The expansion of olive orchards into regions with no tradition of olive production and humid climates, such as Uruguay, with more than 1200 mm of annual rainfall, calls into question the need for irrigation. In these regions, however, years with water deficit during summers are quite common. The vapor pressure deficit during summer is lower than in countries with a Mediterranean climate. The high variability in interannual water availability in the current context of climate change, with a growing tendency for extreme events to occur, emphasizes the need to evaluate the production response of olive trees to irrigation. To achieve this, three irrigation treatments were applied to Arbequina and Frantoio cultivars according to the value of the maximum crop evapotranspiration: a first treatment applying 100% ETc, corresponding to being fully irrigated; a second treatment applying 50% ETc; and a third treatment in which neither irrigation nor rain inputs occurred from the end of the pit hardening period until harvest. Results show the possibility of an increasing fruit weight and pulp/pit ratio through irrigation in the local environmental conditions. The oil content in response to irrigation was different within cultivars. Water restriction conditions did not affect the oil content of olives in Arbequina, while in Frantoio it increased it. Polyphenols in fruit increased under water stress for both cultivars. The technological applicability of the results obtained must be accompanied by an economic analysis. The results obtained highlight the need for better use of irrigation water during the growth and ripening phase of the olive fruit under a humid climate.

In greenhouse conditions, soil salinity and N leaching depend on the provision of irrigation, the irrigation water quality and the application of fertilizers and organic amendments. The objective of this study was to quantify and analyze the accumulation and/or leaching process of NO3- and Na+ in greenhouse tomato production in the south region of Uruguay in fine-textured soil under different fertigation regimes. The study was conducted in four tomato crops during 2019/20/21 seasons. Three fertigation regimes were applied. Irrigation volume was the same for all treatments. Drainage was determined by using free drainage lysimeters. Concentration in soil solution and leaching of NO3- and Na+ was measured by monitoring soil solution and drainage solution. Yield, N uptake and N utilization efficiency were determined for each treatment. Soil total drainage was the main factor explaining N and Na+ leaching. The leaching of N ranges from 0 to 23.4 kg N ha-1 per tomato crop with total drainage between 0 and 46.2 % of total irrigation. Drainage necessary to avoid Na+ accumulation was 13 % of total irrigation. This drainage produced 8.4 kg of N leaching per ha-1 during tomato cropping period. Optimizing irrigation is the key factor to the salinity-nitrogen leaching paradox. Irrigation amount and timing should attempt: (1) to avoid excessive irrigation when NO3- concentration in soil solution is high, and (2) to apply leaching irrigation when Na+ concentration in soil solution is high. Soil solution monitoring with suction probes and rapid chemical analysis systems could be a useful tool to identify periods of high risk of N leaching and the right time for leaching irrigation.

Furrow irrigation systems have been widely evaluated around the world. However, there is no national data indicating how efficient furrow irrigation is under Uruguayan conditions. The objective of the present work was to evaluate the performance of a system of furrow irrigation in two different soils texture. Seventeen irrigation events were analyzed in sugar-cane cultivation in northern Uruguay during 2016-17 and 2017-18 irrigation seasons. The water advance and recess curves were determined; flow rate during irrigation and runoff were monitored. The maximum furrow length studied was 100 m and the average slope was 0.24%. Application efficiencies in both types of soils were observed above 75%. These field data were compared with data simulated by the WinSRFR model, where high correlations were observed in the results of water application efficiency, distribution uniformity and runoff. These first results encourage to continue working in the efficient use of water, not only thinking about a better use of the resource but also in less loss by run-off, and therefore, less possibility of contamination and lower cost of energy and labor.

The significant climatic variability present in Latin America and the Caribbean (LAC) generate marked regional differences in needs, availability, and management of water resources for agriculture. The availability of large-scale technological tools for monitoring crops and environmental conditions within their surroundings, becomes imperative in scenarios with a lack of water availability. To address this challenge, irrigation specialists from INIA-Chile, INTA-Argentina, Agrosavia-Colombia, INIA-Uruguay, Irrigation-Mendoza, and the Institute of Regional Development of UCLM-Spain, with co-financial support from FONTAGRO, are developing an initiative called "New technologies for increasing water use efficiency in LAC agriculture by 2030". The main objective of the initiative is the modernization of technological tools for efficient management of water resource in agriculture. Our conceptual framework for analyzing crop water consumption is based in the standardized methodology FAO-Manual N°56 with the improvement of use satellite vegetation index information. Based on the availability of a time series of satellite imagery (NDVI index) as a technological basis, we provide detailed analysis and advice for irrigation management at plot scale, as well as at regional areas where a soil water-balance model is implemented to estimate regional water consumption. At both working scales, the validation of this conceptual-technological framework has been carried out using technological pilots. Our results confirm the operability of the proposed framework in both scales under various agricultural contexts. Therefore, the effectiveness of technologies for crop monitoring, for precise estimation of water consumption, and for the ability to improve water use efficiency has been validated.