Peruvian Agricultural Research

Evaluation of Tithonia diversifolia as a potential ingredient in animal feed

Anahi Jobeth Borrás-Enríquez — 2025-02-14

Objective: To develop a sustainable solution for controlling the invasive plant Tithonia diversifolia by evaluating its compositional and phytochemical properties for potential use as feed for fattening sheep. Methodology: Tithonia diversifolia was collected and its three components (leaf, flower, and stem) were dehydrated. Their nutritional composition, polyphenol content, and antioxidant activity were assessed. Results: The leaves and flowers exhibited the highest protein content, at 8.58% and 10.35% respectively. The stem had the highest total carbohydrate content (82.23%) and lignin (48.56%). In terms of bioactive compounds, the leaves had a greater total phenolic content (99.42 mg EAG/100 g) compared to the stems and flowers. Conversely, the stems (77.47%) and flowers (74.54%) demonstrated greater antioxidant capacity than the leaves (60.79%). Conclusions: The carbohydrates, proteins, lipids, lignin, minerals, phenolic compounds, and antioxidant activity present in the invasive plant Tithonia diversifolia indicate its viability as feed. The flowers and leaves provide protein, while the stem has an important amount of fiber, which are attractive for use as animal food.

Impacto de la descarga de aguas residuales domésticas sobre la carga orgánica y coliformes termotolerantes en el río Ichu, Sierra Central del Perú

Kevin Ortega-Quispe — 2025-02-14

Objetivo: Este estudio tuvo como objetivo evaluar el impacto del vertido de aguas residuales domésticas en la carga orgánica y presencia de coliformes termotolerantes en el río Ichu, ubicado en la sierra central del Perú. Metodología: Se tomaron muestras de agua en dos puntos del río, tanto aguas arriba y aguas abajo. La recolección de las muestras siguió los protocolos nacionales para el monitoreo de la calidad del agua, las cuales luego fueron analizadas para determinar los niveles de Demanda Bioquímica de Oxígeno (DBO5), Demanda Química de Oxígeno (DQO), coliformes termotolerantes y aceites y grasas, utilizando métodos científicos estandarizados. Resultados: El estudio mostró diferencias significativas entre los puntos de muestreo. La concentración de coliformes termotolerantes aguas abajo superó los estándares de calidad ambiental, lo que indica una contaminación bacteriológica considerable debido a descargas domésticas sin tratamiento adecuado. Los valores de DBO5 y DQO también fueron más elevados aguas abajo, reflejando un incremento en la contaminación orgánica. Los aceites y grasas se mantuvieron dentro de los límites aceptables, pero fueron mayores en las aguas abajo en comparación con las aguas arriba. Conclusión: Los resultados evidencian el impacto negativo de las descargas de aguas residuales domésticas sin tratamiento en el río Ichu, con niveles elevados de coliformes termotolerantes y contaminación orgánica en las aguas abajo. El estudio destaca la necesidad urgente de implementar medidas correctivas para mejorar la calidad del agua y proteger la salud pública y el ecosistema acuático.

Potencial de hidrógeno y conductividad eléctrica: dos parámetros esenciales en el crecimiento de Alnus acuminata

Kevin Abner Ortega-Quispe — 2025-02-14

Objetivo: El estudio busca determinar si existen diferencias significativas en el potencial de hidrógeno (pH) y la conductividad eléctrica (CE) entre los suelos pedregosos y profundos en los que se distribuye Alnus acuminata en el Área de Conservación Privada (ACP) Ilish Pichacoto. Metodología: Se tomaron muestras de suelo cercanas a 38 árboles utilizando un transecto lineal aleatorio en un radio de 1 m alrededor de cada árbol. Cada muestra de suelo se extrajo contra la pendiente del terreno a una profundidad de 20 cm, empleando sondas manuales. El pH se midió con un potenciómetro de precisión, mientras que la CE se registró con un conductímetro eléctrico. Para el análisis estadístico, se utilizó una prueba t de Student para muestras independientes. Adicionalmente, se generaron ecuaciones de regresión y coeficientes de determinación (R²). Resultados: Los resultados mostraron que el pH medio de los suelos pedregosos era de 5,77, significativamente superior al pH medio de 4,78 de los suelos profundos. En cuanto a la CE, la media fue de 0,15 dS/m en los suelos pedregosos y de 0,5 dS/m en los suelos profundos, lo que representa una diferencia significativa entre ambos tipos de suelos. Conclusión: Existen diferencias sustanciales en pH y CE entre los suelos pedregosos y profundos en los que crece Alnus acuminata. Esta especie arbórea muestra mejor crecimiento en suelos pedregosos que en suelos profundos dentro del área de estudio.

Physicochemical properties and antioxidant capacity of purple Mashua yogurt

Ibalut Ibarra Luna — 2025-02-14

Objective: To determine the physicochemical characteristics and antioxidant potential of yogurt optimized with Tropaeolum tuberosum (“purple mashua”). Methodology: Natural yogurt was prepared and mashua puree was added in ﬁve diﬀerent concentrations (16.67, 33.45, 50.04, 66.33 and 83.55 g per liter of yogurt); the optimum concentration was determined using the cut-oﬀ point graphical method. The physicochemical properties (pH, titratable acidity, density, syneresis and viscosity), the antioxidant potential by ABTS+ assay, the amount of total polyphenols by Folin-Ciocalteu colorimetric reaction were evaluated. Results: The concentration of optimized pure de mashua purpura added to plain yogurt was 55.67 g. Its physicochemical properties were as follows. Its physicochemical properties were: pH: 4.40, titratable acidity 0.61 % lactic acid, density 1.051 g/cc, syneresis 39.62 and viscosity 998.63 cp. It presents an antioxidant activity of 420.56 uMol ET and total polyphenols of 951.36 mg Gallic Acid Equiv. per 100 grams of yogurt. Conclusions: With the inclusion of 55.67 g of purple mashua puree and 19.62 g of stevia per liter of plain yogurt, an acceptable product is produced with a similar color to commercial blackberry yogurt. In addition, the product improves its physicochemical properties and antioxidant capacity.

Agricultural fertilization practices in crop production: a literature review

Vladimir Alex Cáceres Salazar — 2025-02-14

Objectives: To describe the appropriate and eﬃcient agricultural fertilization practices that contribute positively to crop production with minimal environmental contamination, and to raise awareness of the importance of organic fertilizers in agriculture. Methodology: Diﬀerent databases were used to locate bibliographic documents; then, articles that prioritized the theoretical foundations of agricultural fertilization were selected. To begin preparing the review article, a documentary analysis, group discussion, and quality evaluation of the articles found were carried out. Results: It is important to perform a soil analysis to determine the amounts of nutrients present, and thus avoid excesses in fertilization, adding the appropriate nutrients in the correct proportion. This helps to avoid overfertilization and to apply nutrients correctly. Conclusion: Adequate fertilization contributes to healthy plant growth, increases crop production, and can be a crucial component in sustainable agriculture.

Caracterización física de perfiles de suelos de las principales zonas productoras de aguacate (Persea americana Mill) en Ecuador

Paúl Mejía-Bonilla — 2025-02-14

Objetivos: El objetivo de este estudio fue caracterizar físicamente los perﬁles de suelo de 7 huertos comerciales de las variedades
Hass y Fuerte, injertados en portainjertos Nacional y Zutano, en las principales provincias productoras de aguacate de Ecuador:
Carchi (C), Imbabura (I), Pichincha (P), Tungurahua (T) y Santa Elena (SE). Metodología: Se realizaron calicatas en cada área de
estudio, se tomaron y caracterizaron los horizontes del perﬁl del suelo mediante análisis físico en campo. Los datos de
rendimiento por variedad fueron recolectados de los propietarios de huertos y/o técnicos. Resultados: Los resultados mostraron
un mayor uso de portainjertos Nacional (mexicano) e identiﬁcaron cuatro ubicaciones óptimas desde una perspectiva edáﬁca (San
Vicente-P, Yachay-I, San Joaquín-I, Tomebamba-I), basadas en la profundidad efectiva, textura, estructura y salinidad. Con una
adecuada gestión agronómica (reducción del pH y adición de materia orgánica), estas áreas podrían generar altos rendimientos y
cultivos de calidad exportable. Se identiﬁcaron dos zonas (Písquer-C y Los Andes-T) donde las enmiendas (aumento de materia
orgánica, reducción de pH y control de salinidad) y correcciones físicas del suelo (aumento de la profundidad efectiva y
estructuración) podrían crear condiciones adecuadas para la producción de aguacate. Una zona (El Azúcar-SE) fue clasiﬁcada
como no adecuada para el cultivo de aguacate debido a la baja profundidad efectiva (15 cm), texturas arcillosas (> 89%),
-1
estructuración masiva, pH alcalino (> 8.45) y suelos salinos (2.74 mS cm ). Conclusiones: Los suelos destinados al cultivo de
aguacate son diversos y, en algunos casos, no cumplen con los requisitos físicos necesarios. El uso de portainjertos Nacional
(mexicano) propagados sexualmente es común en Ecuador, pero la variabilidad del suelo y las condiciones limitantes no siempre
se tienen en cuenta. Para las áreas con restricciones edáﬁcas leves, son necesarios el acondicionamiento y las enmiendas.

Effect of cattle manure and inorganic fertilizer on the initial growth of paprika pepper (Capsicum annuum)

Karla Noelia Cubas Tarrillo — 2025-02-14

Objective: To evaluate the eﬀect of cattle manure and an inorganic fertilizer on the initial growth of paprika pepper. Methodology: A completely randomized design with a 3 x 2 factorial arrangement was implemented, with three -1 levels of cattle manure as the factor (0, 280 and 560 g plant ) and two levels of inorganic fertilizer as the factor -1 (without and with). Ammonium sulfate (21% N) was used as the inorganic fertilizer source and 13 g plant was applied. The combination of both treatments resulted in six treatments, which had three repetitions. 10 L bags, sandy soil and paprika pepper seedlings were used. The data obtained were subjected to variance analysis using the F test, after evaluating normality and homogeneity of variances. The Tukey test at 5% was used to compare means. The statistical software SISVAR 5.6 was used. Results: For the set of variables evaluated, interaction was found between the factors under study. The addition of inorganic fertilizer to diﬀerent levels of cattle manure favored the achievement of greater plant height, dry matter production (roots, stems and total) and total chlorophyll content. Conclusion: The addition of inorganic fertilizer to cattle manure positively inﬂuences the improvement of the initial growth characteristics of paprika pepper. These results support the implementation of integrated fertilization practices that combine organic and inorganic sources to optimize crop growth and yield in a sustainable manner.

Morphological characterization of Capsicum spp. germplasm. in the Instituto National de Innovación Agraria, Peru

Melanie Fiorella Castañeda Blas — 2025-02-14

Objective: To evaluate and identify the morphological characteristics of four species of Capsicum spp. from the germplasm bank
of the National Institute of Agrarian Innovation in Huaral, Peru. Methodology: Qualitative and quantitative character data of
Capsicum accessions from the germplasm bank of the Instituto Nacional de Innovacion Agraria (Peru) were entered into a matrix
of accessions and characters to perform principal component analysis (PCA) and estimate variability among accessions. To
identify groups of individuals by species, discriminant analysis was performed; a distance matrix between accessions was
calculated and the proximity between them was analyzed, which was visualized using the clustering method (UPGMA). Results:
Morphological characterization revealed the discriminant power between quantitative and qualitative descriptors, which were:
corolla color, calyx ring constriction, corolla spot color, number of ﬂowers per axle, fruit shape with pedicel and calyx margin.
They formed two hierarchical cluster groups, one between C. frutescens and C. chinense and another cluster between C. baccatum
and C. annuum. Conclusion: The morphological characterization of Capsicum spp. from the Peruvian germplasm bank revealed
high discriminant power for the quantitative and qualitative descriptors.

Phytoremediation plants and organic matter reduction in wastewater from the Supe animal feedlot: pilot scale analysis

Jean Carlos Alfonso Padilla Ramirez — 2025-02-14

Objectives: To evaluate the eﬀect of phytoremediation plants on reducing organic matter in wastewater from the Supe municipal wastewater treatment plant at a pilot scale. Methodology: The reduction of biological oxygen demand (BOD5) and chemical oxygen demand (COD) was evaluated and compared with the maximum allowable values (MAV) allowed by Peruvian regulations for wastewater. The treatments evaluated were T1: Nasturtium oﬃcinale, T2: Eichhornia crassipes and T3: Thypa latifolia. Wastewater was collected at the discharge point during the processing period, and then poured into 15-liter plastic containers, where the phytoremediation plants were introduced for 14 days. Samples were taken at the beginning and end of the treatment. Data processing was performed using variance analysis and Tukey's test. Results: Nasturtium oﬃcinale reduced COD by 48.1% and BOD5 by 84%, Eichhornia crassipes reduced COD by 64.9% and BOD5 by 89.2%, and Thypa latifolia reduced COD by 70% and BOD5 by 89.1%. Conclusions: The phytoremediation plants Thypa latifolia, Eichhornia crassipes and Nasturtium oﬃcinale are only eﬃcient in reducing BOD5 values below the AMV of wastewater from the Supe municipal slaughterhouse.

Natural treatments for the removal of heavy metals and turbidity in the Pativilca river, Peru

Roberto Carlos Fernandez Moreno — 2025-02-14

Objective: To determine the eﬀect of natural and conventional treatments on removing turbidity, heavy metals, and
complementary parameters of the Pativilca River water. Methodology: A pre-sampling was conducted to select a stretch of the
river with high concentrations of metals, followed by sampling at the identiﬁed point (EM.RPATI-I). Six treatments were
evaluated in each sample: two natural (powdered prickly pear mucilage and activated carbon from lignocellulosic ﬁbre of prickly
pear), two conventional (conventional activated carbon and aluminium sulfate), and two mixtures (powdered prickly pear
mucilage plus prickly pear activated carbon and aluminium sulfate plus conventional activated carbon). The doses used were 0.7
mg/L, 10 g/L, 0.1 g/L, and their combinations. The study was conducted over 150 days analysing the variables: turbidity, lead
concentration, iron concentration, pH, electrical conductivity, total dissolved solids, and water temperature. Results: The most
eﬀective treatments for turbidity removal were prickly pear activated carbon (98.79%), aluminium sulfate (98.72%), and
conventional activated carbon (98.47%); for lead removal, they were aluminium sulfate plus activated carbon (94.89%) and
conventional activated carbon (94.15%); and for iron removal, prickly pear activated carbon (73.67%) showed the best eﬃcacy.
Conclusion: The mucilage and lignocellulosic ﬁber from prickly pear, as a ﬂocculant and activated carbon, showed a similar
eﬀect (p < 0.05) to that of conventional treatments in improving the water quality of the Pativilca River.