Modernizing Agricultural and Manufacturing Bonds Act This bill amends the Internal Revenue Code, with respect to qualified small issue bonds for manufacturing purposes, to expand the definition of "manufacturing facility" to include a facility that (1) is used in the creation or production of intangible property; or (2) is functionally related, subordinate to, and located on the same site as a facility used in the manufacturing or production of tangible or intangible personal property. The bill also increases from $10 million to $30 million the maximum bond size limitation. The bill also modifies requirements for private activity bond financing for first-time farmers. The modified provisions (1) increase from $450,000 to $552,500 (adjusted annually for inflation) the amount of bond proceeds that may be used by a first-time farmer to acquire land for farming purposes, (2) repeal the separate dollar limitation on the use of bond proceeds for used farm equipment, and (3) modify the definition of "substantial farmland" to determine farm size by reference to the average (instead of median) size of a farm in the county in which the farm is located.