Spatial Variability of the Water Depth Applied by Fixed Sprinkler Irrigation Systems

Abstract

The uniformity of water application is an important factor in the evaluation of sprinkler irrigation systems. This uniformity depends on the type of sprinkler and its operating conditions, such as the arrangement and spacing between the sprinklers in the area; velocity and wind direction during the period of water application and the pressure variation of the irrigation system. The objective of this study was to model, analyze and compare the structure of spatial dependence, as well as the spatial variability of the water depths applied by a sprinkler irrigation system with compensating and non-compensating sprinklers, using geostatistical methods and measurements of accuracy or similarity between the applied water depth maps. The experiment was carried out in an agricultural area, in the city of Cascavel-Paraná-Brazil. A total area of 10 x 10 m was used, with 04 compensating and 04 non-compensating sprinklers installed at a height of 1.5 m. For each type of sprinkler, water levels were measured in 100 collectors spaced 1 x 1 m in the study area in 32 trials. On each test sprinkling was carried out for one hour. The conditions of wind, temperature and air humidity were evaluated at the beginning of each test and at 10-minute intervals with a climatological station. As the geostatistical analysis showed the existence of directional trends, the coordinates were incorporated as covariates to the linear spatial model in the study of the spatial dependence of the average depth of the irrigation water for the two types of sprinklers. The spatial dependence structure that best fits the data when using the compensating sprinklers was the Gaussian model and when the non-compensating sprinklers were used, it was the exponential model. The spatial variability maps of average irrigation water depth (mm) of the trials, obtained by universal kriging, revealed that for both sprinklers there was an increase in the mean level average values in the northwest-southeast direction (135 o in the azimuth system) in the area under study, influenced by wind direction and velocity during the execution of the experiment.

Use of indirect methodologies for determining the flow rate in water pumping systems

“…Irrigation is considered an old technique to provide water supply when plants need it and in the exact amount (Tamagi et al, 2018). Furthermore, it is an essential operation in the life cycle of agriculture (Al Zayed et al, 2016).…”

Evaluación del desempeño del riego por aspersión en lotes con cultivo de banana en Chiapas, México

“…La evaluación de un sistema de riego, permite determinar, a partir de parámetros cuantitativos, problemas en algún elemento del mismo y determinar la forma en que se está aplicando el riego (Martínez, 1991, Mansour et al, 2019Zhang et al, 2019). La uniformidad de aplicación es el parámetro más importante en la evaluación de un sistema de riego, el cual depende del tipo de aspersor, de las condiciones de operación, así como del espaciamiento entre regantes y aspersores (Dieter et al, 2014;Mohamed et al, 2019;Tamagi et al, 2018). En la bibliografía especializada existen pocos reportes sobre evaluación de sistemas de riego por aspersión para el cultivo del banano bajo condiciones normales de operación; se cuenta con estudios en Ecuador (Caicedo et al, 2015), en Cuba (Rodríguez et al, 2007).…”