OPTIMIZING WHEAT YIELD AND WATER PRODUCTIVITY USING AQUACROP AND APSIM-WHEAT MODELS IN NORTH NILE DELTA, EGYPT

Abstract

The calibration of APSIM-Wheat and AQUACROP models had been done manually for anthesis date, maturity date, grain yield and total biomass of one recent spring wheat cultivar (T. aestivum) under irrigated conditions in Egypt. Various treatments of planting dates, irrigation and fertilization were applied during two successive growing seasons of 2014/2015 and 2015/2016 in a split split plot design replicated three times. The calibration of APSIM-Wheat and AQUACROP was done for Misr3 cultivar using genetic parameters based on observed field data. Both models simulated anthesis, maturity dates, grain yield and total biomass accurately, with high values of determination coefficient (R2), and D-index greater than 0.8 as well as lower values of root mean square deviation (RMSD) in most cases. The calibrated models were then employed to explore wheat yield and water productivity in response to irrigation and nitrogen fertilization options. Scenarios analysis indicated that water productivity and yield of wheat ranged from (1.2-2.0 kg m-3) and (6.8-8.7 t ha-1) respectively. Application of 0.8 from actual evapotranspiration along with 120 % from recommended nitrogen dose was the best predicted scenario achieving the highest value of crop water productivity. Investigating the suitable option achieving the current wheat yield by farmers (7.4 t ha-1), models demonstrated that application of 1.4 from actual evapotranspiration with 80 % from the recommended nitrogen dose was the best option to achieve this yield. At this point predicted water productivity was low and recorded 1.5 kg m-3. Quantifying wheat yield in all districts of the studied area was also predicted using both models. APSIM-Wheat and AQUACROP can be used to drive the best management strategies in terms of N-fertilizer and water regime for wheat under Egyptian conditions.