Assessing the climate change and its impact on rice yields of Haridwar district using PRECIS RCM data

Abstract

In the past few decades, continuous intervention with the environmental landscape in the form of land use practices (water diversions, deforestation, local agriculture practices, industrialization etc.) in the Haridwar district of Uttarakhand, India, has impacted the region on various accounts. This is likely to be further aggravated in view of the increasing variability in the weather condition. Thus, there is urgent need felt to quantitatively asses the future climatic scenario for initiating and effectively undertaking the adaptation strategies for safe and sustained agricultural growth. For undertaking this study, PRECIS RCM data was downloaded for Roorkee grid station for the period (1961–2090). This PRECIS RCM data was biased corrected by merging two different bias correction methods which involves correcting mean and standard deviation simultaneously. Observed and bias corrected daily data was tested for their significance at 95% probability of occurrence employing various statistical methods such as correlation coefficient, mean bias error, normalized mean squared error, and Z and F statistical tests. These tests revealed that the difference between the observed and bias corrected PRECIS RCM data was insignificant. Trend analysis was done using Mann-Kendall’s test and Theil Sen’s Slope. Analysis of the bias corrected data revealed that the Roorkee station will, in general, record increasing trends in rainfall (at 5.83 mm/year), maximum temperature (at 0.05 °C/year), and minimum temperature (at 0.04 °C/year). This indicates that by 2090 AD present normal rainfall of 1006 mm/year will rise to 1447 mm/year; maximum temperature of 30.1 °C will rise to 33.9 °C and minimum temperature of 17.5 °C will rise to 20.5 °C by 2090. This weather scenario cautions at the future agronomic practices for sustained productivity. Grain yield of rice cv. Sharbati for the period 2014–2090 was simulated by running DSSAT CERES rice model with PRECIS RCM weather data of Haridwar district and RCP CO₂ emission scenarios. The simulation result showed that if the crop is grown with the existing soil and crop management conditions, rice productivity of Haridwar in general will decrease 31.7 kgs/ha/year. This could be attributed to the climate change and decreased rice yields from increased maximum temperature. In the case of RCP 2.6 and RCP 4.5, the effect of CO₂ on grain yields is more pronounced compared to RCP 6.0 and RCP 8.5. With the higher CO₂ concentrations (above 450 ppm), the rice crop cv. Sharbati did not show much CO₂ fertilization effect. DSSAT CERES rice simulations under climate change and higher CO₂ concentrations showed that the yields will decline with the advancing climate change but CO₂ intervention will compensate the loss in yield.