And of course the devil is in the details. For optimal zero-tillage effect, certain croping systems will require the application of glyphosate, so that weeds won't out-compete the food crops. Just think on that: Monsanto might turn out to be an accidental climate savior.
Per a story in SciDev.Net, Brazilian farmers are foremost in the world with use of Zero Tillage, a cropping method that is greener, boosts productivity, and helps the climate. "Called direct drilling, no-tillage or zero tillage (ZT), the technique is in part praised for fixing carbon in the soil, thereby reducing the amount of carbon dioxide — a greenhouse gas — released into the air. It also prevents soil erosion and therefore demands less irrigation". Because this story is complex, we highly recommend the entire article, which is posted here. In general, the practice of zero tillage agriculture reduces erosion, partitions water into groundwater instead of runoff, increases the organic content of soil, and helps fix more carbon in it. From the SciDev article:- "With the best systems you have over a ton of carbon sequestered [in the soil] per hectare per year. When you consider there are a hundred million hectares under ZT in the world, this is an awful lot of carbon dioxide taken out of the atmosphere," says British agronomist John Landers, who has promoted the technology in Brazil since the 1970s".