[midjji]

I dont understand why this would be hard. The amount of carbon stored is directly proportional to the height the land rises year by year due to the buried plant matter. Simply use a high accuracy gps lidar combo, compensate for the landmovements by measuring nearby non cultivated land, and the amount of carbon stored is quite simple to compute. If it is small enough you cant tell, its probably effectively zero anyways. But even then you can always grow crops, carbonize them, weigh them and bury them. So whats the problem?

[OzyM]

I don't know enough about carbon capture to agree with the statement that it's directly proportional to land height. Even if it were, trying to calculate an inch of height difference through rotating cover crops and possible inches of snow at different points throughout the year seems infeasible at best.

Same for weighing - this sounds like an implementation nightmare. The cost of equipment and time to weigh every piece of vegetation grown (then the cost of developing the mathematical models to subtract out carbon emissions, possible loss of carbon sink, etc.) sounds wildly expensive for something easily gamed by any nontrustworthy farmer.

That said though, if you have a vision for this that would solve these problems, you could probably create an extremely successful startup with it. There's hundreds of millions of dollars in the market of carbon indulgences.

[midjji]

Assuming the soil type and waterlevels are sustainable, the carbon capture would be proportional to the land level increase over the bedrock plus farm runoff. I would outright discard the latter as its more of environmental hazard than a benefit, but it is also bound by the upper limit of particulate matter the rivers can sustainably move even if we discard all the other problems. Its a coarse model to be sure, but there is no problem at all to measure this effect for the only large scale carbon capture currently in use. Landfills (10% carbon) can be visibly seen growing in height year, and do so despite the same kind of runoff as farms. It seems highly unlikely that farms can reach zero carbon emissions while powered by coal and oil, but the carbon captured in the ground should be measurable, or I suspect its largely a pleasant sounding lie.

The problem with simply weighing it isn't the cost, ore processing facilities already do this at scale. The problem is the cost of fertilizers and that you need heat it up to turn it into mostly coal first, or the methane generated by large scale decomposition after dumping it in a pile somewhere will be far worse than the carbon captured. Heating and transportation could be solved by nuclear and electric vehicles respectively, but its still a rather bad idea. Not to say that biological carbon capture cannot work, there are good ways to do so.