|  Shrimp farming in Bac Lieu had recently become very profitable, following the introduction of large varieties raised for export. It is also a gamble—a high-stakes investment always in danger of being wiped out by disease or fluctuating prices. As elsewhere in Southeast Asia, divergent priorities have long pitted rice and shrimp farmers against each other, echoing the rivalry in the late 19th century between herders and cultivators on the Great Plains of North America.
“Shrimp is too risky to try,” says 42-year-old Nguyen Van Mao, a successful rice farmer. “I grew up here and saw neighbors lose their farms and houses through shrimp failure. Rice production may have smaller profit margins, but it’s stable enough to keep my children in school.”
 Mao is fortunate that his cautious approach to farming is a good match for the soil of his medium-sized holding of 3.9 hectares, which remains fertile under the double cropping of rice that saline protection now makes possible. Many of his neighbors aren’t as lucky because their soil is potentially acidic.
A comprehensive study led by the International Rice Research Institute (IRRI) and financed by Britain’s Department for International Development highlights the problem. Duong Van Ni, project coordinator with the Mekong Delta Farming Systems R&D Institute of Cantho University, one of IRRI’s local collaborators on the Bac Lieu livelihood project, explains that potentially acidic soil becomes actually acidic when it dries out too much.
“The recommended use for such land in Bac Lieu is to grow rice in the rainy season and shrimp in the dry, to reduce land-preparation time and keep the soil wet during the dry season,” explains Dr. Ni. “Aside from providing basic food security for farmers—and perhaps a small surplus to sell—the single rice crop leaves straw to feed the blue algae that are the main food for the following shrimp crop.”
Acidic soils are concentrated in “downstream,” newly protected areas of Bac Lieu. At the urging of shrimp farmers, officials began approving the occasional opening of some sluice gates to let salt water flow into these areas. The decision reflected rethinking of the government’s priorities away from the determined pursuit of higher rice production toward a more complex weighing of alternatives.
The question then became how best to manage the sluice gates to balance competing demands: the shrimp farmers’ need for brackish water in the dry season, the rice farmers’ desire to retain the benefits of year-round saline protection, and the imperative to prevent the accumulation of pollutants in the waterways, to protect the inland fisheries vital to the poorest residents, especially the landless.
Mao expected the mitigation of saline protection to erode some of his newly won 250% gain in rice productivity, as salt intrusion would likely affect the yield of his second, September-December rice crop. At the same time, he strives to be a good neighbor and supports the balanced sharing of natural resources. He is confident that he can minimize his losses by planning ahead, but only if a fixed schedule for opening the sluice gates is publicized in advance.
Determining an optimum gate-management regime was a task of daunting complexity. IRRI water management scientist To Phuc Tuong, project manager of the Bac Lieu Livelihood Project and head of IRRI’s Crop, Soil, and Water Sciences Division, explains that researchers had to understand the water quality requirements of rice and shrimp farmers at different times of the year, model how various gate-opening scenarios would affect water quality—particularly salinity—at different places and times, and determine which scenarios could satisfy farmers’ requirements.
More broadly, gauging the socioeconomic impact of policy decisions entailed surveying existing patterns of how people made a living and how well they did, estimating the effect of various proposed policies on the livelihoods of different groups, and predicting how people would respond to change, in particular how they might choose to use their land differently. The complexity of the problem was compounded in that rice-farming families typically grow other crops in addition to rice and often draw income from sideline occupations away from the farm.
In partnership with farmers, researchers tested the sustainability of new and existing agricultural technologies. They compared the performance of traditional and improved rice varieties under local conditions, seeking advantageous combinations of salinity and acidity tolerance, pest and disease resistance, yield potential, and grain quality and marketability. Similarly, they assessed customary and innovative approaches to such cultural practices as seeding, watering, fertilizing, weeding, controlling pests and diseases, and harvesting. The IRRI-led team also aimed to help rice-shrimp farmers understand how water salinity and acidity affects shrimp and how to avoid crop-devastating disease.
The Bac Lieu livelihood project reflects a trend in agricultural research toward a holistic and integrated approach to using natural resources, dubbed ecoregional integrated natural resource management (INRM). The approach adopts a problem-oriented framework for tackling agricultural challenges that deploys the full range of scientific assets that can be brought to bear, from laboratory-bound disciplines like biotechnology to such “soft sciences” as sociology. By working closely with policymakers and farmers and by facilitating a mutual learning process, it strives to address issues linking agriculture and natural resource management beyond the field scale. It also aims to bridge the gap between this bottom-up approach and the top-down view of planners and policymakers.
Researchers hope and expect that the lessons learned in the Mekong Delta ecoregion will be applicable in other parts of South and Southeast Asia, where 2 million hectares of tidal-saline rice lands are farmed by people who are among the poorest and most food-insecure in the world. Fears that global warming may cause sea levels to rise, pushing saline intrusion inland, lend urgency to the task. A study led by Reiner Wassmann, formerly of IRRI, classified 60% of the Mekong Delta as highly vulnerable to sea-level rise and another 15% as moderately vulnerable. The study noted that, within the Greater Mekong Subregion, coastal rice lands in Thailand and Myanmar are also at risk.
In an up-and-coming field such as ecoregional INRM, research methods can be as eye-catching as the results they produce. One valuable tool for interdisciplinary study is map-making with geographic information systems (GIS), which allows scientists to layer wide-ranging data into compact, analyzable packages.
“GIS is a computer-based technology for integrating maps and data, both biophysical and socioeconomic, from various sources,” explains Suan Pheng Kam, IRRI’s GIS specialist. “In this project, we used a combination of satellite images, existing statistical data, and field interviews to analyze and better understand how the water-control scheme affects land use and farmers’ livelihoods in the study area. GIS also made it easier for scientists to present the results of complex water-flow and water-quality models to local authorities, so that they understood the implications of their decisions on what farmers can do with their land and water resources.”
In addition to modeling changes in water quality and monitoring land-use conversion, IRRI performed the central role of coordinating the activities of various collaborators in the Bac Lieu livelihood project.
The good news for Nguyen Van Mao is that researchers submitted their findings to local officials and worked with them to delineate land-use zones and develop a hydraulic model to guide sluice operation in line with each zone’s soil conditions and water-quality requirements. Then, for 2 more years, the scientists continued monitoring water and soil quality to fine-tune management of the Quan Lo-Phung Hiep Water Control Project, and so helped lift the farmers of Bac Lieu out of poverty.
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