evolving thinking on agricultural water productivity: lessons learned from 20 years of research
TRANSCRIPT
Evolving thinking on Agricultural Water Productivity: Lessons learned from 20 years of research
Meredith A. Giordano International Water Management Institute (IWMI)
Peter G. McCornickRobert B. Daugherty Water for Food Global Institute
World Bank Water WeekMarch 15, 2017
1996
Agricultural Water Productivity: Origins of water productivity research at IWMI
• Efficiency is a “tricky” concept in the field of water (does not account for capture and reuse of water)
• Scope for real water savings is often less than imagined
• New concepts are needed to address the “increasingly difficult problems facing water management”
• Water Productivity: Output (kg/$) in relation to water use (in terms of water withdrawn, applied or consumed)
> 300 journal articles, reports and other documents on water productivity:
methods, tools and applied research in diverse settings
Case Study: Water savings myths and realities
Background• Objective: Assess the impact of “resource conservation” practices on
water application, water productivity and real water savings• Location: Rechna Doab, semi-arid Punjab Province, Pakistan
Rice–wheat cropping zones in the Indus Basin of Pakistan and location of sample farms surveyed in and near Rechna Doab, the Punjab, Pakistan. Source: Ahmad et al. 2007, 2014
At field scale: Water application reduced
Field-scale impacts of laser leveling and zero tillage technologies (Ahmad et al. 2014)
At field scale adoption of resource conservation technologies led to• 24-32% reduction in water
application at the field scale• Increased farm level incomes
At system scale: Water consumption increased
Ahmad et al. 2007
Overall water consumption at the system scale increased by 59 million cubic meters/year following the adoption of “resource conservation” technologies.
Belief Reality
Transpiration Evaporation
Flood irrigation
Zero till
Transpiration Evaporation
Transpiration Evaporation
Flood irrigation
Transpiration Evaporation
Zero till
Some of the “wasted” water had actually been reused
Flood irrigation
Zero till
• Reductions on water applications at the field scale translate into reduced water consumption in the system (i.e., farmers won’t use the “saved” water).
• Net farm incomes increased.
• Increased profitability incentivized farmers to expand cultivated area and/or increase cropping intensity.
Belief Reality
Impact depends on physical setting
Groundwater quality in the Indus Basin, Ahmad et al. 2014
2017• Define terms carefully (e.g., water applied versus consumed) • Scale and context matter • Know your objective (i.e., improving
water productivity is not the end goal)• Be clear on the use and limits of
single factor measures
Agricultural Water Productivity Lessons learned from 20 years of applied research
Thank You
Ahmad, M.D.; Masih, I.; Turral, H.; Giordano, M.; Masood, Z. 2006. Opportunities and challenges in saving water and improving productivity through resource conservation technologies: Examples from Pakistan. In: International Workshop on Water Saving Technologies, Amritsar, Punjab, India, February 22-24, 2006. New Delhi, India: United States Educational Foundation in India. Pp. 120-139.
Ahmad, M.D.; Giordano, M.; Turral, H.; Masih, I.; Masood, Z. 2007. At what scale does water saving really save water? Lessons from the use of resource conservation technologies in Pakistan. Soil and Water Conservation 62(2): 29A-35A.
Ahmad, M.D.; Turral, H.; Masih, I.; Giordano, M.; Masood, Z. 2007. Water saving technologies: Myths and realities revealed in Pakistan’s rice-wheat systems. Colombo, Sri Lanka: International Water Management Institute (IWMI). 38p. (IWMI Research Report 108).
Ahmad, M.D.; Masih, I.; Giordano, M. 2014. Constraints and opportunities for water savings and increasing productivity through Resource Conservation Technologies in Pakistan. Agriculture, Ecosystems and Environment 187: 106-115.
Giordano, M.; Turral, H.; Scheierling, S. M.; Tréguer, D. O.; McCornick, P. G. 2017. Beyond “More Crop per Drop”: evolving thinking on agricultural water productivity. Colombo, Sri Lanka: International Water Management Institute (IWMI); Washington, DC, USA: The World Bank. 53p. (IWMI Research Report 169).
Seckler, D. 1999. Revisiting the" IWMI paradigm:" Increasing the efficiency and productivity of water use. International Water Management Institute (IWMI): Colombo, Sri Lanka
References