Critical analysis of the drip irrigation method under the conditions of Uruguay

Abstract

This paper presents objective information on irrigation efficiency and water savings with drip irrigation under the soil and climate conditions of Uruguay. Regarding the efficiency, the soil water content was monitored weekly in a drip irrigated adult citrus tree. Results show that, despite being an extremely dry summer, water leakage by deep percolation was observed. Although the leakage was not quantified it was evident. With regards to water savings, a hydric balance of a maize crop was simulated with the WinISAREG model, using a 33-year climatic series with daily precipitation and ETo data, watered with drip irrigation (Readily Available Water, RAW 6 mm) and with «traditional» irrigation (RAW 42 mm). Running a frequency analysis to meet the needs for 50 % of the years, the «traditional» method required 388 mm of irrigation in the season, while the drip irrigation method required 545 mm (40 % more). Per each millimeter of additional rain in the season, the need for «traditional» irrigation was reduced by 0,44 mm, whereas in the case of drip irrigation this reduction was only 0.33 mm. Preliminary data of compaction due to drip irrigation is also presented, increasing the apparent density from 1,19 to 1,30 g cm-3. This first experimental evidence of compaction due to drip irrigation should be confirmed or rejected in future studies.