Analysis of sprinkler irrigation management in the LASESA district, Monegros (Spain)

Good management of water in agriculture is essential in semiarid areas, as irrigation is the main user of a scarce resource. The present paper analyses the water use and the quality of irrigation in LASESA (LD), a mature sprinkler irrigation district of the Ebro valley, NE Spain, during the years 2009 and 2010. The water use was studied through field data and water balances by the calculation of several irrigation quality indexes. The results give an annual irrigation volume higher than that of neighbouring irrigated sprinkler districts, which have a slightly different percentage of crops. An average irrigation efficiency of 76% has been obtained. The major problems detected in the irrigation management are low irrigation efficiency for corn (73%) and a high water deficit for alfalfa (16%). In addition, many irrigators follow a fixed pattern regardless of the water requirements of the crops. Average water productivity of irrigation water is 1.69 kg m−3, similar to that obtained in other sprinkler irrigation areas of the Ebro valley. A change of the current irrigation scheduling is proposed in light of a simulation carried out seeking to reduce the underground drainage and the water deficit. The new schedule could improve the irrigation efficiency up to 83%, eliminate the water deficit and reduce drainage values to 4%, but it would require 7% more irrigation water.