Simulating the yield of wheat under futuristic climate change scenarios in lower Shivaliks of Punjab

KuldeepKaur

Simulating the yield of wheat under futuristic climate change scenarios in lower Shivaliks of Punjab

Date

2023

Authors

KuldeepKaur

Publisher

Punjab Agricultural University

Abstract

The study was conducted during the rabi season 2020-21 and 2021-22 at Regional Research Station, BallowalSaunkhri to produce field data for the calibration and validation of the CERES-wheat model using seven wheat cultivars (HD3226, Unnat PBW 343, Unnat PBW 550, PBW Zn1, PBW 725, PBW 660 and PBW 752) sown during 11th November (D1) and 15th December (D2). The daily future data (2010-2095) for lower shivaliks of Punjab (BallowalSaunkhri) was downloaded from Marksim weather generator using outputs of CSIRO-Mk3-6-0 climate model under four RCP scenarios (RCP 2.6, RCP 4.5, RCP 6.0 and RCP 8.5). The bias correction of model data (temperature, rainfall and solar radiation) was done by developing correction functions (using model and observed data from 2010-2015) from different bias correction methods (difference method, Leander and Buishand method, modified difference method, linear scaling, variance scaling and quantile mapping). The difference method was used for further correction of data as this method gave good statistical results with low error and high efficiency. Further, the model data (2016-2020) was corrected using the best bias correction method which was then validated against the observed data (2016-2020). The validation of the correction function by reduced the biases between model and observed data. The correction of the future data (2021-2095) and further projections on annual, seasonal and monthly basis was done using the difference method of bias correction.The study revealed that the annual maximum temperature by the end of 21st century is likely to increase by 1.3°C, 6.8°C, 6.3°C and 8.3°C and minimum temperature increased by 0.7 °C, 1.7 °C, 1.3°Cand 2.6 °C under RCP 2.6, RCP 4.5, RCP 6.0 and RCP 8.5 respectively. The annual rainfall may decrease under RCP 2.6 (-22.4 mm) whereas increased under RCP 4.5, RCP 6.0 and RCP 8.5(147 mm, 291.6 mm and 30.1 mm) respectively. The analysis of the corrected data on annual basis revealed that solar radiation may increase by 0.6 MJ/ m2 /day, 0.7 MJ/ m2 /day, 1.0MJ/ m2 /day and 0.9 MJ/ m2 /day under RCP 2.6, RCP 4.5, RCP 6.0 and RCP 8.5 respectively. For the annual, kharif, rabi, winter, pre-monsoon, monsoon and post-monsoon maximum temperature would rise by 0.01 to 0.06, 0.01 to 0.05, 0.01 to 0.06, 0.01 to 0.07, 0.01 to 0.06, 0.01 to 0.06 and 0.01 to 0.05°C per year under different RCP scenarios by the end of 21st century. Similarly, minimum temperature would increase by 0.01 to 0.07 °C for annual, kharif,rabi, monsoon and post-monsoon respectively while 0.01 to 0.08°C for winter and 0.01 to 0.06°C for pre-monsoon increases per year under different RCP scenarios. The rainfall under different RCP scenarios would change by 1.75mm, -1.98mm, 0.25mm, 0.27mm, -0.01mm, -1.55mm and -0.48mm for annual, kharif, rabi, winter, premonsoon, monsoon and post-monsoon per year respectively. For the annual, kharif, rabi, winter, pre-monsoon, monsoon and post-monsoon solar radiation would rise by 0.01 MJ/m2/day under different RCP scenarios per year. The calibration and validation of the CERES-wheat model showed good agreement between the observed and simulated values with NRMSE value of 0.5 and 0.4 for anthesis and maturity respectively, and 9.0 and 8.4 for grain yield and biomass yield respectively. The simulation of phenology and yield using CERES-wheat model under projected climate scenarios showed the significantly decreasing duration 6 to 31 days for 11 November and 3 to 15 days for 15 Decemberand grain yield 259 to 1981 days for D1 sowing and 85 to 1285 days D2 sowing datesof wheat crop under different RCP scenarios in BallowalSaunkhri, Punjab. The reduction in the maturity period is more under RCP 8.5 (30 days for HD 3226; 31 days for Unnat PBW 550 and 30days for PBW 660) followed by RCP 4.5 (17 days for HD 3226; 18 days for Unnat PBW 550 and 16 days for PBW 660), RCP 6.0 (19 days for HD 3226; 20 days for Unnat PBW 550 and 19 days for PBW 660) and RCP 2.6 (7 days for for HD 3226; 5 days for Unnat PBW 550 and 6 days for PBW 660).The higher temperature may be the reason behind the more grain yield reduction because the physiology of the crop is adversely affected under high temperature conditions. The study concluded that more decrease in grain yield was more in 11th November sowing as compared to the 15th December sown crop, therefore delaying the sowing time in December will be helpful in combating the effect of increasing temperatures on crop duration and yield of wheat crop in the future.

Citation

Kuldeep Kaur (2023). Simulating the yield of wheat under futuristic climate change scenarios in lower Shivaliks of Punjab (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.