الفهرس | Only 14 pages are availabe for public view |
Abstract Modeling for irrigation scheduling attempts to answer two basic questions posed by irrigators; when to irrigate and how much water to apply. These two decisions require a through understanding of the complex behavior of climatic, soil and plant factors which independently determine irrigation frequency and water quantity for crops. A friendly user computer program was developed to schedule irrigation for different locations positioned geographically on the Egyptian map. This computer program was named ?ComputerAided Mapping Irrigation Scheduling Model?; CAMISM. The advantages of this program may be summarized as follows: 1 It calculates the real time irrigation scheduling for 36 mapped Egyptian zones and more. 2 To give this program the characteristic of wide use application; four methods of reference crop evapotranspiration calculations were introduced; BlanyCriddle, solar radiation, modified FAO PenmanMonteith and Pan evaporation. 3 The crop module data base included seven crop categories representing 65 crop types and species to calculate the crop evapotranspiration according to three crop development stages. 4 The soil module data base added up to 13 different soil textures to cover almost all soil types. 5The leaching requirements module was included to add the amount of water required to control salinization. 6The irrigation system module contained four types; surface, improved surface, sprinkle and drip to quantify that extra amount of water accounted for the application deficiency. To evaluate and verify the CAMISM predictions; all necessary steps required to develop such models were followed with proper justification. On real application five different locations were chosen to represent study cases to validate the CAMISM output results. Toshka, Maruot, AlArish, Kafer AlSheekh and AlBostan were considered in this respect. Verification proved that CAMISM predictions are either above or below and/or at the perfect line of agreement according to suitability of ETo method for the chosen location as well as availability of weather data. Nevertheless, in all cases the CAMISM predictions were highly significantly correlated with the ETo values obtained from the Central Laboratory of Agricultural Climatic ?CLAC?, Desert Research Institute and Sakha Station. The modified FAO PenmanMonteith method for ETo calculations has given the best verification ever proving once more the fact of its wide application. |