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6. Agro-forestry and perennial cropping systems

Diversity in space
Diversity in time
Agro-forestry integration with acquaculture and livestock
Lissez-faire biocontrol
Innovation at Tomé-Açu
Revival in the Bragantina zone
The pioneer experience: Transamazon and Rondônia
The emergence of nurseries for perennial crops
Comparisons with the Old World tropics
Cash crops on the horizon
Constraints on further intensification

Many perennial crops are grown in agro-forestry systems, thereby diversifying sources of income for farmers. A strong trend to growing perennials is noted throughout the Amazon basin, even in the early phase of settlement. Our definition of agro-forestry embraces a mixture of perennials grown on the same plot. In some definitions of agro-forestry, annual food crops must be part of such systems. In the Brazilian Amazon, however, few instances are found where annual food crops are planted alongside perennials. Many polycultural perennial systems contain plants that provide important sources of food as well as cash income, such as banana. The agro-forestry systems explored here are found in home gardens as well as in separate fields.

Some farmers cultivate perennials as monocrops in small orchards. Sweet oranges (Citrus sinensis), in particular, are often grown in pure stands. Nevertheless, farmers may also have polycultural fields with a mixture of perennials, as well as diverse home gardens. The resulting farm landscapes in many areas are thus a patchwork quilt of perennial crops, annuals, pasture, second growth, and forest.

Agro-forestry and monocultural cropping with perennials investigated here are oriented strongly to markets and have not evolved primarily for food production. Although boosting the productivity of food crops is certainly desirable, attention also needs to focus on upgrading cash-cropping systems. The rural poor are not necessarily best served by focusing exclusively on food crops (Carney 1990). Nutritional gains can be achieved by increasing the income of farmers, so that they can purchase or barter for foodstuffs. In the vicinity of Ouro Preto in Rondônia, for example, farmers who cultivate perennials have generally fared better than those who rely on annual crops (Southworth, Dale, and O'Neill 1991).

Heavy reliance on annual food crops in upland areas is understandable during early phases of settlement, but yields generally decline rapidly and farmers must move on to open new patches in the forest, or intensify production on existing cleared areas by shifting to perennials, as in the Bragantina zone (Egler 1961). Annual crops, such as rice, maize, and beans, are typically cultivated during the first phase of settlement in forested areas, but continued reliance on these crops for cash and subsistence often leads to farm failures (Leonard 1989). Perennial cropping systems are helping to revive several "failed" colonization efforts in the region (Homma et al. 1992a).

Two features are typically found with successful farmers in the Brazilian Amazon: the deployment of perennial crops and/or mixed farming with livestock (Veiga and Serrão 1990). One JapaneseBrazilian with a 25 ha farm near Igarapé Açu, Pará, for example, has 4 ha in African oil-palm (Elaeis guineensis), 3 ha of lemon (Citrus limon), 3 ha of passionfruit (Passiflora edulis), 1 ha of "Sunrise Solo" papaya (Carica papaya), as well as several hectares of vegetables grown for market. Livestock provide manure for crops and aqua-culture, and diversify sources of income.

Agro-forestry systems can play a vital role in helping Amazonian agriculture become more sustainable because of the wide array of environmental services they perform. For example, protecting soil from excessive soil erosion or compaction is essential to the long-term viability of land-use systems (Fernandes and Serrão 1992; Smith 1990). Agro-forestry systems are especially appropriate for the humid tropics since they address many of the ecological problems associated with farming, such as helping to conserve soil moisture and fertility (Nair 1991; Nair and Dagar 1991; Padoch et al. 1985; Peters and Neuenschwander 1988: 34). Indeed, diversity and information, rather than energy and chemicals, are the linchpins of sustainable agriculture (Ryan 1992: 35), and polycultural systems employing perennials exemplify this principle.

Diversity in space

Home gardens

Home gardens are the most diverse agro-forestry systems encountered in the Brazilian Amazon, a reflection of the desire to group numerous useful plants close to the kitchen, to offer shade, to provide a forum for trying out novel crops, and to serve as living pharmacies for treating a wide array of afflictions. A total of 74 perennial plant species, excluding ornamentals, medicinal plants, and vegetables, were found in just 31 home gardens in upland areas of the Brazilian Amazon (appendices 3 and 4). If all plants are considered, several hundred species are undoubtedly cultivated in home gardens throughout the Brazilian Amazon. Women are especially important in recruiting plants for home gardens and in experimenting with novel crops.

The home gardens of people native to the region are especially rich in species, and contain a variety of plants for food, fibre, medicine, and aesthetic pleasure. Immigrants to Amazonia, such as from the North-east region and from Japan, are also quick to adopt diverse home gardens. The number of species in home gardens ranged from four in the case of a recent arrival from Maranhão, to a high of 25 around the home of a long-time resident of Pará, The extraordinary richness of home gardens has been noted in other parts of the Amazon basin; at Santa Rosa along the lower Ucayali, for example, two home gardens had 74 and 73 annual and perennial plant species, respectively, with only 34 species in common (Padoch and de Jong 1991).

Home gardens typically contain a mixture of exotic and native species (appendix 3). Of the 74 species found in our home garden sample, approximately 46 per cent are indigenous to Amazonia and some 27 per cent are from the Old World. A precise breakdown is not possible, because the origins of some tropical perennials are obscure, and the precise identity of some of the species is uncertain. Two of the most common perennials in home gardens are from the Asian tropics: mango (Mangifera indica) and sweet orange. Other, more recent exotics are finding their way into backyards, such as Barbados cherry (Malpighia glabra), an indication of the willingness of farmers to experiment with new possibilities.

Home gardens serve as important launching pads for exotic crops. By planting a few individuals of an unknown crop in the backyard, a farmer makes a minimal investment while observing its performance and trying its products. Home gardens also serve as "low-cost" arenas for trying out new domesticates. When clearing forest or old second growth for their home-sites, farmers sometimes leave native trees if they are deemed useful. Forest vestiges often produce seedlings in home gardens, where they are tended. Another way that wild species enter the proto-domestication stage is when seedlings sprout spontaneously in house yards, either as a result of natural dispersion from surrounding vegetation or from seeds discarded by family members. Wild species are also deliberately planted, as in the case of a farmer in the Lastancia Community near Itupiranga, Pará, who planted towering buriti (Mauritia flexuosa) in the backyard. Buriti palm is normally found along rivers and on poorly drained savannas and its fruits contain generous amounts of vitamins A and C. Home gardens are thus propitious "hunting grounds" for promising new crops in Amazonia and could serve as important sources of germ plasm for agroforestry and perennial cropping systems.

Several trees in forest or old second growth are deliberately left in home gardens when clearing a homestead, including jangada, embileira, piquia (Caryocar villosum), babaçu (Attalea speciosa), and morototó (Didymopanex morototoni; appendix 4). Spontaneous seedlings of wild cacao (Theobroma cacao), Brazil nut, babaçu, and bacaba (Oenocarpus distzchus) are sometimes protected in home gardens. The age-old process of plant domestication around homesites, often cited as one of the principal sites for crop origins, continues.

Home gardens sometimes "spill over" into adjacent fields. In some cases home gardens and cleared fields form a continuum, whereas in other instances the separation of door yard gardens and fields is abrupt. The pronounced dry season in eastern and central Amazonia is sometimes cited as the main reason farmers do not replicate the complexity of their home gardens in fields. Seedlings of perennial crops often perish before the regular rains return.

Polycultural fields

Agro-forestry configurations vary considerably throughout the Amazon, a testament to the innovative spirit of farmers. Ninety-seven distinct agroforestry configurations were noted on small and medium-sized farms in Pará, Amazonas, Rondônia, and Acre (appendix 2). Farmers are clearly conducting experiments on a gigantic scale. Of the 97 configurations noted, only 11 were encountered on more than one occasion. The most common association, black pepper (Piper nigrum) and orange, was found five times in the sample of 121 fields with mixed perennial crops. The second most common combinations were manioc (Manihot esculenta) and banana, and manioc and orange, with four occurrences each. A strong trend towards diversifying fields with a considerable repertoire of perennial crops is thus discernible throughout the Brazilian Amazon. A remarkable diversity of agroforestry systems is evident in areas of dynamic growth as well as in more isolated areas with traditional farmers.

Farmers deploy a range of perennials to achieve diversity in time as well as in space. Sixty species were found in 121 polycultural fields involving perennials (appendix 5). About seven species are found relatively frequently: orange, cupuaçu (Theobroma grandiflorum), black pepper, manioc, cacao (Theabroma cacao), rubber (Hevea brasiliensis), and banana. The first three crops, orange, cupuaçu and black pepper, are among the most profitable cash crops. Cacao and, especially, rubber are currently declining in importance. Interestingly, Brazil nut was found in 12 agro-forestry configurations, a clear indication of the rapid transition of the giant tree from an extractive species in forest to a crop.

As in the case of home gardens, polycultural fields contain a mix of indigenous species and exotics. But agro-forestry systems in fields contain a much higher proportion of exotics than do home gardens. Only about onethird of the species found in the sampled polycultural configurations in fields are native to Amazonia - a finding that belies the oft-heard recommendation that agricultural development should focus primarily on indigenous species. Although increased attention to the native plants of Amazonia is certainly warranted, progress in raising yields and incomes for rural folk also hinges on the timely introduction of crops from other regions, and even other continents.

Nevertheless, most of the crop combinations in polycultural fields involve only two or three species. It is not surprising that polycultural fields are less diverse than home gardens; the investment is much greater in fields, so fewer risks are taken. Greater diversity in fields was noted in areas dominated by more traditional farmers. Four kilometres from Itacoatiara along the road to Manaus, Amazonas, for example, one farmer who grew up in the area maintained a field interplanted with guaraná (Paullinia cupana), lime (Citrus aurantifolia), mango, pineapple (Ananas cosmoses), coconut (Cocos nucifera), cashew (Anacardium occidentale), avocado (Persea americana), jackfruit (Artocarpus heterophyllus), and guava (Psidium guajava). Several Brazil nut trees and tucumã (Astrocaryum aculeatum) had been spared when the forest was cleared. The polycultural fields cultivated by peasants (caboclos, colonos, pequenos produtores) do not generally contain as rich a mixture as is often found among indigenous groups, where numerous crop species and varieties are commonly planted in a single field (Dutour 1990; Lathrap 1970: 59; Parker et al. 1983).

Diversity in agricultural systems can lead to greater "sustainability" up to a point. Greater diversity does not necessarily mean greater stability or productivity in agro-ecosystems, nor are indigenous fields always polycultural. In the most productive ecosystems, species diversity typically declines (Pimm and Gittleman 1992). Species simplicity does not necessarily lead to instability (Pimm 1984). Furthermore, some indigenous polycultural swiddens are actually dominated by one or two crops. Among the Witoto and Andoke in the Colombian Amazon, for example, manioc, typically accounts for much of the planted area in fields (Eden 1988). Some indigenous groups cultivate mainly monocultural fields, such as manioc, among the Kuikuru and Piaroa, and banana and plantain in the case of the Emberá and Shipibo (Beckerman 1987).

As long as the mix of perennials helps protect the soil and provides some buffer to fluctuations in commodity prices and disease epidemics, reliance on two or three species for the bulk of agricultural production and income will probably work. Many of these agroforestry systems, however, are highly dynamic, with some perennials being replaced by others after several years. Agro-forestry systems, including managed fallows, can remain productive for decades and provide appreciable income when close to markets, as along the lower Ucayali (Padoch et al. 1985).

Diversity in time

Four main crops have served as "launching pads" for agro-forestry in the Brazilian Amazon: black pepper, cacao, coffee (especially robusta coffee), and manioc, (appendix 2). Interestingly, two of these mainstays of polycultural systems are exotics: coffee and black pepper. Each of the four main cash crops has served as a springboard for diversifying farming operations for different reasons - black pepper after disease took a serious toll, cacao and coffee because of a sharp drop in prices in the late 1980s, and manioc, because it has traditionally served as the last crop in swidden fields before the plot is abandoned to second growth.

Instead of allowing a field to go fallow, some farmers are prolonging its useful life by opting for agro-forestry. A similar trend is noted on Borneo where some small farmers are planting perennials, such as rubber and durian, instead of allowing swidden fields to go fallow (Brookfield, Potter, and Byron 1995). In the sample of 121 polycultural fields, manioc, was present in 25, and the hardy tuber cultigen was the fourth most common crop in sampled polycultural fields (appendix 5). The tendency to interplant longer-lived perennials with manioc, is particularly noticeable in the Santarém area (appendix 2).

Farmers know that black pepper will eventually fall victim to Fusarium wilt so they often interplant other perennials, such as passionfruit or oil-palm, so that the land still produces income as the black pepper is phased out. As Fusarium symptoms become progressively worse, farmers gradually replace black pepper with other perennials, such as African oil-palm, passionfruit, Barbados cherry, or cupuaçu Even so, black pepper is still the main "money earner" for many farmers engaged in market-oriented agro-forestry systems in the Brazilian Amazon; the labour-intensive crop is the third most common component in the sample of 121 polycultural fields (appendix 5).

In this manner, farmers incorporate diversity into their cropping systems over time. Black pepper paves the way for other crops because fertilizers enrich the soil and rice husks, often placed around the base of black pepper plants, help build up organic matter.

Some of the intercropped perennials are productive for only a few years, so the composition of agro-forestry systems is highly dynamic. Passionfruit, for example, normally produces for only three to five years. Longer-lived perennials are often intercropped as the passionfruit vines mature; one farmer in Tomé-Açu, for example, has intercropped his passionfruit field with various timber trees. A farmer near Capitão Poço has intercropped his passionfruit with longer-lived sweet orange and annatto (Bixa orellana) trees (fig. 6.1). At Sitio Andiroba, near Castanhal, a 25 ha field formerly planted to passionfruit and papaya was replanted with sweet orange after the productivity of the former intercrops declined. With periodic doses of NPK fertilizer, the 5,000 trees in the 25 ha orchard produce about 2.7 kg of oranges per tree every year.

Agro-forestry integration with aquaculture and livestock

Many farmers have prospered in the Brazilian Amazon by integrating agro-forestry with livestock and aquaculture. Only a few examples are given here to illustrate the increasing importance of cattle-raising for small farmers. Smallholders employ cattle manure to fertilize their cash crops as well as their vegetable gardens for home consumption and market. For example, a Paraense farmer along a sideroad at km 105 of the Marabá-Altamira stretch of the Transamazon Highway collects cow manure to enrich potting soil for cupuaçu seedlings. This farmer, also the leader of the rural workers' syndicate for the municipality of Itupiranga, raises cattle on 25 ha of pasture; the remaining 125 ha on his lot are in crops, forest, and second growth.

At Granja Yoshirokato near Santa Isabel in the Bragantina zone, chicken manure fertilizes ponds that contain tilapia, which in turn are fed to highly prized pirarucu (fig. 6.2). When the pirarucu reach 2-4 kg, the owner sells them to other farmers and ranchers to stock ponds. Dead chickens are also fed to the carnivorous pirarucu. The medium-sized farm, which operates without fiscal incentives, also produces citrus, guava, and other fruits for the growing Belém market. Black pepper farmers in the Brazilian Amazon take advantage of chicken manure when it is available to cut down on the cost of inorganic fertilizers.

Cattle-raising is also sometimes integrated with agro-forestry and perennial monocropping systems, particularly as a source of manure. On the Rio Branco ranch near Ariquemes, Rondônia, for example, cattle manure is applied to 45 ha of citrus orchards, mainly the Pêra variety of orange. Sweet orange is planted at various locations on the 7,000 ha property, half of which remains in forest. Even at the rate of 30 kg of dung per seedling, however, cattle manure is only a supplement to the commercial fertilizers needed to establish an orange grove. Orange seedlings are also given 500 g of lime and 400 g of superphosphate, together with some micro-nutrients such as zinc and sulphur, to help get them started. By diversifying their farm operations, ranchers and growers reduce fertilizer costs and are better insulated from the wild price swings typical of many commodities.

At least one Japanese-Brazilian farmer in the vicinity of Tomé-Açu is contemplating diversifying into cattle production, in part to generate manure for his perennial crops. A shift by the Japanese-Brazilian community to cattleraising is significant, since it underscores the strong market forces favouring cattle production in Amazonia.

A farmer from Rio Grande do Sul with a 100 ha lot at km 74 of the Altamira-Itaituba stretch of the Transamazon derives a variety of benefits from his small herd of cattle. Livestock manure is used for fertilizer and to generate gas for cooking, lighting, and refrigeration. The mixed farm is planted to cacao and an assortment of other crops, and has 30 head of cattle. Dung from the cattle is fed into a rudimentary biogas digestor and the resulting methane is piped into the home to fuel a stove, two lights, and a couple of refrigerators. When the biogas digestor is cleaned out, the residue is placed on a vegetable plot.

Complementarities also exist between farmers devoted exclusively to agro-forestry and nearby cattle ranches. For example, several oilpalm factories have sprung up in the Bragantina zone to serve large and small growers. After the oil has been extracted, the pressed kernels are sold to ranchers for cattle feed. Similarly, small factories established to express castor oil sell the pressed seeds to ranchers for feed. Castor bean is a cash crop for small farmers in parts of Pará, and exemplifies the strengthening integration of livestock and crop production in Amazonia.

Laissez-faire biocontrol

Few farmers routinely use pesticides on their perennial crops in the Amazon, and then only sparingly. Vegetable growers, particularly near the major cities, use the most pesticides. The high cost of pesticides is a major constraint to their use. Experience is showing, however, that growing perennials in discrete patches or in mixed cropping systems often reduces the need for pesticides. Also, patches of forest and old second growth may allow biocontrol agents to thrive, as appears to be the case with oil-palm plantations along the PA 150 road in Pará, Much research remains to be done, however, to understand the interaction of crops and pest populations, and the role of vegetation in suppressing or encouraging pests.

The owner of the Rio Branco ranch near Ariquemes, Rondônia, notes that orange trees appear more vigorous near a strip of exotic bamboo he has planted along the road dividing his property. The bamboo was originally planted for ornamental purposes, but the rancher plans to plant more near his orange plantings. Bamboo's effects on the orange orchards are unclear; the perennial grass may be benefiting the orange trees by providing a haven for predators of insect pests, or it may be serving as a windbreak. Elsewhere in pioneer areas of Amazonia, bamboo is planted as a door yard plant for construction material; Japanese-Brazilians also harvest bamboo shoots for a variety of dishes.

Innovation at Tomé-Açu

Tomé-Açu in central Pará, has proved a particularly innovative pole for agricultural development in eastern Amazonia. Many of the most productive cash crops and intercropping systems in Amazonia were first tried out by Japanese farmers in the Tomé-Açu area, some 130 km south of Belém A similar pattern of eager experimentation with perennial cash crops has been noted among Japanese farmers in the Bolivian Amazon (Hiraoka 1980b: 117).

Japanese immigrants founded Tomé-Açu in 1929, and began their malariastricken pioneer life by growing upland rice (Oryza saliva). Rain-fed rice yields were disappointing on the poor oxisols, so the Japanese settlers began planting black pepper on a commercial scale in 1947 and it soon became the main cash crop (CAMTA 1975; Staniford 1973: 46). Farmers at Tomé-Açu planted black pepper as a monocrop, and then abandoned their plantations to second growth after about a dozen years. Now farms are much more intensively managed, with few areas left to fallow.

Even though black pepper is not as dominant as formerly at Tomé-Açu and elsewhere in Amazonia, the high-value crop still provides a good return. No effective treatment for Fusarium, caused by Fusarium solani f. sp. piperis, has emerged. First reported in Pará, in 1957, the fungal disease destroys black pepper plantations after about eight years. Far from "dooming" black pepper cultivation (Fearnside 1980a), however, farmers can still make handsome profits from black pepper for the first few years in spite of the ravages of Fusarium. A well-managed black pepper plantation can produce 3 kg of peppers/ plant/year (Penteado 1968: 128).

Although black pepper is still grown extensively, other crops, such as cupuaçu and passionfruit, are increasingly important. cupuaçu is the second most commonly planted crop in the sample of 121 polycultural fields (appendix 5), and Japanese-Brazilian farmers in the Tomé-Açu area are already dispatching frozen cupuaçu pulp to markets in the United States. Recently, for example, the R. W. Knudsen Company of Chico, California, began selling a "cupuassu" fruit drink containing a blend of white grape juice, mango pulp, translucent cupuassu pulp, papaya pulp, passionfruit juice, and hibiscus flower extract. Knudsen buys most of its cupuaçu pulp from Tomé-Açu, and also uses it to flavour its guanabana and calamansi juices, as well as its rain-forest fruit spreads and Rainforest Mist Spritzer (Kevin Kimbell, pers. comm.).

Tomé-Açu accounted for 327,128 kg of cupuaçu pulp produced in Pará, between 1984 and 1990, approximately 60 per cent of the state total (Falesi and Osaqui 1992). Much of the cash-crop production in the Tomé-Açu area is marketed by CAMTA (Cooperative Agricola Mista de Tomé-Açu) a co-op run by Japanese-Brazilian farmers. In 1989, passionfruit and cupuaçu accounted for 7 and 3 per cent, respectively, of CAMTA's receipts; by 1990 their proportion had grown to 23 and 8 per cent, respectively. Many farmers at Tomé-Açu have thus diversified their operations with a suite of perennial crops. Black pepper often remains the financial foundation for farmers in the Tomé-Açu area until other perennial crops become established.

A major reason that Tomé-Açu has prospered over the years is that the farmers have focused on cash crops and set up a cooperative with marketing skills and a mandate to experiment with new crops. CAMTA was formed soon after Japanese settlers arrived at Tomé-Açu, and has provided credit and marketing facilities. Flexibility in the face of constantly changing environmental conditions is the key to the success of farmers at Tomé-Açu (Barros 1990: 39). The generally well-managed CAMTA cooperative has helped farmers to adapt to shifts in markets and challenges to crop productivity. In 1988, for example, CAMTA was marketing over 25 different crops, a much more diversified base for farmers than in 1968 when black pepper accounted for 99 per cent of the co-op's sales (Barros 1990: 59, 67).

Another factor in the continued success of many farmers in the Tomé-Açu area is that facilities have been built to process some of the agricultural products for market. With support from the Japanese Development Agency (JICA), CAMTA built a plant for processing pulp from such fruits as cacao, cupuaçu "Keitt" mango, bacuri (Platonia insignia), cashew, Barbados cherry, and açai (Euterpe oleracea) palm. Inaugurated in 1987, the plant separates the fruit pulp, using a mixture of machinery and manual labour, freezes the pulp in plastic bags, and then sends them to major urban markets, particularly Belém. About 3 tons of passionfruit are needed to make 1 ton of juice, and the CAMTA plant processed 30 tons of passionfruit juice in 1991.

Sporadic outbreaks of cholera in the Brazilian Amazon in 1991 and 1992 temporarily dampened demand for fruit juices and ice-cream, thereby adversely affecting some growers. Generally poor hygiene standards in the region have facilitated the spread of the pathogen down the Amazon from Peru. By 1994, however, the disease appeared to have run its course. Another reason Japanese-Brazilian farmers have often fared so well is that some of them have spent months or even years working in Japan to generate savings, some of which were invested on their farms around Tomé-Açu and in the Bragantina zone. This practice was particularly common during the height of the recession in Brazil during the late 1980s and early 1990s.

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