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.