Examinando por Autor "Requena Rojas, Edilson Jimmy"

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Assessment of soil characteristics and the productive potential of native Poaceae forage species in the Central Highlands of Peru
(Polish Society of Ecological Engineering, 2025-06-10) Arias Arredondo, Alberto; Yalli Huamaní, Teodoro Bill; Cruz Luis, Juancarlos Alejandro; Requena Rojas, Edilson Jimmy; Solórzano Acosta, Richard Andi
Given the increasing pressure on natural grassland ecosystems in the Peruvian high Andes, optimizing the use of native forage species has become essential for understanding the relationship between soil characteristics and the productive potential of these plants. This study evaluated the relationship between soil properties and the produc tive potential of three native forage species: Festuca dolichophylla, Cinnagrostis vicunarum, and Jarava ichu. The research was conducted in natural grasslands in the district of Yauli, province of Yauli, department of Junin, at approximately 4000 m.a.s.l. During the dry season 2023, soil samples were collected following standardized protocols, and key soil parameters were analyzed. The nutritional characteristics of the forage species were also assessed, including dry matter content, total protein, calcium, phosphorus, in vitro organic matter digestibility, and metabolizable energy. The results revealed significant differences among species. Festuca dolichophylla exhibited the highest protein content (10.7%), superior digestibility (52.5%), and greater metabolizable energy (8.4 MJ∙kg-1), making it the most suitable forage option for livestock in the highland ecosystem over 4000 m.a.s.l., where en vironmental factors constrain agricultural activity. In contrast, Cinnagrostis vicunarum and Jarava ichu showed lower protein levels, with Jarava ichu displaying particularly low digestibility (28.9%) and energy content (4.6 MJ∙kg-1), limiting its productive potential despite its high dry matter yield. These findings provide a strong scien tific foundation for developing sustainable grassland management strategies in the Peruvian Andes, supporting the implementation of agronomic practices that enhance forage productivity while contributing to biodiversity conser vation. Moreover, this study highlights the importance of soil characterization as a key tool for optimizing forage resource utilization in high-altitude farming systems, facilitating informed decision-making in land management and environmental remediation policies.
Biomass production of tropical trees across space and time: The shifting roles of diameter growth and wood density
(Wiley-Blackwell Publishing Ltd, 2025-08-26) Hornink, Bruna; Zuidema, Pieter A.; van der Sleen, Peter; Zanne, Amy E.; Assis Pereira, Gabriel; Ortega Rodriguez, Daigard Ricardo; Fontana, Claudia; Portal Cahuana, Leif Armando; Requena Rojas, Edilson Jimmy; Campos Barbosa, Ana Carolina Maioli; Granato-Souza, Daniela; Guimarães Pereira, Lucas; Lisi, Claudio Sergio; Nunes Menezes, Itallo Romany; Venegas Gonzalez, Alejandro; Jaén Barrios, Nelson; Roig, Fidel A.; Tomazello Filho, Mario; Groenendijk, Peter
1. Woody biomass in tropical trees contributes significantly to global carbon stocks; however, these stocks are increasingly affected by climate and land-use changes. Understanding the growth mechanisms driving woody biomass production is essential for assessing the short- and long-term contributions to carbon stocks and dynamics in tropical forests. 2. Trees accumulate biomass by increasing their size (wood volume) and/or tissue density (wood density). However, estimates of tree biomass production are often based solely on size increment through measurements of stem diameter growth, overlooking the potential spatial and temporal variation in wood density within trees. Tree-ring analysis can be applied to reconstruct past tree volume-growth and wood-density variations, allowing the quantification of their relative contributions when reconstructing past woody biomass production. 3. Here, we studied trees of the widespread Neotropical genus Cedrela along an environmental (climate and soil) gradient to address two key questions: (1) How does temporal variation in tree diameter growth and wood density affect biomass production? (2) To what extent do these relationships vary along the environmental gradient? We examined both long-term (ontogenetic) and short-term (annual) variations in diameter growth and wood density, covering eighteen sites in the Amazon rainforest, Atlantic Forest, Cerrado savanna and Caatinga dry forest. 4. We found that diameter growth and wood density drive short- and long-term biomass production dynamics. Interestingly, diameter growth patterns predominantly explained short-term variability in biomass production at all sites, whereas wood density explained ontogenetic biomass patterns mainly at humid sites. These results highlight the importance of accounting for both short- and long-term variation, including climatic and ontogenetic drivers, to increase the accuracy of biomass estimations in tropical trees, particularly in humid forest ecosystems such as the Amazon. 5. Synthesis. Diameter growth is an important and good indicator of forest carbon production. However, size-related changes in wood density, which are usually neglected, are critical for accurate short- and long-term carbon assessments, especially in tropical humid sites.
Ecological and carcinogenic risk assessment of potentially toxic elements in rangelands and croplands around Lake Junin (Peru): Integrating remote sensing, machine learning, and land cover segmentation
(Elsevier, 2025-08-27) Pizarro Carcausto, Samuel Edwin; Requena Rojas, Edilson Jimmy; Barboza, Elgar; Peña Elme, Eunice Dorcas; Arias Arredondo, Alberto Gilmer; Ccopi Trucios, Dennis
The Junín Lake basin, a critical high-altitude ecosystem in the central Peruvian Andes, faces severe contamination from potentially toxic elements (PTEs) driven by mining activities, agriculture, and urbanization. This study evaluates the spatial distribution, ecological risk, and human health implications of 14 heavy metals, metalloids, and trace elements in surface soils surrounding the lake. Using 211 soil samples, we integrated remote sensing, land cover classification, and Random Forest machine learning models with spectral, edaphic, topographic, and proximity-based environmental covariates to predict contamination patterns and assess risk. Results reveal extreme contamination, with arsenic (As), lead (Pb), cadmium (Cd), and zinc (Zn) concentrations exceeding ecological thresholds by over 100-fold in agricultural zones. Ecological risk assessments using contamination degree (mCD), pollution load index (PLI), and risk index (RI) indicated that over 99 % of the study area exhibits very high to ultra-high contamination levels. Human health risk analysis identified unacceptable carcinogenic risks from As, Pb, and Cr across adult and pediatric populations, with arsenic presenting the greatest concern. The integration of geospatial tools and machine learning enabled precise identification of contamination hotspots and vulnerable land cover types, demonstrating the value of AI approaches for monitoring contaminated territories. These findings underscore the urgent need for coordinated environmental management, targeted remediation strategies, and community-based monitoring to protect public health and preserve Andean ecosystem integrity.
Effects of Glomus iranicum inoculation on growth and nutrient uptake in potatoes associated with broad beans under greenhouse conditions
(MDPI, 2025-07-21) Contreras Pino, Douglas Lenin; Pizarro Carcausto, Samuel Edwin; Verastequi Martínez, Patricia; Solórzano Acosta, Richard Andi; Requena Rojas, Edilson Jimmy
The rising global demand for food, including potatoes, necessitates increased crop production. To achieve higher yields, farmers frequently depend on regular applications of nitrogen and phosphate fertilizers. As people seek more environmentally friendly alternatives, biofertilizers are gaining popularity as a potential replacement for synthetic fertilizers. This study aimed to determine how Glomus iranicum affects the growth of potatoes (Solanum tuberosum L.) and the nutritional value of potato tubers when grown alongside broad beans (Vicia faba L.). An experiment was conducted using potatoes tested at five dosage levels of G. iranicum, ranging from 0 to 4 g, to see its impact on the plants and soil. Inoculation with G. iranicum produced variable results in associated potato and bean crops, with significant effects on some variables. In particular, inoculation with 3 g of G. iranicum produced an increase in plant height (24%), leaf dry weight (90%), and tuber dry weight (57%) of potatoes. Similarly, 4 g of G. iranicum produced an increase in the foliar fresh weight (115%), root length (124%), root fresh weight (159%), and root dry weight (243%) of broad beans compared to no inoculation. These findings suggest that G. iranicum could be a helpful biological tool in Andean crops to improve the productivity of potatoes associated with broad beans. This could potentially reduce the need for chemical fertilizers in these crops.
The importance of tropical tree-ring chronologies for global change research
(Elsevier Ltd., 2025-03-06) Groenendijk, Peter; Babst, Flurin; Trouet, Valerie; Fan, Ze Xin; Granato Souza, Daniela; Maselli Locosselli, Giuliano; Mokria, Mulugeta; Panthi, Shankar; Pumijumnong, Nathsuda; Abiyu, Abrham; Acuña Soto, Rodolfo; Adenesky Filho, Eduardo; Alfaro Sanchez , Raquel; Anholetto Junior, Claudio Roberto; Vieira Aragao, José Roberto; Assis Pereira, Gabriel; Astudillo Sánchez, Claudia C.; Barbosa, Ana Carolina; de Oliveira Barreto, Nathan; Battipaglia, Giovanna; Beeckman, Hans; Botosso, Paulo Cesar; Bourland, Nils; Brauning, Achim; Brienen, Roel; Brookhouse, Matthew; Buajan, Supaporn; Buckley, Brendan M.; Camarero, J. Julio; Carrillo Parra, Artemio; Ceccantini, Gregorio; Centeno Erguera, Librado R.; Cerano Paredes, Julian; Cervantes Martínez, Rosalinda; Chanthorn, Wirong; Chen, Ya-Jun; Barçante Ladvocat Cintra, Bruno; Cornejo Oviedo, Eladio Heriberto; Cortés Cortés, Otoniel; Matos Costa, Clayane; Couralet, Camille; Crispin DelaCruz, Doris Bianca; D’Arrigo, Rosanne; David, Diego A.; De Ridder, Maaike; Del Valle, Jorge Ignacio; Díaz Carrillo, Oscar A.; Dobner Jr, Mario; Doucet, Jean Louis; Dünisch, Oliver; Dünisch, Oliver; Enquist, Brian J.; Esemann Quadros, Karin; Esquivel Arriaga, Gerardo; Fayolle, Adeline; Anete Bergamo Fenilli, M. Eugenia; Ferrero, M. Eugenia; Fichtler, Esther; Finnegan, Patrick M.; Fontana, Claudia; Francisco, Kainana S.; Fu, Pei-Li; Galvao, Franklin; Gebrekirstos, Aster; Giraldo, Jorge A.; Gloor, Emanuel; Godoy Veiga, Milena; Guerra, Anthony; Haneca, Kristof; Harley, Grant Logan; Heinrich, Ingo; Helle, Gerhard; Hernandez Díaz, José Ciro; Hornink, Bruna; Hubau, Wannes; Inga, Janet G.; Islam, Mahmuda; Jiang, Yu-mei; Kaib, Mark; Hassan Khamisi, Zakia; Koprowski, Marcin; Layme Huaman, Eva; Leffler, A. Joshua; Ligot, Gauthier; Lisi, Claudio Sergio; Loader, Neil J.; de Almeida Lobo, Francisco; Longhi Santos, Tomaz; Lopez, Lidio; Lopez Hernández, María I.; Penetra Cerveira Lousada, José Luis; Manzanedo, Rubén D.; Marcon, Amanda K.; Maxwell, Justin T.; Mendivelso, Hooz A.; Mendoza Villa, Omar N.; Nunes Menezes, Itallo Romany; Ribeiro Montoia, Valdinez; Moors, Eddy; Moreno, Miyer; Muniz Castro, Miguel Angel; Nabais, Cristina; Nathalang, Anuttara; Ngoma, Justine; de Carvalho Nogueira Jr., Francisco; Morales Oliveira, Juliano; Morais Olmedo, Gabriela; Ortega Rodriguez, Daigard Ricardo; Rodríguez Ortíz, Carmen Eugenia; Pagotto, Mariana Alves; Paredes Villanueva, Kathelyn; Pérez De Lis, Gonzalo P; Ponce Calderon, Laura Patricia; Portal Cahuana, Leif Armando; Pucha Cofrep, Darwin Alexander; Quadri, Paulo; Rahman, Mizanur; Ramírez, Jorge Andrés; Requena Rojas, Edilson Jimmy; Ribeiro, Adauto de Souza ak; Robertson, Lain; Roig, Fidel Alejandro; Roquette, José Guilherme; Rubio Camacho, Ernesto Alonso; Sánchez Salguero, Raúl; Sass Klaassen, Ute; Schongart, Jochen; Callegari Scipioni, Marcelo; Sheppard, Paul; Silva, Lucas C.R.; Slotta, Franziska; Soria Díaz, Leroy; K.V.S. Sousa, Luciana; Speer, James H.; Therrell, Matthew D.; Ticse Otarola, Ginette; Tomazello Filho, Mario; Torbenson, Max C.A.; Tor Ngern, Pantana; Touchan, Ramzi; Van Den Bulcke, Jan bi; Vazquez Selem, Lorenzo; Velázquez Pérez, Adin H.; Venegas González, Alejandro; Villalba, Ricardo; Villanueva Diaz, José; Vlam, Mart; Vourlitis, George; Wehenkel, Christian; Wils, Tommy; Zavaleta, Erika S.; Asfaw Zewdu, Eshetu; Zhang, Yong-Jiang; Zhou, Zhe-Kun; Zuidema, Pieter A.
Tropical forests and woodlands are key components of the global carbon and water cycles. Yet, how climate change affects these biogeochemical cycles is poorly understood because of scarce long-term observations of tropical tree growth. The recent rise in tropical tree-ring studies may help to fill this gap, but a large-scale quantitative analysis of their potential in global change research is missing. We compiled a list of all tropical tree species known to form annual tree rings and built a network encompassing 492 tropical ring-width chronologies to evaluate the potential to generate insights on climate sensitivity of woody productivity and to build centuries-long reconstructions of climate variability. We assess chronology quality, length, and climatic representativeness and explore how these change along climatic gradients. Finally, we applied species-distribution modeling to identify regions with potential for tree-ring studies in ecological and climatic studies. The number of tropical chronologies has rapidly increased, with ~400 added over the past two decades. Yet, tree-ring studies are biased towards high-elevation locations, with gaps in warmer and wetter climates, on the African continent, and for angiosperm species. The longest chronologies with strongest climate signals (i.e., synchronous growth variations among trees) are from cool regions. In wet regions, climate signals and precipitation sensitivity decrease. Most tropical regions harbor 5–15 (and up to 80) species with proven potential to generate chronologies. The potential for long climate reconstructions is particularly high in drier high elevation sites. Our findings support strategies to effectively expand tree-ring research in the tropics, by targeting specific species and regions. Tropical dendrochronology can importantly contribute to global change research by generating historical context of climate extremes, quantifying climate sensitivity of woody productivity and benchmarking vegetation models.