Somerville is offering to trade some gardening and chicken-keeping know-how to people willing to volunteer at gardening projects around the city. The city and Somerville-based urban agriculture company Green City Growers are seeking applicants to participate in a program that will train 20 residents in urban growing techniques in exchange for 30 hours of volunteer service in garden projects. The Urban Agriculture Ambassador program is returning this year after running as pilot program in 2013, and will be held on four consecutive Saturdays from March 29 to April 19 , according to the city. Participants will learn how to build raised garden beds, plant and harvest, and troubleshoot pests, and will receive an introduction to bee- and chicken-keeping. The partnership between the city and Green City Growers seeks to share knowledge about growing food in an urban environment and increase access to healthy food and nutrition education. Somerville residents can apply to the program until March 10 by e-mailing firstname.lastname@example.org or by submitting an application that can be picked up at public libraries in the city.