I'm a big fan of chopping and dropping. It just makes sense to keep biomass directly where it comes from (providing it isn't diseased or full of unwanted seeds). But of course as soon as it's down, it begins to dry out. Now in my mind, I mostly associate GREEN biomass with NITROGEN, and BROWN biomass with CARBON. I may not completely or clearly understand how this works--and please correct me if I'm wrong--but I get the impression that by letting the fresh material dry out on the surface, I am loosing both nitrogen and moisture. So what I have begun to do in my garden is simply lift the existing mat of dry mulch material and just tuck the new green stuff underneath it. This allows it to stay moist and green, more like a green manure than a dry mulch.
To test the efficacy of my little experiment, I have left some spots with their existing mulch layer (no additional material) and some spots normally chop and dropped on top. Whether or not I am correct about saving nitrogen, I have to say it is working well for me. The control areas do their expected part in conserving moisture and suppressing weeds of course, but not much else can be said. However where I have chopped and tucked, the soil is more moist, there is a good deal of insect activitiy, and a few worms have ventured out above the surface of the soil on a 90 degree day to have a munch.
For what it is worth, this is a new garden as of this year, so there is a clear division between the soil surface and the straw & leaf mulch. Also this is also not a forest garden, but some beds turned out of a yard in full sunlight all day. I don't know if tucking would make much difference in a place with more established soils or more perennial cover.
Any thoughts on this would be appreciated.