David, You are wrong about the carbon that would be emitted during transportation of residues to the sea. Our calculation of 92% carbon sequestration efficiency for CROPS is based on truck transport to the upper Mississippi and barging to deep water in the Gulf. If you want a reprint please ask and I will send. Nothing against no-till; it seems a good way to improve soil fertility and not waste root carbon, but it is still a lossy way to sequester above ground crop residue carbon.
= Stuart = Stuart E. Strand 167 Wilcox Hall, Box 352700, Univ. Washington, Seattle, WA 98195 voice 206-543-5350, fax 206-685-3836 http://faculty.washington.edu/sstrand/ From: David Schnare [mailto:[email protected]] Sent: Monday, February 02, 2009 9:04 AM To: Stuart Strand Cc: [email protected]; [email protected] Subject: Re: [geo] Re: Crop residue ocean permanent sequestration Stuart: I've been studying notill agriculture that relies, in major part, on building soil carbon to hold nutrients in the soil (reducing application requirements and keeping it out of streams). While a 14% sequestration (limited to only about 20 years before maxing out on sequestration potential) seems small compared to 100% if dumped into the ocean deeps, it seems to me that when used in places more than 150 miles from the ocean, it is carbon reduction efficient (based on fuels needed for transport). As such, shouldn't we be narrowing the crop waste discussion to coastal agriculture only, and give credit for soil sequestration where that's as good as is available? David Schnare On Mon, Feb 2, 2009 at 11:54 AM, Stuart Strand <[email protected]<mailto:[email protected]>> wrote: By straw we are referring to the stalks of agricultural plants, wheat stalks and corn stover. The water and nutrients were expended to grow the grain. Straw has a low nutrient content (C/N = ca 50/1). Presently straw is wasted by allowing it to decay on the soil surface (only 14% or less of the straw carbon is incorporated into the soil). A variety of processes are available to get energy out of crop residues, but they are limited by the poor specific energy of biomass. Our focus is how to efficiently remove Pg amounts of carbon from the atmosphere and permanently sequester it in the least environmentally harmful manner. = Stuart = Stuart E. Strand 167 Wilcox Hall, Box 352700, Univ. Washington, Seattle, WA 98195 voice 206-543-5350, fax 206-685-3836 skype: stuartestrand http://faculty.washington.edu/sstrand/ Using only muscle power, who is the fastest person in the world? Flying start, 200 m 82.3 mph! http://en.wikipedia.org/wiki/Sam_Whittingham Hour http://en.wikipedia.org/wiki/Hour_record 55 miles, upside down, backwards, and head first! From: [email protected]<mailto:[email protected]> [mailto:[email protected]<mailto:[email protected]>] On Behalf Of [email protected]<mailto:[email protected]> Sent: Wednesday, January 28, 2009 7:16 PM To: [email protected]<mailto:[email protected]> Subject: [geo] Re: Crop residue ocean permanent sequestration Stuart, Why bundle and stash terrestrial straw. Growing straw requires substantial fresh water and nutrients. You could bundle and stash algae instead. How about sargassum or kelp? A macro-algae can be bundled in large mesh "tea bags" with much of the water being squeezed out during the bundling process. Then, as long as you've got bundles of biomass, why not separate the nutrients from the carbon before you stash the carbon? That way, you can recycle the nutrients back to the ocean surface for growing more biomass. High-pressure anaerobic digestion will release the carbon in two separate streams; one gaseous CH4, one dissolved CO2, which easily converts to liquid CO2 at typical ocean temperatures and pressures. Would you or others be interested in a California Energy Commission grant to run a few bench experiments on high-pressure anaerobic digestion? I can send a draft abstract. <http://social.telematicsupdate.com/content/dynamic-carpooling-your-mobile> Mark E. Capron, PE Oxnard, California www.PODenergy.org<http://www.podenergy.org/> -- David W. Schnare Center for Environmental Stewardship --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~----------~----~----~----~------~----~------~--~---
