EUROPEAN SOIL BUREAU RESEARCH REPORT NO. 7 Farmer classification. An approach to soil qualityin Murcia, SE of Spain ANDRADE-LIMAS1 Elizabeth, FAZ-CANO Ángel2, GARCÍA-FERNÁNDEZ Gregorio2 & ARNALDOS-LOZANO Raquel2 1División de Estudios de Postgrado e Investigación. Universidad Autónoma de Tamaulipas, México. E-mail: eandrade @uamac.uat.mx 2Departamento de Producción Agraria. Universidad Politécnica de Cartagena, Murcia, España. E-mail: [email protected] Abstract There has been very commonly an absence of correspondence between modern systems of soil taxonomic classification and the agronomical qualities of the soils. For this reason, this study has resorted to tapping the knowledge of the farmers that know best these agronomical properties in a practical sense, in order to obtain an agronomical classification of the soils. This rural classification has been determined for three typical agricultural zones near the Mediterranean coast of Spain. Four types of soils located in the study area and characterized according to the World Reference Base as Luvisol, Calcisol, Regosol and Fluvisol, were differentiated on the basis of physical and agronomics characteristics into 8 different classes according to the local farmers. The names given by the farmers, which refer to some distinctive feature of the soil’s physiognomy, are the following: "black", "mud", "red", "slate" or "sluggish”, "coloured ("red") or "moyas", "sand", "smooth" and "hard" soils. To this effect, this system exhibited a very high knowledge of the physical, chemical and agronomics properties of the soils. In a sense, this rural classification can be very helpful for a better knowledge of the soils, and to establish more effective technologies for the management and conservation of the agricultural lands. Keywords: rural soil classification, ethnoedaphology, soil quality. Introduction The Region of Murcia, located in SE Spain, has a semiarid climate that determines sparse vegetation and a high rate of erosion. It has been formed by a complex geological process (Arana Castillo et al., 1999). These particular geological conditions have given rise to prevalence of a mining industry in the region. The semiarid landscape of the Spanish South-east constitutes one of the European enclaves where the fingerprints of geological processes can be more clearly observed (Arana Castillo et al., 1999). Under these environmental conditions, a variety of soils have been formed a long thousands of years, with well developed profiles and differentiated horizons. Inside the studied area, four groups of soils have been found (FAO-ISRIC-ISSS, 1998): Luvisols, Calcisols, Regosols and Fluvisols (Alías Pérez et al., 1986). Most of these soils present a great agricultural potential, and they has been traditionally used for agriculture for centuries. Nevertheless, the traditional use of them have been altered since two decades ago, due to the construction of a big hydraulic system that has made possible the irrigation of thousands of hectares, which previously were devoted to rain fed crops. On the other hand, and due to the mining activity, many soils in the Region of Murcia have been, directly or indirectly, affected by this activity. Agriculture always implies the modification to a smaller or greater extent of both physical and chemical properties of soils. In SE Spain, where agriculture is one of the most intensive in Europe, the lack of An approach to soil quality in Murcia, SE of Spain. Andrade-Limas et al.. 157 EUROPEAN SOIL BUREAU RESEARCH REPORT NO. 7 rainfall and the increase in irrigated crop cultivation due to external demands has sometimes led to the use of irrigation water with a high salt content. Incorrect or intensive ploughing and excessive use of agrochemical compounds are other features that may lead to soil degradation. Consequently, soils of these agricultural areas are exposed to a very high erosion problem, and sometimes to a high salinity level. This has led to the plantation of salt-resistant crops in places. Some mineralogical, physical and chemical properties of the soils have been considered, which have served for its classification in the World Reference Base (FAO-ISRIC-ISSS, 1998). In this respect, it is convenient to highlight the lack of correspondence between the agronomical qualities of soils of similar typology, which seems to be related with the lack of detail and the technical limitations that the proper system of classification presents. Another common situation solved by this farmer’s approach is when the investigator tries to classify a soil and faces a scarcity of information. The present work had as general aim to demonstrate the usefulness of the rural knowledge on the different classes of soils placed in the Region of Murcia, as a frame of reference for the macromorphologic characterization and for the knowledge of use and management of these soils facing its conservation. Materials and methods Location of the studied area The present study was realized from February to April 2001, in three clearly delimitated stands sited around areas of Cartagena and Murcia city (SE of Spain), close to the Mediterranean sea. These different places were located in the central and east part of the Region of Murcia, two close to the locality of Cartagena and one near Murcia city, were considered. In three different typical agricultural areas of Murcia, SE Spain, an ethno-edaphological study has been carried out. The management of these soils was quite different in each case: dry lands in La Azohía (Table 3), drip irrigation in El Beal (Table 2) and flood irrigation in the Huerta de la Vega Media del Río Segura (Table 4). These three areas were selected because the farmers have traditionally worked these soils using traditional land management and the obtained production is used for the family consumption. Likewise, the land uses are representative of the different forms of traditional management of the soils in the Region of Murcia. The used methodology recognizes the existence of the empirical knowledge of the use of the natural resources, which has allowed to the peasants to establish an environmental nomenclature, which is neither commercial nor technical, but has a semantic soundness to name to the soils. The climatic characteristics of this area are determined by its geographical situation in the south east of the Iberian Peninsula characterized by summer drought, scanty cloud cover and a high index of radiation. Physiographically there is a big contrast between the mountainous –forest- and the plain –agricultural- areas, so that vegetation changes depend on the climate and the relief (ITGME, 1999). Precipitation ranges from 200 mm to 300 mm, and temperature averages 18 °C throughout the year. The agriculture of the zone is of great importance with crops such as almond tree and cereals in dry lands, and vegetables as potatoes, cabbage and pepper among others, and irrigated fruit trees such as the lemon tree, orange tree, peach and plum tree. In rain fed lands sheep keeping was of great importance, principally ovine and caprine production. Field and laboratory work Several soil types were located in each study site (Table 1) according to the rural classification system of soils (Ortiz et al., 1990). It includes open interviews to the farmers joint with a direct observation in the field and complemented with the use of air photographs, edaphology maps, topographic maps and plans of the communities. Besides, conventional soil profiles classified by World Reference Base soil classification system (FAO-ISRIC-ISSS, 1998) were used for comparison purposes. The knowledge of the soil resource generated by the farmers, based on his traditional experience, leads to a better and more practical agronomic denomination. This is a rural classification of soils or ethnoedaphology (Ortiz et al., 1990). 158 An approach to soil quality in Murcia, SE of Spain. Andrade-Limas et al.. EUROPEAN SOIL BUREAU RESEARCH REPORT NO. 7 The guide of interviews carried out included questions about the sowed surface, types of farming, ways of sowing, types of fertilizers and plants that are used (forage, medicinal, ornamental), labors of farming, types of lands and its management. Fields tours were realized to locate the information, and to establish the boundaries of the different classes of soils in its plots. In the second stage, several representative points were selected for every study locality (from two to three per class). Profiles were realized for its field description, according to F.A.O.-I.S.R.I.C. (1990) guidelines. Results and discussions Data related to the description of the different soil types according to the rural classification (Ortiz et al., 1990) are presented. An essential part of this work has been the use of farmer’s knowledge as an information source. When they were contacted it was important to look for expert farmers, with good field knowledge. The process was developed in a soft way, with no pressure at all and in a spontaneous way to enable a quiet conversation. They were in advance informed about our interest in their rural knowledge about the different soils qualities, and about alternative management and conservation techniques of the soils. Using the ethnoedaphologic methodology, soils were classified in each studied site, having in account the interaction between the different soil types and its uses and management techniques. Classification was done to a plot level according to agricultural, livestock and forest production criteria. In this respect, a significant relationship has been found between the soil type and its management, and the soil use and the soil quality. Table 1 presents the data about the different soil types found following the rural classification of soils in three localities in the Region of Murcia, to the southeast of Spain. Eight soil classes according to the methodology published by Ortiz et al. (1990) were found: “black”, “mud”, “red”, “slate”, “reddish o moya”, “sand”, “smooth” and “hard” (Tables 1, 2, 3 and 4). These correspond to just four soil groups according to World Reference Base system (FAO-ISRIC-ISSS, 1998): Calcisols, Luvisols, Regosols and Fluvisols at the Reference Group level.