The degree parchment and an official transcript showing the field of study, together with proof of Canadian or Mexican citizenship and the employer's support letter naming the listed profession and describing the duties. Professional designations may support the file but do not replace the degree the entry requires.
Lead with the degree, support with the transcript
Order the file the way the entry is written. First, citizenship: a passport or citizenship certificate, not a permanent resident card. Second, the degree: the parchment itself, and where the title of the programme does not make the field obvious, a transcript listing the agronomy and soil science coursework that does. Third, the employer's letter, which should name the profession, describe the professional duties in the proportions previously agreed, state the period of employment sought and confirm the applicant will be an employee. Keep certified copies of everything, since the same package will be needed again on each entry and at each extension over what may be several three-year periods, and a set kept together is far easier to maintain than one reassembled each time.
Hypothetical example: a poultry-feed formulation analyst has a degree whose title says animal bioscience rather than agronomy. The first review pairs the parchment with the official transcript, course catalogue excerpts, and the employer’s signed description of formulation duties. The record that settles the issue is the qualification rule for the claimed profession, not a recruiter’s view that the degrees are similar. Assemble citizenship evidence separately from credential evidence and keep the support letter current. If the employer chooses the petition route, its I-129 filing should use the same duty description the applicant will actually perform.