the Rodale Book of Composting is very good and it covers most methods of Composting. the problem with trench composting is tha lack of aerobic action. to get the heat to kill the weed seed you need to have an aerobic action rather that anaerobic action. both with work if cone right. in the anaerobic system used in India they submerge the composting material under water and a side benefit is bio-gas. the benefit of the aerobic system is faster composting and a wider spectrum of microorganisms.