Growing plants on atoll soils
Many years ago people living on atolls depended entirely on foods gathered from the sea and reefs and grown on land. Only a few plants, such as coconut (ni), Pandanus (bob), and arrowroot (mok-mok), could be grown on the lower rainfall atolls, although adequate groundwater conditions also allowed taro (iaraj, kotak, wot) to be cultivated. On higher rainfall atolls, breadfruit (ma) was a major food source, and banana (binana, kepran), lime (laim), and taros (iaraj, kotak, wot) could be grown. The early atoll populations were experts in growing plants that were vital to sustaining their nutrition requirements and to providing materials for thatch, basketry, cordage, canoe construction, flowers, and medicine. They knew which varieties of food plants grew well or poorly on their atolls, how to propagate them, and where on their atoll they grew best. They knew the uses of most native plants and what the various woods were well suited for. Many varieties of Pandanus (bob) and breadfruit (ma) grew well with high rainfall, but only a few produced well on drier atolls. Such information had been passed down through the generations although some of it has been lost in the last century. Today there are new plants and new varieties of existing plants that can be grown on atolls. There are also new materials and information on how to grow both the old and new plants more effectively. However, there are also introduced weeds and pests to control. Today, there is also an acute need to grow more of the useful plants adapted to atolls. Increasing numbers of people living on an atoll without an equal increase in income or food production stretches the available food supplies. Much has been written about the poor conditions for plant growth on atolls. As compared with many places in the world where crops are grown, however, atolls can provide some highly favorable conditions. For instance, the driving force for plant growth is sunlight, and on atolls light is abundant throughout the year. Except on the driest of atolls, air temperature and humidity range only within limits set by the surrounding sea. There are no cold seasons, no frosts, no cold soils, no dry winds, and no periodic plagues of insects or diseases moving from miles away. Problems of soil drainage or salinity are few and easily recognized. Nor are there problems with acid soils, soil crusting, or erosion that challenge cultivators in many other areas. On the contrary, some of the black soils at the center of wide islands rank with the best soils of Russia and the American Midwest, except for their shortage of potassium and the uncertainties of rainfall. Some of these atoll soils contain more total nitrogen than many of the world's most productive agricultural soils and, in some, the total phosphorus content is so high as to be almost unbelievable--two to five tons of the element per acre. Certainly, problems exist in growing plants on atolls. There are also some special concerns not encountered in other environments, such as the wind and salt spray near shore. The two major physical limitations, however, are inadequate rainfall in some years and in many places, and soil fertility limitations. The alkaline or ''limy'' make-up of atoll soils means that a few plant nutrients, especially iron, limit growth of many introduced plants, and this is difficult to correct. As elsewhere in the world, many--but not all--atoll soils lack enough nitrogen and/or phosphorus for high yield, and all lack sufficient potassium. There is no practical way of overcoming drought except by use of tolerant plants such as coconut (ni) and Pandanus (bob), plus collection and careful use of whatever water is available. There are opportunities to overcome nutritional limitations mentioned above, first, by intensive use of all organic debris and household wastes in small gardens and, second, by use of commercial fertilizers. Imported fertilizers are expensive, certainly, but much less so on a family basis than the equivalent costs of imported food.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE Office of Defense Programs (DP) (US)
- DOE Contract Number:
- W-7405-Eng-48
- OSTI ID:
- 756838
- Report Number(s):
- UCRL-LR-137517; HD2006400; TRN: US200510%%158
- Resource Relation:
- Other Information: PBD: 16 Feb 2000
- Country of Publication:
- United States
- Language:
- English
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