Simulated Impacts of Elevated Temperature and CO 2 on Maize Yield for Northern Transitional Zone of Karnataka (original) (raw)

2019, Journal of Agriculture Research and Technology

Climate change is by far one of the most challenging factors influencing of agricultural activities and productivity. Crop production is mainly dependent up on the climatic condition of the given area. Currently climatic factors are changing all over the world. Therefore, the production and productivity of the crops become greatly influenced by the changing climatic variables. Lobell and Field (2007) stated that since 1981 for recent climate trends have suppressed global yield wheat, maize and barley. According to the same authors although % reduction from current yield levels may look small, but the absolute losses in global production due to warming trends since 1981 were substantial. For the 330 ppm CO 2 levels the GCM scenarios projected a decrease in yield of maize, caused by a shorter crop growing season due to higher temperatures and a precipitation deficit. Alexandrov and Hoogenboom (2000) studies predicted that the duration of the regular crop-growing season for maize would be reduced by 5 (HadCM2) to 20 (GFDL-R15) days shorter by 2020s. Similarly, maturity dates for maize were predicted to occur between 11 and 30 days earlier by 2050s under Indian condition. However, these are predicted at a national level using GCMS, needs to be checked and validated in Regional/Zonal level using crops mainly. Considering the existence of regional differences in climatic, geographic, and Abstract Two field studies on four maize hybrids across dates of sowing (three) and N levels (three) were carried out during two successive Kharif seasons of 2015 and 2016 at the main campus of University of Agricultural Sciences Dharwad, Karnataka, India. Out of these four sets of experimental data two sets we reused for DSSAT-CERES-Maize model calibration and other two sets for evaluation. This model was further run for seasonal analysis using 32-years historic weather data (1985-2016) as baseline to study the impact of elevated temperature (+1 and +2 ºC above baseline) and CO 2 (450 and 500 ppm from current levels of 400 ppm) for the first fortnight of June sowing under potential condition. The model simulated values showed that for baseline temperature across the tested hybrids, on average, a grain yield of 8910 kg ha-1 was predicted; however with rise in temperature by 1 and 2°C the grain yield, compared with baseline, reduced by 6.24 and 12.5%, respectively. In contrast, rise in CO 2 levels from the current levels (400 ppm) to 450 and 500 ppm increased the grain yield, on average across hybrids, by 1.0 and 2.0%, respectively, which suggest that negative impact of rising temperature on yield would be compensated with rise in CO 2 levels to an extent of only 1% for every increase in 50 ppm in maize, thus indicating that adverse impact of warmer climate on maize crop heavily overweigh the small benefit of rise in atmospheric CO 2 levels in C 4 crop like maize. Therefore, this study underlines the importance of containing further rise in atmospheric temperature by adopting climate mitigation strategies in agriculture and non-agriculture sectors.