A plasma reactor for enriching water with nitrogen compounds comprising: - a water container; - a microwave generator; - a plasma head connected with the microwave generator by a waveguide; - a quartz tube having a first end situated within the plasma head and a second end that protrudes into the water container; - wherein the second end of the quartz tube has an outlet and is positioned so that upon providing water for enriching to the water container, at least the outlet is submersed in water; - a gas circulator configured to introduce gas into the first end of the quartz tube so that the introduced gas comes out through the second end of the quartz tube; - an electric discharge generating metal rod configured to be inserted into the plasma head within the quartz tube to generate an electric discharge in the quartz tube and to be moved out of the head after the electric discharge has been generated, within a time sufficient to avoid melting of the rod in the plasma head; characterized in that - the discharge is effected in the quartz tube in a microwave field supplied through the waveguide from the microwave generator, so that the gas passing through the quartz tube is ionized in a plasma discharge column; - wherein the gas circulator is further configured to impart a velocity to the gas so that upon passage of the gas through the quartz tube, in the microwave field, the plasma discharge column develops through the quartz tube almost to the outlet of the quartz tube; and - wherein the outlet comprises plurality of holes so that when the gas leaves the second end of the quartz tube it is released in the water in a form of gas bubbles so that upon leaving the outlet of the quartz tube the gas can move in the water in an upwards direction. - a water container; - a microwave generator; - a plasma head connected with the microwave generator by a waveguide; - a quartz tube having a first end situated within the plasma head and a second end that protrudes into the water container; - wherein the second end of the quartz tube has an outlet and is positioned so that upon providing water for enriching to the water container, at least the outlet is submersed in water; - a gas circulator configured to introduce gas into the first end of the quartz tube so that the introduced gas comes out through the second end of the quartz tube; - an electric discharge generating metal rod configured to be inserted into the plasma head within the quartz tube to generate an electric discharge in the quartz tube and to be moved out of the head after the electric discharge has been generated, within a time sufficient to avoid melting of the rod in the plasma head; characterized in that - the discharge is effected in the quartz tube in a microwave field supplied through the waveguide from the microwave generator, so that the gas passing through the quartz tube is ionized in a plasma discharge column; - wherein the gas circulator is further configured to impart a velocity to the gas so that upon passage of the gas through the quartz tube, in the microwave field, the plasma discharge column develops through the quartz tube almost to the outlet of the quartz tube; and - wherein the outlet comprises plurality of holes so that when the gas leaves the second end of the quartz tube it is released in the water in a form of gas bubbles so that upon leaving the outlet of the quartz tube the gas can move in the water in an upwards direction.