Impact of climate change on potato (Solanum tuberosum) productivity in Bihar and relative adaptation strategies

A study was carried out for Bihar state to assess the impact of climate change on potato (Solanum tuberosum L.) productivity using WOFOST crop growth simulation model. Three different maturity group potato cultivars were used (‘Kufri Badshah’-late maturing; ‘Kufri Jyoti’-medium maturing; and ‘Kufri Pukhraj’-early maturing). The study was done for baseline scenario (2000) and for future climate scenarios for the years 2020 and 2055 using A1FI scenario of temperature (SRES A1FI pathway) and atmospheric CO₂ (based on the Bern-CC model for A1FI scenario). Potential production of potato cultivars was estimated for 29 different locations across Bihar. Kriging technique was used to interpolate the data generated through the model and thematic maps were created based on potential productivity in 2000 and changes thereon in future climates. Under baseline scenario, the mean productivity of ‘Kufri Badshah’, ‘Kufri Jyoti’ and ‘Kufri Pukhraj’ was 40.7, 38.7 and 40.8 t/ha respectively. Though the increase in CO₂ concentration is expected to bring an increase of 4.2 to 4.5% in productivity in 2020 and 17.7 to 19.3% in 2055, the corresponding increase in temperature is likely to decrease the mean productivity by 9.0 to 11.0% and 24.3 to 29.1% in 2020 and 2055, respectively. Overall, under the combined influence of increased CO₂ and temperature, the model projected a decline of 5.1, 6.2 and 6.9% in productivity of ‘Kufri Badshah’, ‘Kufri Jyoti’ and ‘Kufri Pukhraj’, respectively, in 2020; and 8.7, 10.8 and 12.7%, respectively, in 2055 without adaptation. Rescheduling planting date can be an immediate option against climate change in Bihar. However, development of short-duration, heat-tolerant as well as nutrient and water-use efficient cultivars with high harvest index along with proper agronomic interventions are required to meet the challenges posed by climatic change.