An agricultural harvesting system has an agricultural harvesting machine with at least one agricultural working unit that performs agricultural work, and an adjusting unit for adjusting the parameters of the particular working unit, a conveyor channel for a crop stream generated in a harvesting process by harvesting a field of crop, and an NIR sensor unit containing an NIR sensor which is configured for detecting constituents and/or properties of the crop stream. The crop stream in the conveyor channel can be guided past the NIR sensor. An on-line data processing unit controls the particular working unit, and generates control data on the basis of crop stream data which have been generated by the NIR sensor unit and correspond to the constituents and/or properties detected by the NIR sensor, and the adjusting unit carries out a parameter adjustment of the particular working unit on the basis of the control data.