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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

#91

Post by tastyfreeze »

Not all rice needs to be grown in paddies. Paddies are primarily used for weed control as rice, as a water side plant, can tolerate root submersion where the competition can't. Some varieties do better than others as "dry land" rice. A perennial dry land rice would be a boon for small holders. A lawn could become a perennial food source.

I am currently working to adapt rice varieties to my temperate environment in a raised bed setting. Not having to use some of my harvested seed to replant would be awesome. The downside is you lose the ability to select for traits without ripping up your current plot.

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

#92

Post by insane_dreamer »

melling wrote: post #30
insane_dreamer wrote: post #25

Earlier quoted context omitted.

The need to eliminate coal emissions does not preclude the need to eliminate emissions from other sources.

I suppose if we didn’t wait decades to eliminate the big problems, we’d have more time to worry about the smaller problems. A 100 years of coal emissions is 1000 years of rice.

So ... all agriculture scientists should stop what they're doing and become clean energy scientists?

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

#93

Post by cmrdporcupine »

colechristensen wrote: post #19
seifertca wrote: post #14

Perennials are such an intuitively appealing idea but a plant expends a lot of energy ensuring it can make it through the fallow/winter season successfully. Thus perennial cereals only make sense where the cost of seed and planting exceeds the impact on yield. My understanding is even at the theoretical minimum energy needed for most cereals in most growing regions to have a 90% chance of surviving perennially you ne…

It’s hard to generalize but seed costs in the ballpark of 20% of revenue. That’s not counting tillage in preparation for planting, the cost of planting, or weed management which will be more difficult without established crops. In other words you can take a significant hit to yields and still come out ahead.

Without yearly tillage (or herbicide spray in case of no-till), weed mgmt is going to be tricky for perennial cash crops. It's certainly tricky for e.g. vineyards and orchards.

I suppose with rice (or kernza wheat) you could use a selective broadleaf herbicide. Doesn't help with invasive grasses.

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

#94

Post by ed25519FUUU »

tastyfreeze wrote: post #91

Not all rice needs to be grown in paddies. Paddies are primarily used for weed control as rice, as a water side plant, can tolerate root submersion where the competition can't. Some varieties do better than others as "dry land" rice. A perennial dry land rice would be a boon for small holders. A lawn could become a perennial food source. I am currently working to adapt rice varieties to my temperate environment in a…

If people want to grow food in lawn there are so many easier options than rice, such as a few large fruit trees.

It’s a cultural problem that lawns are just green spaces sprayed with 2,4-d, not a technological one.

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

#95

Post by nh23423fefe »

matthewdgreen wrote: post #55
xyzzyz wrote: post #45

Earlier quoted context omitted.

> So, perennial rice may end up reduce GHG emissions substantially. Not really. These GHG emissions from rice are in steady state with the amount of CO2 and methane in the atmosphere. They do not add additional GHG to the atmosphere the way burning fossil fuel do. When you burn fossil fuels, the carbon atoms released into atmosphere have been captured from the atmosphere millions years ago. When weeds and other organ…

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.

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

#96

Post by JumpCrisscross »

xyzzyz wrote: post #84
crazygringo wrote: post #74

Earlier quoted context omitted.

> but this is of no practical consequence, because the methane will not accumulate year over year, like the emissions from fossil fuels do. Methane still takes 12 years to break down in the atmosphere, and it's more than 25 times as potent of a greenhouse gas than CO2. CO2 concentrations are currently ~420 ppm, while methane is ~1866 ppb, or 1.9 ppm. If we assume methane is 25 times worse than CO2, that 1.9 ppm is th…

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.

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

#97

Post by xyzzyz »

littlestymaar wrote: post #56
xyzzyz wrote: post #53

Earlier quoted context omitted.

Methane is worse, but it again doesn’t matter here, because the fields are in steady state not only with CO2, but with methane as well. Methane doesn’t linger in atmosphere forever, it decomposes into CO2 in a decade or so. This means atoms of methane emitted from the fields are pretty much exactly paired with atoms of methane in atmosphere decaying into CO2. This means that methane emitted from the fields doesn’t in…

This reasoning is completely wrong: there's an input and an progressive decay as output, the amount of methane in the atmosphere at any given point is directly related to the input.

Yes, this is exactly what I say in my comment. The amount of methane in the atmosphere is directly proportional to the input rate. That’s why, as I said, in steady state, when the we keep steady the amount of rice under cultivation, the amount of methane in atmosphere is not changing over time.

Can you point to which part exactly is “completely wrong”?

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

#99

Post by maxerickson »

twawaaay wrote: post #37
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…

I am not convinced (I grew up on a farm). It is usually harder to get rid of any weeds when your crop is growing on the field. After harvest, you just get rid of everything, turn the soil (but I don't know anything about rice farming) and you kinda get a fresh start. ON THE OTHER HAND, we already have robots that can easily identify weeds with a camera and zap them with lasers or other shit. Which just seems so much…

It seems they are not gently collecting the individual grains of rice.

http://en.people.cn/n3/2021/1025/c90000-9911067.html

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

#100

Post by ericpauley »

ccooffee wrote: post #32
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…

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.
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