In the coming decades it will be crucial to meet the demands for food, without promoting environmental degradation, not only to increase agricultural production amid climate change, but also to develop innovative technologies that increase agricultural yields, minimize inputs and avoid increased environmental contamination, which is why numerous organic products are currently being tested in the world that are applied as nutritional agents or stimulants of plant growth. The objective of this work was to evaluate the agrobiological ef fectiveness of chitosan, mycorrhizal fungi, and humic acids in the growth and development in plants of two varieties of tomato under controlled conditions. The experiment was established in a bifactorial design, with two varieties and application of chitosan (3 g L-1), arbuscular mycorrhizal fungi (20 g of spores mL-1) and humic acids (1:30 v / v), the control treatment was distilled water. The variables evaluated were percentage of total emergence, emergence rate, percentage of germination, stem length, stem diameter, root length and number of leaves, fresh and dry biomass of aerial part, and production indicators: number of fruits per plant, polar diameter, equatorial diameter and yield per plant. The initial development parameters showed signif icant dif ferences to the application of humic acids and chitosan in the Vyta variety, in addition to the emergence percentage of 96% in both varieties, while the fresh and dry biomass of the varieties presented favorable results, as well as the variety Vyta obtained higher yield with the application of humic acids. The use of humic acids showed better results, followed by the use of arbuscular mycorrhizal fungi, because the tomato varieties showed better development, obtaining quality fruits and good weight.

Soil Cd is absorbed by roots and accumulated in cocoa plants, which represents a problem in the commercialization of beans. In order to evaluate whether the exogenous application of macronutrients (N, N-P, N-P-K, N-P-K-S, N-P-K-S-Mg, and N-P-K-S-Mg-Ca) mitigates the absorption, translocation, and accumulation of Cd in plants, soil pH and electric conductivity, dry root and shoot biomass, leaf gas exchange, chlorophyll content, and macronutrient bioaccumulation were evaluated in two cocoa clones (CCN-51 and EET-103) grown in a greenhouse. An increase in macronutrients gradually increased the extraction capacity of Cd in both clones, with the highest Cd values being obtained with the application of N-P-K-S-Mg-Ca. Macronutrient fertilization did not affect leaf gas exchange; however, it caused significant reductions of 30, 40, and 60% in chlorophyll content, shoot, and root dry biomass, respectively. The greatest translocation of Cd from the root to the shoot was obtained with treatments that included N in clone EET-103 and Ca in clone CCN-51. Fertilization with macronutrients did not decrease the absorption and accumulation of Cd in the cocoa seedlings, because a greater removal force of Cd from the adsorption complex towards the soil solution was caused by the exogenous application of Ca and Mg and an increase in soil acidity.

It is estimated that the world production of cacao (Theobroma cacao L.) in the future will not meet its demand due to factors such as losses derived from pests and diseases, aging trees, limited yields, and effects of climate change. The biostimulant Quitomax®, whose main bioactive ingredient is chitosan, is a growth and resistance inducer, and an antimicrobial agent with promising results in agricultural crops. However, since its effect on the rooting, establishment and growth of cacao has not been investigated, the objective of this work was to evaluate the effect of Quitomax® on two commercial varieties of cacao, and compare it with Raizyner GNS commercial product. The experimental design was a factorial arrangement with the two cacao clones (A) and three chitosan concentrations (100, 500 and 1000 mg L-1) (B), with three replicates per treatment. Untreated plants and plants treated with Raizyner GNS (5000 mg L-1) were used as controls. The biostimulant Quitomax® promoted a significant increase in the vegetative growth variables evaluated in the cacao clones compared with the controls. In regards to plant regeneration, Quitomax® decreased the levels of the unrooted stem cuttings by 18% to 50%. In addition, Quitomax® favored the growth promotion and biostimulation of cacao plants during clonal reproduction by cuttings with better results than those obtained with other commercial products such as Raizyner GNS.

The agricultural use of silicon dioxide nanoparticles (SiO2 NPs) has the potential to improve the yield, sensory quality, and nutraceutical properties of various plant species. The objective of this study was to evaluate different concentrations of SiO2 NPs (0, 5, 7, and 9 mg L−1) on the growth, yield, and nutraceutical quality of peppers (Capsicum annuum L.) cv. Quetzal grown under greenhouse conditions. A completely randomized experimental design was established with four treatments and three replicates. SiO2 NP solutions were applied via drenching at specific phenological stages. Agronomic variables (plant height, stem diameter, and dry biomass), productive variables (number and weight of fruits and yield per hectare), and biochemical variables (total phenolic compound content, flavonoids, and antioxidant capacity) were measured. The results indicate that concentrations of 7 and 9 mg L−1 of SiO2 NPs significantly promoted vegetative growth, with increases in plant height (+12.40%) and dry biomass (+60.02%), respectively. Furthermore, increases in fruit number and weight, as well as total yield, were observed. In terms of nutraceutical quality, higher levels of phenolic compounds (+37.14%), flavonoids (+45.44%), and antioxidant activity (+3.71%) were recorded in fruits treated with these concentrations. These findings suggest that the application of SiO2 NPs at optimal doses can improve both the yield and nutraceutical quality of peppers, positioning it as a promising agronomic input for this crop.

La producción ganadera en Ecuador enfrenta el desafío de mejorar la productividad de los pastos de manera sostenible, procurando mantener la economía del sector frente a las fluctuaciones en los precios de la carne y de insumos como los fertilizantes. El objetivo de la presente investigación fue evaluar la producción de biomasa, concentración bromatológica y población microbiológica de las asociaciones de los pastos festuca (Festuca arundinacea) y ray grass (Lolium multiflorum), asociados con trébol rojo (Trifolium pratense) y alfalfa (Medicago sativa) e inoculados con rizobacterias promotoras del crecimiento vegetal. Se evaluaron los siguientes inoculantes bacterianos: Azotobacter chroococum, Azotobacter vinelandii, Azotobacter beijerinck, Pseudomonas fluorecens, y un testigo. Las asociaciones de gramíneas y leguminosas (relación 2:2) estuvieron distribuidas en un diseño de bloques con arreglo de parcelas subdivididas y tres repeticiones. Se destinaron edades de cosechas que fueron 30 y 60 días después de la siembra (DDS) y se evaluaron las siguientes variables: longitud de raíz, peso de raíz, concentración de proteínas, ceniza, extracto etéreo, fibra y materia seca. Se encontró que el pasto L. multiflorum asociado con M. sativa e inoculado con + A. beijerinck tuvo la mayor biomasa seca (2454,75 kg ha-1) y la leguminosa M. sativa asociada con F. arundinacea e inoculada con A. vinelandii, presentó la mayor biomasa seca (1464,40 kg ha-1) a los 60 DDS. Las mayores concentraciones de proteínas con el inoculante A. beijerinki en los forrajes de F. arundinacea + T. pratense y L. multiflorum + T. pratense fueron 28,12% y 26,87%, respectivamente. Se evidenció que los inoculantes bacterianos serían una estrategia amigable con el medio ambiente para mejorar la morfo-productividad y calidad nutricional de las especies forrajeras.

In Ecuador, pepper (Capsicum annuum L.) cultivation has gained importance in recent years due to the crop’s nutritional value and the increasing area devoted to its production. Pepper is moderately sensitive to water stress, a constraint that is becoming increasingly relevant in areas with limited or inefficient irrigation. This study evaluated the effect of foliar spraying with SiO₂ nanoparticles (SiO₂ NPs) on 'Nathalie' hybrid pepper plants subjected to temporary water stress caused by interruption of irrigation. The experiment was conducted in a greenhouse at the Faculty of Agricultural and Forestry Sciences, State Technical University of Quevedo, Ecuador. Seedlings were transplanted into containers filled with a homogenized soil and cow manure compost substrate. Treatments were arranged in a completely randomized design and consisted of a non-stressed control without SiO₂ NPs and three SiO₂ NP concentrations (250, 500, and 1000 mg L⁻¹) applied to plants exposed to a 10-day irrigation suspension, after which irrigation was resumed. Foliar application of SiO₂ NPs improved plant height, stem diameter, leaf area index, fruit length, and fruit mass, with the strongest response generally observed at 1000 mg L⁻¹. These results indicate that SiO₂ NPs may help maintain growth and fruit development in pepper plants exposed to short-term water stress. However, because the design did not include a water-stressed treatment without SiO₂ NPs, the stress-mitigation effect should be interpreted with caution and confirmed under field conditions.