Yield response of important field crops to elevated air temperature and CO2 level

Abstract

Field experiment was carried out to study the yield responses of important field crops to elevated air temperature and CO₂ fertilization at the Indian Agriculture Research Institute, New Delhi. One promising variety each of rice (Oryza sativa L.), wheat (Triticum aestivum L.), chickpea (Cicer arietinum L.), greengram (Vigna radiata (L) Wilczek), groundnut (Arachis hypogaea L.), mustard (Brassica juncea (L.) Czern & Coss) and potato (Solanum tuberosum L.) were grown to full maturity in small temperature tunnels and FACE (Free Air CO₂ Enrichment) under increased temperature (1 - 4°C)and CO₂ level (550 ppm), respectively. Economic yield reduced gradually with rise in temperature in all the crops. Among the crops rice, chickpea and mustard have shown greater thermal tolerance, while wheat and groundnut proved to be more thermal sensitive. In case of greengram and potato, increased temperature effect was intermediate. On the other hand CO₂ fertilization enhanced the yield to varying degree in these field crops with highest effect in chickpea and least in cereals(rice and wheat). Results indicate that elevated CO₂ could alleviate the negative impact of temperature increase up to 4°C in chickpea and 5°C in mustard. In other crops, elevated CO₂ could counter-effect the temperature increase to lesser extent with least degree in wheat (1.5°C). Thus, counter effect of elevated CO₂ to rising temperature seems to be crop and location specific. Although, these results are preliminary in nature as experiments with more variables such as biotic factors like pests and weeds, geographical locations, agronomical practices are needed to find precise responses of crops to future climate change scenario.