Crop water and irrigation water requirements of potato (Solanum tuberosum L.) in the loamy sands of Kuwait

Crop water and irrigation water requirements of potato have been estimated using the FAO CROPWAT model for potatoes grown in the loamy sands of Kuwait. Agro-meteorological data for 43 years recorded at the International Airport Kuwait was used for this purpose. The average annual reference crop evapotranspiration (ETo) over 43 years is estimated as 2882.5- mm. The mean monthly ETo varied from 2.75 mm d-1 (January) to 14.03 mm d-1 (June). The crop water requirement (ETc), the Irrigation Requirement (IR) and Net Irrigation Requirement (NIR) varied with the planting date. The annual rainfall of Kuwait is 138.3 mm, of which 132.7 mm is effective. The period from October15 to December 1 is suitable for potato planting and the lowest water use was observed with the November 1st planting date. The ETc, IR and NIR of potato varied with planting dates and the lowest values were observed with the November 1st planting date and highest with the planting date of January 1. The ETc varied from 266 mm for a 100 day crop to 375 mm for a 130 day crop with the planting date of November 1. The IR varied from 178 mm for a 100 day crop to 290 mm for a 130 day crop with the planting date of November 1. Similarly the NIR varied from 2045 m3 ha-1 for a 100 day crop to 3122 m3 ha-1 for 130 day crop with the planting date of November 1. Potatoes are not planted beyond December in order to economise water use. An irrigation schedule was also developed for potatoes of varying duration for the loamy sands of Kuwait