Interactive Effect of Elevated Carbon Dioxide, Temperature and Nitrogen on the Growth Parameters of Rice at Active Tillering Stage

Ever since industrialization began, carbon dioxide [CO2] concentration in the atmosphere got increased and it consecutively raised the temperature. This change in climate would affect the agricultural production and crop growth. A pot culture experiment was conducted during the Kuruvai season (June - September) of the year 2023 at Anbil Dharmalingam Agricultural College & Research Institute, Tiruchirappalli to assess the rice growth up to active tillering stage under elevated [CO2] and temperature conditions at different doses of nitrogen (N) fertilization. Rice seedlings were grown inside the four Open Top Chambers (OTC) at ambient (422 ppm) and elevated CO2 (550 ppm) conditions as well as chamber controlled and elevated temperature (+2°C) with four different doses of N (control, 100% recommended dose of N (RDN), 150% RDN and 200% RDN). Plant growth parameters like plant height, number of tillers, leaf area, root length and root volume, root and shoot dry matter were increased significantly under elevated [CO2] (eCO2) conditions. Whereas, all the growth parameters were severely influenced by increased temperature. Increasing N concentration increased the plant growth irrespective of the treatments and the effect was more pronounced in eCO2 treatment due to the fertilization effect of [CO2] as it directly necessitates photosynthesis which improves overall growth of rice plants. Under the future changing climatic conditions suitable N doses should be optimized for the better crop production.