GROWTH RESPONSE OF PALM TRESS TO THE FREQUENCY OF IRRIGATION BY BUBBLERS IN KHUZESTAN, IRAN

摘要

Based on the shortage of water resources in Iran and the high evapotranspiration rate in Khuzestan region (2044 mm/year), an irrigation system on Estamaran palm tree in the Experimental Farm of Shahid Rajaee of Omidiyeh plain was conducted. This study had two purposes, namely irrigation frequency and suitable depth of irrigation application of the Estamaran palm trees in Omidiyeh region. This study had two objectives. Irrigation frequency was the primary treatment and the evapotranspiration estimating methods was the secondary treatment. Three irrigation levels. i.e. one day long (A1), two day long (A2) and three day long (A3), were used as irrigation frequency. Also the evapotranspiration estimating methods used were, Penman-Montith 100% (B1), Penman- Montith 70% (B2), class A pan 100% (B3) and class A pan 70% (B4). Since this study had three replications, 36 palm trees were selected for this experiment. Cropwat software V.4 for windows, was applied for the evapotranspiration estimating from Penman-Montieth method. Irrigation scheduling was done according to SCS recommendations. Experimental design was according to split plot method in a randomized block. Finally by measuring the different growth indices of palm trees (leaf number, barb number and leaflet length) at a definite time, the best treatment was determined. The results showed that as a whole all the treatments in this experiment did not show a significant difference (up to 5% level) for the indicated indices. However, at the end of 4 month since the beginning of this study, the growth indices of trees in A2B1, A1B2 and A1B1 increased compared to other treatments. The result also indicated that, A1B2 was the best treatment of all. In comparison with the traditional irrigation by local farmers, using A1B2 treatment for all the palm trees (from Aug to Nov), will have 28422.34 m~3 water saving in 3.87 hectare per month.