Dinámica geoquímica en andisoles alto andinos, caso de estudio, la microcuenca Las Palmas

Abstract

The dynamics of water in basins is regulated by its interaction with soil moisture, vegetation, temperature and precipitation among other factors. The changes in these interactions can be used as tools for the analysis of hydrological processes and generate ecosystem management proposals. The soil is a key element in the water cycle, which regulates most of the processes that take place there, but the growth of anthropogenic agro-industrial activities has brought with it the alteration of ecosystems and a significant deterioration in the quality of surface and underground waters, thus the use of nitrogenous fertilizers has been one of the factors that has led to the progressive pollution of water quality, generating a risk to human health, from the chemical species associated with these fertilizers, the contaminant that requires the most attention is nitrates.

In order to analyze the influence of pollutants such as nitrate on water quality in a basin system where andisol soils are present, the study area was divided into four areas of interest (potato cultivation, pastures, forests and the channel of Las Palmas brook), in the land-use-zones potato crops, grasslands and forests, two experimental plots with sufficient hydrometeorological instruments were used to obtain data on precipitation, surface runoff, infiltration at 0,20 and 0,50 m deep, in addition to a physicochemical analysis of the waters of each of these systems and an analysis of the dynamics of iron in Andisol soils as an indicator of ion mobility. In the interest to relate the hydrological processes based on the chemical species studied, multivariate statistical methods were applied such as the variant analysis of three factors and principal components (PCA), together with linear regressions (ANCOVA); with the purpose of generating information to design better management strategies for the different land uses and mitigate the impacts on bodies of water.

The results found show a lower storage of water in the soil for the forest soils (gallery or riparian forest) due to the high interception by the covers; while soils under crops (Solanum Tuberosum) and grazing (Pennisetum Clandestinum) have high moisture retention. Given the high availability of water in these ecosystems, conditions associated with anaerobic processes prevail in wet seasons and aerobic processes in dry seasons, where water flows in wet seasons have concentrations of less than 50 mg/L NO3-, which does not represent a risk to human health, in dry seasons these concentrations can be exceeded, especially in the forest area with concentrations up to 139 ml/L NO3- (June). The high moisture content of the soil, high rainfall, high infiltration (83-99%) and low runoff (<1%), as well as acidity and a redox potential of less than 450 mV, condition the mobility of contaminants in these environments favoring the resilience of these ecosystems.

La dinámica del agua en las cuencas está regulada por su interacción con la humedad del suelo, la vegetación, la temperatura y la precipitación, entre otros factores. Los cambios en estas interacciones pueden ser utilizadas como herramientas para el análisis de los procesos hidrológicos y generar propuestas de gestión de los ecosistemas. El suelo es un elemento clave en el ciclo del agua, que regula la mayoría de procesos que allí se desarrollan, pero el crecimiento de actividades antropogénicas agroindustriales ha traído consigo la alteración de los ecosistemas y un deterioro marcado de la calidad de las aguas superficiales y subterráneas, así el uso de fertilizantes nitrogenados ha sido de los factores que ha llevado a la contaminación progresiva de la calidad del agua generando un riesgo para la salud humana, de las especies químicas asocias a estos fertilizantes, el contaminante que mayor atención tiene son los nitratos. Con el fin de analizar la influencia de contaminantes como el nitrato en la calidad de agua en un sistema cuenca donde están presenten los suelos andisoles, se realizó una división de la zona de estudio en cuatro áreas de interés (cultivo de papa, pastizales, bosques y el cauce de la quebrada Las Palmas), en las zonas de uso del suelo cultivos de papa, pastizales y bosques, se trabajó con dos parcelas experimentales, con los instrumentos hidrometeorológicos suficientes para la obtención de datos de precipitación, escorrentía superficial, infiltración a 0,20 y 0,50 m de profundidad, además de un análisis fisicoquímico de las aguas de cada uno de estos sistemas y un análisis de la de dinámica del hierro en suelos Andisoles como indicador de movilidad de iones. Para poder relacionar los procesos hidrológicos en función de las especies químicas estudiadas, se aplicaron métodos estadístico multivariantes, como análisis de varianza de tres factores y componentes principales (PCA), junto a regresiones lineales (ANCOVA). con el propósito de generar información para diseñar mejores estrategias del manejo de los diferentes usos del suelo y mitigar los impactos a los cuerpos de agua. Los resultados encontrados muestran un menor almacenamiento de agua en el suelo para suelos forestales (bosque de galería o ripario) debido a la alta interceptación por parte de las coberturas; mientras los suelos bajo cultivos de papa (Solanum tuberosum) y pastoreo (Pennisetum clandestinum) tienen una alta retención de humedad. Dada la alta disponibilidad de agua en estos ecosistemas prevalecen las condiciones asociadas a procesos anaeróbicos en épocas húmedas y procesos aeróbicos en épocas secas, en donde los flujos de agua en estaciones húmedas tienen concentraciones inferiores a 50 mg/L NO3- , lo cual no representa un riesgo para la salud humana, en épocas secas se pueden superar estas concentraciones especialmente en la zona de bosques con concentraciones de hasta 139 mg/L NO3- (junio). El alto contenido de humedad del suelo, las altas precipitaciones, alta infiltración (83 - 99 %) y la baja escorrentía (< 1 %), así como la acidez y un potencial redox inferior a los 450 mV, condicionan la movilidad de contaminantes en estos ambientes favoreciendo la resiliencia de estos ecosistemas. (Texto tomado de la fuente)

The dynamics of water in basins is regulated by its interaction with soil moisture, vegetation, temperature and precipitation among other factors. The changes in these interactions can be used as tools for the analysis of hydrological processes and generate ecosystem management proposals. The soil is a key element in the water cycle, which regulates most of the processes that take place there, but the growth of anthropogenic agro-industrial activities has brought with it the alteration of ecosystems and a significant deterioration in the quality of surface and underground waters, thus the use of nitrogenous fertilizers has been one of the factors that has led to the progressive pollution of water quality, generating a risk to human health, from the chemical species associated with these fertilizers, the contaminant that requires the most attention is nitrates. In order to analyze the influence of pollutants such as nitrate on water quality in a basin system where andisol soils are present, the study area was divided into four areas of interest (potato cultivation, pastures, forests and the channel of Las Palmas brook), in the land-use-zones potato crops, grasslands and forests, two experimental plots with sufficient hydrometeorological instruments were used to obtain data on precipitation, surface runoff, infiltration at 0,20 and 0,50 m deep, in addition to a physicochemical analysis of the waters of each of these systems and an analysis of the dynamics of iron in Andisol soils as an indicator of ion mobility. In the interest to relate the hydrological processes based on the chemical species studied, multivariate statistical methods were applied such as the variant analysis of three factors and principal components (PCA), together with linear regressions (ANCOVA); with the purpose of generating information to design better management strategies for the different land uses and mitigate the impacts on bodies of water. The results found show a lower storage of water in the soil for the forest soils (gallery or riparian forest) due to the high interception by the covers; while soils under crops (Solanum Tuberosum) and grazing (Pennisetum Clandestinum) have high moisture retention. Given the high availability of water in these ecosystems, conditions associated with anaerobic processes prevail in wet seasons and aerobic processes in dry seasons, where water flows in wet seasons have concentrations of less than 50 mg/L NO3-, which does not represent a risk to human health, in dry seasons these concentrations can be exceeded, especially in the forest area with concentrations up to 139 ml/L NO3- (June). The high moisture content of the soil, high rainfall, high infiltration (83-99%) and low runoff (<1%), as well as acidity and a redox potential of less than 450 mV, condition the mobility of contaminants in these environments favoring the resilience of these ecosystems.