Nitrogen solubility in the deep mantle and the origin of Earth's primordial nitrogen budget

•First measurements of nitrogen solubility in transition zone and lower mantle minerals.•Several present atmospheric masses of nitrogen were probably sequestered in the mantle during magma ocean crystallization.•Nitrogen is probably not anomalously depleted on Earth.•Bulk atmospheric pressure may have fluctuated over Earth history due to exchange with the nitrogen reservoir in the mantle.