A method for the controlled spreading of a liquid plant protection agent and/or fertiliser by means of an agricultural distribution machine, in particular by means of a field sprayer , by way of a spray boom mounted to the distribution machine or to the field sprayer , as applicable, wherein the plant protection agent and/or fertiliser is distributed on a crop of plants during a field drive of the distribution machine or of the field sprayer , as applicable, by means of at least one spray nozzle that is mounted to the spray boom , characterised by at least the following method steps in the following order: a) start of the plant protection process; b) input or read-in of target values into a computer system , in particular, for the specification of a defined wetting of the crop of plants with plant protection agent and/or fertiliser; c) variation of spread parameters for the plant protection agent and/or fertiliser controlled by specification from the computer system in consideration of at least the input target values; d) distribution of the plant protection agent and/or fertiliser on the crop of plants based on the spread parameters; e) wetting of the plants of the crop with plant protection agent and/or fertiliser; f) permanent, cyclical, and/or intermittent detection, after distributing the plant protection agent and/or fertiliser, of a wetting of the plants of the crop with plant protection agent and/or fertiliser by means of at least one downstream monitoring means , which is disposed at the spray boom , and, in particular, projects in driving direction backwards beyond the spray boom ; g) comparison by the computer system of the wetting of the plants of the crop with plant protection agent and/or fertiliser as detected by means of the monitoring means with the specified wetting as calculated based on the target value input; h) permanent, cyclical, and/or intermittent adaptation of the spread parameters based on a deviation of the detected wetting from the specified wetting of the plants of the crop with plant protection agent and/or fertiliser; i) finalisation of the plant protection process. a) start of the plant protection process; b) input or read-in of target values into a computer system , in particular, for the specification of a defined wetting of the crop of plants with plant protection agent and/or fertiliser; c) variation of spread parameters for the plant protection agent and/or fertiliser controlled by specification from the computer system in consideration of at least the input target values; d) distribution of the plant protection agent and/or fertiliser on the crop of plants based on the spread parameters; e) wetting of the plants of the crop with plant protection agent and/or fertiliser; f) permanent, cyclical, and/or intermittent detection, after distributing the plant protection agent and/or fertiliser, of a wetting of the plants of the crop with plant protection agent and/or fertiliser by means of at least one downstream monitoring means , which is disposed at the spray boom , and, in particular, projects in driving direction backwards beyond the spray boom ; g) comparison by the computer system of the wetting of the plants of the crop with plant protection agent and/or fertiliser as detected by means of the monitoring means with the specified wetting as calculated based on the target value input; h) permanent, cyclical, and/or intermittent adaptation of the spread parameters based on a deviation of the detected wetting from the specified wetting of the plants of the crop with plant protection agent and/or fertiliser; i) finalisation of the plant protection process. <EOS>