Local soil knowledge and site suitability evaluation in the Dominican Republic

Geoderma 111 (2003) 289 – 305 www.elsevier.com/locate/geoderma

Local soil knowledge and site suitability evaluation in the Dominican Republic Roy Ryder * Department of Earth Sciences, University of South Alabama, Mobile, AL 36688, USA

Abstract Mounting evidence shows that soil surveyors can learn a great deal from traditional farmers. Most studies of local soil knowledge, however, focus on unique cultural groups with centuries of accumulated knowledge of their environmental surroundings. Many farmers in the developing world are non-indigenous peasants who do not benefit from a rich cultural tradition. This paper examines peasant agriculture and awareness of soil in the Central Cordillera of the Dominican Republic. Information on soils was extracted from a geo-coded environmental database compiled by the Dominican Republic’s State Secretariat for Agriculture and processed to produce site suitability ratings for six land uses (coffee, beans, grazing, pigeon peas, garlic, and rice). Farmer information dealing with environmental perception, agricultural technology, and agricultural decision-making factors was obtained in a field survey of 80 farmers. Survey statistics on technology were used to derive a numerical index of modern agricultural technology while factors conditioning choice of principal enterprise were examined using point score analysis. It is shown that peasant farmers in the Dominican Republic use a blend of modern and traditional methods that is neither productive nor ecologically sensitive. In addition, their soil taxonomy is comparatively unsophisticated. On the other hand, this study demonstrates that their empirical knowledge of site suitability is of great value for verification of scientific site suitability ratings derived from parametric indices. It is concluded that the participatory approach to agricultural research and development is particularly relevant in soil survey. D 2002 Elsevier Science B.V. All rights reserved. Keywords: Local soil knowledge; Ethnopedology; Land evaluation; Environmental perception; Participatory soil survey; Dominican Republic

* Tel.: +1-251-460-6381; fax: +1-251-461-1487. E-mail address: [email protected] (R. Ryder). 0016-7061/02/$ - see front matter D 2002 Elsevier Science B.V. All rights reserved. PII: S 0 0 1 6 - 7 0 6 1 ( 0 2 ) 0 0 2 6 9 - 0

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1. Introduction While local knowledge systems of traditional farmers must not be idealized, they are widely respected and offer invaluable guidelines for development planners (Weinstock, 1984; Blaikie and Brookfield, 1987). Mounting evidence shows that soil surveyors can learn a great deal from traditional farmers (Sillitoe, 1998; WinklerPrins, 1999; BarreraBassols and Zinck, 2000). Sophisticated local folk taxonomies have been documented in South America (Ashby, 1985; Hecht, 1990; Sandor and Furbee, 1996), Central America (Williams and Ortiz-Solorio, 1981; Wilken, 1987, 1989; Dunning, 1992), Africa (Osunade, 1988; Tabor, 1992; Dialla, 1993; Birmingham, 1998; Steiner, 1998; Gobin et al., 2000), and Asia (Conklin, 1957; Scott and Walter, 1993; Sillitoe, 1995, 1998). Most studies of local soil knowledge, however, focus on unique cultural groups with centuries of accumulated knowledge of their environmental surroundings. Many farmers in the developing world are non-indigenous peasants who do not benefit from a rich cultural tradition. Of particular concern are 20th century colonists who have thrust the agricultural frontier into rain forest or marginal steeplands. They often find themselves in unfamiliar environments and can draw upon the experience of only a limited number of generations. What is known about the local soil taxonomies of peasant farmers? Is it worthwhile for the soil surveyor to investigate their local soil knowledge? This paper is a synthesis of dispersed research publications on peasant agriculture and awareness of soil in the Central Cordillera of the Dominican Republic. WinklerPrins (1999) emphasizes the need to integrate local and scientific knowledge of the environment while Tabor (1992) recommends that soil surveyors communicate with farmers and herders to determine the relative productivity of soil types and their value for agriculture, forestry and range. The objective of this study of the Dominican Republic is to demonstrate how development planners can take advantage of local soil knowledge to calibrate the resource evaluation techniques that are a fundamental component of land management plans. It is shown that peasant farmers of the Dominican Republic use a blend of western and traditional methods that is neither productive nor ecologically sensitive and they possess a comparatively unsophisticated soil taxonomy. Nonetheless, they have farmed the region long enough to know which sites are suited to particular land uses. As a result, their empirical knowledge of site suitability is of great value for verification of scientifically derived site suitability indices.

2. Materials and methods 2.1. Study area Like other developing nations, the Dominican Republic is faced with rapid population growth and inefficient food production that does not satisfy local needs. The national diet is supplemented with food imports while extensive areas of prime farmland are exploited by large landowners to produce sugar cane (Saccharum officinarum L.), coffee (Coffea arabica L.), cacao (Theobroma cacao L.), tobacco (Nicotiana tabacum

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L.), and meat for export. Less privileged peasant farmers who produce food for subsistence or for the domestic market have invaded steep mountain slopes, cut down the forest, cultivated without conservation techniques and caused devastating soil erosion. The study area is Las Cuevas watershed which covers approximately 600 km2 of the southwestern flank of the Central Cordillera (Fig. 1). It is one of the most poverty-stricken regions in the Dominican Republic. Mulatto, Hispanic farmers, use a fallow system to cultivate both subsistence and cash crops on marginal steep terrain. Social strata include landless peasants, a large number of small farmers who depend on occasional off-farm income, some owners of middle-sized farms, and a privileged minority of large landholders. Land is unevenly distributed with 77% of the farmers cultivating only 14% of the farmland (Nova, 1984). The main short-cycle cropping combination is beans (Phaseolus vulgaris L.) inter-planted with pigeon peas (Cajanus cajan (L.) Millsp.), corn (Zea mays L.), cassava (Manihot esculenta Crantz) and other crops. Some small patches of floodplain and terraces in the western part of the watershed are irrigated and used for rice (Oryza sativa L.) rotated with beans or peanuts (Arachis hypogaea L.). A few farmers cultivate garlic (Allium sativum L.). The only major permanent crop is coffee. About twothirds of the drainage basin has unimproved pasture for cattle (Tirado and Lugo-Lopez, 1984). Elevation ranges from 420 m in the west to over 2500 m in the east but rugged topography prevails throughout the drainage basin. Mountains in the eastern and central watershed are underlain by a large variety of igneous and sedimentary rocks. On the other hand, sedimentary rocks prevail at lower altitudes in the western dissected hill country. Rare gentle slopes are found on the narrow alluvial floodplain and terraces of the Las Cuevas River. The low-altitude western sector has a hot semi-arid climate while cool humid conditions are found in the eastern mountains. Seventy five percent of the watershed has shallow stony Entisols (Troporthents, Ustorthents, Torriorthents) that have been assigned USDA Land Capability ratings of VII or VIII by Dominican surveyors (SEA, 1987) and are considered suitable only for woodland and wildlife. Portions of the central watershed with relatively recent igneous rocks are characterized by Inceptisols (Dystropepts). Like the Entisols, however, these soils are associated with steep slopes, are assigned a rating of VI, and are considered capable only of sustaining pasture and permanent crops. None of the watershed’s soils are recommended for shortcycle crops. 2.2. The environmental survey This study of local soil knowledge was carried out together with analyses of site suitability, agricultural decision-making, environmental perception, and agricultural technology which are described elsewhere (Ryder, 1993, 1994a,b,c, 1998). The multifaceted investigation was structured to build upon unique geo-coded environmental information collected in 1982 by the Dominican Republic’s State Secretariat for Agriculture (SEA) at 350 randomly located survey sites in the Las Cuevas watershed. The sampling scheme was designed by Antonini et al. (1985a). First, a map of the watershed was covered by a grid containing 2312 cells with dimension 0.5
0.5 km. A

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Fig. 1. Location of Las Cuevas watershed.

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random selection was made of 15%, or 350, of the cells. Secondly, each chosen cell was subdivided into 25 sites of 100
100 m of which one was selected at random for field investigation. Field surveyors were allowed to repeat the selection of the 100
100 m site if they considered the initial selection atypical of the 0.5
0.5 km cell. Soils were described in the field and samples were collected for laboratory analysis in the Dominican Republic and at the University of Florida. Laboratory analysis procedures are specified in Ledesma (1983), Antonini et al. (1985b), and Jerez (1985). The spatial resolution of the environmental survey, therefore, is a soil profile considered representative of a 100
100 m site that, in turn, is deemed typical of a randomly selected 0.5
0.5 km cell. 2.3. The farmer survey In 1986, the author plotted the soil survey sites on topographic maps, scale 1:50,000, using coordinates corresponding to the 0.5
0.5 km cells and 100
100 m sites described above. The sites were identified subsequently in the field to observe current use and to determine ownership, using contours, stream networks, trails and other cultural features. Distinguishable environmental site characteristics—slope, drainage, erosion, stoniness, soil depth—were compared to those recorded in the 1982 soil survey in order to confirm site identification. Local farmers served as field guides and aided in determining ownership patterns. A total of 99 sites belonging to 80 farmers were found to be dedicated to crops, fallow or pasture. The multi-dimensional investigation was directed to this sample of 80 farmers. In 1984, Montanez (1985) examined the environmental perception of 211 Las Cuevas farmers who were selected at random from 2154 farmers registered in the national cadastral archives. That database was compared statistically to the author’s 1986 sample using v2 and Kolmogorov tests (Ryder, 1989). The comparative analysis showed no significant difference in farmer age, farmer education, farm ownership, farm fragmentation, or spatial distribution of farmer residences. Each of the 80 farmers was interviewed at home, using a questionnaire that was pretested with the assistance of farmers recommended by SEA officials. Farmers with land containing more than one survey site discussed only the site that they considered of most importance to their livelihood. The spatial resolution of each farmer’s discussion was the plot of land containing the environmental survey site. The questions dealt with land evaluation, environmental perception, agricultural decision-making, and agricultural technology. As most Las Cuevas farmers are illiterate, the survey was implemented orally. To maintain consistency in the oral interview process, all farmers were surveyed in person by the author and questions were read aloud from a typed questionnaire. 2.4. Site suitability analysis Out of 80 farmers, 39 (49%) declared coffee to be their principal agricultural land use. Other major enterprises identified were beans (34% of the farmers), grazing (13%), pigeon peas (2%), garlic (1%) and rice (1%). The Las Cuevas soil survey information

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was used to compute a site suitability index for these six land uses at each of the survey sites. Suitability index computation is an established land evaluation procedure that is useful for determining suitability of specific sites, individual cells in a geographical information system, or specific soil taxa. The index is often referred to in the literature as a parametric index (Riquier, 1974; Conant et al., 1983; Davidson, 1986) although the frequency distribution of the values of the index does not necessarily conform to a standard statistical distribution. Applications of the method in North America include early work by Storie (1933, 1950, 1964) in California and subsequent research by Fenton (1975) in Iowa and Huddleston (1982, 1984) in Oregon. The procedure for site suitability analysis applied in the Las Cuevas project is explained at length in Ryder (1994a). Specific environmental requirements for each of the six land uses were identified in the scientific literature. Information on slope and most relevant soil characteristics was available for analysis. Climatic data were not available but elevation was used as a crude surrogate for temperature regime. Ranked categories for each land characteristic were assigned numerical scores according to their suitability for the land use concerned and these scores were used to compute a multiplicative parametric index of site suitability. To permit comparison of the author’s numerical site suitability measures to ordinal farmer opinions of suitability the parametric index values were classified into one of four ranked site suitability ratings: very good, good, mediocre, or bad. The ordination procedure is outlined in Ryder (1994a) and is based on the following conceptual scale of productivity. The numerical suitability index may be considered a percentage of maximum productivity with optimum value 1.00 (100%) and minimum value 0.00 (0%). Given the multiplicity of site characteristics affecting productivity, few sites can be expected to provide optimum yields. It was assumed, therefore, that farmers consider yields from 90% (0.90) to 100% (1.00) of the optimum as very good. It also was assumed that farmers consider yields good if between 0.70 and 0.90 of the optimum, mediocre between 0.50 and 0.70, and bad when less than 0.50. Once a site suitability index is defined as a function of specific site characteristics, its application becomes straightforward, quantitative and consistent. The reliability of the index, however, can be affected by potential sources of error including the interaction of environmental characteristics. Thus, good drainage is recommended for beans but imperfect drainage may be advantageous and worthy of a high score at sites with coarse-textured soil and marginal rainfall (Sys, 1980). Index precision also depends on current knowledge of the environmental requirements of crops. Export crops such as coffee and bananas have been researched adequately by commercial laboratories but additional investigation is needed to define more precisely optimum environmental conditions for beans, pigeon peas and other subsistence crops. Index accuracy also is influenced by availability of relevant data. The Las Cuevas suitability indices would be more reliable with the incorporation of climatic variables but the study area does not have a network of weather stations. Suitability indices can be verified using crop yields but reliable long-term records are difficult to obtain (Dumanski and Onofrei, 1989). The alternative approach, adopted in this study of Las Cuevas, is to go into the field, communicate with farmers, and take advantage of their knowledge to verify the index values (Buringh, 1986; Siderius, 1986).

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2.5. Farmer perception of the environment The farmer survey included several questions on environmental perception including awareness of soil erosion, soil taxonomy, perceived suitability of selected climatic – edaphic factors for agricultural productivity, and site suitability evaluation. The objective of the questions on suitability was to permit subsequent comparison of scientist and farmer opinion. It is difficult to compare the criteria used by scientists and farmers for site suitability evaluation. Scientific concepts such as pH, cation exchange capacity, phosphate status, and loamy texture are meaningless to the peasant. Even opinions on crop requirements of temperature, rainfall, and slope can be compared only at the ordinal level because most tropical mountain farmers do not recognize scientific scales of measurement such as degrees Centigrade, millimeters of rainfall, and percent slope. Similarly, scientists know little of farmers’ site evaluation criteria including soil aroma, feel and taste. As indicated in Ryder (1994a), the eight land characteristics chosen for comparative study were rainfall, temperature, soil depth, soil colour, drainage, texture, stoniness, and slope. Considered relevant to crop development by scientists, these variables also are obvious environmental characteristics that can be defined by the interviewer in a straightforward manner. The farmer was asked to assign one of three ranked categories—not important, somewhat important, or very important—to each site characteristic according to its perceived significance for his principal agricultural use. For each variable considered somewhat or very important, the farmer subsequently selected one of three appropriate ordinal values. In the case of slope, for example, the farmer was asked to specify which of three conditions—flat land, gentle slopes, or steep slopes—is optimal for his main activity. Each farmer also was asked to evaluate the suitability of the soil survey site located on his land for his principal enterprise. The farmers expressed suitability as one of four ordinal ratings—very good, good, mediocre, and bad. 2.6. Farmer decision-making analysis Existing agricultural patterns do not necessarily reflect land suitability (McRae and Burnham, 1981) and farmers with a profound knowledge of environmental requirements may establish a crop on inappropriate land for overriding socio-personal or economic reasons. Latin American landscapes often reveal disturbing incompatibilities between land suitability and land use. It is not enough for development planners to compile sophisticated inventories and evaluations of natural resources for agriculture. Land evaluations must be complemented with insight into factors that influence choice of land use. As a result, the farmer survey of 1986 also included questions on reasons for the farmer’s choice of principal enterprise. The information on decision-making was processed using point score analysis, a method developed by Ilbery (1977, 1985). In this procedure, each interviewed farmer is presented with a list of decision-making factors. The farmer assigns a point score to each decision-making factor according to his perception of its significance in his choice of enterprise. The sum of scores assigned to each factor by all farmers under study is

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considered a measure of its relative importance in the decision-making process. The list of 18 decision-making factors and the scoring procedure adopted in the Las Cuevas project are described at length in Ryder (1993, 1998). 2.7. Agricultural technology analysis The farmer surveys of 1984 and 1986 both include observations of six major inputs associated with neotechnic agriculture—chemical fertilizer, insecticides, herbicide, irrigation, power (animal or tractor), and application of state-sponsored conservation practices (mainly control of runoff using contoured ditches or barriers of stones and crop residues). A simple index Ti of modern technology was derived for each farmer i using the additive model: T i ¼ c1 þ c2 þ . . . þ cn The values c1 to cn are scores applied to n inputs (Ryder, 1994c). Where present, each input contributes a score of one point to the index which, in this particular study, can have a maximum score of 6. In the case of energy, one-half point was added to the index if the power source was animal and one full point was assigned if tractors and fossil fuels were used. For the sake of simplicity, equal weight was assigned to all inputs.

3. Results and discussion 3.1. Las Cuevas soils Chemical properties are relatively favourable in Las Cuevas soils. Only 6% of the 350 environmental survey sites have soils with extreme acidity (pH < 5.6) or alkalinity (pH>8.4) and mean organic matter content (4.4%) is high. Two-thirds of the sites have high cation exchange capacity (>25 meq/100 g). Linear regression analysis shows that pH and cation exchange capacity both decline at higher altitudes where there are cooler and more humid conditions. On the other hand, the mean gradient observed at the 350 survey sites is 33% and, as a result, soil physical properties in the watershed are not favourable for agriculture. Twothirds of the survey sites have somewhat excessive or excessive drainage and heavy runoff from convectional thunderstorms and sporadic hurricanes has taken its toll on unprotected soils. Mean soil depth to the C horizon is only 44 cm and stones are a prominent feature at 64% of the sites. The environmental survey, therefore, confirms that Land Capability classes of VI, VII, and VIII designated by SEA (1987) are appropriate for Las Cuevas soils. Site suitability index values derived for the 350 survey sites were strongly affected by the unfavourable slope conditions and soil physical properties. Eighty sites have extremely shallow soil ( < 15 cm) while 22 sites have slopes of >65%. In the specific case of the index computed for coffee, none of the 350 sites was worthy of a very good suitability rating. Forty six sites (13%) were assigned a good rating, 101 (29%) were mediocre, and 203 (58%) were bad.

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3.2. Agricultural technology The farmer surveys of 1984 and 1986 both confirm limited adoption of neotechnic methods. Chemical fertilizer is used by less than one-third of the farmers and insecticide is applied on only 19% of the farms. Few farms have irrigation systems or tractors. More than one-half of the farmers do not even make use of oxen. It is not surprising, therefore, that the mean value of the agricultural technology index Ti (with a maximum possible score of 6.0) was only 0.91 in both surveys. Less than 15% of the farmers have a technology index >3.0; they cultivate small mechanized and irrigated farms on patches of alluvial floodplain in the low-altitude western portion of the watershed. Low values of the technology index show that Las Cuevas farmers, in general, cannot be considered neotechnic agriculturalists. It would be inappropriate, however, to assume that their farming methods are traditional because key elements of the paleotechnic model are missing. Like paleotechnic agriculturalists, most Las Cuevas farmers rely on local natural and human resources, cultivate a mixture of crops on irregularly shaped fields and use fallow periods to regenerate soil fertility. Beans are inter-planted with corn in cool high-altitude areas and mixed with pigeon peas, corn and cassava at lower altitudes. Coffee also is inter-planted with bananas until other trees, including avocado, grow tall enough to provide shade. On the other hand, some farms have completely rejected polyculture and have adopted temporal rotation of crops. In particular, irrigated farms on the alluvial floodplain cultivate beans in rotation with peanuts and rice. Paleotechnic units are distinguished by skilful use of multiple varieties of crops that are carefully bred and finely tuned to local environmental variations (Cherret and Sager, 1977; Rindos, 1984; Rigg, 1985; Altieri, 1987). In Las Cuevas, however, there are external forces that encourage adoption of a reduced number of cultivars. Government agronomists have promoted replacement of local strains of typica and bourbon coffee with the dwarf caturra cultivar. Peanut farmers obtain their seeds from the local manufacturing plant and farmers who produce beans are increasingly dependent on seeds supplied by a small number of powerful intermediaries and moneylenders. Paleotechnic agriculture is generally associated with shifting cultivation and long-term fallows, or sophisticated systems based on earthworks and water management, which are passed on from generation to generation. Farmers in Las Cuevas still seek advice from their elders but soil degradation and falling productivity have made them lose esteem for their own farming skills. They increasingly yearn for external technical assistance and the inputs of neotechnic agriculture, especially fertilizer. In short, while Las Cuevas peasants are not neotechnic agriculturalists, they are no more representative of the paleotechnic model. This finding is consistent with the statement by Wilken (1989) that pure examples of paleotechnic and neotechnic systems are scarce; most of the world’s agricultural systems are combinations of traditional and modern technology. Ecologically sound shifting cultivation may have been practised some time ago in Las Cuevas when the population was smaller. Under contemporary conditions, however, the watershed’s agriculture is more akin to the fallow system described by Ruthenberg (1980). Length of fallow is too short for regeneration of forest and soil organic matter is not sufficiently restored by fallow vegetation of bush or grass. Thus, Las Cuevas

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agriculture has neither the ecological virtues of paleotechnic methods nor the productivity of the neotechnic approach. The Las Cuevas farmer surveys of 1984 and 1986 have not been updated. Nonetheless, information provided by the Dominican government (SEA, 2000) and FAO (2000) confirm that there has been no fundamental change in the nation’s agricultural structure. Most rural inhabitants continue to be small producers who cultivate traditional crops with limited access to credit or neotechnic methods. The Central Cordillera is still characterized by deforestation, land degradation and declining agricultural productivity (Sambrook et al., 1999). With the accelerated migration of the rural poor to urban areas, there has been a marked decline in the area dedicated to short-cycle crops (beans, pigeon peas, garlic) in Dominican steeplands (Zweifler et al., 1994). The area under coffee has increased (Zweifler et al., 1994) but yields have declined dramatically since 1985 (FAO, 2000). 3.3. Local soil taxonomy The 80 Las Cuevas farmers surveyed in 1986 were asked to describe soils found on their farms. None of the farmers named more than six soils and only 25% distinguished more than three soils. Table 1 is a list of soils perceived by farmers and the frequency with which they were identified. Colour and texture are the predominant characteristics used by Las Cuevas farmers to distinguish soils. Black soil was the most frequently cited soil colour. White soil, sometimes called caliche, was identified by one-third of the farmers. Gray and grayish-brown soils may be variants of caliche. Other soil colours identified were yellow and red. The most recognized soil texture was clayey soil, which was mentioned by 33 farmers (38%). Clayey soils simultaneously were described as red in colour by six farmers; thus, red soil and clayey soil taxa may overlap. There may be an additional overlap of yellow soil and clayey soil because four farmers declared clayey soil to be yellow. Sandy soils were identified by 15 farmers (19%). Six farmers indicated the existence of gravelly soil while only one interviewee referred to stony soil. The significance of colour and texture in Las Cuevas taxonomy is consistent with the results of similar studies in Latin America (Williams and Ortiz-Solorio, 1981; Wilken, 1987; Sandor and Furbee, 1996) and other Table 1 Soil taxonomy of 80 Las Cuevas farmers surveyed in 1986 Soil classes identified by the farmers

Number of farmers referring to the soil class

Percentage [%]

Black soil (tierra negra) Yellow soil (tierra amarilla) Red soil (tierra colorada) Grayish-brown soil (tierra parda) Gray soil (tierra gris) White soil (tierra blanca/caliche) Clayey soil (tierra barrosa) Sandy soil (tierra arenosa) Gravelly soil (tierra de cascajo) Stony soil (tierra de laja)

74 18 9 4 1 27 33 15 6 1

88 23 11 5 1 34 38 19 8 1

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parts of the world (Dialla, 1993; Kerven et al., 1995; Talawar and Rhoades, 1998). Farmer use of texture as a significant taxonomic criterion is to be expected. Modern soil science also regards soil texture as a primary soil characteristic influencing other properties like structure, consistency, available water capacity, permeability and drainage (Talawar and Rhoades, 1998). Ashby (1985), in a study of Colombian mountain farmers, found that they applied three names—black soil (tierra negra), mixed soil (tierra mezclada), and red soil (tierra colorada)—to the same soil at different stages of soil erosion. She implied that Colombian farmers are aware of the erosive process that gives origin to these three soils. In contrast, the interviews in Las Cuevas revealed that only 4 of the 80 farmers perceived such a relationship between soils of different colour. Like Mexican farmers studied by Williams and Ortiz-Solorio (1981), the majority of Las Cuevas farmers focus on properties of surface soil and they appear to pay little attention to horizons or soil profiles. The farmers were asked to list the soils they knew of in descending order of fertility. All 74 farmers who pointed out the existence of black soil considered it to be the most fertile soil of all. The almost unanimous selection of black soil is compatible with the assertion of Ollier et al. (1971) and Sandor and Furbee (1996) who indicate that indigenous farmers often single out one soil as being superior in productivity. Forty-one Las Cuevas farmers, however, were unable to explain the origin of the black colour. All but one who referred to caliche emphasized its very low agricultural potential. The farmers generally considered yellow, red, clayey, and sandy soils to be inferior to black soil but preferable to caliche. 3.4. Farmer perception of soil erosion Farmers were asked to describe the process of soil erosion. No less than 62 of the 80 farmers (78%) interviewed in 1986 were aware of the ability of runoff to wash soil downslope. This result is compatible with reports of farmer perception of soil erosion in Africa and Asia (Berry and Townshend, 1972; Johnson et al., 1982; Richards, 1985; Steiner, 1998). Thirty-eight Las Cuevas farmers (48%) attributed knowledge of soil erosion to contact with extension agents and, in particular, with representatives of a government-sponsored project that was established to promote soil conservation in the watershed. The other 24 farmers (30%) declared that they learned about soil erosion from their parents or from personal observation. Although the watershed’s farmers seem to be aware of soil erosion there is little interest in soil conservation and only 13 of the 80 farmers (16%) have adopted soil conservation practices. Two farmers have constructed ditches to divert runoff while the other 11 have built barriers of stones or crop residues across the slope to reduce the rate of downhill movement of soil and water. 3.5. Farmer perception of site suitability Las Cuevas farmers consider their farms of little value for agriculture; two-thirds of the 80 farmers surveyed in this project rated the survey site on their land mediocre or bad for present use. Those who grow short-cycle crops are particularly critical; only 6 of the 33 farmers with beans, rice, garlic or pigeon peas assigned a good or very good suitability

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rating. This generally negative farmer perception of Las Cuevas soils is compatible with the poor site suitability ratings described above in Section 3.1. Table 2 (reprinted from Ryder, 1994a) permits detailed comparison of the suitability ratings derived from parametric indices to farmer’s evaluations. Forty-one of the 80 sites (51%) were placed in exactly the same site suitability class. A similar degree of compatibility has been reported by Fisher et al. (1986) who compared land suitability ratings of the Soil Survey of England and Wales to those formulated by 100 farmers in the Welsh Marches (58% of the fields in that study were assigned the same rating by farmer and soil surveyor). Three quarters of the farmers whose evaluations differed from the scientific Las Cuevas suitability ratings (29 out of 39) gave a more favourable appraisal of their site. This finding also is consistent with studies of British farmers who tend to overestimate the capability of poor land and present an over-optimistic evaluation of land for familiar uses (Davidson, 1976). Some peasant overestimation of site suitability in Las Cuevas may be related to the particular perception they have of soil. As indicated in Section 2.5, the farmers were asked to rank several environmental properties according to their significance for their principal agricultural use. Their perception of soil colour, texture, drainage and slope corresponds to scientific opinion (Ryder, 1994b). However, no less than 50 of the 80 farmers did not understand the property of soil depth and rated it unimportant. Las Cuevas farmers do not share the scientist’s perception of soil as a three-dimensional body. In the same way as their Mexican counterparts (Williams and Ortiz-Solorio, 1981), they classify soil according to spatial variation in surface soil. Indigenous groups appear to have a more refined perception of soil depth. Farmers in Rwanda commonly use depth as a criterion for classifying soil (Steiner, 1998) and Quechua farmers in the Peruvian Andes have been shown to recognize variation of soil with depth (Sandor and Furbee, 1996). Perceptions also differ between Las Cuevas farmers and scientists with respect to stoniness. Scientists take a dim view of soils with stones which interfere with tillage and are believed to impair the soil’s capacity to retain moisture (Young, 1976; Willson, 1985). Contrary to scientific opinion, 39% of Las Cuevas farmers attached no importance whatsoever to stone content. In addition, only four of those who rated stoniness somewhat or very important declared that it was preferable to cultivate soils without stones. In disagreement with conventional scientific wisdom, Las Cuevas peasants argue that the presence of a few stones improves moisture retention. Although there are discrepancies, Table 2 reveals a general overall correlation between the scientific suitability ratings and farmer evaluations. The relationship can be examined Table 2 Comparison of farmer site evaluations to the author’s site suitability ratings for all land uses Farmer evaluation

Site suitability rating Bad

Mediocre

Good

Bad Mediocre Good Very good Total

13 10 7 1 31

1 19 9 1 30

1 8 8 1 18

Very good – – – 1 1

Total 15 37 24 4 80

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using the v2 test of statistical association. The reliability of the v2 test, however, is adversely affected by low expected frequencies. As a rule of thumb, for 3
3 tables, the expected frequency should be at least 5 in 75% of the cells in the contingency table and at least 1 in all other cells (Agresti and Agresti, 1979). This condition is satisfied if the categories of good and very good suitability in Table 2 are collapsed. Expressed in this form, statistical association is confirmed by a v2 test statistic of 20.37 at the 99.9% level of confidence. The farmer’s evaluation and the scientific suitability rating are both ordinal variables. As a result, their statistical relationship also can be examined using Kendall’s tau-b (Agresti and Agresti, 1979). Like the linear correlation coefficient used to measure statistical association between variables expressed on an interval scale, tau-b has a value ranging from  1 to + 1. Applied to the collapsed contingency table, tau-b is found to be 0.321 indicating a positive association between farmer evaluations and the site suitability ratings. The relevant test statistic (Agresti and Agresti, 1979, p. 254) also was computed and it shows that the value of 0.321 is significant at the 99% level of confidence. 3.6. Farmer decision-making Point score analysis of decision-making factors revealed that choice of principal enterprise in Las Cuevas is driven primarily by demand, production costs, and the influence of fellow farmers (Ryder, 1993). Environmental factors are somewhat significant to coffee farmers but are virtually irrelevant for those who choose to make bean cultivation their main activity. Las Cuevas farmers are aware of the environmental requirements of their crops and they know how to evaluate site suitability. On the other hand, they have access only to land of poor quality and do not have the opportunity to select optimum sites for cultivation.

4. Conclusions Las Cuevas peasant farmers are worthy of respect. Survival in the face of severe physical and economic constraints is proof of their ability to evaluate and till the soil. They clearly understand crop requirements and share scientific opinions of appropriate rainfall, temperature, slope, drainage, soil colour and texture conditions. The vast majority of Las Cuevas peasants also profess to be aware of the negative impact of soil erosion. This awareness may be incomplete because more than one-half of the farmers do not grasp the concept of soil depth. On the other hand, continued widespread application of erosive practices—deforestation, ploughing on steep slopes, burning of crop residues—is not necessarily a consequence of farmer ignorance or inability to recognize which land is unsuitable for agriculture. Las Cuevas farmers have realistic perceptions of the low agricultural value of their land. Two-thirds of those interviewed in 1986 consider their land mediocre or bad for present use. Thus, many farmers knowingly cultivate land that is environmentally inappropriate. They do not have the privilege of choosing between suitable and unsuitable sites for their crops. It is very important to add a decision-making component to diagnostic studies of rural development. WinklerPrins (2001) has shown how Brazilian Amazon farmers possess

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production-enhancing knowledge and skills but decide not to apply them because they perceive no economic benefit in doing so. The decision-making analysis of Las Cuevas farmers (Ryder, 1993) reveals a significant variation of this discordance between corpus and praxis. Las Cuevas farmers have the ability and desire to cultivate coffee or raise cattle but are impeded from doing so because they do not have access to good farmland, capital, or credit. As a result, their obligatory praxis is production of beans, which favours soil erosion. Rain-fed cultivation of this short-cycle crop is labour-intensive and associated with a high risk of crop failure but beans form part of the national diet, are in demand, entail low production costs, and have a rapid turnover period. Las Cuevas farmers have tilled the mountains for less than 60 years and they are not as ecologically skilled as traditional farmers in other countries who possess wisdom based on centuries of accumulated local environmental experience. Their soil taxonomy is relatively unsophisticated and pales in comparison to that of Peruvian Indians (Sandor and Furbee, 1996) or indigenous farmers in Rwanda (Steiner, 1998). On the other hand, it can be argued that theoretical knowledge of soil genesis or complex soil classification systems are not needed for the evaluation of site suitability. Pragmatic empirical testing of crops reveals the suitability of sites for particular uses. Many farmers indicated during survey interviews that they had experimented with several crops on each field in order to discover the crop that would produce highest yields. The site suitability analysis described in this study shows that the scientist can take advantage of this empirical knowledge. In recent years, planners have indicated the virtues of farmer participation in development programs (Chambers et al., 1989; Bentley, 1994; Bellon, 2000). Rural inhabitants should be involved in the conduct of research, testing of results, and diffusion of development strategies. Geilfus (1998) has shown the effectiveness of the participatory approach in the final diffusion of reforestation methods in the Zambrana – Chacuey district of the Dominican Republic. Farmer participation also should be encouraged during the initial stages of development projects in the Dominican Republic including the collection of environmental information. A two-way dialogue between farmer and soil surveyor in the field would promote timely integration of local soil knowledge and scientific research. This paper has demonstrated how empirical farmer evaluations can be used to verify theoretical scientific estimates of site suitability. There are additional opportunities for farmer participation in soil surveys. Farmers can provide invaluable insight into historical changes in land cover and land management practices that have had an impact on local soils. Surveyors and farmers could combine the criteria they use for soil identification and classification (including colour, texture, structure, aroma, moisture, taste, stoniness, depth, and horizons). They could work together in the field, strive to develop a shared soil vocabulary, and delimit large-scale soil mapping units for individual farms. Scientifically delineated units based on genetically important diagnostic horizons could be compared to units perceived by farmers who are often more concerned with subtle variations in surface soil that have a tangible impact on productivity (Niemeijer, 1995). Participatory soil surveys, therefore, would facilitate the exchange of empirical farmer knowledge and theoretical surveyor knowledge and enhance rural development projects. It is imperative, however, to bear in mind the research by Sillitoe (1998) who demonstrates the danger of misinterpretation of indigenous knowledge. Local knowledge is by definition parochial and culturally specific whereas science is driven by the search for

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