Yield and Nitrogen Uptake in Wheat and Chickpea Grown Under Elevated Carbon Dioxide Level

Increase in the atmospheric carbon dioxide (CO2) concentration has fertilization effect on crops if nutrient supply remains adequate. Response of cereals and legumes to increased CO2 concentration might differ due to the nitrogen fixing ability of leguminous crops. Considering the importance of differential response of cereal and legumes under elevated CO2 concentration, a field study was conducted to compare the effect of elevated CO2 on yield and plant nitrogen uptake in wheat and chickpea crop. Elevated CO2 level (550 ppm) increased yield by 15.1% and 16.7% over ambient in wheat and by 21.1% and 21.9% in chickpea (p ≤ 0.05) during the first and second years of the study. Nitrogen content in wheat grains decreased under elevated CO2 concentration. Chickpea, being a leguminous crop, showed no change in grain N content. However, higher biomass and grain yield resulted in higher N uptake in both the crops under elevated CO2 level. Under elevated CO2 concentration more partitioning of biomass toward seeds lead to higher seed N partitioning in chickpea. The study showed that although growth and yield of crops might increase in high CO2 condition, nitrogen concentration in grains and soil available N status might decrease in cereals like wheat. But chickpea might not get affected due to their ability to fix atmospheric N2.