Calculation of maize evapotranspiration using evaporation and reference evapotranspiration methods

Abstract

Analysis of irrigation scheduling of maize was done by using evaporation from the free water surface (Eo) and correction coefficients (k) and reference evapotranspiration (ETo) and crop coefficients (kc). The field experiment was carried out in 2018 on the Experimental field of the Institute of field and vegetable crops in the Department of alternative crops in Bački Petrovac. Maize hybrid NS 6030 was used for the trials. The plants were irrigated by a drip system with a lateral in each row with drippers spaced every 0.33 m. The drippers had an average flow rate of 2.0 l h-1 under the pressure of 70 kPa. The differences in yield of maize in the irrigation conditions were not statistically significant compared to the variant without irrigation because the year was favorable for maize production. As well there was no difference among variants used for the calculation of maize evapotranspiration. Maize evapotranspiration in the growing season (ETm) were 502 mm and 429 mm by using ETo and kc and Eo and k. Monthly values of ETm during the growing season were consistent regardless of the calculation methods, except in July. Values of ETm in July of 151 mm and 107 mm calculated by using ETo and kc and Eo and k methods as well the daily values which are correlated with the monthly have to be checked in irrigation scheduling of maize in the following investigation period. If statistical significance in maize yield between different methods of calculation is determined, the procedure with a higher yield has to be accepted in the calculation of ETm in the climatic conditions of the Vojvodina region. Otherwise, if the differences in maize yield are not statistical significance a method of calculation by using Eo and k will be recommended, because the value of the lower daily water used on maize evapotranspiration may be considered more realistic.