Jondo Almondo wrote:@JW - With absorbing ammonia emissions from manure, biochar will work ok, but would work better if the whole mix was submerged in water. Can I suggest an extremely thick layer of hay? Many composters use a thick (sometimes compacted and moistened) layer of mulch to 'cap off' their pile and reduce emissions. A tarp over the lot can also contain and condense some of the gasses.
Biochars ability to absorb gasses is related to the duration of high-temperature ranges in it's production. A good biochar for the soil is less ideal for absorbing gasses, activated charcoal (made at higher temps) is great at absorption, not so great for the soil.
Also, if your worried about emissions - burning wet stuff slowly, smoldering matter in a pit is about as emissions intensive as it can get. It's also quite bad for your health. It's potentially worse than a traditional burn pile due to increased dioxin and PM outputs.
That was a very decent article in the NYT. Great to read that individual states are trying to roll out soil education, carbon credits and research in this field. The soil-carbon plan for France is especially ambitious given its national scale.