The specific aims of this project are to: I) establish a repeatable field survey scheme of key soil variables influencing cotton production in the lower Namoi, Gwydir and Macintyre valleys; 2) obtain a quantitative statement of the current status of these variables; 3) develop spatial prediction models for optimal estimation of the variables in each of the valleys; 4) build up a soil data base incorporated into a Geographical Information System (GIS)