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Perennial rice: Plant once, harvest again and again

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Re: Perennial rice: Plant once, harvest again and again

#101

Post by jamiek88 »

twawaaay wrote: post #33

I know Chinese harvest their rice up to three times a year. I don't see how perennial rice could compete. Harvesting normal rice is just grabbing entire plants, as many as you can grab at a time. I may know nothing about how harvesting perennial rice is supposed to work, but I grew up as a farmer and I have imagination. You have to leave some part of the plant for it to keep growing crop which means you can't just gr…

Don't know about point one but for point two:

They got two harvests per year with slightly increased yield per hectare per harvest.

> produced grain for eight consecutive harvests over four years, averaging 6.8 Mg ha−1 harvest−1 versus the 6.7 Mg of replanted annual rice

Re: Perennial rice: Plant once, harvest again and again

#102

Post by xyzzyz »

JumpCrisscross wrote: post #96
xyzzyz wrote: post #84

Earlier quoted context omitted.

Thank you for redoing the math I did, and confirming I was exactly correct with figures. The increase in concentration is observable, but the impact on climate is not. Again: this increase is similar to increase between 2000 and 2020. Without extremely careful and precise measurements, nobody would really be able to perceive any difference in climate between these two dates. This matters, because it is the perceived…

> If the change is only seen on accurate scientific instrument, why should the society care much about it? It’s difficult to perceive this as anything but elaborate climate denial, given it works for any incremental progress towards lower emissions.

No, you missed the point: there is an enormous difference between methane emissions from fresh organic matter, and emission from fossil fuels. The latter accumulate, while the former do not. That’s why as we continue incrementally burning fossil fuels, the effects accumulate and affect climate over decades or centuries, but decaying weeds or (fashionable to discuss a couple of years back) cattle burps and farts do not.

The point is that even if it continues over the centuries, the effect of cattle farts and weeds decaying on rice fields will only ever be observable using precise scientific instruments, whereas effect of burning fossil fuels for centuries will be very readily perceivable with very crude techniques.

Re: Perennial rice: Plant once, harvest again and again

#103

Post by jamiek88 »

efitz wrote: post #46

My wife is from Thailand. My father in law is a rice farmer. I’m unclear about the definition of “subsistence”, because you need more than rice to live, but he grows more than they need to eat and sells the rest to eke out a living. The questions in my mind are: 1. How expensive would these perennial rice strains be (patents)? The cost would have to be ridiculously low by western standards for rural Thai farmers to a…

It actually helps retains soil nutrient including nitrogen.

>accumulating 0.95 Mg ha–1 yr–1 organic carbon and 0.11 Mg ha−1 yr−1 nitrogen

Re: Perennial rice: Plant once, harvest again and again

#104

Post by cyrusatjam »

nh23423fefe wrote: post #95
matthewdgreen wrote: post #55

Earlier quoted context omitted.

Methane and CO2 are very different things. The former has a massively greater warming effect than the latter, and takes long enough to degrade in the atmosphere that it can significantly affect warming times. If you aren’t paying attention to the rising methane levels in our atmosphere (and possible evidence of a feedback loop) with serious trepidation, you’re a lucky person who probably sleeps well at night.

> Serious people panic when I do. But you didn't address why you panic.

wrong thread?

Re: Perennial rice: Plant once, harvest again and again

#105

Post by yunohn »

chris_va wrote: post #18

(disclaimer that I manage a climate group, but not a rice expert) They touch on, but don't get into the details on one of the more interesting aspects of perennial rice. Rice fields are actually a huge emitter of methane. Depending on the accounting, they contribute as much to global warming as the aviation sector. The fields emit methane when flooded, the stagnant water gets oxygen depleted, and the biomass in the s…

Just for context, rice is nearly on the bottom of the list of methane polluters - orders of magnitude lower than meat and even things like coffee.

https://ourworldindata.org/carbon-footprint-food-methane

Re: Perennial rice: Plant once, harvest again and again

#106

Post by Aromasin »

ericpauley wrote: post #100
ccooffee wrote: post #32

Earlier quoted context omitted.

I hadn't heard about rice fields emitting methane before. I was able to quickly find an article, "Methane emissions from global rice fields: Magnitude, spatiotemporal patterns, and environmental controls"[0], which states: > Our study estimated that CH4 emissions from global rice fields varied from 18.3 ± 0.1 Tg CH4/yr (Avg. ±1 SD) under intermittent irrigation to 38.8 ± 1.0 Tg CH4/yr under continuous flooding in the…

To be fair, rice also provides ~20% of global caloric needs, so this isn’t necessarily an outsized contribution.

To put this into context, animal agriculture is responsible for 18% of the worlds CO2 emissions, uses 83% of the world's farmland, but only produces 18% of our calories and 37% of our protein.

Re: Perennial rice: Plant once, harvest again and again

#107

Post by billiam »

xyzzyz wrote: post #90
crazygringo wrote: post #59

Earlier quoted context omitted.

That doesn't make sense mathematically. Because you could start with zero methane in the atmosphere, just lots of CO2, but the rice would introduce methane. Eventually yes you can get to a steady state of methane, but the point is that the more rice there is, the higher that steady state becomes. Which is bad. So the total amount of methane would absolutely increase. (And if you stopped planting rice at all it would…

Yes, I discuss this in my comment here https://news.ycombinator.com/item?id=35483780 The point is, though, that the amount of methane that currently have in atmosphere, is only barely relevant when it comes to how it affects climate from human perspective. If all methane disappeared tomorrow, our climate would be back to 2010, which is hardy a significant change. Nobody would even notice other than climate scientists…

>our climate would be back to 2010, which is hardy a significant change.

Uh, no. It is quite significant, and a mountain of evidence says that the climate changes from concentrations in the last decade are very significant. You appear to be a denier of anthropogenic climate change who is willing to make silly straw men arguments.

Re: Perennial rice: Plant once, harvest again and again

#108

Post by NelsonMinar »

chris_va wrote: post #18

(disclaimer that I manage a climate group, but not a rice expert) They touch on, but don't get into the details on one of the more interesting aspects of perennial rice. Rice fields are actually a huge emitter of methane. Depending on the accounting, they contribute as much to global warming as the aviation sector. The fields emit methane when flooded, the stagnant water gets oxygen depleted, and the biomass in the s…

The Economist had an article this week about rice and global warming: https://www.economist.com/asia/2023/03/28/the-global-rice-cr...

Re: Perennial rice: Plant once, harvest again and again

#109

Post by colatkinson »

ccooffee wrote: post #20
eminence32 wrote: post #3

> They then spent years breeding for the desired traits until they landed on three new perennial varieties to test in the real world Good old-fashioned genetic engineering :)

Well, they've got fancy procedures in there, too: > So what our colleague Duyan Tao did - he, at an early stage, around 10 days after the [by-human-hand] pollination, went in there and dissected out the very young embryo that was developing and put it in tissue culture and gave it nutrients to help it grow. And then he rescued one of these seedlings. And that was the beginning of it. Also, the "old-fashioned genetic…

Ehh it's getting into pedantic territory as to what counts as directed vs undirected, but people figured out pretty quick that if you have an animal with a desirable trait you can breed it with others to maybe get offspring that also have that trait.

As an illustrative example, consider the fancy pigeon (see [0] for some pics). One of Darwin's original areas of study was to prove that these birds, many of which have cool-looking but incredibly maladaptive traits, were actually the same species as the pigeons you'd see on a London street. Prior to that, the scientific consensus was that these were fully distinct species -- i.e. the artificial selection happened so long ago that it was lost to time. Given some breeds have trouble even eating (e.g. look at the beak on this guy [1]), I think it's a pretty safe assumption that this breeding did not happen without careful human intervention.

That's not to say that the kind/degree of artificial selection we see in industrial agriculture isn't worlds away from older forms. Once you've got the basics of evolution and the scale of capitalist production, you're starting down the road to the current world of 100 pound antibiotic-riddled chickens in rows of 10000 cages. But humans have been selectively breeding animals for food, utility, or just because we kinda felt like it since time immemorial.

[0] https://en.wikipedia.org/wiki/Fancy_pigeon

[1] https://en.wikipedia.org/wiki/Oriental_Frill

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