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Spatial modelling of soil quality index using regression–kriging and delineation of nutrient management zones in high-Andean quinoa fields, southern Peru
(MDPI, 2025-12-29) Cuellar Condori, Nestor Edwin; Mejia Maita, Sharon Yahaira; Quiñones Trejo, Robert Adrián; Mercado Chinchay, Ruth Lizbeth; Silva Ali, Cristhian; Chávez Zea, Karla Licelly; Ccosi, Elvis; Cahuide, Madeleiny; Quispe Matos, Kenyi Rolando
The pronounced heterogeneity of high-Andean soils constitutes a critical constraint to the sustainable productivity of quinoa in southern Peru, where current yields (1.6 t ha⁻¹) remain well below potential (>5 t ha⁻¹). This study aimed to develop a spatially predictive model of a weighted soil quality index (SQIw), the edaphic supply of nitrogen (N), phosphorus (P) and potassium (K), and the agricultural gypsum requirement by integrating edaphoclimatic covariates through regression–kriging. A total of 198 quinoa-cultivated soil samples were analysed; a minimum data set (MDS) was defined using correlation and principal component analyses, and regression–kriging was applied to map SQIw and the variables of interest. The MDS comprised electrical conductivity (EC), organic matter (OM), available P, exchangeable Na, sand, clay, and effective cation exchange capacity (ECEC); exchangeable Na (Wi = 0.160) and available P (Wi = 0.158) received the largest weights in the SQIw. SQIw values ranged from 0.22 to 0.84 and supported a five-class soil quality taxonomy; spatial modelling revealed a dominance of moderate-quality soils across the territory (85.21% of the agricultural area, 13,461.19 ha). The model achieved R² = 0.56, RMSE = 0.05, and MAE = 0.04 for SQIw. Most of the area (12,175.65 ha; 77%) exhibited an intermediate gypsum requirement (9.73–14.33 t ha⁻¹). Nitrogen and phosphorus showed the greatest territorial limitations, whereas potassium was largely non-limiting (84.82–570.17 kg ha⁻¹). These results indicate that sodicity and N–P deficiencies are the primary functional constraints; the generated maps enable prioritisation of gypsum amendments and targeted variable-rate fertilisation strategies to optimise the sustainability of quinoa production in the Altiplano.
Assessment of flood-prone areas in the Lacramarca River Basin in the Santa Clemencia and Pampadura region, Peru, under climate change effects
(MDPI, 2026-03-26) Pérez Camponanes, Giovene; Romero Valdez, Karla Karina; Martínez García, Víctor Manuel; Cacciuttolo, Carlos; Bernal Camacho, Jesús Manuel; Carbajal Llosa, Carlos Miguel
Floods are among the extreme events associated with climate variability in the Lacramarca River basin, located in the department of Ancash, Peru. Meteorological phenomena such as El Niño during the periods 1982–1983 and 1997–1998, as well as the Coastal El Niño in 2017, constitute key reference events that motivated the development of the present study, based on a case study conducted in the area between the rural settlements of Santa Clemencia and Pampadura. This research is based on maximum precipitation data derived from historical climate records and from the climate scenarios ACCESS 1-3, HadGEM2-ES, and MPI-ESM-MR, as well as the median projected scenario for 2050, obtained from the National Meteorology and Hydrology Service of Peru (SENAMHI) data platform. This information was analyzed considering the spatial location of the basin and its position relative to the area of interest, using Intensity–Duration–Frequency (IDF) curves. To demonstrate the changes in the river hydrological behavior before and after the 2017 Coastal El Niño event, a Random Forest modeling approach was applied using Sentinel-2 satellite imagery. Design peak discharges for return periods of 50, 100, and 140 years were estimated using the HEC-HMS software. Hydraulic simulation of the Lacramarca River basin, carried out using HEC-RAS version 6.7 beta 3 and IBER version 3.3.1 software, made it possible to identify flood-prone areas affecting agricultural land and areas adjacent to population centers, covering 149,000 m² and 172,000 m² for return periods of 100 and 140 years, respectively, based on information from the historical scenario. In contrast, using data from the 2050 projection scenario, affected areas of 242,000 m² and 323,000 m² were estimated for the same return periods.
Soil organic carbon content mapping along the coast of northern Peru: an ensemble machine learning approach
(Frontiers Media SA, 2026-03-26) Salazar Coronel, Wilian; Carbajal Llosa, Carlos Miguel; Chuchon Remon, Rodolfo Juan
Introduction: Soil organic carbon (SOC) content plays a fundamental role in regulating the global carbon cycle and mitigating climate change. It is also a key marker of soil health and a vital plant component. Its distribution in space varies in dry ecosystems, where climate and land use affect it. This study aimed to estimate and map SOC in the Motupe River Basin, northern Peru, by applying machine learning algorithms and ensemble methods. Methods: Four predictive models were evaluated: Support Vector Regression (SVR), Random Forest (RF), Artificial Neural Network (ANN), and Extreme Gradient Boosting (XGBoost), together with two ensemble approaches—simple averaging and weighted — integrating topographic, climatic, edaphic, and vegetation indices variables. Spatial autocorrelation was minimized by spatial block cross-validation. Uncertainty was measured with bootstrapping and the Prediction Interval Ratio (PIR) derived from 90% prediction intervals. Results and discussion: Best performance was achieved by XGBoost (R² = 0.83), weighted ensemble (R² = 0.70), and RF (R² = 0.63). The most influential predictors were EVI, GNDVI, temperature, TRI, and pH. SOC contents showed relatively higher concentrations (>0.7%) in areas with greater vegetation density, within a semi-arid context where SOC levels are generally low. In contrast, lower areas exhibited reduced SOC contents (< 0.6%). The uncertainty analysis indicated that SOC predictions had high to moderate confidence (PIR < 0.2) in the middle-and upper zones of the basin, and moderate confidence (0.1–0.2) in the lower areas. The results suggest that machine learning and ensemble methods improve SOC prediction, benefiting the sustainable management of soil fertility and quality in arid and semi-arid ecosystems of northern Peru.
Production of biochar derived from guinea pig manure as a soil amendment in high Andean and coastal acidic soils in Peru: agronomic potential and cost analysis for sustainable circularity
(Frontiers Media SA, 2026-03-17) Solórzano Acosta, Richard Andi; Damián, Lucía; Herrera, Sherly; Pichis García, Roger; Cabello Torres, Rita; Padilla Castro, Cesar Franco; Arias Arredondo, Alberto; Chávez Collantes, Azucena; Vallejos Torres, Geomar
Introduction: The valorization of local resources, such as guinea pig manure, allows traditional inputs to be transformed into more stable products with higher added value, such as biochar, rather than being used as raw manure. Methods: This study evaluated the physicochemical properties, toxicity, and neutralizing capacity of biochar obtained from guinea pig manure, produced by open pyrolysis in a pyrolytic oven in Huancayo, Junin, Peru. Fresh manure was also characterized prior to pyrolysis, and its median lethal dose was determined. Results: The results indicated that guinea pig manure had an approximate volume of 2,883.99 cm3 in an uncompacted state and 2,205.41 cm3 in a compacted state, with densities of 0.293 and 0.380 kg/cm3, respectively. Guinea pig manure biochar has high N, P, and K contents, as well as a significant percentage of ash (34.6%) and fixed carbon (37.9%). Its alkaline pH (9.17), high cation exchange capacity (48.8 meq/100 g), and high organic matter content (62%) suggest its potential for improving acidic soils. It also has a considerable moisture content (34.8%) and microelements such as Mg, Cu, Ca, and Zn. In economic terms, the production of 1 ton of guinea pig manure has an estimated cost of 231.23 soles, while the sale price of biochar reaches 3,515.31 soles per ton, demonstrating its high added value. Discussion: Biochar derived from guinea pig manure has a superior nutritional profile compared to biochars obtained from plant biomass, making it a viable alternative for agriculture. Its application, however, must take into account specific safety tests for each crop to ensure both safety and effectiveness.
Effects of conservation time and ingredient proportion on the nutritional composition and in vitro digestibility of Musa spp. silages for small ruminant feeding
(Frontiers Media S.A., 2026-03-24) Temoche Socola, Victor Alexander; Villanueva, David; Jibaja, Omar; Godoy Padilla, David; Sánchez , Héctor; Vásquez García, Cesar Alejandro; Soca Jorge, Jhony; Sessarego Dávila, Emmanuel Alexander; Cruz Luis, Juancarlos Alejandro
This study evaluated the effects of conservation time and ingredient proportion on the nutritional composition and in vitro digestibility of Musa spp. silages intended for small ruminant feeding. A 3×3 factorial design was applied, considering three conservation periods (60, 90, and 120 days) and three ingredient proportions (100% fruit, 70% fruit–30% crop residues, and 50% fruit–50% crop residues). Silage samples were analyzed for dry matter, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), ether extract, ash, nitrogen-free extract (NFE), and in vitro dry matter digestibility (IVDMD). Ingredient proportion significantly affected CP content, which ranged approximately from 3.4 to 6.9% of dry matter, whereas IVDMD varied between 50.8 and 74.2%, with the highest values observed in silages produced with 100% fruit at 90 days of conservation (p < 0.05). NDF and ADF contents ranged from 30–40% and 15–35% of dry matter, respectively, showing a significant interaction between conservation time and ingredient proportion. Principal component analysis clearly discriminated treatments according to their nutritional composition and digestibility attributes. Overall, the results demonstrate that both conservation time and ingredient proportion play a decisive role in determining the nutritional and digestive quality of Musa spp. silages, supporting their potential use as a strategic feeding alternative for small ruminants in tropical production systems.
Use of seminal plasma to improve reproductive performance in alpacas (Vicugna pacos) following natural mounting
(CSIRO Publishing, 2016-01) Huanca, Wilfredo; Turin Vilca, Jesús Enrique; Mamani, Camilo; Sanchez, R.; Huanca, Willian Fahrid; Huanca Mamani, Teodosio
Alpacas are classified as induced ovulators, and an external stimulus is required for the occurrence of ovulation. The seminal plasma (SP) of camelids contains a protein identified as ß nerve growth factor with the capacity to induce ovulation and corpus luteum formation. Alpacas have a poor reproductive efficiency and high embryo mortality rate. A study was designed to evaluate the use of SP to improve reproductive performance post natural mating (Exp. 1) and with different mounting time (MT; Exp. 2). Experiment 1: Nonpregnant alpacas (n = 117) exhibiting a dominant follicle = 7 mm, detected by transrectal ultrasonography, were bred by natural mating and then assigned randomly to 1 of 3 treatments: T1 (n = 40), 1 mL of SP IM; T2 (n = 39), 1 mL of GnRH analogue (0.0042 mg of buserelin acetate), IM; and T3 (n = 38), control. Experiment 2: Nonpregnant alpacas (n = 180) exhibiting a follicle = 7 mm were assigned randomly to the following treatments: T1 (n = 30): MT 5 min; T2 (n = 30): MT 5 min + 1 mL of SP; T3 (n = 30): MT 10 min; T4 (n = 30): MT 10 min + 1 mL of SP; T5 (n = 30): MT > 15 min; T6 (n = 30): MT > 15 min + 1 mL of SP. The same male was used for mating females in T1 and T2, T3 and T4, and T5 and T6, respectively. Animals were evaluated by ultrasound with an Aloka SSD 500 (Aloka, Tokyo, Japan) and 5.0-MHz linear transducer on Day 25 for pregnancy diagnosis. In Exp. 1 the conception rate was 67.5, 51.3, and 55.3% for T1, T2, and T3, respectively (P > 0.05). In Exp. 2 the conception rate was 46.2, 67.9, 57.1, 73.3, 61.8, and 72.7% for T1, T2, T3, T4, T5, and T6 (P < 0.05) and was significantly different between T1 v. T2 and T3 v. T4. The results suggest that the use of SP could be one method to improve reproductive performance in alpacas.
Estrategias de suplementación hormonal para mejorar las tasas de embarazo en la transferencia de embriones en alpacas
(CSIRO Publishing, 2016-12-02) Vivanco Mackie, H.W.; Ponce Salazar, M.D.; Gonzales, M. Miguel; Youngs, CR; Osorio Zavala, Cesar Mauro; Asparrin, M.
El objetivo era mejorar la tasa de preñez en alpacas receptoras tras la transferencia de embriones. Se llevaron a cabo dos experimentos, el Experimento 1 en la sierra sur (4.100 m de elevación) y el Experimento 2 (E2) en la sierra central (3.200 m de elevación) de los Andes peruanos. En ambos experimentos, un grupo de donantes de alpaca fue sometido a superovulación y lavado de embriones según los procedimientos ya descritos. Se evaluaron estrategias de suplementación hormonal para mejorar las tasas de gestación en programas de transferencia embrionaria en alpacas. Se aplicaron diferentes tratamientos hormonales a las hembras receptoras para potenciar la receptividad uterina y la supervivencia embrionaria. Los resultados sugieren que el uso de protocolos hormonales específicos mejora significativamente los resultados de gestación, contribuyendo a la eficacia reproductiva en alpacas.
Use of yeasts for the biological control of toxigenic Aspergillus sp. associated with Zea mays L.
(Wiley, 2026-03-09) Sánchez Purihuamán, Marilín; Córdova Rojas, L.M.; Caro Castro, Junior; Barturen Quispe, Ada; Vásquez Llanos, Segundo; Robles Castillo, Heber; Carreño Farfán, Carmen
Zea mays "maize" is one of the most important staple foods for both humans and animals, but it is highly susceptible to pathogens such as toxigenic Aspergillus flavus. Yeasts, however, have the potential to control the growth and activity of toxigenic fungi, representing a viable and economical alternative for biocontrol. This study is aimed at evaluating the efficiency of yeasts in controlling toxigenic A. flavus associated with maize grains. To achieve this, toxigenic A. flavus and yeast isolates were obtained and identified, then coinoculated in vitro to assess their effect on mycelial growth inhibition and total aflatoxin production through yeast-derived volatile organic compounds (VOCs). We found that 147 of the isolated yeasts, when coinoculated with A. flavus, reduced mycelial growth up to 89%. VOCs from five yeast strains of the genera Saccharomyces and Meyerozyma inhibited colony growth up to 86% and induced changes at both the macro- and micromorphological levels in toxigenic A. flavus. Additionally, VOCs from four yeast strains reduced total aflatoxin levels up to 98%. In conclusion, one yeast strain, identified as Meyerozyma caribbica, effectively inhibited both mycelial growth and toxin production in toxigenic Aspergillus sp., demonstrating its potential as a biocontrol agent to reduce fungal contamination in maize grains.
Impact of organic fertilizers on the quality of mango var. ‘Kent’ during physiological and commercial maturity
(MDPI, 2026-03-06) Morocho Romero, Henry Hoseph; Peña Castillo, Ricardo; Morales Pizarro, Arturo; Vilchez Navarro, Sandy Graciela; Casas Niño, Sebastian; Cárdenass Huaman, Gabriela; Nuñez Ticliahuanca, Esdwin Oberti; Montañez Artica, Ana Gabriela; Velarde Apaza, Leslie Diana; Ramirez Rojas, Max; Lozano Isla, Flavio
Mango (Mangifera indica L.) is a key fruit crop in Peru; however, its reliance on chemical fertilizers raises concerns regarding fruit quality and environmental sustainability. This study evaluated the effects of soil-applied compost and foliar-applied biol on the quality of 'Kent' mango fruits at physiological and commercial maturity stages. Conducted during the 2022–2023 season, the experiment used a 3 × 3 factorial design with compost applied at 0, 5, and 15 t/ha and biol at 0, 5, and 10%, plus a chemically fertilized control. Results revealed significant compost–biol interactions. At physiological maturity, treatments 5-10, 15-5 and 15-10 improved pulp color, soluble solids, titratable acidity, and dry matter content, achieving a desirable yellow pulp (2.0 on the scale), 9.29 °Brix, 1.23% acidity, and 20.96% dry matter—surpassing the control. At commercial maturity, these treatments also enhanced fruit firmness (0.42 MPa), reduced acidity (0.47%), increased pulp pH (4.69), and intensified orange pulp color. Overall, organic fertilization, particularly higher compost and biol doses, significantly improved fruit quality parameters compared to conventional chemical management. These findings highlight the potential of integrating organic amendments to promote sustainable mango cultivation while maintaining or enhancing fruit quality, thus providing a viable alternative for eco-friendly nutrient management in mango orchards.
Native entomopathogenic nematodes from Peru control Spodoptera frugiperda, a major pest of Zea mays in the Peruvian Amazon
(MDPI, 2026-03-09) Fachin Ruiz, Grecia; Córdova Sinarahua, Deyvis; Romero Chávez, Lorena Estefani; Alvarado Ramírez, Jaime; Quesquen Lopez, Cesar; Flores García, Eybis; Koch Duarte, Christian; Cerna Mendoza , Agustín; Vásquez Bardales, Joel; Corazon Guivin, Mike
This study evaluated entomopathogenic nematodes (EPNs) isolated from a cacao agroforestry system in the Peruvian Amazon, focusing on their molecular characterization and efficacy against Spodoptera frugiperda (Lepidoptera: Noctuidae) larvae. Thirteen EPN isolates were obtained from 50 soil samples using the Galleria mellonella baiting technique. Mortality assays revealed significant differences among isolates at 24, 48, and 72 h, with isolates 11N-A4 and 8N-B1 being the most virulent, achieving maximum mortalities of 100% and 96.3% at 72 h, respectively. Median lethal time (LT50) values indicated rapid action of these isolates on G. mellonella larvae, with 33.3 h for 11N-A4 and 32.4 h for 8N-B1. Molecular identification using ITS, D2-D3 (LSU), and COI markers confirmed the isolates as Heterorhabditis sp. (11N-A4) and Heterorhabditis amazonensis (8N-B1). In bioassays with S. frugiperda larvae, both EPNs exhibited dose- and time-dependent mortality. H. amazonensis showed rapid action, reaching 100% mortality at the highest dose (60 IJs/larvae) within 48 h, whereas Heterorhabditis sp. displayed a gradual, sustained increase, attaining 91% mortality at 72 h. Median lethal dose (LD50) and LT50 values reflected the efficiency of both isolates, with Heterorhabditis sp. achieving lower LD50 at later stages and shorter LT50 at low-to-intermediate doses. These findings highlight the potential of Heterorhabditis sp. and H. amazonensis as effective biocontrol agents adapted to local conditions and represent the first report of H. amazonensis in Peru. Further studies under field conditions are required to confirm their suitability for incorporation into integrated pest management strategies in the Peruvian Amazon.