Examinando por Autor "Vallejos Torres, Geomar"

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Agroecosystems with greater canopy cover increase soil organic carbon density and reduce soil erodibility in the Peruvian Amazon
(Frontiers Media S.A., 2026-03-11) Chuchon Remon, Rodolfo Juan; Solórzano Acosta, Richard Andi; Cruz Luis, Juancarlos Alejandro; Vallejos Torres, Geomar
Introduction: Soil degradation in tropical agricultural landscapes represents one of the major challenges for sustainability and food security, particularly in the Peruvian Amazon. In this region, the loss of vegetative cover alters carbon storage and increases vulnerability to erosion. This study evaluated how gradients of canopy structure in representative agroecosystems—cassava with no canopy (CV-S), oil palm with intermediate canopy density (OP-S), cacao with medium-density canopy (CC-S), and coffee with high-density canopy (CF-S)—influence soil organic carbon density (SOCD) and erodibility (K factor). Methods: A total of 1,049 soil samples (0–20 cm) were collected across three Amazonian regions and analyzed for their physical, chemical, and textural properties, complemented by multivariate and geostatistical analyses using ordinary kriging. Results: Results showed that SOCD increased consistently with canopy density, from 32.68 t C ha⁻¹ in CV-S to 82.64 t C ha⁻¹ in CF-S. The Factor K exhibited the opposite pattern, decreasing from 0.31 to 0.16 as tree cover increased, indicating greater resistance to erosion. Erodibility was primarily determined by soil texture, with a strong positive correlation associated to silt content (r = 0.89) and a negative with sand content (r = –0.74). Likewise, SOCD showed a very high correlation with total nitrogen (r = 0.96), reflecting a tight coupling between carbon accumulation and nutrient availability under denser canopies. Principal component analysis further revealed that dense-canopy systems are related to higher SOCD and total nitrogen, whereas canopy-free systems are linked to higher bulk density and greater susceptibility to erosion. Discussion: Spatial modeling showed that agroecosystems with more developed canopies exhibit better spatial structure and predictive performance, indicating a more stable edaphic organization under dense tree cover. Taken together, the results demonstrate that canopy structure functions as a key ecological regulator in Amazonian agroecosystems, with higher canopy cover promoting greater soil carbon accumulation while reducing soil erodibility. This highlights that dense-canopy systems, such as coffee and cacao, represent effective strategies to strengthen the sustainability and resilience of agricultural landscapes in the Peruvian Amazon.
Analysis of binder proportions on the calorific value in a briquette made from cocoa pod husk in the Peruvian Amazon
(Frontiers Media S.A., 2025-09-22) Solórzano Acosta, Richard Andi; Paquiyauri, Alexandra; Neyra, Walter; Siqueira Bahia, Rita de Cassia; Vallejos Torres, Geomar
Introduction: The growing global demand for fuel has created challenges in the supply of raw materials, positioning biomass derived from cocoa pod husk waste as an economically viable and environmentally sustainable energy alternative. Methods: This study evaluated the effect of different binder types on the calorific value of briquettes produced from fermented cocoa pod husk waste in the Peruvian Amazon. For the calorific value assay, 1.05 kg of fermented cocoa pod husk waste was combined with 100 g of starch-based binders derived from corn, cassava, or potato, all sourced from the San Martín region. Statistical analyses were performed in R Studio using the dplyr package, and mean comparisons were conducted with Tukey's HSD test (p < 0.05). Results: The lowest ash content was obtained with the potato-starch binder (7.03%), whereas the highest value was recorded in the control treatment without binder (8.71%). Fixed carbon content ranged from 3.70% to 5.97% across treatments. The lowest calorific value was observed with the corn-starch binder (3,486.0 kcal/kg), while the highest was achieved with cassava starch (3,586.66 kcal/kg). Discussion: These findings demonstrate the technical feasibility of producing high-quality charcoal briquettes from cocoa pod husk waste using starch-based binders, providing a sustainable alternative to conventional fuels.
Carbon reserves in coffee agroforestry in the Peruvian Amazon
(Frontiers, 2024-12-11) Vallejos Torres, Geomar; Gaona Jimenez, Nery; Pichis García, Roger; Ordoñez, Luis; García Gonzales, Patricia; Quinteros , Aníbal; Lozano, Andi; Saavedra Ramírez, Jorge; Tuesta Hidalgo, Juan C; Reategui, Keneth; Macedo Cordova, Wilder; Baselly Villanueva, Juan Rodrigo; Marín, César
Secondary forests and coffee cultivation systems with shade trees might have great potential for carbon sequestration as a means of climate change adaptation and mitigation. This study aimed to measure carbon stocks in coffee plantations under different managements and secondary forest systems in the Peruvian Amazon rainforest (San Martín Region).
Carbon stocks in coffee farms and secondary forest systems in the Peruvian Amazon rainforest
(Research square, 2023-09-15) Vallejos Torres, Geomar; Gaona Jimenez, Nery; Ordoñez, Luis; Vallejos Torres, Andi; Mendoza Caballero, Wilfredo; Arévalo López, Luis Alberto; Saavedra Ramírez, Jorge; Macedo, Wilder; Reategui, Keneth; Baselly Villanueva, Juan Rodrigo; Marín, César
Secondary forests and coffee cultivation systems with shade trees might have great potential for carbon sequestration as a means of climate change adaptation and mitigation. This study aimed to measure carbon stocks in coffee plantations under different managements and secondary forest systems in the Peruvian Amazon rainforest (San Martín Region). The carbon stock in secondary forest trees was estimated using allometric equations, while carbon stocks in soil, herbaceous biomass, and leaf litter were determined through sampling and laboratory analysis. The biomass carbon stock in secondary forests was 132.2 t/ha, while in coffee plantations with Inga sp. shade trees it was 118.2 t/ha. Carbon stocks were 76.5 t/ha in coffee with polyculture farming, and the lowest amount of carbon was found in coffee without shade trees (31.1 t/ha). The carbon sequestered by coffee plants in all agroforestry systems examined had an average of 2.65 t/ha, corresponding to 4.63 % of the total carbon sequestered, being the highest stored in the coffee system with Inga sp. shade trees. A higher content of glomalin-related soil proteins (GRSP) was found in coffee without shade trees, with 18.5 mg/g. This is evidence that Inga sp. is the most compatible model of shade system for coffee farms. We recommend the conservation of secondary forests due to the greater biomass and carbon storage, and establishing coffee plantations with Inga sp. shade trees for its integral benefits, such as climate change mitigation.
Carbon storage in coffee agroforestry systems: Role of native and introduced shade trees in the central Peruvian Amazon
(MDPI, 2025-06-30) Salgado Veramendi, Noelito; Romero Chavez, Lorena Estefani; Huerto Pajuelo, Eldhy Sianina; Ibarra Porra, Carolina del Carmen; Cunyas Camayo, Joseph Michael; Aldava Pardave, Uriel; Vallejos Torres, Geomar; Solórzano Acosta, Richard Andi
What is the potential impact on carbon storage of the native and introduced tree species commonly associated with coffee in the central Peruvian Amazon? Coffee is a pivotal crop within the Peruvian economy. Nevertheless, the establishment of new plantations—driven by the subsistence needs of smallholder farmers—has led to expansion into forested areas. Given the significance of this crop and the demonstrated ecosystem benefits of agroforestry systems (AFSs), the aim of this study was to evaluate the influence of native and introduced shade tree species on carbon storage in coffee plantations. This study was observational and exhibited characteristics of an unbalanced incomplete block design. Agroforestry systems (AFSs) with shade tree species such as Inga, Retrophyllum rospigliosii, Eucalyptus and Pinus, and three unshaded coffee plantations, were included in this study. The total carbon stored in each AFS was higher than in unshaded coffee plantations. Soil contributed between 47% and 91% to total carbon storage, shade trees (24–46%), coffee (2–7%), leaf litter (0.6–1.9%) and shrubs and herbaceous plants (0.02–0.3%). The AFS with R. rospigliosii achieved the highest carbon storage with 190.38 Mg ha−1, highlighting the compatibility of this species with coffee plantations, as well as its positive effect on climate change mitigation in deforested areas.
Climate, carbon, and soil stability: a key link in coffee-growing landscapes of the Peruvian Amazon
(Frontiers Media S.A., 2026-04-14) Romero Chávez, Lorena Estefani; Hermoza Ayme, Nilton Alexander; Chuchon Remon, Rodolfo Juan; Aldava Pardave, Uriel; Arroyo Isuiza, Rosa Karen; Solórzano Acosta, Richard Andi; Vallejos Torres, Geomar
Introduction: Coffee cultivation in the Central Peruvian Amazon, one of the country's most important production regions, faces increasing challenges from soil degradation and climate change impacts. This study aimed to evaluate the influence of the altitudinal gradient on soil organic carbon (SOC) stocks and soil erodibility (K index) in coffee-growing systems. Methods: Three altitudinal zones were established for sampling (0–20 cm depth): zone 1 (900–1200 m.a.s.l.), zone 2 (1201–1400 m.a.s.l.), and zone 3 (1401–1600 m.a.s.l.). Within these zones, physical and chemical soil properties were analyzed, and SOC and soil erodibility (K index) values were calculated. Results: The results revealed a direct and statistically significant relationship between altitude and carbon sequestration capacity. Zone 3 exhibited the highest SOC (63.19 t·ha⁻¹) and organic matter (OM) content (5.49%), compared with zone 1 (37.56 t·ha⁻¹). This difference is attributable to the climatic conditions at higher elevations, characterized by greater precipitation and lower temperatures. Structural equation modeling (SEM) indicated that increasing altitude enhances SOC (b = 0.42), which in turn improves the soil structural stability index (SI) (R² = 0.87) and reduces the K index (b = –0.38). Overall, the findings demonstrate that organic carbon acts as a key mediator between topography, soil texture, and susceptibility to erosion. The altitudinal gradient thus represents a major controlling factor influencing the health and structural stability of coffee soils. Discussion: These results highlight the need to implement site-specific soil management practices, emphasizing intensive conservation strategies in low-altitude coffee-growing systems to mitigate accelerated erosion and ensure long-term production sustainability under changing climatic conditions.
Cutting propagation technique of mahogany (Swietenia macrophylla) in microtunnels from the Peruvian Amazon
(2025-01-28) Vallejos Torres, Geomar; Gaona Jimenez, Nery; Ordoñez Sanchez, Luis; Garcia Gonzales, Patricia; Mendoza Caballero, Wilfredo; Saavedra Ramirez, Jorge; Macedo Cordova, Wilder; Reategui, Keneth; Baselly Villanueva, Juan Rodrigo; Marin, Cesar
Swietenia macrophylla is a forest species of great commercial value that is categorized as vulnerable in Peru. Therefore, the objective of this study is to optimize a protocol for cutting propagation of S. macrophylla using microtunnels in the San Martín, Peruvian Amazon. Three experiments were conducted: sterilization, which tested ethyl alcohol (EA), Tween-80 (T), carbendazim (CZ), and combinations; a rooting experiment with different substrates and doses of indole-3-butyric acid (IBA); and an acclimation experiment of rooted cuttings, with different shade coverage and relative humidity conditions. The lowest contamination of S. macrophylla cuttings (9.75%) was achieved with the combined EA-CZ treatment; this treatment resulted in the lowest necrosis (9.1%) and survival of 86.50%. The best responses in rooting, root biomass, and cutting survival were presented by the combination of sterilized sand with 3,000 mg L-¹ of IBA, with averages of 73.89%, 0.036 g, and 2.22 cm, respectively. The best acclimation was obtained under 80% shade and 60% relative humidity, with an average survival rate of 91.67%. The general results were successful; therefore, they could be a valuable tool for the rescue, conservation, and restoration of ecosystems with cloned S. macrophylla trees that are resilient to climate change.
Dominance of large trees in carbon storage of Peruvian Amazon forest
(Frontiers Media S.A., 2026-01-26) Lozano, Andi; Gaona Jimenez, Nery; Alvarado, Jaime W.; García Gonzáles, Patricia; Alva Arévalo, Alberto; Ordoñez, Luis; Saavedra Ramírez, Jorge; Tuesta Hidalgo, Juan C.; Vilela, Luis; Tuesta Hidalgo, Oscar A.; Baselly Villanueva, Juan Rodrigo; Chuchon Remon, Rodolfo Juan; Rengifo Del Águila, Sofía; Marin , César; Vallejos Torres, Geomar
Introduction: Forest carbon accumulation is crucial to mitigate ongoing climate change, as large individual trees store a substantial portion of the total carbon in biomass. In this study, large trees and carbon storage were estimated in five forests in the Peruvian Amazon. Methods: For the study, 100 plots were selected (twenty 500 m2 plots per forest site), distributed between 382 to 2086 meters above sea level. Various relationships were explored between the diameter at breast height (DBH) of the most abundant tree species and above- and below-ground carbon. The average carbon content in the tree was calculated based on 50% of the total tree volume at five sites of the Peruvian Amazon. Results: The site with most tree species (Alto Mayo Forest), had 59 tree species. The species Brosimum alicastrum, Ficus insipida, Manilkara bidentata, Inga sp., and Pourouma cecropiifolia showed an average aboveground carbon of 2.31, 3.09, 2.52, 2.78, 2.93 t ha-1, respectively, and values of 0.35, 0.48, 0.38, 0.42 and 0.43 t ha-1 of belowground carbon in trees with ≥ 46 cm DBH. Nectandra sp. showed an above and belowground carbon of 2.50 and 0.38 t ha-1 in trees with ≥ 46 cm DBH, while Cedrelinga catenaeformis showed averages of 5.21 and 0.74 t ha-1 of above and belowground carbon in trees with ≥ 61 cm DBH. Discussion: It was concluded that given the urgency of keeping carbon reserves out of the atmosphere, it is necessary to conserve trees larger than 41 cm, this also allows conserving forest biodiversity and microfauna by buffering the microclimate in the face of future climate changes.
Estimates of Soil Organic Carbon in the Ojos de Agua and El Quinillal Forests in the Central Huallaga of Peru.
(Wiley., 2024-10-05) Mendoza Lopez, Karla; Ordoñez Sanchez, Luis; Valdez Andia, Manuel Jesus; Lozano Chung, Andi; Garcia Gonzales, Patricia E.; Saavedra Ramirez, Jorge; Macedo Cordova, Wilder; Baselly Villanueva, Juan Rodrigo; Reategui, Keneth; Gaona Jimenez, Nery; Vallejos Torres, Geomar
The Peruvian Amazon has experienced large losses of forest cover due to changes in land use, contributing to increases in CO2 in the atmosphere. This study estimated the organic carbon content of forest soil in two forests "Ojos de Agua" and "El Quinillal" in the Central Huallaga of Peru, establishing three types of cover: (i) primary, (ii) intervened, and (iii) deforested. For this purpose, 24 plots of 100 m² were established and samples were extracted at a depth of 0-20 cm. The effect of the type of forest cover on soil carbon (Organic Carbon-SOC, Inorganic Carbon-SIC, Saturated Carbon-SC, Critical Carbon-CC, Saturated Carbon Deficit-SCD, and Organic Carbon-OC) was analyzed by means of an Analysis of Variance, correlation. Likewise, the relationship between carbon (C) and soil properties was evaluated by principal component analysis and correlation network. The results indicated that the highest SOC averages were found in the primary forests of Ojos de Agua and El Quinillal with 3.54% and 2.51%. The lowest values were found in the deforested forests with 1.34% and 1.46%. The calculation of the saturated C levels of the soil showed an average of 28.63% ± 2.14% and the saturated carbon deficit of 26.63% ± 2.45%, whereas the critical threshold of C showed an average of 2.21% ± 0.18%. The highest SOC content found in the Ojos de Agua primary forest is due to the presence of dominant forest species such as Manilkara bidentata and Brosimum alicastrum. Likewise, the C deficit in the soils of the study area is very alarming because it is very close to saturation levels, especially in deforested forests.
Evaluación del prendimiento y desarrollo de clones de caucho (Hevea brasiliensis) propagados por injerto en la selva peruana
(Universidad Autónoma de Yucatán, 2024-07-15) Navarro, Jorge M.; Alva Arévalo, Alberto; Lozano, Andi; Alva Arévalo, Celso Misael; García Gonzales, Patricia; Gaona Jimenez, Nery; Baselly Villanueva, Juan Rodrigo; Saavedra Ramírez, Jorge; Vallejos Torres, Geomar
The latex yield in Hevea brasiliensis trees is highly variable; Therefore, it is important to propagate commercial clones of this species by grafting in order to standardize or improve latex yields and therefore improve the economic income of producers in this part of the Amazon region. Objective. To evaluate the attachment and development of rubber clones propagated by grafting in the Peruvian jungle. Methodology. Nine-month-old patterns installed in the field were used. These were grafted with budding rods from the commercial clones TR-1, FX-3864, RRIM-600, IAN-873 and MDF-180. A completely randomized block design was used with five treatments and three blocks with 15 experimental units; each containing 30 repetitions. The data obtained were subjected to analysis of variance and Tukey's multiple range test (p<0.05) and the Kruskal Wallis test. Results. The best results in attachment and number of shoots were obtained in grafts with clone MDF-180 with values of 73.33 % and 7.83 shoots respectively; Regarding days to the appearance of the shoot and length, clone TR-1 presented it with 36.63 days and 27.47 cm; The largest leaf area was presented by the graft with clone IAN-873 with 55.46 cm2, while the highest chlorophyll content was obtained in grafts with clone RRIM-600 with 47.18 SPAD. Implications. More studies are required to establish the quality and adaptability of rubber clones propagated by grafting in different site conditions and establish patterns of tree productivity in a short time; Likewise, it is desired to evaluate the quality and quantity of latex produced by these clones. Conclusions. These results indicate the feasibility of propagating Hevea brasiliensis through shoot grafting in the field, which opens great possibilities for propagating rubber trees with better commercial characteristics, particularly with greater latex production.
Forest land-use change affects soil organic carbon in tropical dry forests of the Peruvian Amazon
(CSIC (Consejo Superior de Investigaciones Científicas), 2024-10-22) Vallejos Torres, Geomar; Lozano Chung, Andi; Ordoñez Sanchez, Luis; Garcia Gonzales, Patricia; Gaona Jimenez, Nery; Mendoza Caballero, Wilfredo; Macedo Cordova, Wilder; Saavedra Ramirez , Jorge; Baselly Villanueva, Juan Rodrigo; Marin, Cesar
Aim of study: The loss of forest cover is a global problem that alters ecosystems, contributing to carbon emissions. This study measured the soil organic carbon (SOC) at different soil depth in tropical dry forests of the Huallaga Central in the Peruvian Amazon. Area of study: San Martín Region, Peruvian Amazon. Material and methods: A total of 24 plots of 100 m² were selected in primary (~200 years), intervened (~50 years since intervention), and deforested forests (10 years ago), with 120 soil samples collected across five depths. Soil texture (hydrometer), bulk density (cylinder method), SOC content, SOC density, and erodibility (K parameter) were calculated. Main results: SOC content in the 0-20 cm soil horizon was 79.5±21.3 t ha-¹ for the primary forest, 58.5±11.8 t ha-¹ for the intervened forest, and 41.8±10 t ha-¹ for the deforested forest. A soil erodibility K of 0.065 was observed for primary forests and 0.076 and 0.093 for intervened and deforested forests. In average, the SOC density obtained in this study was 7.6±5.1 t ha-¹ in the primary forest, 6.2±3.6 t ha-¹ in the intervened forest, and 4.7±2.7 in the deforested forest. Research highlights: Primary forests had the highest SOC content and SOC density, followed by intervened and deforested forests, while the opposite pattern was found for soil erodibility. These patterns were especially marked in the first 40 cm of soil depth.
Geospatial distribution of cadmium in soil profiles of cacao (Theobroma cacao L.) plantations in the Peruvian Amazon basin
(Frontiers Media S.A., 2026-02-25) Vallejos Torres, Geomar; Chuchon Remon, Rodolfo Juan; Gaona Jimenez, Nery; Marín, César; Cruz Luis, Juancarlos Alejandro; Solórzano Acosta, Richard Andi
Introduction: Cacao plants can translocate heavy metals from the soil to vegetative tissues, potentially leading to concentrations that exceed maximum permissible limits. This study aimed to analyze the geospatial distribution of cadmium (Cd) in soil profiles of cacao (Theobroma cacao L.) plantations in the Amazon basin of Peru. Methods: The research was conducted in the localities of Jeberillos, Arahuante, and Luz del Oriente, within the department of Loreto. In each locality, 10 plots of 100 m² were selected, totaling 30 plots. Cd concentrations and physicochemical soil parameters were evaluated. Results: In cacao soils from Luz del Oriente at 0–30 cm depth, Cd concentrations averaged 1.11 ± 0.26 mg.kg⁻¹, representing the highest values; whereas the lowest average was recorded in Arahuante at the same depth, with 0.61 ± 0.15 mg.kg⁻¹. Cd levels in Luz del Oriente cacao soils (0–30 cm) were above the average among all localities, while Jeberillos and Arahuante soils showed comparatively lower Cd levels. Discussion: Overall, Cd in cacao soils was found to be strongly associated with edaphic factors such as pH, texture, effective cation exchange capacity (CEC), and cation composition. The maps represented the spatial distribution of the metal and guided the identification of potential accumulation zones. These findings provide essential insights for guiding agricultural management decision-making, environmental monitoring, and metal contamination risk assessment in cacao-growing areas and other agrarian systems in the Peruvian Amazon basin.
Impact of forest degradation on soil properties in the Peruvian Amazon
(Springer Nature, 2026-01-16) Vallejos Torres, Geomar; Gaona Jimenez, Nery; Lozano, Andi; Saavedra , Harry; Alva Arévalo, Alberto; Ríos Vargas, Caleb; Saavedra Ramírez, Jorge; Tuesta Hidalgo, Juan; Tuesta Hidalgo, Oscar A.; Vilela, Luis; Valdez Andia, Manuel Jesús; Reategui, Keneth; Baselly Villanueva, Juan Rodrigo; Marín, César; Vento, Bárbara
Background: The Amazonian forests are increasingly threatened due to continuous changes in land use, particularly deforestation. This study aimed to quantify and analyze the vertical distribution of soil glomalin and its relationship with carbon, climate, and soil properties across three forest types of the Peruvian Amazon. A total of 18 plots were selected and sampled in forests with different vegetation cover types: deforested, disturbed, and primary forest. The vertical variation of total glomalin (TG), easily extractable glomalin (EEG), and the number of arbuscular mycorrhizal fungal (AMF) spores was estimated, as it was the relationships of these variables with soil depth, physical-chemical properties, and climate conditions. Results: The mean values for TG, EEG, and AMF showed vertical variations in the three forest cover types, with high values in disturbed forests and degraded soils. Overall, higher mean values were found in the surface soil layers compared to the deep layers. TG, EEG, and AMF were positively corelated with soil organic carbon (SOC) and soil organic matter (SOM). Moreover, the total nitrogen (N), SOC, OM, total phosphorus (P), and soil water content (SWC) presented higher values in the topsoil than the deep layers. Conclusions: The highest production of glomalin in disturbed forests is probably a response to degradation processes. This work is a contribution to expand knowledge about glomalin dynamics in forest soils of the Amazon rainforest and provides essential information for future soil ecosystem restoration practices in tropical forests.
Impact of liquid biofertilizer from cocoa shells on the growth and chlorophyll content of sweet peppers (Capsicum chinense L.) in San Martín, Peru
(Frontiers Media S.A., 2025-09-24) Solórzano Acosta, Richard Andi; Cruz Luis, Juancarlos Alejandro; Gaona Jimenez, Nery; Lozano , Andi; Díaz Chuquizuta, Henry; Vallejos Torres, Geomar; Siqueira Bahia, Rita de Cassia
The growth and yield of sweet peppers are constrained by factors such as fertilization practices and edaphoclimatic conditions, which ultimately threaten global food security in the context of an ever-growing population. This study evaluated the effect of a liquid biofertilizer derived from cocoa husks on the growth and chlorophyll content of sweet pepper (Capsicum chinense) cultivated in San Martín, Peru. The experiment was conducted at the experimental station of the National Institute of Agrarian Innovation in Tarapoto, San Martín, Peru (6°35′00″ S, 76°19′46″ W). A completely randomized design was applied, consisting of five treatments (0, 750, 1250, 2250, and 3000 mL) with 20 plants per treatment, totaling 100 experimental units. The biofertilizer was applied eight days after sowing (days). Plant height, stem diameter, and leaf chlorophyll content were measured at 15, 35, and 85 days. After 85 days, the highest plant height was observed with the 3000 mL and 1250 mL treatments, reaching averages of 29.98 and 28.25 cm, respectively. Stem diameter was maximized with 3000 mL (6.25 cm), whereas the highest chlorophyll content was recorded with 1250 mL, averaging 35.37 SPAD units. These results highlight the potential of liquid biofertilizers produced from cocoa shells to enhance nutrient uptake, increase plant biomass, and improve photosynthetic capacity, thereby contributing to sustainable sweet pepper production.
Influence of cadmium and arbuscular mycorrhizae on growth and chlorophyll content in Theobroma cacao and Theobroma grandiflorum Plants
(John Wiley & Sons Ltd., 2026-01-20) Vallejos Torres, Geomar; García Vallejos, Noellia; Gaona Jimenez, Nery; Lozano, Andi; Lozano Carranza, Carlos M.; Alva Arévalo, Alberto; Puicón Niño de Guzmán, Víctor Humberto; Saavedra Ramírez, Jorge; Tuesta Hidalgo, Juan C.; Tuesta Hidalgo, Oscar A.; Valdez Andía, Manuel Jesús; Ordoñez Ruiz, Karina M.; Baselly Villanueva, Juan Rodrigo
Inoculation of arbuscular mycorrhizal fungi (AMF) has important benefits, not only for plant growth but also for reducing Cd absorption in Theobroma plants. This study aimed to investigate the influence of cadmium (Cd) and arbuscular mycorrhizae (AM) on growth and chlorophyll content (CC) in Theobroma plants. This experiment had a 3 × 2 × 2 factorial design with species of Theobroma cacao and Theobroma grandiflorum, AMF inoculation (mycorrhizal control and AMF inoculation), and Cd addition (0, 1, and 3 mg kg⁻¹), arranged in a completely randomized design with three repetitions. The AMF inoculum consisted of applying 1500 units to each seedling. The results showed that the Cd content decreased in the stems with AMF treatment for T. cacao as well as in the soil, showing significant differences in both variables. However, a reduction of Cd could also be observed in T. grandiflorum stems without significant differences with Cd in the soil. The height, diameter, root biomass, and leaf area (LA) of the Theobroma plants increased in most of the treatments studied in comparison with treatments that received Cd, as did CC. The AMFs inoculated into Theobroma plants induced higher CC in leaves. Likewise, T. cacao presented a higher value in morphology and a lower Cd concentration in soil and shoots.
Integrated multivariate analysis of morphological and yield traits in native Capsicum chinense ecotypes grown in acidic soils of the Peruvian Amazon
(Frontiers Media S.A., 2026-04-15) Díaz Chuquizuta, Henry; Manrique Gonzales, Luis Fernando; Sánchez Ojanasta, Martín; Cuevas Gimenez, Juan Pablo; Martínez Zapata, Boris Guillermo; Flores Sinti, Geiner; Kerry Tanchiva, Juan Jose; Vallejos Torres, Geomar
Introduction: The comprehensive characterization of native Capsicum chinense ecotypes represents a strategic priority for genetic improvement, germplasm conservation, and the sustainable use of Amazonian crops. The objective of this study was to evaluate morphological, phenological, and productive variability among 12 ecotypes from the Peruvian Amazon by integrating multivariate análisis and machine learning with soil physicochemical characterization. Methods: The research was conducted on acidic tropical soils with low organic matter content and limited availability of exchangeable bases, conditions representative of degraded Amazonian agroecosystems, which enabled the assessment of soil–plant interactions and their influence on phenotypic expression and crop yield. Results: The results revealed a broad, well-structured range of phenotypic variability, with fruit diameter, fruit length, fruit weight, and seed weight identified as the primary morphological determinants of yield and adaptive capacity under low-fertility soil conditions. Principal component analysis indicated that four components explained more than 70% of the total variance, primarily associated with productivity, fruit morphometry, and phenological traits. Cluster análisis identified groups with high internal consistency, while linear discriminant analysis validated the phenotypic structure, achieving a classification accuracy of 91.8%. The ecotypes JEB-028 and LAG-022 exhibited superior productive performance, whereas BAL-012 and YUR-001 demonstrated greater phenotypic stability under restrictive soil conditions. Discussion: Overall, these findings confirm the strategic value of native Amazonian germplasm and underscore the importance of integrating edaphic diagnostics into genetic selection programs and into strategies for the sustainable management and restoration of degraded agricultural soils in the Amazon.
MultiProduct Optimization of Cedrelinga cateniformis (Ducke) Ducke in Different Plantation Systems in the Peruvian Amazon
(MDPI, 2025-01-16) Baselly Villanueva, Juan Rodrigo; Fernández Sandoval, Andrés; Salazar Hinostroza, Evelin Judith; Cárdenas-Rengifo, Gloria Patricia; Puerta, Ronald; Chuquizuta Trigoso, Tony Steven; Rufasto Peralta, Yennifer Lisbeth; Vallejos Torres, Geomar; Goycochea Casas, Gianmarco; Araújo Junior, Carlos Alberto; Quiñónez Barraza, Gerónimo; Álvarez Álvarez, Pedro; Garcia Leite, Helio
This study addressed multi-product optimization in Cedrelinga cateniformis plantations in the Peruvian Amazon, aiming to maximize volumetric yields of logs and sawn lumber. Data from seven plantations of different ages and types, established on degraded land, were analyzed by using ten stem profile models to predict taper and optimize wood use. In addition, the structure of each plantation was evaluated using diameter distributions and height–diameter ratios; log and sawn timber production was optimized using SigmaE 2.0 software. The Garay model proved most effective, providing high predictive accuracy (adjusted R2 values up to 0.963) and biological realism. Marked differences in volumetric yield were observed between plantations: older and more widely spaced plantations produced higher timber volumes. Logs of optimal length (1.83–3.05 m) and larger dimension wood (e.g., 25.40 × 5.08 cm) were identified as key contributors to maximizing volumetric yields. The highest yields were observed in mature plantations, in which the total log volume reached 508.1 m3ha−1 and the sawn lumber volume 333.6 m3ha−1 . The findings demonstrate the power of data-driven decision-making in the timber industry. By combining precise modeling and optimization techniques, we developed a framework that enables sawmill operators to maximize log and lumber yields. The insights gained from this research can be used to improve operational efficiency and reduce waste, ultimately leading to increased profitability. These practices promote support for smallholders and the forestry industry while contributing to the long-term development of the Peruvian Amazon.
Niveles de glomalina y carbono en función de los agregados del suelo en la Amazonía peruana
(Universidad Centroccidental Lisandro Alvarado (UCLA), 2024-09-01) Vallejos Torres, Geomar; Mendoza López, Karla; Ordoñez Sánchez, Luis; Lozano Sulca, Yimi; Gaona Jimenez, Nery; Baselly Villanueva, Juan Rodrigo
La selva amazónica de Perú ha experimentado grandes cambios en el uso de suelos, mediante la deforestación del ecosistema forestal para la instalación de silvopasturas y cultivos agrícolas como café y cacao, lo que ha contribuido al aumento de CO2 en la atmósfera. Este estudio evaluó los niveles de glomalina y carbono en función de los agregados del suelo en estos ambientes. Se estudiaron tres tipos de ecosistemas: i) ecosistema de bosque, ii) agroecosistema de silvopastura y iii) agroecosistema de café. En cada uno se establecieron nueve parcelas de 100 m2 y se extrajeron muestras de suelos a una profundidad de 0-20 cm. Se evaluó el carbono orgánico del suelo (COS) así como la glomalina extraíble (GE) y total (GT), en cuatro diferentes rangos del tamaño de los agregados (>2 mm, 2-1 mm, 1-0,25 mm y 0,25 mm). El efecto del tipo de ecosistema y agregados sobre el COS y glomalina se analizó mediante un ANOVA, así como con una prueba de regresión. Los ecosistemas estudiados influyeron significativamente en la disponibilidad de COS y glomalina; se obtuvo mayor COS en el agroecosistema de café, seguido del ecosistema de bosque con 101,08 y 80,17 t·ha-1. El bosque presentó mayor concentración de GE y GT respecto al cafetal y las silvopasturas. El tamaño de los agregados influyó significativamente en la disponibilidad de COS, GE y GT; cuando fueron de menores dimensiones, los contenidos de COS y glomalina disminuyeron. El tipo del sistema y los agregados del suelo influyeron significativamente en la disponibilidad de COS y glomalina en los tres ambientes estudiados.
Optimizing maize yield and nutritional quality through synergistic use of guinea pig manure and mineral fertilization: a sustainable approach for coastal Peru
(Frontiers Media S.A., 2026-02-25) Calero Rios, Emilee Nahomi; Cruz Luis, Juancarlos Alejandro; Solórzano Acosta, Richard Andi; Gaona Jimenez, Nery; Vallejos Torres, Geomar
Introduction: Excessive reliance on mineral fertilizers in maize cultivation has raised environmental concerns, highlighting the need for more sustainable alternatives. This study evaluated the effects of guinea pig (Cavia porcellus L.) manure and the application of N, P and K fertilizers on the yield and nutritional quality of hybrid maize grown in the central Peruvian coast. Methods: A split-plot design with three replications, was implemented, testing four manure doses (0, 2, 5, 10 t ha⁻¹) in combination with four mineral fertilizer levels (0, 50, 75, and 100% of recommended N, P and K). Results: The 5 t ha⁻¹ manure + 75% mineral fertilizer treatment achieved the highest yield (8.82 t ha⁻¹), representing a 28.38% increase relative to the full mineral fertilization treatment, accompanied by a grain weight of 152.80 g and an ear weight of 171.31 g. Nutritional quality peaked at 5 t ha⁻¹ manure + 100% mineral fertilizer, with 7.85% protein and 363 kcal 100 g⁻¹ energy content. Multivariate analysis revealed strong positive correlations between combined organic-mineral inputs and key productivity parameters. These findings demonstrate that the strategic integration of 5 t ha⁻¹ of guinea pig manure with a 25% reduction in mineral fertilization (i.e., 75% of the recommended dose) enhanced both grain yield and nutritional value. Discussion: This combination offers a practical, cost-effective pathway for smallholder farmers to improve yellow maize production under coastal Peruvian conditions while reducing dependence on chemical fertilizers. These results demonstrate a clear synergistic interaction between organic and mineral fertilization, leading to improved crop productivity under conditions of limited soil organic matter in the coastal soils of Peru. This finding supports the use of guinea pig manure as a sustainable and environmentally friendly agricultural input.
Paraglomus occidentale, a new arbuscular mycorrhizal fungus from the sources of the Amazon river in Peru, with a key to the Paraglomeromycetes species.
(Verlag Berger, 2020-02-06) Corazon Guivin, Mike Anderson; Cerna Mendoza, Agustín; Guerrero Abad, Juan Carlos; Vallejos Tapullima, Adela; Ríos Ramírez, Orlando; Vallejos Torres, Geomar; De la Sota Ricaldi, Ana María; Santos, Viviane Monique; Alves da Silva, Gladstone; Oehl, Fritz
A new arbuscular mycorrhizal fungus, Paraglomus occidentale, was found in an agricultural plantation of the inka nut (Plukenetia volubilis) in the Amazonia region of San Martín State in Peru. The inka nut was grown in mixed cultures together with Zea mays and Phaseolus vulgaris. The fungus was propagated in bait and single species cultures on Sorghum vulgare, Brachiaria brizantha, Medicago sativa and P. volubilis as host plants. The fungus differentiates hyaline spores terminally on cylindrical to slightly funnel-shaped hyphae, singly in soils or rarely in roots. The hyaline spores have a triple layered outer wall and a bi- to triple-layered inner wall. They are (59)69–84(92) µm in diameter. The new fungus is distinguished from all other known Paraglomus spp. by spore wall structure including staining characteristics in Melzer’s reagent, which is yellow-grayish to grayish on the outermost and generally dark yellow on the second spore wall layer. Phylogenetically, the new fungus is recognized in a well-separated clade, near to P. laccatum and P. occultum. Finally, an identification key to the Paraglomeromycetes species is included comprising all known species of the genera Paraglomus, Innospora and Pervetustus.