A method for the qualitative and quantitative in-situ, real-time determination of the ammonium and nitrite content and the ammonium conversion to nitrite in soil, wherein a measuring arrangement is used which comprises at least the following components: one or more gas sampling devices, at least one multi-gas measuring device, at least one mass flow device, at least one readout device, and at least one evaluation device for the multi-gas measuring device, comprising the following method steps: a) sampling soil emissions from a soil by means of one or more gas sampling devices and transporting these soil emissions to at least one multi-gas measuring device, b) determining the mass flow of the soil emissions to the multi-gas measuring device using a mass flow measuring device, c) determining the gas emission rates f of NH 3 and NO from the soil using a readout device from the data of the multi-gas measuring device and the mass flow measuring device relative to the surface area of the soil covered by the gas sampling device, d) calculation of the ammonium and nitrite content of the soil by means of an evaluation device, wherein, in order to determine the ammonium content, the determined gas emission rate f of NH 3 is compared with calibration data previously determined for the soil and, in order to determine the nitrite content, the determined gas emission rate f of NO from step c) is compared with calibration data previously determined for the soil, whereby the local concentration of the ammonium and nitrite content of the soil is determined quantitatively in situ and the conversion of ammonium to nitrite is determined qualitatively in real time. one or more gas sampling devices, at least one multi-gas measuring device, at least one mass flow device, at least one readout device, and at least one evaluation device for the multi-gas measuring device, comprising the following method steps: a) sampling soil emissions from a soil by means of one or more gas sampling devices and transporting these soil emissions to at least one multi-gas measuring device, b) determining the mass flow of the soil emissions to the multi-gas measuring device using a mass flow measuring device, c) determining the gas emission rates f of NH 3 and NO from the soil using a readout device from the data of the multi-gas measuring device and the mass flow measuring device relative to the surface area of the soil covered by the gas sampling device, d) calculation of the ammonium and nitrite content of the soil by means of an evaluation device, wherein, in order to determine the ammonium content, the determined gas emission rate f of NH 3 is compared with calibration data previously determined for the soil and, in order to determine the nitrite content, the determined gas emission rate f of NO from step c) is compared with calibration data previously determined for the soil, whereby the local concentration of the ammonium and nitrite content of the soil is determined quantitatively in situ and the conversion of ammonium to nitrite is determined qualitatively in real time. a) sampling soil emissions from a soil by means of one or more gas sampling devices and transporting these soil emissions to at least one multi-gas measuring device, b) determining the mass flow of the soil emissions to the multi-gas measuring device using a mass flow measuring device, c) determining the gas emission rates f of NH 3 and NO from the soil using a readout device from the data of the multi-gas measuring device and the mass flow measuring device relative to the surface area of the soil covered by the gas sampling device, d) calculation of the ammonium and nitrite content of the soil by means of an evaluation device, wherein, in order to determine the ammonium content, the determined gas emission rate f of NH 3 is compared with calibration data previously determined for the soil and, in order to determine the nitrite content, the determined gas emission rate f of NO from step c) is compared with calibration data previously determined for the soil, whereby the local concentration of the ammonium and nitrite content of the soil is determined quantitatively in situ and the conversion of ammonium to nitrite is determined qualitatively in real time.