Residue spread monitoring

A system for monitoring the distribution of residue material from a spreader tool of an agricultural machine, the system comprising:

• a first LIDAR sensor having a two-dimensional sensing region defining a first two-dimensional sensing boundary corresponding to a first direction with respect to the agricultural machine, the first two-dimensional sensing boundary comprising a first vertical plane relative to a ground surface;
• a second LIDAR sensor having a two-dimensional sensing region defining a second two-dimensional sensing boundary corresponding to a second direction with respect to the agricultural machine, the second two-dimensional sensing boundary comprising a second vertical plane relative to the ground surface;
• and
• at least one controller, configured to:
• receive data from the first LIDAR sensor indicative of a measure of residue material crossing the first sensing boundary;
• receive data from the second LIDAR sensor indicative of a measure of residue material crossing the second sensing boundary;
• determine, from the data received from the first and second LIDAR sensors, a distribution of residue material associated with the spreader tool;
• and
• output at least one control signal for controlling at least one operational system of the agricultural machine in dependence on the determined distribution.