Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Objective: Characterize the avocado production system in Huatusco, Veracruz. Design/methodology/approach: Interviews based on the snowball method were applied to avocado producers in Huatusco, Veracruz, and fruit and water samples were also taken to perform a multiresidual analysis of pesticides. Results: The plantations are rainfed and in monoculture with a density of 100-150 trees/ha. The Hass variety predominates on Andosols soils, and slopes of 5-100%. Most of the producers (92 %) carry out conventional management with the application of pesticides and chemical fertilizers. In the control of weeds, in addition to herbicides, they use brush cutters. No pesticides were detected in the water samples, while Imidacloprid, Thiabendazole and α-Cypermethrin were identified in a fruit sample with concentrations allowed in Mexico of 0.0038±0.0014 mg/kg, 0.0022±0.0009 mg/kg and 0.0703±0000 mg /kg, respectively. Limitations on study/implications: Detailed and frequent sampling of avocado fruits should be carried out to determine pesticide residues. This type of analysis should also be carried out on running water near the avocado orchards. Findings/conclusions: The empirical knowledge of the producers in the case of soils is more specific than the scientific classification, since they identify five classes of land beyond Andosols. On the other hand, there is a marked inequality in land ownership given that 25% of the producers (large scale) own 86% of the established area. Although the concentrations of pesticides in a preliminary sampling did not exceed the limits of residues allowed in the avocado pulp, it is recommended to reduce the number of pesticide applications.

Objective: To diagnose the market situation of fertilizers through the statistical analysis of the main market variables, considering the importance of fertilizers as a strategic input for increasing productivity in the agricultural sector. Methodology: The growth of the apparent domestic consumption of fertilizers for the 2007-2020 period, the variables that determine it, and the current and potential demand per state in 2019 were estimated. Results: During the period under analysis, fertilizer consumption grew at an annual rate of 4.8 %, reaching 6.3 million tons in 2020. Almost 75 % of consumption was supplied by imports and only 25 % was supplied by domestic production. If 100 % of the sown area was fertilized, the potential demand for fertilizers would exceed 8 million tons. Implications: The country's heavy dependence on fertilizer imports means that the Mexican agricultural sector is vulnerable to a potential increase in fertilizer prices, as a result of the crisis that the global agrochemicals market is currently facing. Conclusions: Given Mexico's dependence on fertilizer imports, the domestic industry must be strengthened, in order to increase production and satisfy a greater percentage of the domestic demand.

Objective. Analyze the characteristics and demand for jalapeño pepper in the restaurant sector in Quintana Roo to identify the supply requirements of this sector. Design / methodology / approach A random sample of 72 restaurants surveyed online was used. Results. 87.5% of restaurants have been established in less than six years, and although most of the establishments sell Mexican food, only 41.6% are interested in supplying jalapeño pepper producers. Limitations/implications. Formalizing a supply strategy requires the social capital of the producers. Findings/conclusions. Restaurants require consistent delivery frequency, product size, spicy pepper, and color.

The presence of weeds in a cereal field is detrimental for several reasons. In this study, we chose four adventitious species to test their allelopathic effect on the germination of seeds and the development of seedlings of the durum wheat variety "Simeto". We tested the allelopathic effect at the laboratory level, by mixing weed seeds and durum wheat. In these trials, the allelopathic effect was measured. The inhibitory effect of these adventitious species manifests itself much more on the development of the seedlings, especially on the aerial parts. The bindweed (Convolvulus arvensis L) is the most inhibiting.

Objetive: To evaluate species diversity and abundance of rodents, as well as vegetation cover, in three habitat conditions in the Altiplano Potosino Oeste. Design/methodology/approach: The work was carried out in eight sites with good (3), fair (2) and poor (3) vegetation cover conditions. For vegetation, frequency, basal and aerial cover data were collected in three plot sizes; for arborescents 20X20 m, shrubs 3 of 5X5 m and herbaceous in 2 of 1X1m. Three sampling nets with 100 Sherman traps were used to collect rodent data. Rodent species richness was determined using the Shannon-Whinner index and abundance using the Relative Density Index. Differences were analyzed by ANOVA. Results: Grass cover decreased with condition, but shrub cover did not. The overall richness was 21 rodent species (16 in fair, 15 in good and 14 in poor condition). The total IS-W and IDR) decreased with condition. The most abundant and best scattered species were Dipodomys ornatus, D. merriami and Chaetodipus nelsoni. Limitations/implications: The study was conducted in the most restrictive season and under drought conditions, which had consequences for cattle, but not for rodents. However, although their plasticity maintained relatively stable RDI values, the indices decreased with the condition. Findings/conclutions: Despite the habitat conditions, we found a greater diversity and abundance of rodents than reported in the literature. Therefore, it is recommended that further studies of this nature be conducted using rodents as bioindicators.

Objective: to identify the diversity and selection of their diet at UMA Rancho San Juan, Monclova, Coahuila, from October 2018 to August 2019. Design/methodology/approach: the composition of the white-tailed deer diet was identified with the microhistological technique. With the Canfield lines method, the availability of forage per season was calculated. The diversity of diet and forage, with the Shannon index and its relationship based on simple linear regression. The selection of the diet with the X2 test and the Ivlev index. Keywords: Canfield, availability, Ivlev, desert scrub, microhistological technique. Results: 49 species and 20 families were identified in the diet. Which is made up of 49.84% shrubs, 18.38% succulents, 16.02 % herbaceous and 15.72 % grasses. The deer selected Opuntia engelmannii, consumed Acacia rigidula and Cenchrus ciliaris proportionally to their availability, and consumed Acacia berlandieri, Jatropha dioica and Karwinskia humboldtiana below their availability. Limitations/implications: It is recommended to continue this line of research including aspects of nutritional quality of forage and variations in the diet between years of demonstration. It is recommended to favor the presence of herbaceous plants through habitat improvement techniques. Conclusions: the diversity of the diet was not related to that of the forage. When forage diversity is needed, increase grass intake.

Objective: To characterize the morphology of 18 ecotypes of Elephant grass (Pennisetum purpureum Schumach) in Chiapas. Design/Methodology/Approach: The morphological characterization was carried out with 34 quantitative and qualitative descriptors. A principal component analysis and a hierarchical cluster analysis were performed based on the average data. Results: In the principal component analysis, five of the principal components accounted for 70.7% of the total variability in the 18 ecotypes of Elephant grass. The variables that made the most significant contributions in each CP were: in CP1, internode diameter (p<0.01), internode length (p<0.05), color of internode without wax (p<0.01), number of innovations (p<0.01 ), prophylls (p<0.01), number of prophylls (p<0.01), external length of the sheath (p<0.01), internal length of the sheath at its opening point (p<0.01), opening of the auricle (p<0.01 ); for CP2, the number of visible internodes (p<0.05), channel width (p<0.05), size of innovations (p<0.05), adventitious root, number of internodes (p<0.01), wax under the sheath (p<0.05); and for CP3, number of visible internodes (p<0.05), color of the internode with wax (p<0.001), channel depth (p<0.001), ligule shape (p<0.05) and leaflet tip (p< 0.05). As a result of the hierarchical cluster analysis and the semipartial correlation coefficient, five morphologically distinct groups were determined. Study Limitations: A more accurate description of the morphological diversity of the grasses requires the characterization of the inflorescence and the spikelet. Findings/Conclusions: The 18 ecotypes of the Elephant grass (Pennisetum purpureum Schumach) collected and characterized were dissimilar with each other; consequently, they are considered a genetic resource with potential importance as forage on the Chiapas coast.

Objective: Analyze changes in land use and vegetation (USyV; from 1985 to 2014) in the collection sites of 16 pines listed in NOM-059-SEMARNAT-2010 located in northern Mexico. Design/methodology/approach: We integrate a georeferenced database of the species under study from consultations of botanical collections. A point coverage was created to add USyV vector information from Series I (1985) and VI (2014). Subsequently, spatial analysis and geoprocessing identified class changes during the period. Results: A total of 2,242 georeferenced records of pine species were obtained. The results indicated that 50.0 % of the total number of pine records consulted in collections with Series I information are in other USyV categories than primary forest. At the same time, with Series VI, this condition rises to 58.7 %. Consequently, the most critical changes in the period under study occurred in converting primary forests to agriculture, pasture, secondary vegetation of coniferous and oak forests, and urban areas. Limitations/implications: The availability of larger scale cartographic material, to generate a risk analysis study of changes and threats to the conservation of pine species. Findings/conclusions: The number of collection sites recorded in primary coniferous, scrub, and oak forests in Series I decreased significantly compared to Series VI, shifting to agriculture, water bodies, grassland, and urban areas.

Objective: To evaluate some reproductive aspects of D. latifrons and the nutritional quality of its eggs. Design/methods/approach: Eighty-two fish were randomly collected (August 2021), and their sex, length, weight, somatic indices, Fulton condition index (K), proximate composition, and amino acid and lipid composition (fatty acids) of the gonads were determined. Results: Of the total specimens collected, 62% were females; length and weight values were higher in males, but their gonadosomatic index (GSI) was lower than in females. Somatic indices did not show differences between different weight ranges. In the roe of D. latifrons, the average proximate composition was 24.3% protein and 8.5% lipids. The most abundant essential amino acids were leucine and lysine. Linoleic acid (C18:2n6) was the fatty acid with the highest concentration. Limitations/implications: It is necessary to complement the analysis of the amino acid and fatty acid profile of the roe in wild organisms to relate the changes caused by balanced feed. Findings/conclusions: This study shows that the D. latifrons roe is a good source of amino acids and PUFA. Keywords: proximate composition, fatty acids, essential amino acids

Objective: The objective was to evaluate Stevia rebaudiana in climatic conditions in the state of Tabasco, México. Design/methodology/approach: Plants of stevia were sowings in three times consecutive for one year, this were progressively adapting the management and establishment of the crop according to the results obtained in the previous seeding. The percentage of survival was calculated at 15 days ddt. Plant height was measured at 60 days and the problems observed in each cycle were documented. Climatic variables were recorded. Results: As a result, it was discovered that sowing December (2019) there were bending problems, soil splashing on the leaves and foliar fungal diseases, with 71 % of plant survival. In the sowing of April (2020), there was 40 % of plant survival, plants generalized chlorosis and no growth caused by excessive solar radiation; finally, in August (2020), 89 % of plant survival with height of 20.55 cm average. Limitations on study/implications: A limiting factor for achieve this research was the rainfall that caused flooding in June and October 2020; is necessary finish the crop to know the quality of the harvest by determining steviosides content. Findings/conclusions: In conclusion, the cultivation of stevia can be cultivated in the climatic conditions of Tabasco, if rainy seasons and high temperatures are avoided during the first stage of cultivation; water is a limiting factor that causes phytopathological problems and the death of the plant.