Cálculo de los requerimientos hídricos del maíz y ajuste del Kc mediante el uso de lisímetros de drenaje en el Valle Inferior del río Negro

Abstract

The usage of the irrigation constitutes an essential practice for the production in the Valle Inferior of the Negro river. In this kind of production, it is likely to happen that the producers may make more use of the water than needed, replenishing the irrigation schemes before the 20% of the available water in the soil has been consumed, resulting in a loss of this resource by percolation. The aim of this project was to find the hydric requirements of the corn crop in its different conditions and the calculation of its appropriate crop coefficients, which are also known as Kc. To achieve this goal, a drainage lysimeter was used, consisting of a container in which water is added in a certain volume, measured by a flowmeter. The excess is withdrawn and the divergence between both constitutes the water volume evaporated and transpired by the cultivation. The tests were made during the 2014/15 and 2015/16 campaigns and seeded in December and November respectively. The water volumes measurements were carried out weekly and the values were uploaded to a spreadsheet which let us gauge the values of initial, middle and final Kc. It was also determined the volume of the produced dry material, the output and the efficiency of the water usage. The ETc values found were of 628mm in the campaign of 2014/15 and 580mm in the campaign 2015/16, and the output obtained was 13.5 and 13.8 tn.ha -1 respectively. The efficiency of the water usage that was calculated consisting of 4 kg.mm -1 in the first year and 3.91 kg.mm -1 in the second year. The Kc that were found giving a result, an initial Kc of 0.35 in season 2014/15 and 0.2 in 2015/16, a middle Kc of 1.3 and 0.94, and a final Kc of 0.45 and 0.66 respectively.