Sait Juanes-Márquez

The objective of this study was to evaluate the regrowth capacity of Amelichloa clandestina at different regrowth intervals after non-selective grazing in different seasons of the year. The study was carried out on a 2.23 ha⁻¹ site in northeastern Mexico. Plots of 600 m² were used, with three replications, and were subjected to grazing at 333 LU ha⁻¹ at the beginning of every season, with biweekly evaluations. Dry matter yield (DMY) was determined by harvesting 1 m² per plot and extrapolating it to kg ha⁻¹. Morphological composition was evaluated from a 10% subsample of the total biomass. The height of 12 plants and light interception were measured with a ruler and a Quantum meter, respectively. The data were analysed using a randomized complete block design (RCBD) with a split-plot in time structure, evaluating Season (S), Days After Regrowth (DAR), and their interaction (S × DAR). Means were compared using the Tukey test in JMP 14 Pro. In autumn, DMY peaked at 535.0 kg ha⁻¹ at 90 DAR (p ≤ 0.05), accompanied by a maximum canopy height of 28.7 cm and a light interception of 30.3% at the same interval. Leaf biomass was highest in autumn, with a seasonal mean of 220.8 kg ha⁻¹ across all regrowth intervals. A significant correlation was found between plant height and light interception (r = 0.67, p ≤ 0.001). Autumn favoured A. clandestina productivity under a high stocking rate.

Introduction: Addressing the scarcity of national studies, this research evaluated seasonal effects of non-selective grazing on infiltration, soil compaction, soil moisture, and vegetation structure in an Amelichloa clandestina pasture in northeastern Mexico across four seasons. Methods: Using a randomized block design (4 seasons, 3 replicates), non-selective grazing was evaluated pre- and post-grazing (333 LU ha ^-1 , where 1 LU = 450 kg live weight) in 600 m ² plots. Infiltration (Kostiakov-Lewis), compaction (0-10 cm), and vegetation (dry matter, height, cover) were assessed before and after grazing. Analyses included ANOVA/Tukey for the seasons, Student's t-test for grazing ( p < 0.05), and Spearman's correlation. Results: Seasonality varied post-grazing cumulative infiltration by 52% (spring: 14.8 cm vs. autumn: 7.1 cm) and the instantaneous infiltration rate by 68% (47.5 to 15.2 cm h ^-1 ) ^. Grazing effects on infiltration were non-significant in three seasons ( p ≥ 0.05), yet it consistently increased subsoil compaction (>1800 kPa at 7.5-10 cm) and reduced dry matter by up to 89% (3347 to 218 kg DM ha ^-1 ). Vegetation correlated with infiltration (r = 0.38). Discussion: While seasonality significantly influenced soil infiltration and moisture, non-selective grazing increased subsoil compaction (7.5-10 cm), degrading vegetation and reducing infiltration. Adaptive grazing, adjusted to seasonal moisture, is required to maintain productivity. Conclusion: Seasonality drove infiltration 2-4 times more than grazing; adaptive management aligned with seasonal conditions is essential for grassland resilience.

This study evaluated the effect of intensive non-selective grazing on the richness, diversity, and structure of a grassland dominated by Amelichloa clandestina (Hack.) Arriaga & Barkworth at Rancho “Los Ángeles”, Saltillo, Coahuila. Experimental plots of 600 m² were established in a 2.23 ha area, with three replicates per season. Two treatments were applied: grazed and ungrazed (control) plots, separated by electric fencing. These plots were subjected to intensive grazing 333 livestock units (LU ha^-1) at the beginning of each season, beginning in the winter of 2023. In the fall of 2024, the cover of all species in five quadrats (1 m²) per plot was quantified. Richness (Margalef), diversity (Shannon-Wiener), dominance (Simpson), evenness, and floristic similarity (Sørensen-Dice) indices were calculated. Canonical correspondence analysis (CCA) was used to evaluate the relationship between moisture and compaction. ANOVA and Tukey's test were performed. Thirty-seven species grouped into 19 families were recorded, with the greatest species richness in winter (30 species; Margalef index of 4.2). Spring and summer showed the most significant similarity (80%). The species A. clandestina, Ambrosia confertiflora, and Clematis drummondii were associated with higher humidity in summer and autumn. In conclusion, intensive non-selective grazing, carried out in different seasons, enhanced species richness and diversity, particularly during winter, spring, and summer.

This study evaluated the growth patterns of sideoats grama [Bouteloua curtipendula (Michx.) Torr.] across its basal (BS), middle (MS), and apical (AS) strata. The experiment began from April to August 2022 at the Renewable Natural Resources (RNR) greenhouse of the Antonio Narro Autonomous Agrarian University (UAAAN), Saltillo, Coahuila, Mexico. Leaf area index (LAI), specific leaf area (SLA), leaf area duration (LAD), biomass duration (BDM), absolute growth rate (AGR), relative growth rate (RGR), net assimilation rate (NAR), and crop growth rate (CGR), were measured at 14-day intervals over 120 days after sowing (DAS). Means were compared using ANOVA and Tukey’s HSD post-hoc test (p < 0.05). At 92 DAS, the basal stratum exhibited a maximum LAI of 2.83. The SLA was higher in apical stratum at 120 DAS, reaching 679.1 cm² g^-1. The highest LAD was recorded in middle stratum at 92 DAS, with a value of 7302.2 cm² day^-1. The highest BMD was recorded in stratum BS at 120 DAS, with a value of 523 g day^-1. The AGR was higher in stratum BS (p ≤ 0.005), with maximum values recorded at 92 DAS, reaching 0.694 g day^-1. The RGR showed the highest growth in basal stratum (p ≤ 0.005), with a maximum growth recorded at 50 DAS of 0.192 g g^-1 day^-1. Regarding NAR, the highest value was observed in basal stratum at 50 DAS, with 0.0048 g cm² day^-1. The highest values were also present in stratum BS at 92 DDS, with a value of 0.00364 g cm² day^-1. The basal stratum showed the greatest increase in all the variables measured, highlighting in RGR, AGR and NAR, indicating its greater productive potential and better-quality forage, useful to optimize management and productivity in pastures with sideoats grama.

This work aims to evaluate and compare the chromatic characteristics, mineral concentration, and phenolic compound content (total phenols, total flavonoids, anthocyanins, and condensed tannins), as well as antioxidant capacity levels (DPPH, ABTS, and FRAP) in maize genotypes with white, yellow, orange, and blue/purple grain pigmentations. The results showed that the lightness, colour saturation, and hue angle (L*, C*, and h°) values ranged from 25.33 to 69.15, 1.51 to 32.22, and 32.38 to 92.07, respectively. All the maize varieties studied showed a high concentration of N, P, K and Mg. In the case of Fe, Mn, Zn and Cu, lower values were obtained with ranges of 2.18 to 3.01, 0.43 to 0.79, 1.61 to 2.43 and 0.08 to 0.42, respectively. The content of total phenols and flavonoids (free + bound) was in a range of 236.11 to 1296.16 mg GAE/100 g, and 29.20 to 221.22 mg CE/100 g, respectively, showing that the bound fractions were higher than the free fractions. Condensed tannins were only found in pigmented maize varieties in the free fraction, with values ranging between 46.58 and 411.87 mg CE/100 g, while the concentration of total anthocyanins ranged between 1.15 and 265.61 mg C3GE/100 g. Finally, the antioxidant capacity (free + bound) expressed in μmol TE/100 g was from 870.37 to 10763.34 for DPPH, from 1396.10 to 10895.26 for ABTS, and from 634.95 to 2185.92 for FRAP, with mean values of 6.5 mg/mL for the IC50 in DPPH and ABTS. A negative correlation was found between the total phenol content and the color parameters L*, C* and h°, indicating that red and purple maize grains presented the highest levels of antioxidant compounds.

Los pastizales desempeñan un papel importante en la regulación del ciclo del agua, funcionando como captadores de agua de lluvia.

Revista Bio ciencias comenzo en el año 2010 como una publicación electrónica, científica de periodicidad semestral, arbitrada e indizada que nace dentro del posgrado del Área de Ciencias Biológico Agropecuarias y Pesqueras de la Universidad Autónoma de Nayarit (UAN). Desde entonces difunde información científica relacionados con las ciencias biológicas, agrícolas, pecuarias y pesqueras, en formato de investigaciones originales, de revisión, editoriales, artículos breves, noticias y cartas al editor. Actualmente, la Revista Bio Ciencias está incorporada a diversos índices especializados internacionales, lo que la convierte en una revista indizada y arbitrada, ya que todos los documentos publicados en ésta, son revisados por pares académicos especializados en el área correspondiente. De esta manera, la Revista Bio Ciencias, tiene como Objetivo difundir información técnica de calidad en las áreas Biológicas y Agropecuarías, así como promover un espacio de reflexión de los paradigmas actuales y tendencias en las ciencias biológicas, lo anterior desde enfoques disciplinares, interdisciplinares y transdisciplinares. Mientras que su Misión es ser un espacio que expresa información científica, para promover la investigación, reflexión y discusión en temas relacionados con las ciencias biológicas y agropecuarias. Por su parte, la Visión es ser un espacio líder que promueva la difusión de información científica de calidad a nivel local, nacional e internacional.

El rendimiento de forraje de una pradera de alfalfa depende del intervalo de corte, ya que éste influye en la dinámica de crecimiento. Por tanto, se debe identificar el momento de corte óptimo después del rebrote, donde se pueda cosechar la mayor cantidad de biomasa y una correcta estructura de la pradera en función de sus componentes morfológico. El objetivo fue evaluar el comportamiento productivo estacional de alfalfa variedad Premium a diferentes edades de rebrote e identificar el punto de mayor acumulación de biomasa en el sureste de Coahuila, México. Los ocho tratamientos fueron evaluados mediante un diseño de bloques completos al azar, con tres repeticiones. Los tratamientos consistieron en cortes semanales sucesivos, durante ocho semanas de rebrote, en cada estación del año. El rendimiento de forraje (RF) se incrementó de los 7 a 56 días de rebrote (DDR), con promedio de 1071 a 12,125 kg ha^-1. El rendimiento mayor se registró en primavera, con 3226 kg ha^-1 (P ≤ 0.05); la hoja tuvo el aporte mayor con 50 %. La relación: hoja/tallo disminuyó (P ≤ 0.05) a mayor DDR, pero en invierno fue mayor, con 1.6. La altura de planta (AP) máxima fue de 61 cm a los 42 DDR en primavera (P ≤ 0.05). La correlación máxima (R² = 0.99) entre RF y AP se registró en invierno. En conclusión, el mejor comportamiento productivo de la variedad Premium se registró en primavera, con mayor rendimiento de forraje y altura de planta, variables que aumentaron con los días de rebrote, por lo que, la correlación entre estas dos variables es un método indirecto confiable para estimar rendimiento de forraje.

El banco de semillas incluye propágulos viables presentes en el suelo por períodos variables de tiempo, su estudio permite obtener información sobre la riqueza, abundancia y predicción de la presencia de especies nativas, cuando el área es impactada. Con el objetivo de caracterizar el banco de semilla de un zacatal de Amelichloa clandestina en un área de 60 ha en el sureste de Coahuila, se colectaron 36 muestras de suelo en los 10 cm superficiales, en un cuadrante de 12 × 12 cm. Las muestras se colocaron en charolas de aluminio y se cubrieron para evitar la contaminación por el viento. Se aplicaron riegos periódicos, las especies se contabilizaron a intervalos de dos días y el registro de germinación se realizó durante tres meses. La riqueza de especies está integrada por 23 especies que pertenecen a 12 familias. A. clandestina inició la mayor germinación a partir de los 48 días y fue la especie que presentó mayor germinación de semilla con 1 030 (ind m-2). En el zacatal existe una elevada reserva de semilla de A. clandestina además de que es la especie dominante y por ello la riqueza de especies del zacatal es baja.

Abandonment of agricultural land is currently one of the main land use changes in developed countries. This change has an impact at the economic level and from the point of view of conservation. Therefore, recovering these areas after abandonment is, in many cases, necessary for ecological restoration, especially as they can be invaded by exotic or dominant species, preventing recovery of the original plant species community. The objective of this study is to examine changes in plant species richness and composition after the application of different treatments to eliminate Amelichloa clandestina, a species that dominates pastures abandoned 12 years ago in an area located in northern Mexico. The area is a semi-desert grassland dominated by buffalo grass Bouteloua dactyloides. We used different eradication techniques such as burning, herbicides, and clipping. Although the treatments had significant effects on species richness and composition and resulted in a relative reduction of the target species, the abundance of Amelichloa clandestina was still substantial. Burning is effective, favoring the increase of species richness and provoking a lower presence of A. clandestine but with a dominance of annuals. The most important impact on the total cover of A. clandestina is shown by the herbicide treatment. However, monitoring of these areas will still be required to consider the long-term impact and success of treatments.