Remote sensing –Beyond images
Mexico 14-15 December 2013
The workshop was organized by CIMMYT Global Conservation Agriculture Program (GCAP) and funded by the Bill & Melinda Gates Foundation (BMGF), the Mexican Secretariat of Agriculture, Livestock, Rural Development, Fisheries and Food (SAGARPA), the International Maize and Wheat Improvement Center (CIMMYT), CGIAR Research Program on Maize, the Cereal System Initiative for South Asia (CSISA) and the Sustainable Modernization of the Traditional Agriculture (MasAgro)
Land use - Case study from Bangladesh for technology targeting
1. Land use - Case study from Bangladesh for technology
targeting
Urs Schulthess
Timothy J. Krupnik
Andrew McDonald
And many other partners
Workshop:
Remote Sensing – Beyond Images
Dec 14 & 15, 2013
Mexico City, Mexico
2. Rising food prices
Effect of a 50% food price increase on household income
use (Bouis 2011) After 2008
Before 2008
Staples: rice &
wheat
wheat
Animal
Nonstaple
foods
Staples: rice &
Fish+
Meat
Non-Food:
education – health –
housing – risk
management
Nonstaple
foods
Fish +
Meat
Non-Food:
education – health –
housing – risk
management
Courtesy M.
3. Bangladesh: Hot, flat and crowded
(borrowing from Freidman 2008)
150.5 million people (WB
2011)
Extreme
poverty
Climate
change
vulnerable
(Rawlani et al. 2011)
(UNDP 2011)
75% rural
(Huq et al. 2008)
Low-intensity
cropping in
South
4. Abundant water, but little irrigation in
the South
• Irrigation facilities least
developed in the South.
• Shallow aquifers are
usually saline.
• Surface water alternative?
Deep and
shallow
tube
wells
5. Surface water irrigation to hedge risk
The Axial Flow
Pump:
Up to 50% more
fuel efficient for
low-lift pumping
6. Surface water irrigation to hedge risk
• Location and quantification of low intensity dry season land (Following
Maas and Rajan 2008)
• < 40% ground cover: Approximately 180,000 ha
• After surface water buffering: ∼ 83,000 ha
• Surface water salinity sampling stations (dots)
16. Open research topics
• Perennial water way detection
– Landsat too coarse
• Soil moisture status in critical period before
planting of winter crop
• Irrigation scheduling
– Contribution from ground water table
– Crop water use estimation
Bangladeshi households are also very vulnerable to food price spikes like those seen in the 2008 and 2011.
Here we see the distribution of household income expenditure in Bangladesh before the 2008 food price crisis. Note the expenditure on non-food items like education, health, housing, and risk management, all of which are essential to development, as well as on non-staples, meat and fish, which provide nutrition.
Following the 2008 food price spike, we saw an alarming shift in expenditures at the expense of non-staple nutritious foods, education, health, housing and risk management, making households even more vulnerable.
Located in South Asia, Bangladesh is infamous for being hot, flat and crowded. It is world’s largest Deltic floodplain, and drains three major and numerous minor rivers originating in the Himalayas.
Bangladesh is about the same size as Wisconsin – though it boasts over 150 million people - resulting in the world’s densest population with enormous pressure on the land.
Ranked as one of the world’s poorest countries, the population is 75% rural and agricultural.
Although national cropping intensity is about 190%, farmland is also shrinking at an unprecedented rate as urbanization accelerates, and large areas in the South remain under relatively low levels of intensification with large opportunities for agricultural development.
Bangladesh also is widely recognized as one of the world’s most climate change vulnerable countries because of exposure to climate extremes (especially in the South) and low capacity to adapt.
The role of irrigation in mitigating climate related production risks can not be understated.
The north of the country is known for groundwater irrigation, although water tables are declining.
CLICK
Conversely, irrigation facilities are the least developed in the south central part of the nation.
Shallow aquifers are the easiest to tap, but in the South they are also usually saline, so what tube wells do exist are usually used by local business elites primarily for brackish water aquacultural production.
And where tube wells are used for crops, the cost for pumping water to the surface is increasing. As a result, the use of surface water is a logical solution, so long as fuel and cost efficient pumping can be delivered, and saline coastal waters can be avoided.
The Master Plan for Southern Bangladesh emphasizes the surface water irrigation to intensify dry season production and hedge risk.
However, the capital cost for the instillation of a conventional pump set and associated energy costs for pumping can be prohibitive for marginal farmers. This irrigation bottleneck can be broken by facilitating broad-based access through service provision of cost-effective and efficient mobile pump sets to decentralize irrigation.
One such promising alternative is the axial flow pump, which consists of a propeller inside a sealed tube, that can be powered by the engine of any two wheeled tractor, which are ubiquitous in Bangladesh. The axial flow pump is ideal for low-lift surface water irrigation, and is up to 50% more fuel efficient than centrifugal low-lift pumps. They are low cost and easy to transport and deploy in a variety of situations.
In order to better target irrigation interventions, CSISA is identifying high-priority irrigable lands that are currently fallowed or that have a low-level of crop intensification across Southern Bangladesh. This is primarily the work of Urs Schulthess, who I must acknowledge here.
Using remotely sensed satellite imagery, we have employed atechnique developed by Maas et al. to calculates ground cover during the height of the dry season using the ratio of the perpendicular vegetation index for an image pixel to the same value that corresponds to full vegetation canopy. Assuming that pixels showing < 30% ground cover are fallow, or are under low intensity cropping, or water stress, we arrived at an estimate of about 180,000 ha shown in orange to red.
The axial flow pump can be combined with flexible hose piping to deliver irrigation up to 500 m from surface waters. As such, we next buffered riparian areas in the South – as sown on the map to the right - to arrive at approximately 83,000 ha of potentially irrigable area. We then populated the rivers with a network of water salinity sampling stations.