Response of Greengram to Climate Change in Northern Transition Zone of Karnataka: DSSAT Model Based Assessment

Abstract

Background: Rise in temperature and expected changes in erratic rainfall patterns projected under future climates are going to affect the performance and productivity of most crops, especially under rainfed condition. But, extent of adverse effect would vary from location to location and crop to crop. Greengram is an important Kharif season crop of Northern Transition Zone (NTZ) of Karnataka mainly grown under rainfed conditions. Methods: Calibrated and validated DSSAT-CROPGRO model was used to study response of greengram to climate change in NTZ of Karnataka. A combination of three temperature (control, +1°C and +2°C) and three rainfall (control, -10% and -20%) scenarios resulting nine combinations were used to simulate phenology, yield and total biomass using weather data for the period of 32 years (1985-2016). Result: Model based seasonal analysis showed that the greengram is more sensitive to change in rainfall than temperature. Rise in temperature by 1-2°C, reduced days to physiological maturity by 2 to 3 days and yield by 1.7 to 3.5%. On the contrary, reduction in 20% rainfall alone reduced grain yield and total biomass by 9.5% and 10.48%, respectively. Combined effect of reduced rainfall (-20%) and elevated temperature (2°C) resulted in 16.36 and 21.16% reduction in grain yield and total biomass, respectively. This indicates that, rainfall plays greater role on kharif greengram yield in NTZ.