Classes of land in La Soledad Salinas

The class’s maguey mezcal producing lands were identified through field trips with authorities and members of the agricultural subcommunity of the town of La Soledad Salinas, the Municipality of San Pedro Quiatoni. On trips was requested to the members of the agrarian subcommunity to indicate the location of land classes where grown the mezcal maguey, and a brief description of its characteristics and properties. The characteristics most frequently mentioned were those related to moisture retention, stone size, color, and marbled (cracks). The use of qualitative by producers for classification of land and to name them has been documented by several authors (^{Shan, 1993}; ^{Krasilnikov and Tabor, 2003}; ^{Barrera-Bassols and Zinck, 2003}; Ghana and ^{Dawoe et al., 2012}). This information allowed to obtain data to differentiate six kinds of lands and their characteristics, to finally recognize them during field trips.

The support of the members of the agrarian subcommunity was very important, because in this region, people speak their native language, Zapoteco of Region Valles Centrales of Oaxaca. The members of the subcommunity, served as translators contributed information during visits especially for producers who do not understand Spanish. The information to characterize each of the classes of land was obtained through a free, spontaneous participation and unpaid producers and allowed to consult when information began to be repetitive. First, they were asked as he was called to the kind of land they were working. All producers identified land classes in Zapotec and producers who speak Spanish, gave his name in this language, the identified classes are: Yuu gitaák (land pedrero), Yuu gebriu (land gravel), Yuu sea (red land) Yuu seed (terrero land), Yuu nkich (white ground) and Yuu Llas (black land), whose definitions are given in the following paragraphs:

Land Pedrero (Yuu gitaák), is characterized by 90% of stoniness, keeps a lot of moisture due to the number of stones. In the opinion of the producers in this kind of land the maguey is evergreen and where it grows more, especially when just touching the ground and the soil quality is maintained during the first two cycles because the land is new, and maguey cones 200 are obtained 250 kg.

Red Land (Yuu sea), is a reddish land color with gravel, has exposure to the sun throughout the day, is not sticky, has stoniness but to a lesser extent than in the terrero land and can work when the ground is wet.

White Ground (Yuu nkich), is a land of white, loose, with little rock salt is not sticky or gummy, are calcareous soils; It is not good for the production of maguey; magueyes with little juice, small and underweight occur.

Land Gravel (Yuu gebriu) are less stony land and stones are smaller than on Land Pedrero, about 60% of stones, has small stones and gravel. Keeps moisture on the hillside and has more strength to the maguey; by the presence of stones you can only work making bowls for maguey with auger. It is the land that likes to maguey because their roots can grow better. Producers recognize two classes of crushed stone lands according to their color, black colored gravel and crushed stone.

Black Land (Yuu Llas), this class is located in the plain, has no high humidity, it is very chewy and also that it has no nutrients marbling. It is flooded in the rainy season because the water does not fall on the ground and also sealed at the time of lent the plant wilts for lack of water. This land produces pineapples 100 to 150 kg.

Land Terrero (Yuu seed) is in flat parts, it is very slippery when it rains and you cannot get to work. This land holds little moisture and maguey withers in dry season. The maguey plants growing on these lands do not have much weight.

Mapping land classes. The distribution of land classes in the town of La Soledad Salinas is illustrated in Figure 2. The largest area is occupied by the Land Pedrero, which represents 71.3%, followed in the gravel land surface (15.3%). Land classes were less surface terrero, white land, black land colored gravel and crushed stone (Table 1).

Figure 2 Types of land identified in the town of La Soledad Salinas, Oaxaca. 

Once generated the class map land, surface and length of each was measured and the results are shown in Table 1. It is important to note that for classes of land terrero and white land not their surfaces were quantified because they correspond to dispersed areas within the study area. From Table 1, it is stated that pedrero class is the dominant land with an area of 2703 hectares and that occupies the lower surface is the black land with 128 ha.

Physical and chemical soil analysis. The number of horizons and therefore soil samples varied in the different types of land, Land Gravel Red had one horizon in Land Red and Land two horizons were determined. In the Land of Gravel Black, Black, White and Terrero three horizons were described.

Regarding chemical determinations, the pH ranges from 6.0 to 8.7, the lowest value corresponds to the surface horizon of the red soil (0-20 cm) and the highest to the deepest horizon land terrero class (40- 60 cm). The electrical conductivity (CE) was low in all soils. The organic carbon content was higher in the first horizon of all soils, the highest content was found on white ground with 1.5%, and lowest in the third horizon soil of black land (35-50 cm) and the land of black gravel (38-55 cm). The same trend as to the content of organic matter which was 2.6% in the first horizon on white ground was observed. The carbonate content is the property that showed the greatest difference between soil classes, the highest content is presented on white ground with more than 25% full thickness (Table 2).

With regard to the physical properties of the different classes whose results are shown in Table 3, it may indicate that the highest values of bulk density are presented in the first horizon of pedrero land (2.0 g/cm³) and black land (1.9 g/cm³). Soil textures vary from medium to fine. In the second horizon in the pedrero land, black land and terrero a clay texture was determined. As for the PMP and CC content of soil moisture with higher values they occurred in the black land.

Soil classification

System of soil taxonomy. The moisture regime and soil temperature were obtained with data from the weather station Shrimp, Yautepec, applying the Newhall simulation model, the results indicate that the regime is Isohyperthermic soil temperature and moisture regime is Ustic.

Of the seven soil profiles that were made in the town of La Soledad Salinas, it was found that Soil Taxonomy version 2014, classes of red land, scree, colorado gravel and black gravel, are composed of soil level group are classified as Lithic ustortents, the black land soils are classified as: vertic haplustepts, those of land Terrero as Aridic Haplusteps and finally white ground soils has referred to as: Aridic Calciusteps (Table 4).

Referential system based soil (WRB)

According to the results of the description field and laboratory tests, soil classification was performed with the WRB system, for the seven profiles, and found that the red lands, scree, red gravel and black gravel have soils are classified as level Unit: Leptosols, stop the black lands and terrero are classified as: Cambisols and white land have Calcisols. In Table 4, in addition to soil classification unit level primary and secondary qualifiers are indicated.

This indicates that the land classification based on local knowledge generated the largest number of classes, indicating that traditional knowledge is as detailed as that obtained with scientific classifications of WRB and soil taxonomy, results Similar were reported by ^{Sánchez et al. (2002)}. In this sense, ^{Ortiz and Gutiérrez (2001)} indicate that the related traditional knowledge with scientific facilitates communication between technicians and producers.

Furthermore, these results contrast with those reported in the soil maps of the study area (^{INEGI, 2010}), where the existence of Phaeozem, Luvisols and Leptosols states because not Phaeozem and Luvisols were found, but match the presence of Leptosols. In addition, these results are consistent with other studies that indicate that the official soil information is of poor quality (^{Sánchez et al., 2002}; ^{Cruz et al., 2008}).