A pneumatic distribution system for pneumatically distributing material in an agricultural vehicle is described. In one example, the pneumatic distribution system comprises an air source having an outlet with different air pressures defining a pressure gradient across the outlet, and a plurality of inlet ports configured to receive air from the outlet for a plurality of distribution streams, comprising at least a first distribution stream with a first pressure loss value and a second distribution stream with a second pressure loss value that is greater than the first pressure loss value. The inlet ports for the first and second distribution streams are located relative to the pressure gradient such that the second distribution stream receives a higher air pressure than the first distribution stream.