Hi Bart - You'll find many discussions about the various pros and cons of each of these over on the Soil, Compost & Mulch forum. Now that the search is working again, they should be easy to find.

Other than that, I can only offer my personal opinion on each. Top soil is a "catch-all" label used for many different types and qualities of 'dirt'. As such, you never know what you are getting. It's nutrient value can range from fair to non-existent and it may or may not improve your soil. I think of it as "filler".

Composted manure is just that - various manures (usually cattle but the bag should indicate which type) mixed with other carbons such as sawdust or straw and allowed to 'cook' for an unspecified length of time. Its quality depends on what components are used and under what conditions it was composted but its nutrient levels will be higher than top soil and it is good soil amendment.

Humus is well-aged or 'finished' compost and can be composed of a wide variety of organic materials - only the manufacturer knows for sure. ;) Its nutrient value will be quite low when compared to chemical fertilizer numbers but the nutrients are in a form readily available to the plants. It, like the composted manure, will also improve the tilth of your native soil.

Bottom line - assuming quality components, I'd stick with a mixture of the composted manure and the humus and skip the top soil.

Hope this helps.

Dave

Thanks Dave! I should have known someone with the name "digdirt" would have the answer!

Thanks again,
Bart