Comment by Panino | Hacker News Reader

Comment by Panino | Hacker News Reader

Parent Full thread

When Gabe Brown switched from conventional agriculture to regenerative agriculture, he increased water infiltration in his soil from 0.5 inches (1.25cm) per hour to 30 inches (75cm) per hour. So imagine if he and all his neighbors had the same beautiful soil -- flooding just couldn't happen.

I haven't seen a list of such measurements from permaculture, but I know it can be used to regreen deserts (as shown in Jordan, Saudi Arabia, Arizona and elsewhere). And I assume permaculture vastly increases water infiltration. Geoff Lawton has videos showing Zaytuna Farm happily surviving drought and flood alike.

If farmers switched from conventional agriculture to some combination of regenerative agriculture and permaculture, most flooding would be prevented. Their own fields would easily infiltrate rain, eliminating runoff that builds up into flooding.

The article mentions that in addition to Pakistan getting double the normal amount of rain, increased glacier melt is filling the Indus river. I assume that in the theoretical situation of all farmers in Pakistan practicing regenerative ag or permaculture, that land on the Indus would flood. But not 1/3 of the country as we're seeing now, and the flooded areas would recover faster.

Water infiltration is measured by digging a small hole, filling it with water, and seeing how fast it drains. There's no way that regenerative agriculture has changed soil composition multiple feet down, which is what would be needed for the soil to absorb multiple feet of water.

I went to check the above sentence, and the first hit was this detailed article from Washington State, which analyses Brown's claims in detail, and explains why the scientific community is skeptical of them:

https://csanr.wsu.edu/regen-ag-solid-principles-extraordinar...

Anyway, even if, as Gabe Brown claims, regenerative agriculture is an order of magnitude more effective than expected, and you applied it to 100% of the land in Pakistan, it would still only reduce flooding by less than a foot.

> . There's no way that regenerative agriculture has changed soil composition multiple feet down

How do you know that?

How deep do roots go? Do worms dig? Do you know?

I do not. But I am not making assumptions

Read the article I cited.

> Water infiltration is measured by digging a small hole, filling it with water, and seeing how fast it drains.

Informally yes, but the scientific way is to use a ring infiltrometer: https://www.fao.org/3/s8684e/s8684e0a.htm -- Basically instead of digging a hole, you pound a pipe into the ground and then fill the pipe with water.

As for agricultural practices being able to change soil composition multiple feet down, trees and tap-rooted plants are very effective at placing large volumes of organic matter at depth. One example, Lacy Phacelia (Phacelia tanacetifolia) is an annual plant that produces a dense fibrous root system that reaches a depth of 4 feet; in the fall the Phacelia plants die, and their roots decompose at depth, creating pathways for water infiltration while also increasing soil organic matter at depth. The same goes with other trees and shrubs. The farmer from the "It ain't much but it's honest work" meme, Dave Brandt, has some really enjoyable presentations on youtube about improving soil composition at depth.

Any link to read about this 0.5 - 30 inch/hr conversion? Cultivated soil or already wetted soil will absorb much more readily than not, was this a carefully controlled experiment? Anyway it would take some serious modelling not handwavy yes or no as to whether permaculture/regenerative techniques (and a well defined definition of success of mitigation) could work. I absolutely admit that it could help on the margins, but would it have really have changed the image featured in this comment: https://news.ycombinator.com/item?id=32692060 ? Is the supposition that this water would find its way to some aquifer?

> Any link to read about this 0.5 - 30 inch/hr conversion?

Read From Dirt to Soil by Gabe Brown. He also mentions the first inch (2.5cm) infiltrates in 9 seconds! So his soil drinks up more water in 9 seconds than nearby farms do in an entire hour.

> was this a carefully controlled experiment?

NRCS water infiltration tests.

https://www.nrcs.usda.gov

Living in similar conditions in Florida, I know at about 4 inches per hour on a plain, you're screwed. It floods badly. And we have excellent drainage systems.

Check out: Treating the Farm as an Ecosystem with Gabe Brown Part 1, The 5 Tenets of Soil Health https://www.youtube.com/watch?v=uUmIdq0D6-A

His neighbor's farm floods, his land soaks it up like a sponge.

Year-on-year his topsoil gets deeper.

Maybe even relatively simple but massive reforestation efforts could help mitigate climate change effects in the long run.

Forests are not very good carbon sinks except in the short run.

They have three problems when used as carbon sinks:

1) They tie up land for one, otherwise, non productive purpose (the wild species living in them do not mind that, must be said)

2) Once fully grown they reach a carbon balance. This can happen surprisingly quickly, a few decades.

2) Forests do not simply sit there like a rock. Eventually they will burn unless managed. Then they simply release all that stored carbon into the atmosphere.

Regenerative agriculture is a much better carbon sink. The process of storing the carbon increases the soil fertility so it is a win/win. Soils can get very deep so there is not a natural limit like for forests.

A draw back is measuring the carbon sunk. I do not know of anybody doing that (a market opportunity?). An important part of carbon farming is selling the "carbon credits" (a mad bad and sad idea, but it is a thing) to do that there must be an accepted measure of carbon sequestration, like there is for trees.

At least over here, trees grow for centuries. Big trees survive forest fires as well.

Not a short term carbon sink only.

Agree but don't forests do much more for weather events than being carbon sinks?

AFAIK they also create a more moderate micro climate, reducing soil temperature, retaining humidity and rain while keeping it in the soil, reducing the risk of draughts.

Of course regenerative agriculture is much better but the effort to implement it at a scale is incomparably greater, while it should not be shunned.

Also agroforestry will help with making agriculture possible in larger areas of land.

Gabe Brown's work is primarily on improving soil health, not on earthworks for flood prevention, aquifer recharge, etc. His gains in rainwater infiltration is a secondary effect of the steps he's taken to improve his soil.

In terms of projects whose primary aim is flood prevention / aquifer recharge, John D. Liu, Andrew Millison, and Geoff Lawton all have documented quite a few projects that have been very successful in addressing the problem.

naive q: does that still help if the aquifer gets saturated?

Is an aquifer ever likely to get saturated? I have no expertise in this area, but in the US at least the concern is always over aquifers being depleted, not so fully saturated that they can't absorb more water. My understanding was that it takes very long time for water to actually get from ground level down into an aquifer.

At some point the ground cannot accept anymore water, no matter what.

Proof: oceans exist.

The key to the whole thing is if you can slow it down enough so that a sudden deluge over a day/week/month has time to slowly drain out.

Getting water into an aquifer takes time depending on how the soil is, but eventually the aquifer would rise to the surface and you'd have a marsh. Or it would rise higher and you'd have a lake.

This depends entirely on where you live. Sure in the Southwest, there's a big problem with drought. But along the Gulf Coast, the water table is astonishingly close to the surface. When my family put in an in-ground pool in Louisiana, they had to start filling the concrete pool with water even before finishing it because if they left it empty, the surrounding water table would push it up out of the ground like a floating boat.

Yeah just imagine if a billion people completely changed their way of life.

I'm not sure if you're being sarcastic or not. Climate change is going to require changes of at least that scale, whether we reduce emissions or not.

Luckily for humanity that won’t actually be necessary.

In the next 20-30 years I suspect we’ll just moderate total solar irradiance as-needed by injecting moon dust into L1.

The only issue is if there are powerful countries that are actually benefiting from the warming and don’t want to cool it down bit.

Luckily for humanity that won’t actually be necessary because in the next 20-30 years we're likely to revert to savagery and barbarism, and "civilized" behaviors won't matter anymore (assuming one of our "leaders" doesn't do the epic stupid and get us all "nuked" out of existence).

Imagine if they don't.

I think that's pretty easy if government incentives are in place.

Reply on news.ycombinator.com