Revista de la Facultad de Agronomía de la Universidad del Zulia

Microbial respiration and soil acidity under liming and organomineral amendment

Ana González-Pedraza, Cristian Vivas , Claudia Aragón , Juan Escalante — Thu, 09 Apr 2026 00:00:00 +0000

Soil acidity severely limits biological activity in high Andean systems, where aluminum toxicity and low pH reduce agricultural productivity and constrain microbial processes. In this context, the effect of calcium carbonate (CaCO₃), applied both individually and in combination with a commercial organo-mineral amendment, was evaluated on soil pH, exchangeable aluminum, and microbial respiration in an acidic soil collected from an agricultural farm located in the mountainous region of Pamplona (Norte de Santander), through a 15 day controlled incubation conducted between March and May 2021. A completely randomized design with four treatments (control, 100 % CaCO₃, 50 % CaCO₃, and 50 % CaCO₃ + amendment) and five replicates per treatment was used, measuring chemical variables and respiration at multiple incubation times; statistical analyses included ANOVA, Spearman correlations, and multiple linear regressions. Results showed that CaCO₃ significantly increased pH (up to +0.62 units at the full dose) and reduced exchangeable aluminum only in this treatment, while all amended treatments enhanced microbial respiration, particularly during early stages, with a tendency toward a stronger response in the organic combination. However, multivariate analysis revealed that chemical variables did not independently explain respiratory variability, highlighting the predominance of the integrated treatment effect. It is concluded that liming, especially when combined with organic amendments, corrects chemical acidity and revitalizes microbial activity through systemic effects, with practical implications for the sustainable management of high Andean soils.

Floristic composition and ecological parameters of weeds in corn (Zea mays L.), in Tosagua, Ecuador

Wed, 15 Apr 2026 00:00:00 +0000

Corn is one of the most important species worldwide due to its uses for feeding humans and animals. In Ecuador, the province of Manabí is considered the area with the largest cultivated area nationwide. This work aimed to characterize weeds' floristic composition and predominance in El Junco, Tosagua corn production systems. To estimate the dominance of existing weeds, 10 farms were selected, where thirty random samplings were carried out for each farm using a 0.50 x 0.50 m quadrant. At each sampling point, the existing weeds and their respective identification were counted. In total 39 species were identified, 32 belonging to the Magnoliopsida class (dicotyledons) and 7 to the Liliopsida class (monocotyledons) and grouped into 16 botanical families. The families with the greatest representation were: Poaceae (25,06 %), Euphorbiaceae (18,61 %), Cyperaceae (14,79 %), Asteraceae (9,76 %) and Malvaceae (8,49 %). The most frequent species were Urochloa fasciculata, Euphorbia hirta, Cyperus rotundus, Cyanthillium cinereum, Richardia scabra, Corchorus hirtus and Alternanthera sp. The species U. fasciculata, E. hirta, and C. rotundus obtained the highest dominance values with 3.88, 3.49, and 3.03 % respectively. In this way, we concluded that the Poaceae family, presented the greatest number of weeds in the corn production systems in the El Junco locality. Adequate knowledge of the floristic composition of an agroecosystem will allow the development of appropriate weed management strategies in different commercial corn fields.

Effect of hydroponic barley supplementation on production and physicochemical composition of milk from Normande cows

Abdenour Bir, Aissa Meredef, Mohamed Benidir, Charef Eddine Moufok — Thu, 26 Mar 2026 00:00:00 +0000

This study explores the potential of hydroponic barley as an innovative feed strategy to address shortages in intensive livestock production, with a focus on small-scale landless farms. Twelve three-parous Normande cows, averaging 717 ± 34 kg, were allocated into two homogeneous groups based on body weight, calving date, and previous lactation performance. Both groups received identical total mixed rations (TMR), while the experimental group was supplemented with 10 kg of hydroponic barley per cow per day. Over the lactation period, cows in the experimental group exhibited higher daily dry matter intake (20.62 ± 1.21 vs. 19.13 ± 1.14 kg.d^-1) and milk production (22.17 vs. 18.91 kg.d^-1), resulting in a 17.25 % increase in total lactation yield (6,760.80 vs. 5,765.68 kg). Feed efficiency improved by 9.09 %, and milk composition analysis revealed elevated fat (40.13–42.49 g.kg^-1) and protein (32.21–34.87 g.kg^-1) concentrations. Daily fat and protein yields were also significantly higher in the experimental group (942 and 758.06 g.d^-1, respectively) compared to the control (777.76 and 609.09 g.d^-1). No significant differences were observed in body weight or body condition score between groups. These results suggest that hydroponic barley supplementation can enhance both milk yield and quality by improving nutrient intake and digestibility. However, to fully understand the mechanisms underlying these benefits, further investigations are needed to assess its effects on rumen metabolism and gut microbiota. Overall, this study highlighted the practical potential of hydroponic barley as a sustainable, high-value feed supplement in modern dairy systems.

Chemical characterization of Musa acuminata AAB Peels (Plantain, Blue Java)

Wed, 15 Apr 2026 00:00:00 +0000

The peels of Musa acuminata constitute a by-product of interest due to their richness in metabolites that influence important biological activities. The objective of the study was to evaluate the chemical composition of the peels (maturation stage 1) of Musa acuminata AAB (Blue Java), through the application of chemical and physicochemical methods, for their utilization. A comparative study was carried out with a single experimental factor and two independent samples: treatment without antioxidants (ST) and treatment with antioxidants (T). The proximate analysis performed demonstrated the presence of fiber, proteins, and minerals; moreover, it was verified that the application of antioxidants does not alter the nutritional profile. The absence of heavy metals was confirmed, ensuring the safety of the samples. For the identification and structural characterization of specialized metabolites, an HPLC-MS-UV study was carried out, which allowed the identification of 9 flavonoid glycosides in the acetone extracts of the peels. A higher concentration of phenols and tannins (20.21 mg GAE.g^-1; 8.36 mg GAE.g^-1) was quantified in the samples treated with antioxidants (T) compared to the untreated samples (ST) (6.46 mg GAE.g^-1; 1.71 mg GAE.g^-1), demonstrating that the application of antioxidants inhibits oxidative degradation and preserves these metabolites. These findings show that the immature peels of Musa acuminata AAB of the Blue Java variety constitute a viable and safe source of phytonutrients and phenols. Additionally, the effectiveness of a treatment with antioxidants was confirmed for preserving these metabolites without compromising their nutritional composition.

Functional relationships and productivity factors of the fine aroma cocoa production system

Julia Martínez, Fátima Urdaneta, María Peña, Ángel Casanova† — Tue, 31 Mar 2026 00:00:00 +0000

In the South of Lake Maracaibo, fine aroma cocoa production systems (FACPS) have been developed where good quality beans are produced, but with low yields; this situation can beassociated with multiple social, technical and economic factors, whose interrelationships require a comprehensive analysis to be able to identify their limitations and potentialities. This research was proposed with the objective of explaining how the functional relationships of the FACPS affect its productivity, as well as weighing the productive factors. A sample of 84 producers from the South of Lake Maracaibo was taken. Data were analyzed by Cluster analysis to group the production units by their functional similarities according to four calculated indices: Agronomic Practices Index (API), Labor Force Index (LFI), Production Means Index (PMI) and Socioeconomic Environment Index (SEI), then an analysis of variance was performed to establish the productivity differences between groups. The factors weighting was carried out by a logistic regression model. Results showed the formation of four functional groups with their arrangement of components and relationships. Productivity indicators were significantly different (p ≤ 0.05) among groups, this indicates that the way the system's components are arranged affects its productive outputs. The logistic regression model indicated that the educational level, the low percentage of flat surface and the farm size are the main factors that increase the probability that a production unit belongs to the group with the highest yields.