Two additional Grammy Awards in the rap field will be presented next year.

National Academy of Recording Arts & Sciences trustees have voted to expand the rap field by including a best rap/sung collaboration category and by giving a Grammy to the mastering engineer on the rap album of the year, Academy President Michael Greene said Tuesday.

"The academy's board of trustees continues to demonstrate its passionate commitment to education, human services and keeping the Grammy Awards' process relevant and responsive to our dynamic music community," Greene said.

The rap field now grows to four categories: best rap solo performance, best rap performance by a duo or group, best rap album and the new best rap/sung collaboration. Collaborative efforts of rap and sung performances were previously placed in the best rap performance by a duo or group category.

Collaborative performances have grown significantly in recent years, the academy noted. There were at least 50 recordings released during last year's eligibility period.

The addition of the mastering engineer as a Grammy recipient in the best album category "acknowledges the significant technical and creative contributions of these professionals," the academy said.