This study investigates the hydrological dynamics of the Pativilca Basin in the Southern Hemisphere using the SWAT (Soil and Water Assessment Tool) model. Seventy-seven watersheds across a mountainous region were analyzed using elevation data, land cover, soil type, and gridded meteorological products (RAIN4PE and PISCO) for hydrological simulations. Watershed delineation, aided by a Digital Elevation Model, enabled the identification of critical drainage points and the definition of Hydrological Response Units (HRUs). The model calibration and validation, performed using the SWAT-CUP with the SUFI-2 algorithm, achieved Nash–Sutcliffe Efficiency (NSE) values of 0.69 and 0.72, respectively. Cluster analysis categorized the watersheds into six distinct groups with unique hydrological and climatic characteristics. The results showed significant spatial variability in the precipitation and temperature, with pronounced seasonality influencing the daily flow patterns. The higher-altitude watersheds exhibited greater soil water storage and more effective aquifer recharge, whereas the lower-altitude watersheds, despite receiving less precipitation, displayed higher flows due to runoff from the upstream areas. These findings emphasize the importance of incorporating seasonality and spatial variability into water resource planning in mountainous regions and demonstrate the SWAT model’s effectiveness in predicting hydrological responses in the Pativilca Basin, laying the groundwork for future research in mountain hydrology.

Land use change has played a crucial role in altering the hydrological behavior, making detailed assessments essential to ensure sustainable water resource management and the conservation of natural ecosystems. This study focuses on simulating the impact of different Land Use and Land Cover (LULC) scenarios for the years 1985, 1995, 2005, and 2015 on the water balance in the Puyango-Tumbes River basin, which spans across Ecuador and Peru, during the period 1981-2015. The results indicated an 18.3% increase in the grassland areas and a significant 38.2% reduction in the savanna zones, contributing to an annual 2.1% increase in the Evapotranspiration (PET) rates. These land use changes led to a 29.2% decrease in the Percolation (PERC), a 20.7% decrease in the Surface Runoff (SURQ), a 33% reduction in the Groundwater Flow (GW_Q), and a 26.6% decrease in the Annual Water Yield (WYLD), as well as a slight reduction of 0.9% in the Lateral flow (LAT_Q). These findings highlight the importance of considering land use changes to ascertain the sustainable management of natural resources, particularly in a transboundary basin.

El presente estudios da a conocer el comportamiento agronómico de seis genotipos (INIAP Estela, INIAP Natividad, Superchola, clon 10 – 10 – 97, clon 07 – 29 – 11 y clon 98 – 02 – 06), mediante el factor riego a través de dos métodos: 1) condiciones óptimas durante todo el ciclo de cultivo (Con riego) 2) suspensión de riego en la etapa fenológica de floración por un periodo de 20 días (Sin riego), permitiendo así la cuantificación del requerimiento hídrico y determinar el genotipo con tolerancia al déficit híbrido, de la evaluación agronómicamente de seis genotipos de papa (Solanum spp), en el recinto Macaji, provincia de Chimborazo – Ecuador. Con los siguientes parámetros de evaluación: contenido gravimétrico de agua en el suelo, potencial mátrico del suelo, evapotranspiración del cultivo de referencia (Eto), evapotranspiración del cultivo (Etc), datos que permitieron determinar los requerimientos hídricos por estado fenológico (Kc). Las variables para identificar el grado de tolerancia al déficit hídrico fueron: contenido de clorofila, contenido relativo de agua, número de tubérculos por plantas, rendimiento por planta, rendimiento por tamaño de tubérculo, rendimiento total y materia seca del tubérculo. Se concluye que las variedades INIAP- Estela, INIAP Natividad y los clones 98-02-06, 10-10-97 presentaron valores altos por los que las considera como tolerancia a la sequía.

The estimation of evapotranspiration (ET) and crop water requirements are crucial for the proper management and allocation of water resources in terms of quantity, quality, and timeliness. Therefore, remote sensing estimation of ET using the SEBAL algorithm (Surface Energy Balance Algorithm for Land) can provide spatio-temporal, non-punctual data, unlike traditional calculations relying on the nearest meteorological station. This research analyzed ET using SEBAL, based on ten Landsat 8 satellite images processed with a program developed in the Model Builder of ArcGis® version 10.2. The analysis was conducted during the vegetative period of starchy corn from May to October 2016. Validation of the results happened with a drainage lysimeter installed in a monitoring plot. Additionally, the statistical indices – such as percentage relative error (PRE) (0,09), root mean square error (RMSE) (0,30), R2 (0,92), and Nash-Sutcliffe efficiency (NASH) (0,91) – indicated a good correlation of ET for starchy corn in the central highlands of Peru. The ET identified at ten monitoring points ranged from 1,05 to 7,79 mm d-1. La estimación de la evapotranspiración (ET) y los requerimientos de agua de los cultivos son muy importantes para un adecuado manejo y gestión del recurso hídrico, tanto en su cantidad, calidad y oportunidad; por lo que la estimación de la ET con la percepción remota (RS) mediante el algoritmo SEBAL (Algoritmo de Balance de Energía de Superficie para Tierra) es útil para obtener datos espacio - temporales y no puntuales, como sucede en el cálculo tradicional (estación meteorológica más cercana). En la investigación se analizó la ET con el SEBAL en base a 10 imágenes satelitales Landsat 8 usando una programación elaborada en el Model Builder del ArcGis versión 10,2; durante el periodo vegetativo del maíz amiláceo entre los meses de mayo a octubre en el 2016. La validación de resultados se realizó con un lisímetro de drenaje instalado en una parcela de monitoreo, así mismo los índices estadísticos como ERP (0,09); RMSE (0,30); R2 (0,92) y NASH (0,91) indicaron que la ET del maíz amiláceo en la sierra central del Perú, presenta buena correlación. La ET identificada en 10 puntos de monitoreo osciló en el rango de 1,05 mm d-1 a 7,79 mm d-1. The estimation of evapotranspiration (ET) and crop water requirements are crucial for the proper management and allocation of water resources in terms of quantity, quality, and timeliness. Therefore, remote sensing estimation of ET using the SEBAL algorithm (Surface Energy Balance Algorithm for Land) can provide spatio-temporal, non-punctual data, unlike traditional calculations relying on the nearest meteorological station. This research analyzed ET using SEBAL, based on ten Landsat 8 satellite images processed with a program developed in the Model Builder of ArcGis® version 10.2. The analysis was conducted during the vegetative period of starchy corn from May to October 2016. Validation of the results happened with a drainage lysimeter installed in a monitoring plot. Additionally, the statistical indices – such as percentage relative error (PRE) (0,09), root mean square error (RMSE) (0,30), R2 (0,92), and Nash-Sutcliffe efficiency (NASH) (0,91) – indicated a good correlation of ET for starchy corn in the central highlands of Peru. The ET identified at ten monitoring points ranged from 1,05 to 7,79 mm d-1.

A desirable water supply in agriculture requires quantitative methods to determine crop requirements. Determination of hydric request of maize Var INIAP 102 is promising, mainly at altitudes over 2000 meters above sea level. This study analyzed three methods (lysimeter, evaporimeter tank, and empiric formula FAO) to determine Chimborazo province's hydric requirements for Var INIAP 102. Vegetative and yield variables were recorded, and the effect of different water films on the vegetative growth of maize was determined. When water was more available in the soil, the vegetative growth, yield, and pod weight per plant of maize Var INIAP 102 were higher. This study is of great importance because determining the hydric requirement of maize Var INIAP 102 was done for the first time in Chimborazo province and will support farmers in better water use for irrigation.

The efficient management of water resources using techniques that improve it uses, based on knowledge of evapotranspiration are key elements for crop production. Amongst main techniques for water management, the use of drainage lysimeter installed in the field below vegetable fields may be used to quantify the amount of water needed. The aim of this work is to design, install and calibrate a set of lysimeters for adjusting crop coefficient (Kc). In the calibration of the lysimeters, it was obtained that to induce drainage in lysimeters from one to five, an over-irrigation of 25% of the field capacity was needed, while the rest needed 50%. With lysimeters built the physical characteristic of soil could be simulated in this study.