Productivity of mungbean (Vigna radiata) with elevated carbon dioxideat various phosphorus levels and cyanobacteria inoculation

Increase in the concentration of atmospheric carbon dioxide (CO2) has significant impact on crop growth and productivity. A study was undertaken during the kharif season to study the impacts of elevated CO2 and cyanobacterial inoculation on growth and yield of mungbean crop under different doses of P using Free Air Carbon dioxide Enrichment (FACE) facility. The crop was grown under two CO2 levels i.e., ambient (400 µmol mol-1) and elevated (550 ± 20 µmol mol-1), with five levels of P (0, 8, 12, 16 and 20 mg P kg-1 soil) and 2 levels of calothrix sp. (with and without cyanobacteria) inoculation. Elevated CO2 level increased seed yield by 35.0% and biomass yield by 31.3%. Leaf area, photosynthesis rate and leaf chlorophyll content significantly increased at high CO2 level. Yield attributes such as number of pods plant-1, number of seeds pod-1 and test weight also increased at high CO2 level. Application of P and cyanobacterial inoculation further increased growth and yield of the crop. The study showed that application of P as well as cyanobacteria could help in improving productivity of legumes under elevated CO2 condition.