Raised fields are classified on the basis of their size, shape and topographical location. This last criterion indicates differences in adaptation to the hydrographical conditions and to the nature of the soil.
Four types of raised field are distinguished: (1) Small rounded raised fields range in size from 30 to 50 cm diameter and in height from 20 to 30 cm. They are almost invisible on the aerial photographs at 1:10,000 and were found during the ground reconnaissance.
Figure 13.3. Medium-sized rounded raised fields in the Diamant site, east of Kourou River. (Stephen Rostain)
They cover the entire surface of the seasonally flooded savannas, which are totally dry in August. (2) Medium-sized raised fields are rounded, square or rectangular (Figure 13.3). Their size ranges from 1.5 to 3 m diameter and 20 to 30 cm high. They occur in large clusters. Today, they are sometimes under forest cover and it is not possible to see them on the aerial photographs. They were raised in open areas but vegetation has grown on these areas since the Indians left. (3) Large raised fields range in size from 2 to 5 m diameter and from 30 to 100 cm height (Figure 13.4). These raised fields, generally rounded-off, are found around Kourou and Sinnamary, but they are more square or rectangular west of Cayenne Island. They are clearly visible on aerial photographs. This type of raised field is characteristic of more flooded areas and their sizes are smaller in the deepest swamps. Such raised fields are also found in eastern Suriname. (4) Ridged fields are distinguished from the other raised fields by being very long. They are elongated and narrow, measuring between 1 and 3 m wide, 5 to 30 m long and 30 to 80 cm high (Figure 13.5). They follow the slope between the sandy ridges and the swamp, and their distribution is related to the altitude and the water level. At the foot of the Quaternary sand ridges, elongated raised fields are positioned in the direction of the slope to allow easy drainage. Near the top of the sand ridges, the ridged fields are arranged perpendicular to the slope for optimal water retention. These raised fields also occur in eastern Guyana and in Suriname.
In Suriname, two types of raised fields are distinguished: regular and irregular ones. On the eastern coast and in some areas of the western coast, the regular raised fields are rounded-off rectangular to square. Their size ranges from 3 to 4 m wide, 4 to 30 m long and 50 to 100 cm high. On the western coast, irregular raised fields are located south of the artificial Hertenrits residential mound. They are distributed arbitrarily or arranged in groups of 2 to 10. They are rounded-off rectangular to oval, measuring between 3 and 6.5 m wide, 8 to 140 m long, with an average of 4-5 x 20-30 m (Boomert 1976).
Figure 13.4. Large rectangular and rounded raised fields in the Maillard site, between Kourou River and Cayenne Island. (Stephen Rostain)
Figure 13.5. Ridged fields in the Diamant site, east of Kourou River. These elongated raised fields measure 1 to 3 m wide, up to 30 m long and 30 to 80 cm high. (Stephen Rostain)
In eastern Guyana, 787 rectangular raised fields are distributed in a linear configuration. Their size ranges from 1.7 to 6.9 m wide, 5 to 8.2 m long and 50 to 170 cm high. They are associated with a residential mound along the Canje River (Plew 2005).
Along the French Guiana coast, raised fields are generally arranged in rough squares and, often, the largest are located in the deepest and wettest areas. The raised fields seem to be organized into relatively homogeneous areas that average 0.5 ha each, placed side by side. A precise stereoscopic analysis of aerial photographs combined with field data shows that the raised fields were made and distributed in accordance with differences of water level during the two annual seasons.
In fact, water is the main physical constraint. The location of raised fields between the high and low areas in the landscape suggests a careful selection by the Indians. However, this was not always enough to prevent drowning of the raised fields. For that reason, it was necessary to surround some groups of raised fields by a belt ditch (Figure 13.6). In some cases the checkerboard distribution of the ridged fields also helped control the water level. In some areas, the whole surface of the lower area is covered by raised fields, and in other areas, only the edge of the sandy ridges has raised fields.
A general study of the raised fields reveals the importance of local differences along the French Guiana coast. Four main categories of organization and types of raised fields can be distinguished from west to east (Figure 13.1). In the lower Mana, there is a unique site with perpendicular groups of parallel, ridged fields in a flooded depression (Figures 13.7, 13.8, 13.9). Between the Iracoubo and Sinnamary rivers, savannas are covered by a large number of rounded medium-sized raised fields (Figures 13.10, 13.11). Between the Sinnamary and Kourou rivers, rounded or square raised fields associated with ridged fields are located in the savannas and along the edge of the sandy ridges (Figures 13.2, 13.3, 13.5).
Figure 13.6. Interpretation of an aerial photograph (IGN 003.100 no. 52, 1955, 1/10,000), east of Kourou River showing belt ditches and other features. (Stephen Rostain)
Figure 13.7. Piliwa site, between the Mana and the Maroni rivers. This site is located in a flooded depression of circa 1.2 kms long and 150 m maximum width, between two sand ridges. The modern Kali’na village of Awala is situated on the southern sand ridge. (Stephen Rostain)
Figure 13.8. Pirliwa site, between the Mana and the Maroni rivers. Nowadays, the ridged fields are above the water level during the dry season but they are under water with only the vegetation emerging during the rainy season. When in use in the past their surfaces were probably dry all year round. (Stephen Rostain)
Figure 13.9. Map of the Pfliwa raised fields. The site is separated from the river at the west by an artificial causeway. (Drawn by Georges Clement)
Between Kourou River and Cayenne Island, rounded or square raised fields cover the savannas as between Iracoubo and Sinnamary rivers (Figure 13.4). These variations may represent cultural, chronological or technical differences.
Raised fields had two main functions: to create dry soil for cultivation and to concentrate fertile nutrients. Ditches dug in order to raise the fields served as drainage and allowed elimination of noxious gas that can be harmful for plants. Risk of root deterioration, especially for tubers, is in this way considerably reduced. The second function is to improve the soil structure. The most fertile material is concentrated in the raised fields by collecting the top layer of the savanna. The top of the raised fields is covered by secondary, mostly gramineous, vegetation. In addition, the raised field technique aerates the soil, allowing a better growth of the plants because the roots can penetrate deeper. The fields are regularly renovated with a new layer of earth and fertilized by organic matter in it. Physical and chemical limitations can be overcome relatively easily by an efficient water control and a slight improvement of the fertility.
The raised field technique is well adapted to the cultivation of tubers (this is well documented in the Lake Titicaca basin), but also for other crops. Bitter manioc (Manihot sp.), maize (Zea mays), yam (Dioscorea sp.) and sweet potato (Ipomoea batatas) could have been the main cultivated plants. When they come to maturity, manioc tubers reach depths of 25-30 cm. They never reach the water level where they could rot because raised fields are always higher than 30 cm, but roots can still reach water during the dry season.
Most of the available archaeological data suggest that maize and bitter manioc were the predominant cultigens on the raised fields of lowland South America (Darch 1983; Denevan et al. 1987; Spencer et al. 1994; Zucchi and Denevan 1979). On the middle Orinoco,
Figure 13.10. Canal in Grand Macoua Savanna, west of Iracoubo River. This canal cut the large raised fields area, connecting the sand ridge to a small water pond. It measures 573 m long and 5.3 m wide. Recent investigations have shown that this canal is modern. (Stephen Rostain)
Figure 13.11. Corossony North site, west of Sinnamary River. A causeway bordered by two canals reaches a sand ridge. The canals were dug to raise the causeway, which measures 400 m long and about 5-8 m wide. The savanna is covered by medium-sized raised fields delimited by rows of large raised fields. There is an artificial circular pond at the end of the causeway, on the slope of the sand ridge. The precolumbian settlement was probably located on the sand ridge. (Stephen Rostain)
It seems that manioc was the first main crop on raised fields, but after ca. AD 800 population growth corresponded to the introduction of maize (Roosevelt 1980). Juan Gumilla (1963) describes a predominance of bitter manioc and maize but also several other plants in the eighteenth century. Indeed, ethnography shows that Amazonian Indians generally cultivate many species in their gardens, including plants for purposes other than eating.
In French Guiana, some artifacts found on archaeological sites associated with raised fields indicate a high consumption of cultivated plants. Ceramic griddles can be used either for maize or manioc. They are particularly abundant in one site between Kourou River and Cayenne Island, suggesting that this settlement could have been specialized in griddle manufacture. Stone manos are also frequent, but metates are more rare. Cassava grating seems to have been done mainly on rough granite slabs, more than with teeth inserted into a wooden board. The lack of nutting stones in the Arauquinoid sites may mean that the inhabitants collected less palm fruits than the Ariste people, living east of Cayenne Island where no raised fields are found. Anyway, all these artifacts are related to the preparation of cultivated plants for eating.
World History
