EFFECT OF CLIMATE CHANGE ON FCV TOBACCO PRODUCTIVITY AND QUALITY TRENDS DURING THE LAST TWO DECADES IN SOUTHERN TRANSITIONAL ZONE OF KARNATAKA

Abstract

Flue Cued Virginia (FCV) tobacco is an important commercial crop grown under rainfed conditions in the Southern Transitional Zone (STZ) of Karnataka which is typically characterized by a sub humid to semi-arid climate with a bimodal rainfall pattern. Even though FCV tobacco is regarded as a hardy and drought tolerant crop and produces better quality leaf in light soils of Karnataka, continuous monocropping, lack of crop diversity/crop rotation practices coupled with erratic / uneven rainfall and unpredictable rains during recent times is greatly affecting the production and quality of this export-oriented crop with unsustainable productivity and farm income. The analysis of two decades of rainfall (for the period from 2002-03 to 2022-23) has indicated rainfall variability with a high coefficient of variation of 27.8%. Further, the month of July considered to be very critical for moisture stress showed a wide variation of 42.3% in terms of the quantum of rainfall and number of rain events (C.V.26.9%). Regarding the other weather factors analyzed, the photoperiod (sunshine hours/day) showed comparatively higher variability (13.8%) compared to the average mean temperature (5.7%) during the crop growing season indicating minimum sunlight period for optimum productivity level. The average productivity level over two decades was observed to be 1123 kg/ha with a variation of around 12.0%. However, in 60% of the years the productivity was below normal. Anything above >450 mm during the crop period was detrimental to productivity. Optimum rainfall is observed to be around 370-450 mm during the cropping season with July (critical period) month rainfall not falling below 50 mm (and also not exceeding 120 mm) with better sunlight intensity (minimum of 4.0 hours/day and above) for optimum productivity and quality of FCV tobacco in KLS.