The Doctoral advisory committee shall consist of a minimum of four members having academic rank of Assistant Professor or above, and all members shall hold a PhD degree. A minimum of three members of the advisory committee, including the major professor, must be approved by The Graduate School to direct doctoral research. Two or more members, including the major professor, are to be from the Biosystems Engineering & Soil Science Department. One or more members are to be from outside the department. If a student selects a minor, at least one faculty member must be from the minor department. Because of the diverse nature of the departmental faculty, BSE doctoral candidates must be chaired by a faculty member with disciplinary training in engineering, while PSES-Soils doctoral committees must be chaired by a faculty member with disciplinary training in soil science, environmental science, or a closely related discipline.