... Vietnam, and Soil Constraints to Productivity of Major Upland Crops Grown by Smallholders PW MoodyA and Phan Thi CongB A Queensland Department of Natural Resources and Water, ... link soil constraints to the soil requirements of the major upland crops and develop management guidelines for the management of specific soil types for specific crops. 2. Major Soils used ... are to: review existing information on the identification and extent of upland cropping soils in Gia Lai Province, Vietnam. identify the major soils used for smallholder cropping, and...