LAUSR

Increase in the atmospheric carbon dioxide (CO 2 ) concentration has fertilization effect on crops if nutrient supply remains adequate. Response of cereals and legumes to increased CO 2 concentration might differ due to the nitrogen fixing ability of leguminous crops. Considering the importance of differential response of cereal and legumes under elevated CO 2 concentration, a field study was conducted to compare the effect of elevated CO 2 on yield and plant nitrogen uptake in wheat and chickpea crop. Elevated CO 2 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 CO 2 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 CO 2 level. Under elevated CO 2 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 CO 2 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 N 2 .