Forecasting Wheat Crop Production Under Climate Change Scenarios in Pakistan

Abstract

Agriculture as entirely dependent on weather conditions, is highly sensitive to climate change. Wheat is among those major crops that are more severely affected due to climate variability. The study was design with the aim to use high Resolution CORDEX-SA RCM-projections to quantify the impacts of climate variability on wheat yield production under future scenarios (RCP 4.5 and RCP 8.5) for period 2020 -2100 and to evaluate, different adaption strategies under both rainfed and irrigated condition in Pakistan by using well-known STICS crop model. Initially calibration and validation was done for both rainfed and irrigated regions. Further, Bias Corrected CORDEX-SA RCM-projections were used to quantify the impacts of climate change on wheat crop phenology and yield in crop model. Subsequently, the adaptation strategies including the alterations in sowing dates (early sowing), irrigation (I1: 15% and I2: 30% additional) and combination of both were utilized to mitigate the negative climate change impacts on wheat crop. Results showed declining trend of yield was associated with the increasing trend of temperature (increase in number of hot days (max Temp >32 °C) with least value of 9 days for both RCP4.5 and RCP8.5 in Islamabad) and declining trend of precipitation. Detailed analysis throughout growing season showed backward shift in Anthesis and Maturity days over both study regions. Additionally, for rainfed regions the sowing adaptation strategies particularly sowing-2 (S2) showed a substantial improvement in wheat crop yield simulated by STICS model. While, for irrigated regions irrigation-2 (I2) and combination of sowing-1 + Irrigation-2 (S1+I2) showed more substantial improvement under both RCPs. Overall, it is observed that the RCP8.5 showed significant change in crop phenology and yield in comparison to RCP4.5 in context of climate change impacts over rainfed and irrigated regions due to more adverse climatic condition.