Composición Florística, estructura y servicios ecosistémicos en sistemas agroforestales con Theobroma cacao L. en el departamento del Huila
47 plots (1000 m2 each) with agroforestry systems (AFS) were characterized based on the floristic composition and aspects of the vegetation structure. Statistical analyses (analysis of main components, conglomerates and univariate variance) were used to form AFS typologies based on these aspects, ri...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2016 |
| País: | Colombia |
| Institución: | Universidad Nacional de Colombia |
| Repositorio: | Repositorio UN |
| Idioma: | español |
| OAI Identifier: | oai:repositorio.unal.edu.co:unal/78109 |
| Acceso en línea: | https://repositorio.unal.edu.co/handle/unal/78109 |
| Access Level: | acceso abierto |
| Palabra clave: | 570 - Biología Composición florística Estructura Rendimiento Sistemas agroforestales Bosque tropical seco Variables ambientales Flujo de savia Floristic composition Structure Yield Agroforestry systems Tropical dry forest Environmental variables Sap flow |
| Sumario: | 47 plots (1000 m2 each) with agroforestry systems (AFS) were characterized based on the floristic composition and aspects of the vegetation structure. Statistical analyses (analysis of main components, conglomerates and univariate variance) were used to form AFS typologies based on these aspects, richness, density of individuals and incident ra-diation. After defining the types of PBS, the yield of cocoa in each of them was evaluated, as well as its relationship with floristic composition, aspects of structure, richness, density of individuals that make up the AFS, incident radiation, and it was compared with cocoa production systems with free TEL exposure (14 plots of 1000 m2 each). Carbon storage in aboveground biomass was compared between production systems (PBS and TEL). In order to know how the flow of sap and water potential of cocoa trees is influenced by the floristic composition, aspects of structure, incident radiation and microclimatic conditions of PBS types, measurements were made of sap flow (Vs), water potential, relative air humidity (RHa), average day temperature (Ta), photosynthetically active radiation (PAR), vapour pressure deficit (VPD), soil temperature, volumetric water content in the produc-tion systems (PAS and TEL) at two times (wet season - maximum precipitation and mini-mum dry season precipitation). Vegetation was classified into seven groups based on characteristic species - dominant or differential: PBS dominated by Guarea guidonia and Pseudosamanea guachapele, Erythrina poeppigiana and Matisia cordata, Musa paradi-siaca, Gliricidia sepium and Cordia alliadora, Gmelina arborea, Psidium guajava and PBS dominated by Manguifera indica. Two types of PBS were discriminated: multiple complex with high diversified shade (CMAD) and simple complex with low specialized shade (EDB), statistically different due to the richness of tree species, the Shannon and Sim-pson Index, total density of individuals, density of musaceae, crown area, crown area of musaceae, basal area, average hours of shade per year, leaf area index (transmitted radiation) and variance in the morning, midday and afternoon. Correlation analysis allowed to explain the direct and indirect effects between the variables radiation, structure (they affect 78% of the total variability of cocoa yield in an agroforestry system). It was found that the radiation component (shadow hours and Foliar Area Index variables) was the most important factor that influenced yield variability. The cocoa bean yield presented a higher value in TEL (71 Kg/plot and 719 Kg/ha), although there were no significant dif-ferences with the PBS type EDB (63 kg/plot and 703 Kg/ha). The AFS type CMAD registered the lowest value (36 kg/plot and 338 kg/ha). The highest values of total carbon stored in aboveground biomass were recorded in Ficus dendrocida, Sapium cuatrecasii, Enterolobium cyclocarpum, Erythrina poeppigiana, Ficus pallida, Guazuma ulmifolia, Cedrela montana, Ficus hartwegii, Erythrina fusca and Jacaranda caucana (between 5.9 and 1.2 Mg of carbon in 0.1 ha). In the carbon stored in the stem, the species with the highest content were Sapium cuatrecasii (45.29%) and Enterolobium cyclocarpum (44.74%) and species such as Casearia corymbosa (40.72%), Pseudosa-manea guachapele (44.33%), Anacardium excelsum (33.48%) and Maclura tinctoria (32%) are typical of Dry Forest ecosystems. The AFS CMAD stored the highest amount of carbon in aboveground biomass (4.43 Mg C/0.1 ha), followed by the AFS EDB (1.7 Mg C/0.1 ha) and the lowest value in the TEL free-exposure system (0.3 Mg C/0.1 ha). Du-ring the monitoring period the values of cocoa sap flow in the productive systems varied between 0.25 L h-1 and 0.18 L h-1 with the lowest value recorded in the AFS - CMAD and the highest value in the TEL plot. The water potential farthest from zero (-1.49 Mpa) was observed in the TEL plot and the one closest to zero (-0.47 Mpa) was recorded in CMAD. The behavior observed in the flow of sap and water potential in cocoa plants depends on the meteorological conditions RHa (%), Ta (ºC), PAR (μmol m-2 s-1) and VPD (kPa) and varies according to the time of year, the time of day and the cocoa production system (PBS or free exposure). |
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