A soil processing machine, in particular a soil compactor, comprising a hydraulic drive system, wherein the hydraulic drive system comprises: - a pressurized fluid source with at least one hydraulic drive pump, - a hydraulic drive circuit supplied with pressurized fluid by the at least one hydraulic drive pump, - at least one hydraulic drive motor (56, 58) supplied with pressurized fluid from the hydraulic drive circuit, - a discharge valve assembly for discharging fluid from the hydraulic drive circuit into a fluid reservoir, - a control unit for controlling the discharge valve assembly, wherein the hydraulic drive system is designed to operate the discharge valve assembly as a function of at least one of the following parameters for discharging fluid to the fluid reservoir: - a temperature of the fluid in the hydraulic drive circuit, - a temperature of the fluid in a fluid return to the fluid reservoir, - an ambient temperature, - a viscosity of the fluid in the hydraulic drive circuit, - a degree of contamination of the fluid in the hydraulic drive circuit, - a period of time since the last start-up of the hydraulic drive system, - a period of time since the last fluid discharge from the hydraulic drive circuit, wherein the hydraulic drive system is designed to operate the discharge valve assembly to discharge fluid to the fluid reservoir when the temperature of the fluid in the hydraulic drive circuit is above a predetermined discharge fluid threshold temperature and/or is within a predetermined discharge fluid temperature range, characterized in that the pressurized fluid source is an electrohydraulic pressurized fluid source with at least one electric motor, and when the discharge valve assembly is operated to discharge fluid from the hydraulic drive circuit to the fluid reservoir the amount of fluid discharged to the fluid reservoir or/and the fluid discharge rate is set as a function of at least one of the following parameters: - an ambient temperature, - a degree of contamination, - a period of time since the last start-up of the hydraulic drive system, - a period of time since the last fluid discharge from the hydraulic drive circuit. - a pressurized fluid source with at least one hydraulic drive pump, - a hydraulic drive circuit supplied with pressurized fluid by the at least one hydraulic drive pump, - at least one hydraulic drive motor (56, 58) supplied with pressurized fluid from the hydraulic drive circuit, - a discharge valve assembly for discharging fluid from the hydraulic drive circuit into a fluid reservoir, - a control unit for controlling the discharge valve assembly, wherein the hydraulic drive system is designed to operate the discharge valve assembly as a function of at least one of the following parameters for discharging fluid to the fluid reservoir: - a temperature of the fluid in the hydraulic drive circuit, - a temperature of the fluid in a fluid return to the fluid reservoir, - an ambient temperature, - a viscosity of the fluid in the hydraulic drive circuit, - a degree of contamination of the fluid in the hydraulic drive circuit, - a period of time since the last start-up of the hydraulic drive system, - a period of time since the last fluid discharge from the hydraulic drive circuit, - a temperature of the fluid in the hydraulic drive circuit, - a temperature of the fluid in a fluid return to the fluid reservoir, - an ambient temperature, - a viscosity of the fluid in the hydraulic drive circuit, - a degree of contamination of the fluid in the hydraulic drive circuit, - a period of time since the last start-up of the hydraulic drive system, - a period of time since the last fluid discharge from the hydraulic drive circuit, wherein the hydraulic drive system is designed to operate the discharge valve assembly to discharge fluid to the fluid reservoir when the temperature of the fluid in the hydraulic drive circuit is above a predetermined discharge fluid threshold temperature and/or is within a predetermined discharge fluid temperature range, characterized in that the pressurized fluid source is an electrohydraulic pressurized fluid source with at least one electric motor, and when the discharge valve assembly is operated to discharge fluid from the hydraulic drive circuit to the fluid reservoir the amount of fluid discharged to the fluid reservoir or/and the fluid discharge rate is set as a function of at least one of the following parameters: - an ambient temperature, - a degree of contamination, - a period of time since the last start-up of the hydraulic drive system, - a period of time since the last fluid discharge from the hydraulic drive circuit. - an ambient temperature, - a degree of contamination, - a period of time since the last start-up of the hydraulic drive system, - a period of time since the last fluid discharge from the hydraulic drive circuit.