In reply to druss:
We watched this - some impressive and persuasive evidence. The message in a nutshell: Working the soil - ploughing etc - (and thus denuding the surface), along with use of chemicals - is responsible for increased erosion, death of micro-organisms, and release of CO2. Otherwise the maintaining of pasture/prairie for cattle-livestock with long feed-lot rotations.
The alternative methods, correctly implemented, would cut out agro-chemicals, avoid use of amazon felled soybean culture, and eliminate intensive meat production. With further benefits from more humane treatment of animals. It's not clear whether such systems could support current levels of meat consumption.
Further benefits from the sequestering of CO2. Organic matter trapped and recycled in the soil can hold impressive volumes of CO2. Think prairies, not just your back garden. The use of glyphosate seems to be especially detrimental.