Drain for Gain: Managing Salinity in Irrigated Lands Webinar #8 Henk Ritzema Wageningen University, Wageningen, The Netherlands

Worldwide agricultural areas with/without irrigation and drainage Nijland et al., 2005; Ritzema, 2009

Waterlogging and salinity in irrigated agriculture IndicatorUnitWorldEgyptIndiaPakistan Irrigated area(Mha) Drained Area(Mha) of which SSD(Mha) Salt-affected areas(Mha)10-16% of which waterlogged(Mha) ICID, 2003 Ritzema, 2009

Artificial drained areas Feick et al, 2005; Ritzema, 2009

Sources of the salts Irrigation   Capillary Rise Precipitation  De Ridder and Boonstra, 2006

Irrigated agriculture: source of salts Salts in irrigation water: 0.2 – 0.8 mg/l = 2.5 – 10 ton/ha/year

Example Egypt Irrigation: V i = 1240 mm/year = 1240 x x 10 4 m 3 /ha/year = 12.4 x 10 3 m 3 /ha/year Salinity of irrigation water: EC i = 0.3 dS/m = 0.3 x 640 mg/l = 192 mg/l = 1.92 x ton/m 3 Total salts brought into the soil: S = V i x EC i = 12.4 x 10 3 m 3 /ha/year x 1.92 x ton/m 3 = 2.4 ton/ha/year Salts are brought in with irrigation water Ritzema, and Braun, 2006

Leaching requirement Irrigation & Precipitation ET watertable Deep Percolation R* Root zone Van Hoorn and Van Alphen, 2006

Drainage needed to remove the salts

Irrigation efficiency   Leaching requirement Brouwer et al, 1989 Leaching requirement 10 – 40 % depending on EC i and EC e Ayers and Westcot, 1994

Salinization is a slow process Van Hoorn and Van Alphen, 2006

DRAINAGE: The forgotten factor in agricultural water management  Seven reasons why drainage is needed!  Seven institutional aspects why drainage is different.  Seven challenges to make drainage work! Scheumann, 1997

Seven reasons why drainage is needed (1) Drainage protects the resource base for food production Ritzema et al,, 2007 Pearce and Denecke. 2001

Seven reasons why drainage is needed (2) Drainage sustains and increases yields and rural incomes. IDNP, 2003 Ali, et al., 2001

Seven reasons why drainage is needed (3) Drainage protects irrigation investments IDNP, 2003

Seven reasons why drainage is needed (4) Drainage infrastructure serves rural and urban residents as well as industry Scheumann, 1997

Seven reasons why drainage is needed (5) Drainage protects human lives IDNP. 2003

Seven reasons why drainage is needed (6) Drainage services improve health conditions Ritzema and Braun, 2006

Seven reasons why drainage is needed (7) Drainage and the protection of water quality El-Guindy, S., 1989

Seven reasons why drainage is needed SUMMARY 1. Drainage protects the resource base for food production. 2.Drainage sustains and increases yields and rural incomes. 3.Drainage protects irrigation investment. 4.Drainage infrastructure serves rural and urban residents as well as industry. 5.Drainage projects human lives. 6.Drainage services improved health conditions. 7.Drainage and the protection of water quality.

DRAINAGE: The forgotten factor in agricultural water management Seven reasons why drainage is needed! Seven institutional aspects why drainage is different. Seven challenges to make drainage work!

Seven institutional aspects why drainage is different (1) Drainage is at the end of the pipeline Madramootoo, 1997, IDNP, 2003

Seven institutional aspects why drainage is different (2) Enforcement of rules and regulations is difficult IDNP, 2003

Seven institutional aspects why drainage is different (3) With small farmers, drainage is always a joint- effort IDNP, 2003; Ritzema, 2009

Seven institutional aspects why drainage is different (4) Boundaries irrigation unit ≠ drainage unit Bos, 2006

Seven institutional aspects why drainage is different (5) Disposal of drainage water creates off-site externalities Roest et al., 2006

Seven institutional aspects why drainage is different (6) High initial investments versus long-term benefits Ritzema et al., 2007

Seven institutional aspects why drainage is different (7) Reuse of drainage water IDNP, 2003

Seven institutional aspects why drainage is different SUMMARY: 1.Drainage is at the end of the pipeline 2.Enforcement of rules and regulations is difficult 3.With small farmers, drainage is always a joint- effort Boundaries irrigation unit  drainage unit 4.Disposal of drainage water creates off-site externalities 5.High investment costs & benefits are long-term 6.Reuse of drainage water.

DRAINAGE: The forgotten factor in agricultural water management  Seven reasons why drainage is needed!  Seven institutional aspects why drainage is different.  Seven challenges to make drainage work!

Seven challenges to make drainage work (1) Institutional menu for drainage goods and services Ritzema, et al., 2003

Seven challenges to make drainage work (2) Investments in drainage infrastructure: low or high Nijland, et al., 2005

Seven challenges to make drainage work (3) Organisation: Irrigation and/or Drainage Departments to be modified? IDNP, 2003; Ritzema, 2009

Seven challenges to make drainage work (4) Maintenance of the drainage infrastructure IDNP, 2003; HW Wallingford

Seven challenges to make drainage work (5) Participatory drainage management Malano, 2000

Seven challenges to make drainage work (6) Reuse of drainage water El-Din El-Quosy, D., 1989

Seven challenges to make drainage work (7) Safe disposal Ritzema and Brain, 2006

Seven challenges to make drainage work SUMMARY: 1.Institutional menu for drainage goods and services 2.Investments in drainage infrastructure: low or high? 3.Organisation: State Irrigation Departments have to be modified? 4.Maintenance of the drainage infrastructure 5.Participatory drainage management 6.Reuse of drainage water 7.Safe disposal

DRAINAGE: The forgotten factor in agricultural water management CONCLUSIONS: 1.Drainage is needed 2.Drainage pays 3.Drainage & irrigation 4.Role of Government in financing, regulation and supervision 5.Decentralised drainage management 6.Stakeholders participation in planning, investment and management 7.Co-ordination among the organisations should be institutionalised.

The Way Forward Balancing top-down against bottom-up From standardization to flexibility Focus on capacity development. Ritzema, 2009

Drain for Gain: Managing Salinity over Irrigated Lands Henk Ritzema

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