USCID fourth international conference

Presented at the Role of irrigation and drainage in a sustainable future: USCID fourth international conference on irrigation and drainage on October 3-6, 2007 in Sacramento, California.Includes bibliographical references.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 m3 water saving in 3.87 hectare per month

USCID fourth international conference

Presented at the Role of irrigation and drainage in a sustainable future: USCID fourth international conference on irrigation and drainage on October 3-6, 2007 in Sacramento, California.Includes bibliographical references.Backpropagation Neural Network is applied to establish the relationship between meteorological factors and evapotranspiration, which is then used to predict the evapotranspiration in ChiaNan irrigated area, Taiwan. It takes the weather data from Irrigation Experiment Station of ChiaNan Irrigation Association as the input layer, which include the following weather factors: (1) the highest temperature; (2) the lowest temperature; (3) average temperature; (4) relative humidity; (5) wind speed; (6) sunlight hours; (7) solar radiation amount; (8) dew point; (9) forenoon ground temperature; (10) afternoon ground temperature. From the result it can be known that the correlation coefficient reaches 0.993 between the evapotranspiration in 2004 calculated by FAO56 Penman-Monteith method and the one predicted by the neural network model with a hidden layer of 10 nodes. The actual evapotranspiration is 911.6cm and the prediction by the neural network is 864.4, between which the error ratio is 1.67%. The correlation coefficient is 0.708 between the actual evaporation in 2004 and the prediction by the neural network with a hidden layer of 10 nodes and an output layer with the pan evaporation as its target output. The pan evaporation is 1674.1cm, while the prediction by the neural network is 1451.7cm, between which the error ratio is 13.23%