Terrain warnings resulted when an MD88 flight crew departed ABQ with incorrect interpretation of the voluntary noise abatement procedure delineated by the several publications -- company and federally -- provided for their use.

Narrative

Prior to departure out of ABQ; the Copilot briefed the departure including the 'Air Carrier special pages' and the SID. It was determined that we would follow the 'voluntary noise abatement procedure' which would have us make no turns prior to 13.5 DME from ABQ VOR. Once cleared for takeoff; we were given a heading of '170 degrees after departure.' Copilot continued to 13.5 DME and started a turn to heading 170 degrees. He continued to clean up the aircraft and left the aircraft at 15 degrees of bank. I suggested leaving the slats out where we could get to 25 degrees quicker per the flight plan. He continued to accelerate to reach clean speed to get to 25 degrees. During the turn; Approach Control said they were getting a 'terrain alert and MVA was 5;500 FT MSL.' At that time we also got a GPWS warning for the hill that we had visually below us. We were already at 6;700 FT MSL at that point. Approach asked if we were doing the noise abatement procedure as 'it isn't needed to the south' and we said 'yes.' We later reviewed the SID and our 'special pages' to see where the misunderstanding arose. The ABQ2 vector SID says that the noise abatement procedure is only valid for a left turn. Our 'special page' says that it should be followed per SID or ATC clearance. The chart view of our 'special page' for engine-out procedures also displays the 13.5 DME fix with turns to the south which reinforced the issue. Another issue is what is an 'ATC clearance on departure' i.e.; a heading) sans a SID departure -- especially when the SID is just a vector. Since our 'special pages' take precedence over a SID; this could have been avoided with a better worded flight plan or a remark stating that 'noise abatement is not required to the south.'