Flood-plain orchards

At first glance, flood plains might appear to be inappropriate for perennial crops. Although flood plains seem flat from the air, they are a complex of ridges, swales, and broad terraces. Some parts of the flood plain may be swamped for seven months or more, while higher portions may be under water for a month or less. Still other areas of the flood plain may be inundated only every 5-15 years or so during exceptional floods. Subtle but significant differences in topography create many micro-environments for different crops.

Many economically viable perennials are suited to the varied drainage conditions of flood plains in Amazonia. At least 80 species of perennials are grown in home gardens of the middle Amazon flood plain (Smith in prep.). Some of the plants are relatively well known, such as the palms agai (Euterpe oleracea) and buriti (Mauritiaflexuosa), while others are in the process of domestication. Home gardens contain a wealth of species and varieties adapted to the Amazon flood plain, some of which could be grown on a larger, commercial scale.

Açai palm, for example, is already an important component of riverine vegetation in many parts of Amazonia, particularly in the estuarine area, but is not common along the middle Amazon. açaí, is harvested from natural and planted stands for its fruit and heart-of-palm (Anderson 1990b). Agai fruit finds a ready market in both rural and urban areas, where it is mixed with manioc flour to make a thick, purple porridge; taken with water as a refreshing "milk" shake; and made into ice-cream. More flood-plain forests could be enriched with this graceful palm to boost food production and diversify sources of income, particularly near the mouth of the Amazon.

Numerous other native fruit trees thrive on the flood plains of white and clear water rivers, such as buriti palm, cajá (Spondias mombim), and cacao. Extensive stands of buriti palm are found along the upper Amazon, particularly between Leticia and Iquitos, but they are being felled to harvest the vitamin C-rich fruits. Improved harvesting techniques, and replanting devastated areas with this towering palm, would help ensure plentiful supplies of nutritious buriti fruit for generations to come.

Indigenous nuts, such as sapucaia (Lecythis pisonis), are a common backyard tree on the middle Amazon flood plain. Sapucaia also occurs in the remaining forest patches and could be planted more extensively in orchards and second-growth communities. Specimens of sapucaia on the flood plain are much shorter than populations in upland forests, so the nut cases can be harvested before the lid falls off and bats abscond with the nuts. Sapucaia rivals the better-known Brazil nuts in taste; indeed, to some, sapucaia nuts are creamier and more savoury than their distant cousin, the Brazil nut.

Although some time might be required before desirable selections of sapucaia are available for more widespread planting, other perennial crops well adapted to the flood plain could be promoted for planting in polycultural orchards or single stands. cupuaçu, for example, thrives on higher parts of the flood plain, and could become a viable cash crop along the Amazon, particularly if floating pulp processing plants could be established. With the help of simple freezers, upland-based farmers' and growers' associations are marketing ever-increasing quantities of cupuaçu for the ice-cream and juice trade. Flood-plain farmers are being bypassed by the cupuaçu boom; small, barge-based agro-industrial plants combined with cheap water transportation could help rectify the situation. Large, low-fibre selections of mango, such as "Kent" and "Keitt," might also help flood-plain farmers boost their incomes.

Tree crops thus provide many benefits and warrant more attention on the várzea. Labour costs are lower than for most annual crops, and discarded or rotten fruit and nuts provide food for fish. Several species of forest trees are tended in home gardens for fish bait, such as tarumã (Vitex cymosa) and catauari (Crutnevu benthami), and some of them could be grown in larger agro-forestry fields to supply upland-based fish farmers. Within the past two decades, fish culture has progressed to the point that some pond-raised species are already reaching the market, as in the case of tambaqui (Colossoma macropomum) from ranches in the vicinity of Rio Branco, Acre. Tambaqui is one of the most commercially valuable fish in Amazonia and, although an omnivore, depends heavily on fruits and seeds in the wild. In fish ponds, tambaqui thrives on starchy rations, but its flavour is reputedly not the same as wild tambaqui. Fish farmers might well be interested in buying fruits and nuts favoured by tambaqui to improve flavour and conditioning, particularly just before the fish are harvested for market.