Abstract

The need to know the water consumption of a crop during its vegetative period, be it annual or perennial, is fundamental due to the climate change underway, which manifests both a decrease in the amount of precipitation in different areas of our country and a concentration of this precipitation. In addition, it is necessary to be efficient and effective in the use of water resources for irrigation in agriculture, both in open and protected environments, and thus to strive for sustainable development. To achieve this, it is necessary to know the values of reference evapotranspiration, actual evapotranspiration and crop coefficient in order to estimate and project water applications through irrigation systems as close to reality as possible.

For generations, crop coefficient values of a crop have been used independently of the mathematical method of estimating reference evapotranspiration without knowing whether or not there are differences in the results obtained in the estimated water consumptions. However, by means of mathematical methods for estimating reference evapotranspiration using data on relative humidity, temperature and solar radiation inside a greenhouse, a significant difference in crop coefficient values was found. The methodologies of Ivanov and Camargo did not show significant differences (0,05) with respect to the methodologies of Benavidez, Linacre, Hargreaves and Turc; the methodologies of Benavidez and Linacre presented significant differences (0,05) both among them and with respect to the methodologies of Ivanov, Camargo, Hargreaves and Turc; and Hargreaves and Turc did not present significant differences among them but significant differences (0,05) were found with respect to the methodologies of Ivanov, Camargo, Benavidez and Linacre.

Keywords Reference evapotranspiration; water consumption; actual evapotranspiration; onion; greenhause; hidric resource; crop coefficient