Examinando por Materia "Precipitation"

Mostrando 1 - 3 de 3

The distribution of cadmium in soil and cacao beans in Peru
(Elsevier, 2023-04-11) Thomas, Evert; Atkinson, Rachel; Zavaleta, Diego; Rodriguez, Carlos; Lastra Paucar, Sphyros Roomel-Luciano; Yovera, Fredy; Arango, Karina; Pezo, Abel; Aguilar, Javier; Tames, Miriam; Ramos, Ana; Cruz, Wilbert; Cosme, Roberto; Espinoza, Eduardo; Chavez, Carmen Rosa; Ladd, Brenton
Peru is the eighth largest producer of cacao beans globally, but high cadmium contents are constraining access to international markets which have set upper thresholds for permitted concentrations in chocolate and derivatives. Preliminary data have suggested that high cadmium concentrations in cacao beans are restricted to specific regions in the country, but to date no reliable maps exist of expected cadmium concentrations in soils and cacao beans. Drawing on >2000 representative samples of cacao beans and soils we developed multiple national and regional random forest models to develop predictive maps of cadmium in soil and cacao beans across the area suitable for cacao cultivation. Our model projections show that elevated concentrations of cadmium in cacao soils and beans are largely restricted to the northern parts of the country in the departments of Tumbes, Piura, Amazonas and Loreto, as well as some very localized pockets in the central departments of Huánuco and San Martin. Unsurprisingly, soil cadmium was the by far most important predictor of bean cadmium. Aside from the south-eastern to north-western spatial trend of increasing cadmium values in soils and beans, the most important predictors of both variables in nation-wide models were geology, rainfall seasonality, soil pH and rainfall. At regional level, alluvial deposits and mining operations were also associated with higher cadmium levels in cacao beans. Based on our predictive map of cadmium in cacao beans we estimate that while at a national level <20 % of cacao farming households might be impacted by the cadmium regulations, in the most affected department of Piura this could be as high as 89 %.
Patterns of Plumericin Concentration in Leaves of Himatanthus tarapotensis (Apocynaceae) and Its Interactions with Herbivory in the Peruvian Amazon
(MDPI, 2022-04-08) Amasifuen Guerra, Carlos Alberto; Patel, Kirti; Delprete, Piero G.; Spina, Andréa P.; Grados, Juan; Vásquez Ocmín, Pedro; Gadea, Alice; Rojas, Rosario; Guzmán, Jesús; Sauvain, Michel
We explored the concentration patterns of the bioactive metabolite plumericin produced by Himatanthus tarapotensis (Apocynaceae) under different edaphic conditions and variations in rainfall intensity, as well as its potential role in the chemical defense against insect herbivores. Values of plumericin concentration from leaves were obtained by High-Performance Liquid Chromatography, and evaluated as a function of differences in soil types, variation of precipitation, and variation of the abundance of insect herbivores, using first a Repeated Measures Correlation (rmcorr) and then a Generalized Linear Mixed Model (GLMM) analysis. Plumericin concentration is highly variable among plants, but with a significantly higher concentration in plants growing on clay soil compared to that of the white-sand soil habitat (p < 0.001). Plumericin concentration is not affected by precipitation. The caterpillar of Isognathus leachii (Lepidoptera: Sphingidae) is the most conspicuous herbivore of H. tarapotensis, and its presence is continuous but not related to plumericin concentration, probably because of its capacity to elude the chemical defense of this plant. Nevertheless, our multivariate model revealed that plumericin concentration is related to the abundance of Hymenoptera (Formicidae), and this relationship is significantly influenced by the soil parameters of carbon percentage, clay percentage, and phosphorous percentage (p < 0.001). Plumericin is a mediating agent in the interaction between H. tarapotensis and its natural environment. Variation in plumericin concentration would be induced by the abundance of Hymenoptera (Formicidae), probably as a chemical response against these insects, and by differences in soil nutrient availability.
Relación de la deforestación y las variaciones climáticas en el distrito de Nueva Requena, Ucayali – 2019
(Universidad de las Ciencias Informáticas, 2022-07-01) Mori Montero, César; Pastor Picón, Guillermo Augusto; Zorrilla Murayari, Wilkin; Amaringo Córdova, Luiz Paulo; Baselly Villanueva, Juan Rodrigo
El objetivo de la investigación fue analizar la deforestación del bosque del distrito de Nueva Requena, la variación de la temperatura y las precipitaciones. La data de las variables deforestación, temperatura y precipitación se obtuvo del 2001 al 2019. El nivel de estudio fue descriptivo, la investigación fue retrospectivo, transversal y correlacional. Los resultados indican que la deforestación en 19 años tiene una correlación positiva alta con la temperatura mínima y máxima, y que tiene una correlación positiva débil con la precipitación con resultados de negativa débil. Se concluye que la deforestación fue altamente significativa y la correlación con el clima no fue significativa, existiendo factores que amortiguan la temperatura y precipitación como la resiliencia de los bosques y los vientos.