A system comprising a baler machine configured to receive a plant material and to compress, shape, and secure the plant material into a bale, a cutter mechanism configured to cut a portion of the plant material in the bale into similarly-sized particles of the plant material; a mixer mechanism configured to mix the similarly-sized particles of the portion of the plant material into a homogenous aggregate of the portion of the plant material; a compression chamber configured to compress, shape, and secure the homogenous aggregate of the portion of the plant material into the individual bale, and the cutter mechanism is positioned in the compression chamber so as to cut the portion of the plant material in the bale without damaging a binding material which secures the plant material into the bale; and a near-infrared testing system configured to receive near-infrared radiation reflected by the homogenous aggregate of the portion of the plant material, analyze the near-infrared radiation, and generate evaluation data reflecting one or more properties of the plant material in the bale, characterised in that the compression chamber includes a center rail structure, and the mixer mechanism is a relief feature on the center rail structure which allows the plant material to expand and mix after cutting; a projecting feature on the center rail structure physically pushes against the bale to compress the homogenous aggregate of the portion of the plant material so as to present a substantially flattened surface to a near-infrared sensor of the near-infrared testing system; and the near infrared sensor is mounted to the center rail structure so as to cause the near-infrared sensor to exert a pressure against the surface of the bale. a baler machine configured to receive a plant material and to compress, shape, and secure the plant material into a bale, a cutter mechanism configured to cut a portion of the plant material in the bale into similarly-sized particles of the plant material; a mixer mechanism configured to mix the similarly-sized particles of the portion of the plant material into a homogenous aggregate of the portion of the plant material; a cutter mechanism configured to cut a portion of the plant material in the bale into similarly-sized particles of the plant material; a mixer mechanism configured to mix the similarly-sized particles of the portion of the plant material into a homogenous aggregate of the portion of the plant material; a compression chamber configured to compress, shape, and secure the homogenous aggregate of the portion of the plant material into the individual bale, and the cutter mechanism is positioned in the compression chamber so as to cut the portion of the plant material in the bale without damaging a binding material which secures the plant material into the bale; and a near-infrared testing system configured to receive near-infrared radiation reflected by the homogenous aggregate of the portion of the plant material, analyze the near-infrared radiation, and generate evaluation data reflecting one or more properties of the plant material in the bale, characterised in that the compression chamber includes a center rail structure, and the mixer mechanism is a relief feature on the center rail structure which allows the plant material to expand and mix after cutting; a projecting feature on the center rail structure physically pushes against the bale to compress the homogenous aggregate of the portion of the plant material so as to present a substantially flattened surface to a near-infrared sensor of the near-infrared testing system; and the near infrared sensor is mounted to the center rail structure so as to cause the near-infrared sensor to exert a pressure against the surface of the bale. a near-infrared testing system configured to receive near-infrared radiation reflected by the homogenous aggregate of the portion of the plant material, analyze the near-infrared radiation, and generate evaluation data reflecting one or more properties of the plant material in the bale, characterised in that the compression chamber includes a center rail structure, and the mixer mechanism is a relief feature on the center rail structure which allows the plant material to expand and mix after cutting; a projecting feature on the center rail structure physically pushes against the bale to compress the homogenous aggregate of the portion of the plant material so as to present a substantially flattened surface to a near-infrared sensor of the near-infrared testing system; and the near infrared sensor is mounted to the center rail structure so as to cause the near-infrared sensor to exert a pressure against the surface of the bale.