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

Objective: To evaluate the possible negative impacts on soil fertility, as a result of the soil use change from the grassland to oil palm. Design/methodology/approach: The following variables were evaluated: soil organic matter (SOM), bulk density (BD), mechanical penetration resistance (MPR), root system distribution, and infiltration in 5-, 11- and 25-year-old oil palm plantations, as well as in an adjoining grassland —whose land use had not changed to oil palm cultivation. Results: During the first years of cultivation, the substitution of the grassland for oil palm caused SOM losses, increased BD and MPR, and reduced infiltration levels. After 11 years, these effects became stable and were reversed. Therefore, in mature plantations of >25 years, the soil and infiltration conditions improved, even surpassing the grassland. These changes occur at a depth of 40 cm and are attributable to the SOM provided by the root system; consequently, root distribution does not block infiltration, becoming a beneficial factor, particularly in mature plantations. Study limitations/implications: The research must be replicated under other soil conditions, in order to observe the fertility behavior. Findings/conclusions: After the grassland is replaced by oil palm, soil fertility deteriorates during the first years; fertility becomes stable and recovers after 11 years. Meanwhile, the effect reverses and surpasses grassland fertility levels after 25 years.

The taro (Colocasia esculenta (L) Schott) is a herbaceous plant that produces a highly nutritious corm, and is adapted to lowlands and highlands. Due to the climate and soil requirements, this plant is capable of being cultivated in the state of Tabasco, so the objective of the research was to analyze the productive potential of taro in the state of Tabasco, to suggest the edaphoclimatic zones with the best conditions for its use. For this, an analysis was carried out using geographic information systems QGIS 3.16.1 and Arc GIS 10.2.2, to generate spatial interpolations of edaphic and climatic variables. Through map algebra, the edaphoclimatic zoning was generated for this crop in the state. The results indicate that the edaphoclimatic conditions allow the establishment of this crop in 1 608, 565 hectares, which is equivalent to 67% of the territory of Tabasco, although the optimal surface is only 655, 632 hectares (27%). The main limitations for cultivation are mainly edaphic, rather than climatic. From the edaphic point of view, the most suitable soils are flat, deep, with loamy or clayey textures, with slightly acidic or neutral pH. The physiographic areas of the alluvial plain, river valley and hills are the optimal ones for the cultivation of taro. The unsuitable areas are found in areas with permanent flooding and close to the coast, as well as in the highest areas of the Sierra de Tabasco.

Objective. The aim was to assess the effect of pruning on Jatropha curcas L. seedlings during the nursery stage. Design/Methodology/Approach. In order to determine the effect of pruning on Jatropha curcas L. seedlings under nursery stage, a study was carried out at the nursery of the CPA “Abel Santamaría” of the Martí municipality, Cuba. A complete randomized design was used. Three treatments (T) were tested: 1) control (without pruning), 2) pruning at 30 cm from the soil and defoliation of seedlings, 3) pruning at 30 cm from the soil and without defoliation of seedlings. Descriptive analysis was performed to determine survival, regrowth and quantity of plants with primary branches. For the number of leaves and branches, height and diameter, a simple variance analysis was used, with partitions for each observation. Results. It was found that no treatment influenced the plant survival and regrowth. With T2 and T3 up to 2 branches per plant obtained. The height was higher with T1 (38,63 cm) and differed from T2 and T3. The highest quantity of branches that formed primary branches was obtained by pruning and without defoliating (28 vs. 22 and 0, for T2 and T1, respectively). Study Limitations/Implications. Pruning is an option to increase agronomic yield in Jatropha, but it has not been studied at nursery conditions. Findings/Conclusions. It is concluded that pruning J. curcas seedlings in nursery at 30 cm of height with regards to the soil, with defoliation or without defoliation; neither affects crop survival or regrowth and the development of primary branches. However, it is possible to obtain more plants with primary branches and higher stem diameter by performing pruning without defoliation.

Objective: Estimate potential and current water erosion in the Necaxa System and propose alternatives to reduce the problem of siltation of the hydraulic infrastructure Design/methodology/approach: The Universal Soil Loss equation will be applied through algebra of maps processed in a Geographic Information System. Results: It was estimated that the current water erosion in the Necaxa system is 159 tons / ha * year, a factor that affects the loss of land for crops, loss of nutrients in the soil, accumulation of material towards urban areas, silting up of streams, reservoirs and loss of capacity of the hydraulic works of the system. Limitations on study/implications: There is no information on runoff batches in the field that allows the current water erosion values to be compared with those obtained by the EUPS applied by map algebra. Findings/conclusions: By proposing reforestation and carrying out conservation agriculture, it could be reduced to 16 tons / ha * year. However, if control actions are not carried out and the current coverage is not preserved, the problem can increase until reaching potential erosion values higher than 200 ton / ha * year.

Objective: To assess the antibacterial and antifungal activity of hydroethanolic extracts of Dionaea muscipula J. Ellis against model bacteria and fungi of agricultural importance. Design/Methodology/Approach: In vitro plants of D. muscipula were propagated and acclimatized for three months. The antibacterial activity of the hydroethanolic extracts against Escherichia coli and Bacillus cereus and the antifungal activity against Aspergillus niger, Fusarium oxysporum and Pseudocercospora fijiensis were evaluated. An analysis of variance (ANOVA) was performed to compare the means obtained with a Tukey test (p?0.05). Results: The hydroethanolic extracts of D. muscipula in vitro and acclimatized showed a bacteriostatic activity against the bacteria E. coli (65.20 and 69.78% inhibition) and B. cereus (91.75 and 92.61% inhibition) and an antifungal activity against the fungus P. fijiensis of 7.56 and 14.21% of inhibition, respectively. Study Limitations/Implications: The hydroethanolic extracts of D. muscipula in vitro and acclimatized did not show antifungal activity against A. niger and F. oxysporum. Findings/Conclusions: The hydroethanolic extracts of D. muscipula in vitro and acclimatized showed a bacteriostatic activity against the bacteria E. coli and B. cereus and antifungal activity against the fungus P. fijiensis.

Objective: To analyze the morphological and physiological responses of three wild castor bean (Ricinus communis L.) ecotypes with four levels of substrate gravimetric moisture. Design/methodology/approach: Wild castor bean seeds were collected in the Durango State’s arid zone, Mexico. Three possible ecotypes of seeds were selected according to seed size and shape. A completely randomized greenhouse culture was established with the three wild castor bean ecotypes in substrate with four levels of gravimetric moisture (T1?= 24±2%; T2?=20±2%; T3?= 16±2%; T4?= 14±2%). Physiological measurements were performed with a photosynthesis meter LICOR (LI-6400XT). Two-way analysis of variance was performed to obtain significant differences among factors and their interactions. Results: The most striking results are the following: ecotypes 1 and 2 had higher stem height and larger leaves than ecotype 3. The differences in plant growth due to the effect of substrates with gravimetric moisture of 24% and 20% were not significant (p = 0.05). The highest photosynthetic rate corresponds to ecotype 3 (14.77±6.14 ?mol CO2 m-2s-1); however, the differences were not significant among the ecotypes. The differences were mainly determined by the substrate moisture. Limitations on study/implications: Knowing the castor bean water requirement as a crop allows optimizing the use of water in regions where this resource is scarce. Findings/conclusions: The castor bean ecotype 1, whose seeds were of great volume, little eccentricity and very round; they are associated with plants with longer and wider stems, with longer and wider leaves. This genotype could be domesticated considering the substrate moisture 24% and 20%.

Objective: To evaluate the effect of hydrogen peroxide, potassium sorbate, sodium bicarbonate and chitosan, on the in vitro germination and mycelial growth of Colletotrichum sp. Design/methodology/approach: Effectiveness’ evaluation of each treatments was carried out using the methodology of poisoned cultures. The following concentrations were evaluated for hydrogen peroxide and potassium sorbate: 1.0, 0.8, 0.6, 0.4, 0.2, 0.16, 0.12, 0.08 and 0.04 %; for sodium bicarbonate: 1.0, 0.8, 0.6, 0.4 and 0.2 %; and finally for chitosan: 2.5, 2.0, 1.5, 1.0 and 0.5 %. A mycelial growth disc of Colletotrichum sp. six days old was placed on each poisoned culture. The experimental design to measure the inhibition of mycelial growth and conidia germination of Colletotrichum sp. was completely randomized with five replications. Results were analyzed with the Kruskal-Wallis test and average ranges were compared between them. The EC50 and EC95 of each product were determined by probit analyses. Results: The hydrogen peroxide inhibits 100 % of mycelial growth from concentration of 0.16 %, while potassium sorbate from 0.2 %. Regarding to sodium bicarbonate and chitosan, they reached this effect in 1.0 and 2.5 %. Conidia germination was completely inhibited only with hydrogen peroxide and potassium sorbate. The EC50 and EC95 for hydrogen peroxide were 0.1 and 0.12 %, for potassium sorbate: 0.10 and 0.19 %, sodium bicarbonate: 0.16 and 0.88 %, and for chitosan: 1.20 and 2.18 %, respectively. Findings/conclusions: The evaluated treatments represent an effective and viable ecological alternative for the control of Colletotrichum sp.

ABSTRACT Objective: Analyze the effect of open field crop management on gardenia flower development Design/methodology/approach: A randomized block design was used with a factorial arrangement of two factors conformed by field management (four levels: M1 = old plant in natural shade; M2 and M3 = old plant in full sun and M4 = mature plant in full sun) and the floral stages (eight levels: tender, lemony, striped, white, star, caracolled, open and yellow). Eight morphological descriptors were measured: flower weight, perianth length, perianth diameter, calyx length, calyx diameter, corolla width, number of sepals, and length of sepals. Results: The analysis of variance allowed to identify of highly significant differences (P ? 0.05) in the variables weight, perianth length, calyx length and diameter, number of sepals, and length of sepals for the management-stage interaction. In handling M1 and M2, the caracolled flower reached a weight greater than 2.94 ± 0.08 g with a perianth diameter of 60.66 ± 1.23 mm. The open flower presented the largest corolla width of 37.39 ± 1.07 mm. The white button cataloged from the commercial point of view in the category of buttons, according to weight, perianth diameter, and width of the corolla, presented flower characteristics; thus, classifying the floral development in three stages for buttons and five for flowers. Findings/conclusions: Cultivation management with natural shade increases the size of the flowers in terms of weight, perianth diameter, and corolla width. These descriptors can be used as quality criteria when selecting the flower. In addition, the open and caracolled flower can contain the largest reserve of volatile components and, as they are not commercial qualities, it could be used in the extraction of compounds to produce cosmetics.

Objective: To analyze the genotype environment interaction (GEI) in the dry forage production of 24 lines of awnless barley and commercial checks of the same and other species, through five environments.  Design/methodology/approach: A randomly complete block design with three replications was used in the five environments evaluated, forage harvest was done at 105 days after sowing. The data were analyzed as combined randomly blocks over environmentss and the (GEI) was analyzed using the AMMI model. Results: Significative differences (p? 0.01) were detected in the main effects and the GEI. According to AMMI analysis, genotypes G26 (Cerro prieto), G27 (Gabyan95), G10, G3, G19 and even genotype G24, showed near-zero interactions, so they were considered stable, while awnless barley lines: G6, G1 and G2 were rated as desirable for dry forage production base don their superiority over the overall mean and its low IGA. Limitations on study/implications: Results may to vary if different environments and genotypes are considered. Findings/conclusions: Threre are stable and desirable awnless barley genotypes that represents an excellent option for forage production in the studied región. The oat check was considered the least productive and Zaragoza, Coahuila, location is considered a potential environment for the production of dry forage using awnless forage barley as those evaluated in this study, in addition this environment exhibited adequate discriminatory power. Key words: Awnless barley, dry forage, genotype environment interaction, AMMI model.

Objective: To determine the prevalence and risk factors associated with the incorrect application of the anabolic implant in feedlot cattle. Design/methodology/approach: An observational study was carried out in which 888 ears of cattle from 5 feedlot cattle were evaluated. The criteria for the condition of the anabolic implant were correct and incorrect (encapsulated, abscessed, in cartilage, misplaced, crowded, partial and absent). The results were evaluated using the Chi-square test and logistic regression, the alpha level established was 0.05. Results: A 64.30% prevalence of incorrectly applied anabolic implants was observed. At least 50% of the feedlots presented failures in the application of the implant. The encapsulated condition and the misplaced condition represented 91.6% (51.4 and 40.2%, respectively) of the total of the incorrect conditions. The risk that a bovine presents an incorrect condition increases 1.8 times more when it is a feedlot´s size was greater than 4000 bovines (P<0.001) and 4.2 times more when they are female (P<0.001), the season was not a risk factor (P>0.17). Study limitations/implications: The incorrect application of anabolic implants leads to failures that complicate their absorption and integration into the body, therefore, it is suggested to carry out more studies to determine the economic impact that this can cause. Findings/conclusions: It is concluded that the prevalence of implant failure is high, and therefore, the productive and economic benefits that the application of this productive technology favors are not being obtained, and there are also determining risk factors.