Novel approach to evaluate the dynamic variation of wind drift and evaporation losses under moving irrigation systems

Abstract

Evaporation lossCenter pivot Catch can testWater application efficiency Strip testThe increased need for water and food security requires the development of new approaches to save water through irrigation management strategies, particularly for center pivot irrigation. To do so entails monitoring of the dynamic variation in wind drift and evaporation losses (WDELs) of irrigation systems under different weather conditions and for relatively long time periods. The historical catch can method has limited our ability to address this goal. Here, a new and easy-to implement methodology, called the strip test, was developed and validated against the catch can technique. Our results showed strong agreement between the catch can method and the strip test for determining the average water application efficiency (WAE z 1-WDEL). Because the strip test method was measured for shorter intervals compared to the catch can method, the variables influencing WAE were able to be compared during each test. WAE had a large variance over time, which was controlled, in part, by wind speed (>4 m s À1 ). Site-specific characterisation of WDEL is needed to apply this technique. Once applied, it can provide a better understanding of WAE behaviour over the time, and enhance the capability of predicting results for the optimising water use in sprinkler irrigation.

Estudo Comparativo De Três Mecanismos De Redução De Evaporação De Reservatórios

“…A preocupação com a disponibilidade de água para agricultura tem levado muitos países áridos e semiáridos a desenvolverem mecanismos para redução de perdas e para aumento de disponibilidade de água para irrigação (PEREIRA et al, 2009). Tecnologias para reduzir as taxas de evaporação de reservatórios agrícolas são exemplos de mecanismos que podem efetivamente ajudar estes países e regiões a superar a escassez de água, e consequentemente aumentar o rendimento das culturas agrícolas (MARTÍNEZ ALVAREZ et al, 2008;SADEGHI et al, 2015).…”

Droplet characterization and water distribution of fixed spray plate sprinkler used in linearly moved irrigation system

“…The characterization of drops resulting from fixed spray-plate sprinkler primarily implies the determination of their diameter as they approach the soil surface. Fine droplets of water travelling through the air have more evaporation losses rather than coarse droplets with respect to wind speed [9], [24]. Size distribution of the drops discharged by the water jet of an agricultural sprinkler has major influence on evaporation losses, modifying the infiltration capacity of the soil, and distortion of water distribution pattern applied by sprinkler [13], [15], [19], [25].…”

Dynamics of Water Vapor Content around Isolated Sprinklers: Description and Validation of Model

“…However, over the irrigation period, Those models are unavailable to present the developing processes of WDEL, which may be expressed as the water vapor dynamics around the sprinkler. Few studies have paid particular attention to the water vapor dynamics, because catch can tests provide only a single data point following the experiments [29], making it impossible to capture the continuous variation in water vapor content. However, water vapor dynamics are closely related to the generating processes of WDELs; accurate representation of such development features will help to effectively decrease WDELs.…”

“…However, details of the temporal dynamics and spatial variations of the water vapor content during a sprinkler irrigation event are lacking, even in descriptive models. Conversely, Sadeghi et al [29] provided new methodology called a 'strip test' to monitor the dynamic variation in WDELs under a center pivot irrigation system. However, the published results did not provide a theoretical model of the dynamic variation.…”

“…In addition, the water volumes collected by each catch can must be measured immediately, as irrigation completes, to limit evaporation of collected water [21,23]. Catch can measurement therefore requires a massive labor force and is inefficient [29]. For this reason, alternative observation methods have been advocated, e.g., the electrical conductivity method [30], chemical tracer methods using potassium ion [31] and eddy covariance measurements [32].…”