Variabilidad de δ13C y δ15N en suelo y hojarasca de cacao en El Oro, Ecuador

Abstract

The cocoa provides signif icant levels of carbon (C) and nitrogen (N) by the leaf litter; the change of agronomic management causes variation in the contents of these elements in the soil. The objective was to evaluate the variations of the isotopes of δ13C and δ15N between two types of cocoa (CCN51 and Nacional), located in three soil orders in the province of El Oro, Ecuador. Thirty soil samples of 0.30 m deep and 25 samples of leaf litter were taken and the abundance of the isotopes of δ13C and δ15N were analyzed. The data were analyzed including two factors, cocoa types (CCN51 and National) and order of soils (Alf isol, Entisol and Inceptisol). The results showed that the ranges of the isotope of δ13C in soil were -23.81% (CCN51, Entisol) to -26.46% (National, Entisol) and in leaf litter -27.21% (CCN51, Alf isol) to -29.86% (National, Inceptisol). The ranges of the isotope of δ15N in soil were of 7.96% (National, Entisol) and 10.48% (National, Alf isol) and in leaf litter of 4.85% (National, Entisol) to 8.38% (CCN51, Alf isol). The averages of the δ13C in the soil were plants type C3. The values of δ15N in litter and soil was an indicator of low incidence of fertilizers nitrogenous origin inorganic in National and high mineralization of N in CCN51.

Comparación de niveles de cadmio en hojas, testa y almendra en cultivares de Theobroma cacao

“…Las propiedades químicas de los suelos donde se tomó las muestras de tejido vegetal se indican en la tabla 2. El pH fluctuó de menor a mayor de: 4.84-5.56 (F3), 4.37-4.64 (F2) y 5.82-6.66 (F1) rangos que clasifican a los suelos en ácidos a moderadamente ácidos; valores similares a los encontrados por (Salomón Barrezueta-Unda et al, 2017) . Por otra parte, la CE en general fue baja con rangos máximos de 0.42 dS/m (F1), 0.20 dS/m (F2) y 0.11 dS/m (F3), mientras que los valores de MO variaron de 4.30% en F1 a 2.75% en F2, niveles que fueron los adecuados para el cultivo de cacao; debido a que el principal factor para estos niveles es la acumulación de hojarasca en el suelo (Salomón Barrezueta-Unda et al, 2017).…”

“…El clima en la zona es tropical, temperatura media anual de 25.5 °C, precipitación promedio de 838 mm/anual. La clase textural franco-arcillosa predominante en los primero 30 cm, producto de una formación aluvial (Salomon Barrezueta-Unda y Paz-González, 2017…”