Samiha. A.H. Ouda ( 2006). Predicting the Effect of Water and Salinity Stresses on Wheat Yield and Water NeedsJournal of Applied Sciences Research, 2(10): 746-750, 2006
Abstract: A computer model was developed to predict wheat yield and water consumptiveuse. The developed model called "Wheat-Stress". The model calculates water depletion from root zone using equations described at FAOpublication No56. The model was validated using two-year experimental data for wheat planted during growingseasons of 2003/04 and 2004/05 to study the impact of skipping the 5th or the 6th irrigation on the yield of two wheat cultivars i.e. Sakha 93 and Giza 168. To determine the accuracy of the model, both percent error (PE) and root mean square error (RMSE) between actual and predicted yield were calculated. "Wheat-Stress" model was also used to predict wheat yields under the following hypothetical situations: (1 Reducing the amount of irrigation water by 20 %. (2) Using saline water for irrigation. Results showed that the model prediction gave good agreement with actual yield, where both the values of PE andRMSE were low, for both varieties over the two growingseasons. Results also indicated that the yield of both varieties wasreduced under deducting 20% of irrigation water by 8.62 and 8.76 % for Sakha 93 and Giza 168, respectively. Furthermore, using saline water for irrigation reduced wheat yield by 4.14 and 4.38 % for Sakha 93 and Giza 168, respectively. Water consumptive use under total irrigation was reduced by 18.54 and 11.64% for both growing seasons, respectively, under saving 20%of total waterirrigation. Whereas, under saline water irrigation, water consumptive use was reduced by 15.02 and 11.93 % for both growing seasons, respectively. The developed modelcould be modified to predict the yield of other crops, such as maize, sunflowerand cotton using specific crop parameters presented in FAO publication No56.
Keywords: (Wheat-stress model, water stress, salinity stress, yield prediction, water consumptive use.)
