Variable-rate fungicide spraying in cereals using a plant cover sensor

Real-time technology was developed and tested to variably apply fungicides on the plant surface of cereals. An important step towards variable-rate fungicide application in real time is the development and operation of online sensors for measuring plant parameters. The sensor signal of the CROP-Meter (real-time sensor to measure crop biomass density) is correlated with the Leaf Area Index, a measurement characterising the plant surface. Geostatistical analysis of the sensor values in the experimental fields showed that the autocorrelation distance was greater than 25 m, which was wider than the spray boom of the sensor-controlled field sprayer. Control of individual sections of the spray boom was therefore not necessary in the 5-year experiments. In the eleven field trials, average fungicide savings of 22% were achieved. Field scale strip trials were conducted with the sensor-operated field sprayer to analyse the yield response of the crop. Higher, lower, as well as similar yield levels were obtained in the variable-rate plots by comparison with the uniform plots.