4. Saline agriculture - salt-tolerant plants for developing countries.
Report of BOSTID, Nat. Res. Council, 2101 Constitution Avenue, NW Washington DC 20148, USA; ISBN 0-309-04189-9, 1990, 135 pp.
This book covers some of the experiences and opportunities in the agricultural use of saline land and water. It aims to create greater awareness of salt tolerant plants, their current and potential uses, and the special needs they may meet in developing countries.
Salts occur naturally in all soils. Rain dissolves these salts, which are then swept through streams and rivers to the sea. Where rainfall is sparse or there is no quick route to the sea, some of this water evaporates and the dissolved salts become more concentrated. In arid areas, this can result in the formation of salt lakes or in brackish groundwater, salinized soil, or salt deposits.
There are three possible domains for the use of salt-tolerant plants in developing countries. These are:
- Farmlands salinized by poor irrigation practices;
Although irrigation can bring arid land into production, this often leads to salinization. In some countries the amount of newly-irrigated land equals the amount of salinized irrigated land going out of production each year. The use of salt tolerant plants may provide a realistic solution to this problem for many developing countries.
Undomesticated salt-tolerant plants usually have poor agronomic qualities such as wide variations in germination and maturation.
Salt-tolerant grasses and grains are subject to seed shattering and lodging. The foliage of salt-tolerant plants may not be suitable for fodder because of its high salt content. Nutritional characteristics or even potential toxicities have not been established for many edible salt-tolerant plants. When saline irrigation water is used for crop production, careful control is necessary to avoid salt buildup in the soil and to prevent possible contamination of freshwater aquifers.
Most importantly, salt-tolerant plants should not be cultivated as a substitute for good agricultural practice nor should they be used as a palliative for improper irrigation. They should be introduced only when and where conventional crops cannot be grown. Also, currently productive coastal areas (such as mangrove forests) should be managed and restored, not converted to other uses.
All of these limitations are impediments to the use of conventional methods for culture and harvest of salt-tolerant plants and the estimation of their production economics.
Since few crops have been subjected to selection for salinity tolerance, it is possible that variation in this characteristic may also exist.
Conversely, few undomesticated salt-tolerant plants have been examined for variability in their agronomic qualities, and it is even more likely that such characteristics can be improved through breeding programs.
Germplasm collection and classification, breeding and selection, and development of cultural, harvest, and postharvest techniques are all needed. Basic information on the way in which plants adapt to salinity would significantly assist their economic development.
Interdisciplinary communication is particularly important in research on salt-tolerant plants. Cooperation among plant ecologists, plant physiologists, plant breeders, soil scientists, and agricultural engineers could accelerate development of economic crops.
There are four sections in this report. They highlight salt-tolerant plants that may serve as food,fuel, fodder, and other products such as essential oils, pharmaceuticals, and fiber. In each of these sections, plants are described that have potential for productive use. Each section also contains an extensive list of recent papers and other publications that contain additional information on these plants. A list of researchers currently working on these plants or related projects is included at the end of each section.
Although the salt-tolerant plants described in this report typify those that are currently being evaluated or appear to deserve additional attention, the inventory is far from complete. Many other species may have equal or greater potential.
The book is extensively illustrated with black-and-white photographs. It contains much detailed information and tabulated data yet provides an interesting and readable account of the subject.
1273 92 - 14/34
Asia, India, study, field trials, plants, food, indigenous crops
GANGWAR, A.K. and P.S. RAMAKRISHNAN
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