I don't believe that's quite right. The article suggests that manure and fertiliser themselves release greenhouse gases into the atmosphere, potentially negating any increase in sequestration due to plant growth:

Wick wanted to know if he could deliberately replicate this process on his ranch — but without manure, which, as it decomposes, can release potent greenhouse gases like methane and nitrous oxide. The former traps about 30 times as much heat as carbon dioxide, the latter 300 times as much. As a carbon-farming tool, manure might be self-defeating.

Instead they propose that compost be used, while avoiding methods of farming that release carbon from the soil.

Jeff Creque, a onetime organic farmer, had a suggestion: Why not use compost? Compost can contain manure, but whereas manure alone can release nitrogen as nitrous oxide, the nitrogen in compost becomes locked up in complex molecules. At least in theory, that limits the escape of a powerful greenhouse gas.

Silver had thought that the compost would simply break down, releasing its carbon back into the atmosphere or, worse, produce nitrous oxide. But those emissions never occurred; moreover, judging by its chemical signature, most of the carbon moving into the soil came from the air, not the compost. The compost appeared to help the plants draw more carbon from the atmosphere than they otherwise would have.

Fair enough, but can that process be achieved with net-negative carbon emissions ?

I live in rural Marin County which is featured in this article and is (currently) ground zero for this kind of research. There are several ranches near mine that have adopted these practices specifically to combat climate change.[1]

After you raise the cattle (with all of the carbon emissions that entails) and then transport their manure in a large ICE truck (but not large enough to get economies of fuel efficiency like a semi on a highway would have) and then use a big tractor and/or bulldozer to unload and move it ...

You've got four or six or eight guys there at the ranch doing the labor and of course they don't live there - and the reality of Marin County land values and rents dictates that they probably live an hour or more away in Santa Rosa or Vacaville or worse. And of course they drive as large of pickup trucks as their paycheck will possibly support to transport their single body to that worksite.

And then you have to maintain the process by tilling or turning the material - again with tractors or bulldozers and again with more workers who drive to the site.

It sounds like I'm getting unfair and nit-picking here but that's the whole point: the exercise makes no sense unless it is carbon net-negative so you have to add all of these costs to the ledger.

I would be overjoyed if it penciled out, but very skeptical that it does.

[1] https://www.marincarbonproject.org/

https://americancarbonregistry.org/carbon-accounting/standar...

So, manure is decaying animal excrement. Compost is decaying animal excrement plus some additional biological matter handled in such a way that certain species of bacteria take over. Basically, you turn it frequently.

What kind of bacteria take over? Aerobic ones. Now, granted, aerobic bacteria do produce greenhouse gases, but they're in the form of CO2, which really isn't so bad. By contrast, anaerobic bacteria release more potent greenhouse gases such as methane and nitrogen dioxide.

A big steaming pile of manure, left on its own, will easily be overtaken by anaerobic bacteria. With proper treatment, however, aerobic bacteria will dominate.

Worms and bugs need a balanced diet. So a farmer will, presumably, add crop and other agricultural waste to cultivate these helpful aerobics.

(I'm only a backyard horticulturalist. Gardening experts stress adding a balance of leaves, grass clippings and miscellaneous 'organic material' to one's vegie scraps for a healthy urban compost.)

https://www.sciencedaily.com/releases/2017/03/170314111320.h...