basin.
Benchmarking water productivity in Africa
Synthesis of reported WP in literature Zwart and Bastiaanssen (2004):
only WPET and only direct measurements
Here we consider WPET, WPI+P and include
Benchmarking water productivity in Africa
Global range of WPET is 0.6 – 1.6 kg/m3
6 studies address WPET in irrigated rice, none
found for rainfed rice.
WPETrange
(kg m-3)
Location and country Years Source
0.53 – 0.64 Ndiaye & Pont-Gendarme, Senegal 1990 Raes et al. (1990)
0.50 – 0.79 Kadawa, Nigeria 1991-1992 Nwadukwe & Chude (1998)
0.56 Tono, Ghana 2005-2006 Mdema et al. (2009)
0.93 – 1.01 Nile delta, Egypt Not given Keita (2009)
1.25 – 1.65 Nile delta, Egypt 2006 Zwart & Bastiaanssen (2007)
Benchmarking water productivity in Africa
Eight studies provide WPI+P
Only studies for irrigated rice
WPI+Prange
(kg m-3)
Location and country Years Source
0.23 – 1.28 Ndiaye & Fanaye, Senegal 2005-2006 De Vries et al. (2010)
0.27 – 1.07 Fanaye, Senegal 2007 Krupnik et al. (2012)
0.22 – 1.43 Ndiaye, Senegal 2008 Schlegel (2010)
0.34 – 0.88 Gorgo, Mogtedo & Itenga, Burkina Faso 1993-1994 Dembélé (2001)
0.60 – 1.17 Kafr El-Sheikh, North Delta, Egypt 2006-2007 El-Bably et al. (2008)
0.52 – 0.99 Giza, Egypt Not given Nour et al. (1997)
0.50 – 0.80 Gharb, Morocco 1995-1997 Lage et al. (2004)
Benchmarking water productivity in Africa
Complex water balance leads to high uncertainty in reported values
Benchmarking water productivity in Africa
Findings:
• No studies were found for eastern and
southern Africa
• WPET values in Africa are in the lower half of
the global range of 0.6 – 1.6 kg/m3
• WPI+P depicts large variation within the
experiments and between the experiments
• Significant scope for improvement, but take
Introduction
• Rice in Africa
• Benchmarking water productivity
• Improving WP in rainfed rice systems
• …. and irrigated systems
• Landscape approach for water productivity
Improving WP in rainfed rice systems
Rainfed rice is often grown in fields like maize in uplands
Reduce the dependency of crops on water
from rainfall events by storing water in the soil Low input systems require low-cost options
Improving WP in rainfed rice systems
Smart-valleys, a participatory and low-cost
approach for improved water control and harvesting:
- Constructing drains
- Creating bunds around the plots - Levelling of fields
- Creating irrigation facilities if possible
Improving WP in rainfed rice systems
Smart-valleys, a participatory and low-cost
approach for improved water control - Constructing drains
- Creating bunds around the plots - Levelling of fields
- Creating an irrigation system if possible• Rice yields are doubled to 3,5 ton/ha • Farmers report lower impact of drought
• Farmers’ income doubled
Improving WP in irrigated rice systems
Water management in rice water management can be changed from continuous flooding of
rice fields…
…to Alternate Wetting and Drying (AWD)
• Reduce irrigation water diversion to plots
by 30% without yield penalties (WPP+I)
• Effect on evapotranspiration (WPET) is
Landscape approach for water productivity
• Impact of plot level measures for
improvement of WP are under investigated
• Projects that aim increasing water
productivity often lead to increased use of water resources
• Spatially explicit approach that links plot
level measures to landscapes to assess changes in hydrology
Landscape connectivity & differences in quantifying WP
Landscape approach for water productivity
On – farm water productivity:
Testing of land and water management technologies
Transects of different agricultural systems:
Process understanding and interactions on water
productivity
Watershed-basin level:
upland - lowland
interaction effecting water productivity at system level
Key messages
1. Water productivity of rice in Africa is low and significant increases can/must be made 2. Low-cost technologies to improve the
water productivity in rainfed and irrigated rice systems are available
Key messages
3. A landscape approach is required to assess the impact of large-scale introduction and adoption of water productivity
