Beyond drip irrigation to water fields in dry land areas: An interview with David Bainbridge
David Bainbridge has spent over 40 years researching restoration, resource management, and sustainable agriculture in dry land areas. He contributed to the development of the interdisciplinary Dry Lands Research Institute at University of California Riverside, where he co-authored the groundbreaking guide to sustainable agriculture for California in 1991. He is also the author of New Hope for Dry Lands: A Guide for Desert and Dryland, published by Island Press in 2007. Currently, Bainbridge serves as Associate Professor at the Marshall Goldsmith School of Management at Alliant International University in San Diego, where he coordinates the concentration in Sustainable Management.
Can you tell us more about your research on alternative irrigation systems for dry land areas?
In the 1980s, I began to focus on sustainable agriculture, specifically desert restoration and agroecology. I realized water was going to be a critical problem in California, as well as around the world. In remote sites [in the developing world], people sometimes have to carry water as far as 50 to 100 miles, and water is very expensive. So I started exploring ways to irrigate the land by conserving water.
For most people, drip irrigation is where irrigation stops. In the 1950s and 1960s there was a lot of helpful research, but drip systems are usually not so good for remote sites in low-tech areas because they require a lot of technology to keep the systems working. I’ve visited many development sites and found that drip irrigation is not always sustainable because it requires a lot of management.
You have conducted extensive research on the buried clay pot system. How does it work? And what system are you currently working with?
The buried clay pot system is one of the most efficient irrigation methods and is ideal for gardeners and small-scale farmers. Clay pot irrigation uses a buried, unglazed clay pot filled with water to provide controlled irrigation to plants. The water seeps out through the clay wall at a rate that is influenced by the plant’s water needs. When I began the buried clay pot trials, I found that the water efficiency was so good, and I kept up with the research. In India, for example, melon yield with the buried clay pot system was 25 tons/hectare using only 2 cm of water, compared with yields of 33 tons/hectare using 26 cm of water with flood irrigation. But unfortunately scientists don’t typically study these traditional practices.
Currently, I am working on wick irrigation, which is an old, traditional practice that goes back hundreds of years. Wick irrigation can be used in conjunction with the buried clay pot system. A hole or series of holes is punched in the buried clay pot and a porous wick is inserted in the hole. The material wicks the water from the container into the soil and provides a slow, steady source of moisture for plant growth. I conducted experiments in the California desert on these systems and found 2-10 times greater efficiency than drip irrigation systems.
What are some of the advantages of these alternative methods over drip irrigation?
Drip irrigation can be very effective, but the trick is that it has to be well-managed. And there are many problems associated with drip irrigation. On the other hand, the traditional system does not require a pressurized water system, which is difficult to establish and maintain in remote sites. Also, animals chew on the tubing of the drip systems and often, the systems get clogged due to salt build-up, and it stops delivering water the way it is supposed to. To avoid clogging, you must use a filtration system which becomes another headache in remote sites. And even a brief interruption of the water supply in a drip system due to a pump or filter failure can lead to serious problems and crop failure. But the buried clay pot systems may require water only once every few days or once a week.
Clay pots have been used for over 2000 years with success, and this is a good argument to attest that the system works. Most importantly, the system is demand-based, where plant needs determine the amount of water drawn from the pots.
Farmers have been very pleased with the clay pot trials. Crops grown using clay pot irrigation include tomatoes, corn, beans, onions and garlic. Researchers in India have found that the clay pots provide steady moisture so crops like tomatoes have flourished. I know a farmer in Mexico who has put his children through college by growing melon using clay pot irrigation. Using these methods, farmers in Mexico and India are feeding themselves and also have enough to sell their produce on the market.
What is the potential of replicating these innovative systems in dry land regions across the world? What are some of the challenges associated with this?
Most of my research is focused in the California desert but these systems work very well in other dry and semi-dry areas. In China where it is not quite as dry as other regions, these systems are a good way to limit water use, while also requiring less maintenance work. And in the dry areas across Africa’s Sahel region and the Middle East, where it is hard to plant trees, these systems can prove to be very beneficial.
The majority of the world’s dry lands are still farmed by small-scale farmers, and these traditional methods could be of great use on small and medium-sized farms and gardens. But unfortunately they have not been well studied or publicized.
One of the biggest challenges is raising awareness. The systems that I focus on have designs that are fairly easy, but existing agriculture systems don’t do a good job of looking at these small-scale creative designs. The current focus relies heavily on capital-intensive systems and part of the failure is that we have not paid enough attention to these traditional practices. The problem with our current system is that we don’t always respect small growers and local knowledge.
Often, just getting this innovative knowledge into the literature – into a major publication or journal- can make a big difference. And it takes projects like Nourishing the Planet to draw attention to these methods and make people really look at them. My book New Hope for Dry Lands: A Guide for Desert and Dryland focuses on field-based aspects of dry land restoration, and I hope to spread the word to NGOs and practitioners who are doing much of this work around the world.
Based on your experience, how do you think we can reframe the way we think about agricultural development?
One of the most vital things is a closer look at traditional systems around the world – traditional knowledge is better suited to local conditions. And because we continue to ignore this, lots of valuable things are being lost.
Western agricultural systems are being pushed into places where they are not advantageous. A lot of scientists from developing countries are often trained in the U.S., and they promote practices that might be appropriate in Iowa but are not well suited in their local communities.
There is, therefore, a great need to promote sensitivity to local conditions and local systems. And while we’re seeing a push towards this trend, it is not enough.
This approach promotes a careful analysis of what people do, why they do it and how they do it, and it’s not very expensive. When people in local communities are treated as knowledgeable experts rather than victims, it also encourages them.
I’ve had the chance to work with Arturo Gomez Pompa (Professor emeritus at University of California Riverside), who has been very successful in promoting local knowledge in Mexico. His use of local farmers as experts was pivotal – giving them credit and honor for their expertise. He encouraged farmers from one community to teach their skills to other communities so that innovative farmer-led techniques can be replicated. These bottom-up soil conservation and agro-forestry systems can be very beneficial.
Janeen Madan is a research intern with the Nourishing the Planet project.
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