RT Journal Article SR Electronic T1 Cost-effective conservation programs: The role of economics JF Journal of Soil and Water Conservation FD Soil and Water Conservation Society SP 53A OP 54A DO 10.2489/jswc.64.2.53A VO 64 IS 2 A1 Roger Claassen YR 2009 UL http://www.jswconline.org/content/64/2/53A.abstract AB