Rufo Sánchez-Hernández

Importancia del potasio y el anillado en el rendimiento y calidad del fruto de litchi

The litchi (Litchi chinensis Sonn) is an internationally demanded fruit, grown in several states of Mexico with profitable prices, but with low yields. The objective of the research was to determine the effect of potassium and ringing on the yield and quality of the fruit of the lychee cv Brewster. A completely random block experiment was established, with a factorial arrangement of 3 x 2 with 10 repetitions. Factor A consisted of three levels of potassium (300, 600, 900 g per tree-1). The B factor in two levels of ringing in the branches (absence and presence), so six resulting treatments were evaluated. The results indicate that factors A and B, as well as their interaction, are determinant for increasing yield, although they have little effect on fruit quality. The levels of factor A and B that have the greatest effect on yield are 900 g of potassium and the presence of ringing respectively, so treatment six that combines both factors, records the highest yield. Low doses of potassium produce low yields, while banding alone doubles it. Factors A and B present individual effects for the variables weight loss (PPF) and fruit pH, although the effect of the interaction is only present for the pH. It is concluded that the contribution of 900 g tree-1 of potassium and the ringing in trees of litchi, individually and combined positively affect the yield and little to the quality of the fruit.

Ch’ol nomenclature for soil classification in the ejido Oxolotán, Tacotalpa, Tabasco, México

BackgroundThe traditional ecological knowledge of land of the Ch’ol originary people from southeast Mexico forms part of their cultural identity; it is local and holistic and implies an integrated physical and spiritual worldview that contributes to improve their living conditions. We analyzed the nomenclature for soil classification used in the Mexican state of Tabasco by the Ch’ol farmers with the objective of contributing to the knowledge of the Maya soil classification.MethodsA map of the study area was generated from the digital database of parcels in the ejido Oxolotán in the municipality of Tacotalpa, to which a geopedological map was overlaid in order to obtain modeled topographic profiles (Zavala-Cruz et al., Ecosistemas y Recursos Agropecuarios 3:161–171, 2016). In each modeled profile, a soil profile was made and classified according to IUSS Working Group WRB (181, 2014) in order to generate a map of soil groups, which was used to survey the study area with the participation of 245 local Ch’ol farmers for establishing an ethnopedological soil classification (Ortiz et al.: 62, 1990). In addition, we organized a participatory workshop with 35 people to know details of the names of the soils and their indicators of fertility and workability, from which we selected 15 participants for field trips and description of soil profiles.ResultsThe color, texture, and stoniness are attributes important in the Ch’ol nomenclature, although the names do not completely reflect the visible characteristic of the soil surface. On the other hand, the mere presence of stones is sufficient to name a land class, while according to IUSS Working Group WRB (181, 2014), a certain amount and distribution of stones in the soil profiles is necessary to be taken into consideration in the name. Perception of soil quality by local farmers considers the compaction or hardness of the cultivable soil layer, because of which black or sandy soils are perceived as better for cultivation of banana, or as secondary vegetation in fallow. Red, yellow, or brown soils are seen as of less quality and are only used for establishing grasslands, while maize is cultivated in all soil classes.ConclusionsFarmers provided the Ch’ol nomenclature, perceived problems, and uses of each class of soil. Translation of Ch’ol soil names and comparison with descriptions of soil profiles revealed that the Ch’ol soil nomenclature takes into account the soil profile, given it is based on characteristics of both surface and subsurface horizons including color of soil matrix and mottles, stoniness, texture, and vegetation.