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A field crop planted annually that grows faster or bigger isn't likely to make much of a difference to atmospheric CO2 as it will just release it again after ha

A field crop planted annually that grows faster or bigger isn't likely to make much of a difference to atmospheric CO2 as it will just release it again after harvest. Perennial plants (those that don't need to be planted each year) are better at sequestering CO2 in the soil, along with other benefits. The Land Institute does work on this, including developing (through traditional plant breeding) a perennial wheat variety which is being trialed [0]. There are other agricultural practices that promote CO2 sequestration in the soil. You might have a look at Project Drawdown, it ranks solutions to climate change based on impact and has a section on food [1] which includes agricultural solutions. For example, Silvopasture [1], ranked #9 overall amongst all solutions, involves integrating trees with livestock pasture. Another one is conservation agriculture (#16) which uses annual crops but promotes soil health in selection of species and method and timing of planting [3]. [0] https://landinstitute.org/our-work/perennial-crops/ https://landinstitute.org/our-work/perennial-crops/ [1] https://www.drawdown.org/solutions/food https://www.drawdown.org/solutions/food [2] https://www.drawdown.org/solutions/food/silvopasture https://www.drawdown.org/solutions/food/silvopasture [3] https://www.drawdown.org/solutions/food/conservation-agriculture https://www.drawdown.org/solutions/food/conservation-agricul...

mrfusion 8y ago
Why can’t you take all the leftover biomass after a harvest and sequester it? Then it wouldn’t “simply relaase it”. I’d image we only take a small part of the mass for food.
- Maximus9000 8y ago
  for which crop? most of the leftover biomass is used in typical crops. For corn, the stalks are used as silage. For wheat, the stalks are used to make straw.
  - weberc2 8y ago
    > For corn, the stalks are used as silage. How common is this? In my area, the combines chew up the stalks and spit them out as chaff. I don't see many people collecting the chaff.
    - Maximus9000 8y ago
      Not sure. The dairy farm I worked at used the corn stalks. They make a product called "silage" which can be used as winter feed for the cattle.
      - weberc2 8y ago
        Curious. My neighbor was a dairy farmer. They did this too. No one else though.
        Juggerbot 8y ago
        It can depend on the price of fodder. If hay is cheap, there's not much incentive to spend time/fuel on baling stalks. However, if they're not baled, they decompose in the field, which technically reduces fertilizer inputs.
  - pohl 8y ago
    I was under the impression that, in the case of corn at least, harvesting for silage or for grain was an either/or proposition. That is, if the crop is struggling and you don’t expect much yield as grain, then you might want to harvest it for silage to cut your losses. (I’m not a farmer, but I literally grew up in Podunk, Nebraska — a farm-adjacent village.)
  - thinkharder 8y ago
    That's what is known as 'feed corn' and is grown specifically as livestock feed. The specific strains of corn are optimized for producing maximum plant material, which is mostly stalk and leaves. A field of feed corn plants will usually be very tall, 8-15 feet. In contrast a field of sweet corn (grown for human consumption and possibly for processing into other foods), will be much shorter, since it's optimized to produce the most, largest and highest sugar content corn kernels, and any energy the plant spends to grow a tall stalk is wasted. Feed corn is harvested with big combines that just cut down the whole plant at ground level and chop everything up. The results are piled up and left to ferment. Once fermented, you have silage. I'd be surprised to learn anyone was harvesting sweet corn and saving the waste material to make silage. The equipment isn't designed to keep that stuff it just gets dumped back onto the field. And those strains of corn don't produce very much plant material since they're optimized for small plants and big cobs. Additionally you'd have to load all the waste material into trucks, which would significantly raise the cost of harvesting. And dumping that stuff back onto the field is a good thing, it helps keep the dirt down for the winter and decomposes into usable nutrients and fibrous material which helps reduce compacting, etc. It'd be expensive and labor intensive to try to capture the waste material from feed corn. It's easier and more economical to just plant feed corn or buy silage. You're right about straw, though. The harvesters are specifically designed to leave the straw in row pile behind them. Then you run a baler over that and it leaves a row of straw bales in the field. Then you run a stacker over that (or a flatbed trailer and buck 'em by hand) and you have a haystack.
- weberc2 8y ago
  Pretty sure this is more or less what no-till farming does; hopefully someone more knowledgable can weigh in and confirm or correct me.
- thinkcontext 8y ago
  We haven't really figured out sequestration even from extremely CO2 rich sources like power plants. To do it w/ organic field waste you'd have to collect it all, send it somewhere and process it. In terms of sequestration bang for the buck (cost per ton) that sounds like it would make it low down on the list of priorities.
  - nanomonkey 8y ago
    Actually we've know how to do carbon sequestration for plant matter for quite some time. The resulting biomass can be gasified and remaining carbon is turned into biochar which is inert in the soil for thousands of years. Not only is it a viable process, it's a fairly decent energy source which makes it cost productive.
    - FlyMoreRockets 8y ago
      This can be done using solar energy and a parabolic trough. Auger feeds ground biomass in one end, the other end gets biochar, water vapor and a range of fractions, from methane to tars. Methane and the tar can both be burned to power the auger and other processes, though the methane is easier to work with.
- WhompingWindows 8y ago
  If you sequester biomass incorrectly, like burying it underground tightly with no oxygen, you could have further emissions due to microbes digesting plant matter into methane, which is a worse GHG than CO2
- manicdee 8y ago
  Replanting all the forests in the world that have been cut down will only replace all the firsts in the world. Eventually we run out of room for new forests. The major battle in combating AGW is the quantity of carbon we have dug up from the ground and released into the environment.
Maximus9000 8y ago
I'd think bamboo production would be a good candidate for this https://www.drawdown.org/solutions/land-use/bamboo https://www.drawdown.org/solutions/land-use/bamboo

mrfusion 8y ago

Why can’t you take all the leftover biomass after a harvest and sequester it? Then it wouldn’t “simply relaase it”. I’d image we only take a small part of the mass for food.

Maximus9000 8y ago
for which crop? most of the leftover biomass is used in typical crops. For corn, the stalks are used as silage. For wheat, the stalks are used to make straw.
- weberc2 8y ago
  > For corn, the stalks are used as silage. How common is this? In my area, the combines chew up the stalks and spit them out as chaff. I don't see many people collecting the chaff.
  - Maximus9000 8y ago
    Not sure. The dairy farm I worked at used the corn stalks. They make a product called "silage" which can be used as winter feed for the cattle.
    - weberc2 8y ago
      Curious. My neighbor was a dairy farmer. They did this too. No one else though.
      - Juggerbot 8y ago
        It can depend on the price of fodder. If hay is cheap, there's not much incentive to spend time/fuel on baling stalks. However, if they're not baled, they decompose in the field, which technically reduces fertilizer inputs.
- pohl 8y ago
  I was under the impression that, in the case of corn at least, harvesting for silage or for grain was an either/or proposition. That is, if the crop is struggling and you don’t expect much yield as grain, then you might want to harvest it for silage to cut your losses. (I’m not a farmer, but I literally grew up in Podunk, Nebraska — a farm-adjacent village.)
- thinkharder 8y ago
  That's what is known as 'feed corn' and is grown specifically as livestock feed. The specific strains of corn are optimized for producing maximum plant material, which is mostly stalk and leaves. A field of feed corn plants will usually be very tall, 8-15 feet. In contrast a field of sweet corn (grown for human consumption and possibly for processing into other foods), will be much shorter, since it's optimized to produce the most, largest and highest sugar content corn kernels, and any energy the plant spends to grow a tall stalk is wasted. Feed corn is harvested with big combines that just cut down the whole plant at ground level and chop everything up. The results are piled up and left to ferment. Once fermented, you have silage. I'd be surprised to learn anyone was harvesting sweet corn and saving the waste material to make silage. The equipment isn't designed to keep that stuff it just gets dumped back onto the field. And those strains of corn don't produce very much plant material since they're optimized for small plants and big cobs. Additionally you'd have to load all the waste material into trucks, which would significantly raise the cost of harvesting. And dumping that stuff back onto the field is a good thing, it helps keep the dirt down for the winter and decomposes into usable nutrients and fibrous material which helps reduce compacting, etc. It'd be expensive and labor intensive to try to capture the waste material from feed corn. It's easier and more economical to just plant feed corn or buy silage. You're right about straw, though. The harvesters are specifically designed to leave the straw in row pile behind them. Then you run a baler over that and it leaves a row of straw bales in the field. Then you run a stacker over that (or a flatbed trailer and buck 'em by hand) and you have a haystack.
weberc2 8y ago
Pretty sure this is more or less what no-till farming does; hopefully someone more knowledgable can weigh in and confirm or correct me.
thinkcontext 8y ago
We haven't really figured out sequestration even from extremely CO2 rich sources like power plants. To do it w/ organic field waste you'd have to collect it all, send it somewhere and process it. In terms of sequestration bang for the buck (cost per ton) that sounds like it would make it low down on the list of priorities.
- nanomonkey 8y ago
  Actually we've know how to do carbon sequestration for plant matter for quite some time. The resulting biomass can be gasified and remaining carbon is turned into biochar which is inert in the soil for thousands of years. Not only is it a viable process, it's a fairly decent energy source which makes it cost productive.
  - FlyMoreRockets 8y ago
    This can be done using solar energy and a parabolic trough. Auger feeds ground biomass in one end, the other end gets biochar, water vapor and a range of fractions, from methane to tars. Methane and the tar can both be burned to power the auger and other processes, though the methane is easier to work with.
WhompingWindows 8y ago
If you sequester biomass incorrectly, like burying it underground tightly with no oxygen, you could have further emissions due to microbes digesting plant matter into methane, which is a worse GHG than CO2
manicdee 8y ago
Replanting all the forests in the world that have been cut down will only replace all the firsts in the world. Eventually we run out of room for new forests. The major battle in combating AGW is the quantity of carbon we have dug up from the ground and released into the environment.

Maximus9000 8y ago

I'd think bamboo production would be a good candidate for this https://www.drawdown.org/solutions/land-use/bamboo https://www.drawdown.org/solutions/land-use/bamboo