An agricultural machine (100;200;301) comprising: a material distribution system (122;306) comprising a material distribution line configured to convey particulate material to a component (312-1, 312-2); and a sensing system comprising a first sensor configured to generate a first sensor signal indicative of a measure of a flow of the particulate material in the material distribution line; a second sensor configured to generate a second sensor signal indicative of a measure of the flow of the particulate material in the material distribution line; and a correlation generation component configured to receive indications of the first and second sensor signals and to generate a correlation metric that represents a correlation between the first and second sensor signals; the material distribution line further comprising a first material distribution line configured to convey a first flow of particulate material to a first component; and a second material distribution line configured to convey a second flow of particulate material to a second component, wherein the sensing system further comprises a third sensor configured to generate a third sensor signal indicative of a measure of the second flow of the particulate material in the second material distribution line; characterized in that the correlation application component is configured to determine a rate of the second flow based on applying the correlation metric to the third sensor signal. a material distribution system (122;306) comprising a material distribution line configured to convey particulate material to a component (312-1, 312-2); and a sensing system comprising a first sensor configured to generate a first sensor signal indicative of a measure of a flow of the particulate material in the material distribution line; a second sensor configured to generate a second sensor signal indicative of a measure of the flow of the particulate material in the material distribution line; and a correlation generation component configured to receive indications of the first and second sensor signals and to generate a correlation metric that represents a correlation between the first and second sensor signals; a first sensor configured to generate a first sensor signal indicative of a measure of a flow of the particulate material in the material distribution line; a second sensor configured to generate a second sensor signal indicative of a measure of the flow of the particulate material in the material distribution line; and a correlation generation component configured to receive indications of the first and second sensor signals and to generate a correlation metric that represents a correlation between the first and second sensor signals; the material distribution line further comprising a first material distribution line configured to convey a first flow of particulate material to a first component; and a second material distribution line configured to convey a second flow of particulate material to a second component, wherein the sensing system further comprises a third sensor configured to generate a third sensor signal indicative of a measure of the second flow of the particulate material in the second material distribution line; characterized in that the correlation application component is configured to determine a rate of the second flow based on applying the correlation metric to the third sensor signal. a first material distribution line configured to convey a first flow of particulate material to a first component; and a second material distribution line configured to convey a second flow of particulate material to a second component, wherein the sensing system further comprises a third sensor configured to generate a third sensor signal indicative of a measure of the second flow of the particulate material in the second material distribution line; characterized in that the correlation application component is configured to determine a rate of the second flow based on applying the correlation metric to the third sensor signal.