Gross sprinkler evaporation losses (SELg) can be large and decrease irrigation application efficiency. However, it is not universally established how much of the SELg contributes to decrease the crop evapotranspiration during the sprinkler irrigation and how much are the net sprinkler losses (SELn). The components of SEL were the wind drift and evaporation losses (WDEL) and the water intercepted by the crop (IL). The gross WDEL (WDELg) and evapotranspiration (ET) were measured simultaneously in two alfalfa (Medicago sativa L.) plots, one being irrigated (moist, MT) and the other one not being irrigated (dry, DT). Catch can measurements, mass gains, and losses in the lysimeters and micrometeorological measurements were performed to establish net WDEL (WDELn) during the irrigation and net IL (ILn) after the irrigation as the difference between ETMT and ETDT. Also, equations to estimate ILn and net sprinkler evaporation losses (SELn) were developed. ILn was strongly related to vapor pressure deficit (VPD). SELn were 8.3 % of the total applied water. During daytime irrigations, SELn was 9.8 % of the irrigation water and slightly less than WDELg (10.9 %). During nighttime irrigations, SELn were slightly greater than WDELg (5.4 and 3.7 %, respectively). SELn was mainly a function of wind speed
The radial water distribution and irrigation performance of an agricultural sprinkler with plastic nozzles were analysed. Twenty-six tests with an isolated sprinkler corresponding to different
An important modernization process providing pressurized irrigation systems to the traditional surface irrigation districts has taken place in Spain over the last 20 years However, an adverse consequence of modernization is the important increase in the energy cost in the modernized irrigation districts, which is aggravated by the current high energy prices. The Almudévar irrigation district (AID), a traditional surface irrigation district, was transformed into a pressurized sprinkler irrigation system in late 2010. The irrigation network was equipped with a high-level telemetry and remote control system that reaches the hydraulic valves of the irrigated blocks into which the plots are divided. Therefore, the telemetry system enables the centralized management of the irrigation scheduling from the district office. The district is divided into four independent networks with their own reservoirs and electric pump stations. A comparison of the land structure, crop patterns and irrigation management between the modernized AID in 2011 and the pre-modernization AID in 2006-2008 was performed. The temporal evolution of the irrigation water and energy demands in the 2011 irrigation season was analyzed with the available telemetry data from 2011. An irrigation performance index (SIPI) of the monthly and seasonal frequencies was computed for the main crops of the AID. Most irrigation events were performed during the low electricity tariff periods (P6 electric tariff) due to the centralized irrigation scheduling. Meteorological constraints had a low incidence in irrigation scheduling. Generally, a slight decrease in total irrigation deliveries was observed before and after medium-to-large precipitation events, but no changes in irrigation deliveries was observed with increases in wind speed. The exploitation of telemetry data in the AID has been an important tool to optimize the contracted electricity power in each tariff period and in decreasing the electric bill of the AID. This type of telemetry data analysis, similar to the analysis performed in the modernized AID in 2011, could be used in other water use associations as an important decision-making tool to improve water and energy management and to control the irrigation cost
Over the next few years, Tunisia will face a growing scarcity of water. The concept of a food consumption water footprint has been recently applied to expand knowledge about water management and to respond to problems of food insecurity. In this study, following the Water Footprint Network (WFN) method, we assessed and analysed the food consumption water footprint of Tunisian households by geographical location and by group of food products. We used results from national food surveys to collect the quantities of food consumed and the WFN database containing water footprints of food products specific to Tunisia. We found that the average water footprint for the main consumed food groups has increased by 31% during recent decades, from 1208 m 3 /capita/year in 1985 to 1586 m 3 /capita/year in 2010. Despite the decline in cereal consumption in Tunisia, the food water footprint has continued to rise as a result of increased consumption of animal source products. This increase is associated with regional variations in food choices that imply large differences in water footprints. Urban diets present higher water footprints than rural diets proportionally to higher standards of living. This study provides a new perspective on the water footprint of food consumption in Tunisia by using dietary data at the household level and demonstrated significant variability in water footprints due to different food consumption modes, and socio-economic and geographic characteristics. Future food consumption trends will likely create more pressure on water resources, especially in Tunis city and coastal areas of Tunisia. Special measures related to price policies, sensitization of consumers, and changes in production systems may have to be taken by policy makers to reduce the water footprint in order to improve food security strategies and water management in Tunisia.
Over the last 10 years, telecontrol systems have been incorporated into the majority of modern collective pressurized irrigation networks in Spain. This type of infrastructure provides many opportunities for irrigation management but actually, in Spain, is only used for standardized network operations. The Candasnos irrigation district (CID), located in northeastern Spain, is equipped with this system, and contains a variety of different pressurized systems. Telecontrol data and crop water requirements were used to analyze the evolution of irrigation performance (SIPI) of maize, alfalfa, and stone fruits. Irrigation guidelines for stone fruit were analyzed and compared with those of standard and regulated deficit irrigation (RDI) irrigation strategies. Ten solid-set irrigation systems were monitored to determine on-farm irrigation patterns. The average SIPI of maize, alfalfa, and peach was 83, 107, and 123%, respectively. The average SIPI showed a high irrigation performance, but the spatial and temporal variability of SIPI showed possibilities for improvement. Deficit irrigation practices were conducted on peach trees but not adjusted to the recommended RDI strategy. The results of plot monitoring showed crop differences on irrigation time per event (1-1.5 h in maize and 2-3 h in alfalfa) and on time interval between irrigation (larger in alfalfa than in maize). The short and frequent irrigation timing for the corn crop could be a disadvantageous practice because it yielded high evaporation losses from crop-intercepted water. Two irrigation patterns were established at the CID: the first was characterized by structured irrigation schedules and the second was characterized by weekly changes in the irrigation schedule. The second pattern was more commonly employed in solid-set systems than in those with pivots. The analysis of telecontrol data following this methodology could be easily implemented in the daily routines of the district office to improve irrigation management at the plot level. Further, telecontrol data can be an important tool for promoting and facilitating regulated deficit irrigation strategies in stone fruits. © 2012 American Society of Civil Engineer
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