Öz
With the increasing interest in walnut cultivation in recent years, the number of new walnut orchards established has been increasing rapidly. It is necessary to know the water consumption of walnut trees with high fruit yield to be grown in these orchards. In this study, it was aimed to determine the water consumption of Maraş 18 type walnut tree, which has a high fruit yield, in Kahramanmaraş conditions. For this purpose, a weighting lysimeter system (WLS) was created consisting of lysimeter, weighbridge, discharge tank, pluviometer and drip irrigation system. WLS was controlled by Programmable Logic Controller (PLC) device. Firstly, daily water consumption of two years old young walnut tree (ETyoung) were determined by applying one dimensional water balance method under WLS conditions, during the June - October period of 2018. Then, daily water consumptions of mature walnut trees (ETmature) were estimated depending on the amounts of ETyoung. ETyoung amounts ranging from 1.22 to 3.20 mm day-1 were obtained for the young walnut tree. By taking into consideration that two years old young walnut trees consume ratio 30 - 40% water of adult walnut trees, ETmature amounts were estimated for 15 day periods. The amounts of ETmature were estimated as 6.77 mm day-1 for June, 8.49 and 9.14 mm day-1 for July, 5.71 and 6.00 mm day-1 for August, 3.86 and 7.43 mm day-1 for September and 3.49 mm day-1 for October. It has been concluded that ETmature amounts are compatible with “Water Consumption Guide of the irrigated crops in Turkey” at ratio 80% and can be used in irrigation programs to be prepared for mature walnut trees.