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extremely dry soil becomes compact and hence tends to be hydrophobic. If you have houseplants and you're irresponsible like me, you'll notice this phenomena on a small scale in flowerpots.
Not a meteorologist, I'm a Botany student in my third year of my bachelor's degree.
Hobbyist gardener and I can attest to this too! Dry soil is so much harder to water and it’s way more likely the water will sit on top for a good amount of time before soaking through, you have to sort of fluff it up or completely till the soil in order to water it thoroughly after a dry spell
I was taught that if a houseplant had dried out, put an ice cube on it for a day or two, then water as normal. The ice drips on it slow enough so that the water doesn't run off.
Careful to not freeze the roots. Most houseplants have root systems that are sensitive to temperature change.
A good soak usually works to rehydrate the soil.
Unless your indoor temperature is really low, this won't do much. In 72F temperatures, an average ice cube will melt in just a few minutes. Source: my dog playing with ice cubes in the summer.
Dry dirt is insulation. If the houseplant is not in direct sunlight, the ice will last 30 min to an hour. Still that's slow enough to make a difference.
Thrown another ice cube on it later on that night or the next morning, and you are good the following day.
I know that from watering indoor plants. I add a little water first. Once the soil gets wet, it just sucks in the second pour. Otherwise if you do a big pour right away the water may overflow down the sides.
Tilling actually can damage the roots and the mycorrhizal bonds in the soil which can take months to repair. You're better off submerging the entire pot for 5-10 minutes and then draining it
Edit: I realize you're talking about outside. Yeah it takes persistence.
Good. The world needs more people with degrees in Botany. I have undergrad and PhD degrees in botany/plant ecology/evolution and am a prof at a large state university where I teach a variety of courses related to those things. I agree with everything you said; however, this visual is fundamentally flawed. It's hard to know how much water in the first two cups is simply leaking out between the grass and soil thanks to a less than optimal seal between the cup and soil. Can't tell because it's hidden by grass.
Yup. Maybe just trim the grass to ground level. Of course if we're only interested in the effects of soil moisture, independent of the presence of plants/roots, just three containers of soil with varying levels of moisture might do.
Around military towns (did my obligatory 4 years and decided to stay in the town) there are a couple of shops that repair shoes/boots. Being in the south as well a lot of "cowboys" get expensive boots and have repairs done on a $300 pair of boots rather than buying a new pair. I would only buy military approved boots that had replaceable souls so I could just drop off two pairs at the shop and have a 3rd to wear in the meantime. I got to save my annual clothing allowance for beer/video games instead of getting another $140 pair of Rocky's.
Yup. When my potted plants get too dry, I set the entire pot in a bucket of water and let it soak. Aside from the hard, dry soil not absorbing the water very well, it also has shrunken away from the pot, leaving an air gap that your water will run down and out the drain without even affecting the soil.
Anyone saying that the cup on the right is bullshit has never lived in a desert. The ground ends up being dirt dried into damn near concrete that water just beads off of. We have washes that turn into raging rivers for a day after summer monsoons. Shit isn't a joke lmao
You also see this if you have succulents/cacti. They don’t get water very often, so the dirt becomes really compact and almost hydrophobic. You have to “bottom soak” their pots for 15-30 minutes to get water in.
If you’re only sticking holes in a quarter inch or so, roots shouldn’t be disturbed, especially if you normally bottom water. Roots should be deep not wide.
Im with you tho id rather bottom wayer
Yeah, I just figure that you’d need to absolutely decimate that soil if you wanted to aerate it when it’s so compact it’s hydrophobic, so you’d need to skewer it a shitload and you’d 100% be damaging roots. Easier to just bottom water every now and then
\* Also, you don’t want to shallow water regardless. You always want the water to go down deep and not hang around the top, because otherwise you end up with shallow roots. If you’re not going to skewer all the way down to the bottom then you’ve wasted the skewer and your time, and you’ll have to soak it anyway.
Nah, that's never been the case for me, it finds little tunnels down to the bottom and drains out the drainage holes, but if you dig around after 90% of the soil is still bone dry.
It's one of the reasons you know it's time to soak or replace with better soil when your pot is draining super fast - none of it is actually soaking into the soil.
Tried this approach, and the root/stalky part right where it went into the soil straight up rotted. That's why I started with the chopstick in the first place.
Thats why more people drown in the desert than die of dehydration.
Never ever camp in an empty river bed. It could rain a hundred kilometers away and the flash flood can kill you...
In the southwest, we call them "arroyos"; I think it's a shortening for "arroyo seco", dry creek.
But dry creeks don't stay dry. There's a region in North Sacramento County called 'Dry Creek', not far from McClellan Park. The area flooded so many times that the city bought the land and razed the houses, making it into a park. They got tired of helping people rebuild in those locations over and over and over again.
The areas surrounding Sacramento also have levees. A weakness in the levees can cause water to bust through, flooding everything on that side.
Long ago, a few asshole farmers used to bore their own pipes through the levee to steal more water than was allotted to them. 50+ years later, though the pipes were blocked off, the weakness they introduced, during times of high flooding would cause those places to breach. Suddenly there'd be water pouring through what seemed to be an otherwise solid levee. Then they examined and found the old bored-through pipe, stopped off but still weakening the structure.
So a dry area, followed by heavy rain, exacerbated by asshole farmers from 50+ years ago introducing weaknesses into the levee, led to massive flooding around the Sacramento areas. For a change the rich people in Rancho Murieta were also flooded out, instead of just the poor folks around Rio Linda and Del Paso Heights.
I remember walking along a narrow paved canal that replaced a former empty river bed (arroyo) in a city. There was a heavy monsoon a bit away & about 3cm/1inch of floodwater was flowing through it.
All of a sudden, a 40cm/1.3ft tsunami came charging at the speed of a car (in the suburbs) & that water flow kept rushing through at the same height for about 20 minutes. Anything living along that arroyo would've been killed easily by it.
They're also called washes if you live in the US southwest.
I worked at a plant nursery and this was common if the dirt in a pot got too dry. It would become hydrophobic and you would have to water the shit out of it before it would start to take water.
My dumb ass filled in a hole in ny yard with peat moss, because it looked nutritious lmao. I could NOT get that shit to get wet. The water zipped between the particles and shot into the deep hole.
Question. If counties used an aerator after a drought, would it help water get into the ground and not create a flood? Guess that would be a lot of ground to cover, but interested in the science nonetheless.
I was going to say that any serious gardener is familiar with dry peat moss.
Peat moss is down-right hydrophobic until it gets soaked. Peat moss is very often a component of potting soil (for water retention - ironically), so thats why dry soil is a bitch to rehydrate in a well draining pot.
I mean you could give them an example to try. Best one if you're a guy, go piss in the dirt and watch it stay in a raised puddle, when you have to pee again, pee in the grass and watch it stream out
Dude they make devices so us women can pee standing up. Totally contains the spray. You can grab one on amazon for like $10. It has made hiking and camping so much better for me.
You give it a couple arm flicks and it sheds all the pee. Put a tiny blast of water down it from you bottle if you want to be super clean, but it doesn't hold the pee and the outside is always dry.
I worked with an excavation company for a bit. Before we would leave the job site or before a storm we would use the roller to essentially seal the dirt. Water runs off of rolled dirt, and loose dirt becomes a mud pit. Extremely dry conditions gets the same compacted seal on the surface.
Also anyone who has lived with dormant grass knows there'd be more air gaps under the cup since the twiggy stems are more tough, sparse, and tubular than the blades. The dirt literally does not want to drink.
I went to Vegas once when it poured for about 45 minutes and the casino floors flooded and every time I tell the story no one believes me.
Not the entire casino but the parts close to the strip as anyone who's been there would know the downs and ups relative to the street.
Living in Vegas currently, where it's "monsoon season" right now. [Here are photos from this past week](https://www.reviewjournal.com/local/local-nevada/death-valley-before-and-after-flooding-as-seen-from-space-photos-2620480/).
Might be paywalled, fyi.
This is basically every time there is a large storm in Arizona. Most of the ground is super dry, and therefore very compact. The water can’t move through the compacted soil, and just about every major rainstorm we get, it comes with its complementary flash flood warning
It's tragically ironic. Happens in Yemen too - one of the most hyper arid countries in the world, currently being bombed by Saudi forces due to a revolution after the previous mass uprising didn't lead to any real change.
They had like one hurricane in recorded history in 1800s, then got one in 2011 that dropped a **decades worth of rain**.
Water security out there is a huge issue, there's a need to switch to drip irrigation from flood irrigation, as well as create community management of water usage - since rich people can just dig deeper into the well.
This huge issue that's largely responsible for most of the struggle, needing water - and then when it happened it destroyed all their crops (which, farming was like 30% of employment).
One hurricane after 200 years. So much rain, unbelievable levels of destruction.
Then the same thing happened a week later.
Oh man. One time I made the mistake of "staying high" during an AZ monsoon which happened to be a road that sat between two mountains. Biiiiig mistake.
This should be obvious to anyone who has ever had a houseplant and failed to water it.
Damp soil in the pot accepts watering pretty quickly.
If you've waited until the leaves are wilting and the soil has dehydrated to the point of contracting away from the edges of the plant's container and you pour water in, the water runs off the surface, down the sides, overfills the catch bowl and just makes a general mess because of surface tension. The water refuses to soak in. It's like the natural hydrophobic coating on fuzzy leaves. It has to break through to start being absorbed all the way down the soil layer. That's why you pour a little water on the plant, then more as the soil can accept it.
Rainstorms dump a lot at once, so that "fuzzy leaf" effect on the soil is dramatically multiplied to the point of a flash flood.
Yes the grass may change the result a little, but anyone who’s had houseplants should understand what’s its showing.
When I water my herbs daily I just pour water into the top of the pot and it Permeates throughout the soil. When I water my cacti once a month or less I take the pot of hard dry soil and put into a larger pot filled with water and leave it for a couple of hours before the water permeates to the dry soil in the middle.
If the U.K. has heavy rainfall now there will be severe flooding as the ground cannot absorb water quickly.
I garden in the south and maintaining hydration is an interesting battle. Many great parts of soil can actually become hydrophobic when they dry out and they won't hold water until they've had time to soak. I literally do a small pre watering before I water on the hot dry days so the soil will more easily absorb the water.
I question the scientific method here. The first two have a bulk of grass that's preventing the cup from sitting flat and thus allowing air to enter. The third one seems to sit flat on the earth and there's a vacuum created that would slow the flow of the water.
Honestly, if they were to pick up that last cup and the end of the video, it would show that the water would just bead and lay there in a puddle before being absorbed. I think that would have been a better visual for everyone.
The actual commonly practiced scientific method is to use a cylinder infiltrometer, which is literally a slice of metal pipe which you hammer in the ground, add water to and measure infiltration over time. It would not have been hard to acquire such material and it still would have been easy to see and interpret, e.g., hammer a 15 cm diameter cylinder in the ground and dump in a half liter of water, see how long it takes to drain. There are methods that are more accurate (using 2 cylinders or a rainfall simulator), but that would get the point across.
You're right, it's an open cylinder and it doesn't protrude very high above the ground. A half liter in that volume should be only an inch/2.5 cm of water. Very easy to stick a camera over it.
It's an illustration of something already known to be correct, not a scientific experiment.
The end result correlates exactly with what we know happens in practice, via rigorous research, so it doesn't really matter why the illustration worked out, as long as the point is correct, which it is.
This was my first thought too, but think about it: if you have a yard that looks like the first two pictures, what will that yard look like after a heavy drought? ... If the drought is strong enough to kill your plant life, you're going to end up with the picture in the far right.
Sure, but you’re not planning on upturning cups of water so that bit is irrelevant. The question is how does soil absorb water in each condition and this ‘experiment’ is pretty useless at demonstrating that.
In that case, think of potted plants. When the soil has a slight dampness, water poured on it will absorb readily. When the soil is bone dry, the water will just bead on top of it and take a long time to be absorbed
Edit: spelling
The point isn’t that the right scenario is a bad depiction of drought (you’re right: it’s what dry land would look like). The point is that the flat ground against the cup creates more of a vacuum that makes it harder for water to escape. The test should probably be done with open cylinders, so vacuums can’t form
Even with open cylinders, the left and middle cups are both resting more on top of the grass, so the liquid is seeping through the large gaps in the grass. Cylinders would need to be weighted down enough to ensure they were all as close to the actual soil as possible.
If the grass on the far right hand side was long when it died and the cup was on top of it, the cup would also drain quickly if it's not more flush with the ground.
If they wanted to do this experiment using just the transparent cups, the most accurate way would be to have them all standing directly on three different samples of soil.
Dry dirt doesn't take on water. Wet dirt does.
Take a houseplant that hasn't been watered in 2 weeks. The soil absorbs none of the water. The water goes straight through.
When there's nowhere for the water to go, no cracks in the soil, the water will stay right there.
Yeah that's not being questioned here what's correctly being questioned is the method of demonstrating it. Which is absolute garbage.
Bad experimental methods don't invalidate a hypothesis they just mean the results are garbage.
Copied this from someone else:
It seems less like they were trying to conduct an "experiment" than provide a simple visual demonstration that laymen could take in and understand.
We already know dry dirt doesn't absorb water well, so a tightly controlled experiment isn't necessary. This is a pretty decent attempt at communicating information to the general public.
From what I am gathering here the point of this is qualitatively educate people on the difference in water absorption of the soil, not quantitatively. It's meant to display the general idea, which is sound and backed by scientific experimentation and data that the public could look into if they were so inclined.
To me this is a clear and concise demonstration that really gets the point across.
There is definitely no vacuum, you can clearly see big air bubbles move up as soon as the plastic bag is pulled away (and after that as well, just a lot slower).
Also there wouldn't then be such a stark difference between wet grass and normal grass.
What he's saying is the test is to demonstrate how fast and well soil can absorb water. If the cup is just letting water out and spread because it isn't firmly against the soil because its ontop of grass it's not really testing the soil absorption
Rain doesn't fall in upside-down plastic cups that seal to the surface when they hit the ground...
The left video compared to right video is like shotgunning a beer vs. trying to drink from a bottle with your lips sealed around it.
its not porosity its how water interacts with saturated vs. unsaturated media. capillary forces act against the downward migration of water when the soil is unsaturated. its kinda like lubbing the soil up if its already wetted
>There are gaps between the blades of grass and the cup
This was my first thought too. "Of course it's going to seap through the blades of grass better than a flat surface!"
*But*! It still can be a good visual aid when explaining floods after heavy droughts. A heavy drought can cause heavy loss of plant life; if you normally have a yard that looks like the 2 left pictures, a drought *can* leave you with the far right scenario, thus (as the video shows) leaving you at risk for flooding in your yard.
I would be interested to see a similar video where they put the cups on dirt/soul in the left two videos to see what difference that makes.
Came here to say this. In fact, if you play the video in fast-motion you can really see the two cups on the green grass being forced up, allowing even more water out/air in.
But this is a bit misleading. You’re witnessing a vacuum difference as the thicker grass allows more air into the cup so water can escape while the drier, compacted earth does not allow as much. Remember, even with the soil soaking up the water, it still has to be replaced with air.
Well it is all on a patch of gras, don’t think you will find gras like on the left in the current heatwave in Europe unless sonebody either watered it a ton or it is fake
We had quite a drought this past month in Minnesota. A good 2" rain was predicted for this past weekend, so I got out and sprinkled my lawn well the day before to get it prepared.
The way I think of it is that a damp sponge will soak up water much faster & better than a dry sponge. But I love this demonstration!
I live in the desert southwest of the USA, let me tell you something, there’s no such thing as “might” flash flood after heavy drought, no matter what your soil composition. Once the ground goes hard pan, be aware at all times of where you’re at and what the weather is doing, especially upstream.
The cup on the left is being held up by the grass, so the water pours out. And the cup on the right makes a seal with the dirt, so no air can replace the water.
But then the middle cup fucks up my whole theory.
This isn't scientific at all. The cups in the grass will allow air in and water out, while the cup on the dry patch will have a more effective seal against the ground, trapping the water inside for a longer time.
EDIT: The point that's being demonstrated is in fact true. Moist soil absorbs water much better than dry soil, but this demonstration is a very poorly executed example of this fact.
Better demo would be using a glass/plexiglass tank with soil in different states, like regularly watered, moist but not saturated and dried out completely. So no grass is in the way letting air in and water out.
Everyone over here like "It isn't accurate wwwwah" It's accurate enough to show what basically happens. It's showing there's a difference, not writing a dissertation, jesus.
Lol, I did this with my 8-9 year old elementary classroom.
Predict, Observe, Explain.
The dry dirt soaked up the least and I tricked them all.
Muahahah.
Edit: I had the dirt in the cup and then they put the water in. You can submerge chunks of dry dirt and it'll stay dry in the middle even after 5 minutes, it absorbed almost nothing.
The dead grass is flatter than the green grass, it forms a better seal around the plastic cup, this is a factor that is being overlooked.
A lot of the water from the first two cups is travelling sideways, not downwards, because of a bad seal
maybe a dumb observation but if you have a thick grass water will escape to the sides not into the ground. the flatter the surface the more sealed the cup is
I'm sure the gaps at the bottom of the cup caused by grass has absolutely nothing to do with it. Yes the dry dirt is hard packed, but the other 2 cups don't have the same seal to the ground.
Instead, he should have all 3 surfaces flat and free of grass - just dirt.
It doesn’t quite demonstrate what it says it does: the grass on the left and in the middle prevent the glass from making a good seal, so the water is spreading out on the ground. The baked soil on the right does make a seal, and yes, there’s a resistant layer on top that prevents water from being absorbed very quickly.
If you did the same experiment but removed the grass first, the difference is speed between the three options would be much lower, but still pretty different.
(source: I do timed percolation tests in various kinds of soil for determining soil quality for agriculture.)
Same. But it makes sense when you think about it. The ground is hard; no matter how "thirsty" the soil may be, it's difficult for hard soil to absorb water.
I've seen it with potted plants: normally, the soil stays soft from watering it everyday and the water gets absorbed immediately, but if I've just come home from a trip and it's near dying, I have to be careful as I water it because the soil is dry and hard and the water will pool up in the pot as it takes longer to absorb it.
Wow, a picture or in this case video really is worth a thousand words. Many years ago one of our offices is Las Vegas had to close down because of flash flooding due to a very small amount of rain compared to our daily thunderstorms in Florida. I made a joke about how little rain they got yet had flooding…I now feel very silly. Great video.
HI IM GONNA PRETEND THIS IS COMMON KNOWLEDGE BECAUSE I LEARNED IT FIRSTHAND WHILST GROWING CANNABIS
*SOIL/MEDIUMS BECOME EXTREMELY HYDROPHOBIC AFTER DRYING OUT TOO MUCH, YOU CAN DAMAGE YOUR ROOTS VERY BADLY AND UPROOT THEM TO A DEGREE FROM THIS.*
This is obviously totally true but I feel like this experiment had a bit of error that could have been corrected.
The well watered ground has healthy grass in it. That grass stands up and creates an air pocket around the edges of the cup letting it run out pretty quickly, not just soak into the ground. The dead grass on the dry ground doesn't hold the edges of the cup up so it has to soak into the ground to escape.
More incentive for farmers to reduce their use of tillage and grow more perennial/cover crops. The roots act as channels to improve water infiltration, helping the whole system become more drought resistant. The continuous canopy also keeps the soil surface cooler and softer, aiding even more in water infiltration.
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extremely dry soil becomes compact and hence tends to be hydrophobic. If you have houseplants and you're irresponsible like me, you'll notice this phenomena on a small scale in flowerpots. Not a meteorologist, I'm a Botany student in my third year of my bachelor's degree.
Hobbyist gardener and I can attest to this too! Dry soil is so much harder to water and it’s way more likely the water will sit on top for a good amount of time before soaking through, you have to sort of fluff it up or completely till the soil in order to water it thoroughly after a dry spell
I was taught that if a houseplant had dried out, put an ice cube on it for a day or two, then water as normal. The ice drips on it slow enough so that the water doesn't run off.
Huh. I'll have to try this for some of my poor plants.
Careful to not freeze the roots. Most houseplants have root systems that are sensitive to temperature change. A good soak usually works to rehydrate the soil.
Can also let them butt-chug
Love butt chugs
Or just stick your finger in the pot and punch some holes around the base of your plant and then water it.
But buy it dinner first at least
Or you can just soak it in water and be done in 10 minutes.
Or just look it right in the stamen to assert dominance and then pee on it.
Unless your indoor temperature is really low, this won't do much. In 72F temperatures, an average ice cube will melt in just a few minutes. Source: my dog playing with ice cubes in the summer.
Dry dirt is insulation. If the houseplant is not in direct sunlight, the ice will last 30 min to an hour. Still that's slow enough to make a difference. Thrown another ice cube on it later on that night or the next morning, and you are good the following day.
I know that from watering indoor plants. I add a little water first. Once the soil gets wet, it just sucks in the second pour. Otherwise if you do a big pour right away the water may overflow down the sides.
Tilling actually can damage the roots and the mycorrhizal bonds in the soil which can take months to repair. You're better off submerging the entire pot for 5-10 minutes and then draining it Edit: I realize you're talking about outside. Yeah it takes persistence.
Good. The world needs more people with degrees in Botany. I have undergrad and PhD degrees in botany/plant ecology/evolution and am a prof at a large state university where I teach a variety of courses related to those things. I agree with everything you said; however, this visual is fundamentally flawed. It's hard to know how much water in the first two cups is simply leaking out between the grass and soil thanks to a less than optimal seal between the cup and soil. Can't tell because it's hidden by grass.
One way you could maybe account for that would be to clear the grass in an area, but then that would also mess up the soil a bit.
Yup. Maybe just trim the grass to ground level. Of course if we're only interested in the effects of soil moisture, independent of the presence of plants/roots, just three containers of soil with varying levels of moisture might do.
You're a botany student who let's their houseplants die?
Irresponsible botanist, no one said they were good at what they do.
Have you ever seen an auto mechanic's car?
Or a cobbler's children's feet?
Do cobblers even exist anymore?? lol
Not sure. I'm guessing somewhere in the world there exists a cobbler.
Around military towns (did my obligatory 4 years and decided to stay in the town) there are a couple of shops that repair shoes/boots. Being in the south as well a lot of "cowboys" get expensive boots and have repairs done on a $300 pair of boots rather than buying a new pair. I would only buy military approved boots that had replaceable souls so I could just drop off two pairs at the shop and have a 3rd to wear in the meantime. I got to save my annual clothing allowance for beer/video games instead of getting another $140 pair of Rocky's.
Yup. When my potted plants get too dry, I set the entire pot in a bucket of water and let it soak. Aside from the hard, dry soil not absorbing the water very well, it also has shrunken away from the pot, leaving an air gap that your water will run down and out the drain without even affecting the soil.
We have no space for hydrophobia in 2022!
Use warm/hot water on hydrophobic soil to increase the absorption :) i do this for my potted plants i forget about
Anyone saying that the cup on the right is bullshit has never lived in a desert. The ground ends up being dirt dried into damn near concrete that water just beads off of. We have washes that turn into raging rivers for a day after summer monsoons. Shit isn't a joke lmao
You also see this if you have succulents/cacti. They don’t get water very often, so the dirt becomes really compact and almost hydrophobic. You have to “bottom soak” their pots for 15-30 minutes to get water in.
Or just poke it with a chopstick so that it aerates and can be top-watered...
Eh i don’t like breaking the roots if I can avoid it, especially for the biggest and smallest plants
If you’re only sticking holes in a quarter inch or so, roots shouldn’t be disturbed, especially if you normally bottom water. Roots should be deep not wide. Im with you tho id rather bottom wayer
Yeah, I just figure that you’d need to absolutely decimate that soil if you wanted to aerate it when it’s so compact it’s hydrophobic, so you’d need to skewer it a shitload and you’d 100% be damaging roots. Easier to just bottom water every now and then \* Also, you don’t want to shallow water regardless. You always want the water to go down deep and not hang around the top, because otherwise you end up with shallow roots. If you’re not going to skewer all the way down to the bottom then you’ve wasted the skewer and your time, and you’ll have to soak it anyway.
Saving this tip.
or just let the water sit on top and it will soak in eventually
Nah, that's never been the case for me, it finds little tunnels down to the bottom and drains out the drainage holes, but if you dig around after 90% of the soil is still bone dry. It's one of the reasons you know it's time to soak or replace with better soil when your pot is draining super fast - none of it is actually soaking into the soil.
Tried this approach, and the root/stalky part right where it went into the soil straight up rotted. That's why I started with the chopstick in the first place.
“Bottom soak” was my nickname in school. Good times.
Thats why more people drown in the desert than die of dehydration. Never ever camp in an empty river bed. It could rain a hundred kilometers away and the flash flood can kill you...
Yes “wadis” https://en.m.wikipedia.org/wiki/Wadi
Thank you. TIL something new
Most welcome
Also "Arroyo" in the American deserts https://en.m.wikipedia.org/wiki/Arroyo_(creek)
Never knew this and grew up near a city called Arroyo Grande on the central coast of California. Makes a ton of sense actually.
Arroyo del Caca
Ty TIL
Also 'wash' in parts of the US
'warsh' in some areas. "Cricks" in others.
The Arroyo link actually notes this in the first sentence.
In the southwest, we call them "arroyos"; I think it's a shortening for "arroyo seco", dry creek. But dry creeks don't stay dry. There's a region in North Sacramento County called 'Dry Creek', not far from McClellan Park. The area flooded so many times that the city bought the land and razed the houses, making it into a park. They got tired of helping people rebuild in those locations over and over and over again. The areas surrounding Sacramento also have levees. A weakness in the levees can cause water to bust through, flooding everything on that side. Long ago, a few asshole farmers used to bore their own pipes through the levee to steal more water than was allotted to them. 50+ years later, though the pipes were blocked off, the weakness they introduced, during times of high flooding would cause those places to breach. Suddenly there'd be water pouring through what seemed to be an otherwise solid levee. Then they examined and found the old bored-through pipe, stopped off but still weakening the structure. So a dry area, followed by heavy rain, exacerbated by asshole farmers from 50+ years ago introducing weaknesses into the levee, led to massive flooding around the Sacramento areas. For a change the rich people in Rancho Murieta were also flooded out, instead of just the poor folks around Rio Linda and Del Paso Heights.
Wow that is very interesting ty for posting this
I had a feeling it was of Arabic origin
I remember walking along a narrow paved canal that replaced a former empty river bed (arroyo) in a city. There was a heavy monsoon a bit away & about 3cm/1inch of floodwater was flowing through it. All of a sudden, a 40cm/1.3ft tsunami came charging at the speed of a car (in the suburbs) & that water flow kept rushing through at the same height for about 20 minutes. Anything living along that arroyo would've been killed easily by it. They're also called washes if you live in the US southwest.
Thank you McThunderfart But seriously, thank you, very nice bit of obscure advice
>Thank you McThunderfart I thought it was MC Thunderfart, like a rapper; an emcee.
Yup, flash floods are no joke
I worked at a plant nursery and this was common if the dirt in a pot got too dry. It would become hydrophobic and you would have to water the shit out of it before it would start to take water.
My dumb ass filled in a hole in ny yard with peat moss, because it looked nutritious lmao. I could NOT get that shit to get wet. The water zipped between the particles and shot into the deep hole.
Question. If counties used an aerator after a drought, would it help water get into the ground and not create a flood? Guess that would be a lot of ground to cover, but interested in the science nonetheless.
It may, but especially if the organic matter is low it could lead to a lot of erosion and loss of dirt.
I was going to say that any serious gardener is familiar with dry peat moss. Peat moss is down-right hydrophobic until it gets soaked. Peat moss is very often a component of potting soil (for water retention - ironically), so thats why dry soil is a bitch to rehydrate in a well draining pot.
I mean you could give them an example to try. Best one if you're a guy, go piss in the dirt and watch it stay in a raised puddle, when you have to pee again, pee in the grass and watch it stream out
Science!!
I only thought of it because it's what happened this morning. (I'm a driver and yes I keep hand sanitizer in the truck)
Is there something about guy pee that women pee doesn't work?
too many midichlorians
It's more about how we pee, exclusively, where we pee from
Idk about all women, I just know my girlfriend won't because of spray.
Dude they make devices so us women can pee standing up. Totally contains the spray. You can grab one on amazon for like $10. It has made hiking and camping so much better for me.
where do you put it after you pee into it? i feel like it would get your bag wet and i wouldn’t want to touch it with my hands
You give it a couple arm flicks and it sheds all the pee. Put a tiny blast of water down it from you bottle if you want to be super clean, but it doesn't hold the pee and the outside is always dry.
why is this not more popular
Observability, mostly
Not only just for guys, I've seen ladies water dirt too
It's been so dry where I live that the dirt outside my place might as well be stone...you don't even leave visible footprints when you walk on it
I worked with an excavation company for a bit. Before we would leave the job site or before a storm we would use the roller to essentially seal the dirt. Water runs off of rolled dirt, and loose dirt becomes a mud pit. Extremely dry conditions gets the same compacted seal on the surface.
> Shit isn't a joke lmao >lmao is it or isn't it?
Hence major floods after a prolonged drought.
Or allowed their houseplant to completely dry out. The only way to come back is to soak it from the bottom.
Wonder if people can start using a hole piercer, multi spikes on wheels and roll over grounds with it. This may help break it up. ?
see "dust bowl"
It is called aeration and people do it to lawns, football fields, soccer fields, etc.
Also anyone who has lived with dormant grass knows there'd be more air gaps under the cup since the twiggy stems are more tough, sparse, and tubular than the blades. The dirt literally does not want to drink.
I went to Vegas once when it poured for about 45 minutes and the casino floors flooded and every time I tell the story no one believes me. Not the entire casino but the parts close to the strip as anyone who's been there would know the downs and ups relative to the street.
Yeah, had a teacher show us when we had a drought in elementary school, never forgot about it
Living in Vegas currently, where it's "monsoon season" right now. [Here are photos from this past week](https://www.reviewjournal.com/local/local-nevada/death-valley-before-and-after-flooding-as-seen-from-space-photos-2620480/). Might be paywalled, fyi.
Seriously. if you’ve ever been in a desert this isn’t revolutionary. Packed dirt don’t let shit in.
I live in the desert. It rained for 30 minutes and yes all the roads are now flooded. No bullshit detected.
This is basically every time there is a large storm in Arizona. Most of the ground is super dry, and therefore very compact. The water can’t move through the compacted soil, and just about every major rainstorm we get, it comes with its complementary flash flood warning
It's tragically ironic. Happens in Yemen too - one of the most hyper arid countries in the world, currently being bombed by Saudi forces due to a revolution after the previous mass uprising didn't lead to any real change. They had like one hurricane in recorded history in 1800s, then got one in 2011 that dropped a **decades worth of rain**. Water security out there is a huge issue, there's a need to switch to drip irrigation from flood irrigation, as well as create community management of water usage - since rich people can just dig deeper into the well. This huge issue that's largely responsible for most of the struggle, needing water - and then when it happened it destroyed all their crops (which, farming was like 30% of employment). One hurricane after 200 years. So much rain, unbelievable levels of destruction. Then the same thing happened a week later.
That plus the mountain ranges acting like a funnel.
Oh man. One time I made the mistake of "staying high" during an AZ monsoon which happened to be a road that sat between two mountains. Biiiiig mistake.
This should be obvious to anyone who has ever had a houseplant and failed to water it. Damp soil in the pot accepts watering pretty quickly. If you've waited until the leaves are wilting and the soil has dehydrated to the point of contracting away from the edges of the plant's container and you pour water in, the water runs off the surface, down the sides, overfills the catch bowl and just makes a general mess because of surface tension. The water refuses to soak in. It's like the natural hydrophobic coating on fuzzy leaves. It has to break through to start being absorbed all the way down the soil layer. That's why you pour a little water on the plant, then more as the soil can accept it. Rainstorms dump a lot at once, so that "fuzzy leaf" effect on the soil is dramatically multiplied to the point of a flash flood.
Just remembered I need to water my plant.
Everyone in this comments section is a scientist apparently
From what I'm seeing 2 hours later, everyone just forgets to water their plants apparently
Either a scientist or an irresponsible plant owner.
Horrible scientists at that
I did a science fair project on soil in 3rd grade, so you could say I'm something of a leading expert in the field.
Reddit: Home of the Keyboard Bound Specialists
Yes the grass may change the result a little, but anyone who’s had houseplants should understand what’s its showing. When I water my herbs daily I just pour water into the top of the pot and it Permeates throughout the soil. When I water my cacti once a month or less I take the pot of hard dry soil and put into a larger pot filled with water and leave it for a couple of hours before the water permeates to the dry soil in the middle. If the U.K. has heavy rainfall now there will be severe flooding as the ground cannot absorb water quickly.
I garden in the south and maintaining hydration is an interesting battle. Many great parts of soil can actually become hydrophobic when they dry out and they won't hold water until they've had time to soak. I literally do a small pre watering before I water on the hot dry days so the soil will more easily absorb the water.
I question the scientific method here. The first two have a bulk of grass that's preventing the cup from sitting flat and thus allowing air to enter. The third one seems to sit flat on the earth and there's a vacuum created that would slow the flow of the water.
Honestly, if they were to pick up that last cup and the end of the video, it would show that the water would just bead and lay there in a puddle before being absorbed. I think that would have been a better visual for everyone.
The actual commonly practiced scientific method is to use a cylinder infiltrometer, which is literally a slice of metal pipe which you hammer in the ground, add water to and measure infiltration over time. It would not have been hard to acquire such material and it still would have been easy to see and interpret, e.g., hammer a 15 cm diameter cylinder in the ground and dump in a half liter of water, see how long it takes to drain. There are methods that are more accurate (using 2 cylinders or a rainfall simulator), but that would get the point across.
You'd have to put a window in the tube for the demo to work as a video
Or just shoot the video from above, looking into the cylinder.
You're right, it's an open cylinder and it doesn't protrude very high above the ground. A half liter in that volume should be only an inch/2.5 cm of water. Very easy to stick a camera over it.
It's an illustration of something already known to be correct, not a scientific experiment. The end result correlates exactly with what we know happens in practice, via rigorous research, so it doesn't really matter why the illustration worked out, as long as the point is correct, which it is.
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This was my first thought too, but think about it: if you have a yard that looks like the first two pictures, what will that yard look like after a heavy drought? ... If the drought is strong enough to kill your plant life, you're going to end up with the picture in the far right.
True but an open cylinder would have been a more fair comparison due to the vacuum effect.
Sure, but you’re not planning on upturning cups of water so that bit is irrelevant. The question is how does soil absorb water in each condition and this ‘experiment’ is pretty useless at demonstrating that.
In that case, think of potted plants. When the soil has a slight dampness, water poured on it will absorb readily. When the soil is bone dry, the water will just bead on top of it and take a long time to be absorbed Edit: spelling
This is basically what we needed as an experiment.
Given that it's a well established thing, we don't really.
Sure, makes sense.
Agreed. They should have shaved the grass away for each cup to sit on flat soil.
Or placed a weight on top
Maybe- but I feel seeing as only the soil is being tester here, only soil should be in the test.
I would have liked to see a cup turned upright with holes in it, along with a control cup.
Needs a hole poked in the top of the cup
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The point isn’t that the right scenario is a bad depiction of drought (you’re right: it’s what dry land would look like). The point is that the flat ground against the cup creates more of a vacuum that makes it harder for water to escape. The test should probably be done with open cylinders, so vacuums can’t form
Even with open cylinders, the left and middle cups are both resting more on top of the grass, so the liquid is seeping through the large gaps in the grass. Cylinders would need to be weighted down enough to ensure they were all as close to the actual soil as possible. If the grass on the far right hand side was long when it died and the cup was on top of it, the cup would also drain quickly if it's not more flush with the ground. If they wanted to do this experiment using just the transparent cups, the most accurate way would be to have them all standing directly on three different samples of soil.
I always knew that far right is not a good option.
Dry dirt doesn't take on water. Wet dirt does. Take a houseplant that hasn't been watered in 2 weeks. The soil absorbs none of the water. The water goes straight through. When there's nowhere for the water to go, no cracks in the soil, the water will stay right there.
Yeah that's not being questioned here what's correctly being questioned is the method of demonstrating it. Which is absolute garbage. Bad experimental methods don't invalidate a hypothesis they just mean the results are garbage.
Copied this from someone else: It seems less like they were trying to conduct an "experiment" than provide a simple visual demonstration that laymen could take in and understand. We already know dry dirt doesn't absorb water well, so a tightly controlled experiment isn't necessary. This is a pretty decent attempt at communicating information to the general public.
Plus, we have a "similar" setup in wet vs dry grass in the first two slots. Yet, the wet grass absorbed it ridiculously faster.
soil type is also a huge factor. (ie - void sizes, infiltration rates, etc)
But that's part of the point--very dry soil gets extremely compacted with almost no voids.
So you're saying the dirt is air tight?
From what I am gathering here the point of this is qualitatively educate people on the difference in water absorption of the soil, not quantitatively. It's meant to display the general idea, which is sound and backed by scientific experimentation and data that the public could look into if they were so inclined. To me this is a clear and concise demonstration that really gets the point across.
There is definitely no vacuum, you can clearly see big air bubbles move up as soon as the plastic bag is pulled away (and after that as well, just a lot slower). Also there wouldn't then be such a stark difference between wet grass and normal grass.
It's not an experiment but a demonstration. An experiment using the scientific method would be a lot more rigorous than this.
But isn't that more of the point? A drought is likely to have dead grass as option 3, not live
What he's saying is the test is to demonstrate how fast and well soil can absorb water. If the cup is just letting water out and spread because it isn't firmly against the soil because its ontop of grass it's not really testing the soil absorption
Rain doesn't fall in upside-down plastic cups that seal to the surface when they hit the ground... The left video compared to right video is like shotgunning a beer vs. trying to drink from a bottle with your lips sealed around it.
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There are gaps between the blades of grass and the cup. There may be differences in soil porosity but this is a poor demonstration.
its not porosity its how water interacts with saturated vs. unsaturated media. capillary forces act against the downward migration of water when the soil is unsaturated. its kinda like lubbing the soil up if its already wetted
>There are gaps between the blades of grass and the cup This was my first thought too. "Of course it's going to seap through the blades of grass better than a flat surface!" *But*! It still can be a good visual aid when explaining floods after heavy droughts. A heavy drought can cause heavy loss of plant life; if you normally have a yard that looks like the 2 left pictures, a drought *can* leave you with the far right scenario, thus (as the video shows) leaving you at risk for flooding in your yard. I would be interested to see a similar video where they put the cups on dirt/soul in the left two videos to see what difference that makes.
And the dead vegetation makes it easier for soil to erode in a flood too
The one on the right is dry grass, not a flat surface.
There's no vacuum effect of a sealed upside down cup from rainfall. But permeability does depend on water saturation of the soil.
A better demonstration would have used equally matted grass (or just wet, medium and dry soil).
Pull the grass up in a 3x3" spot to get bare dirt. The soil is still affected by the grass, unless you pulled the grass away weeks ago lol
Came here to say this. In fact, if you play the video in fast-motion you can really see the two cups on the green grass being forced up, allowing even more water out/air in.
Common sense would make it seem so.
More people drown in deserts than one might tjink because of this phenomenon
Damn that’s something to think about. I wonder if more people have drowned in a desert or died of heat stroke at sea. I’d guess the latter
But this is a bit misleading. You’re witnessing a vacuum difference as the thicker grass allows more air into the cup so water can escape while the drier, compacted earth does not allow as much. Remember, even with the soil soaking up the water, it still has to be replaced with air.
would poking a hole in the bottom of the cup help avoid differences in vacuum effects?
100%. But also it would be better to have the ground all be the same level and terrain so as to equally “seal” the mouth of the cup.
Well it is all on a patch of gras, don’t think you will find gras like on the left in the current heatwave in Europe unless sonebody either watered it a ton or it is fake
But the ground isn’t the same terrain, that’s the point of the experiment
Remove the bottom of the cup and hammer the cup into the ground to equalize ground contact.
Yup if your plans are super dry and you dump water on em, it’ll just run off. Awesome visual explanation.
We had quite a drought this past month in Minnesota. A good 2" rain was predicted for this past weekend, so I got out and sprinkled my lawn well the day before to get it prepared. The way I think of it is that a damp sponge will soak up water much faster & better than a dry sponge. But I love this demonstration!
I live in the desert southwest of the USA, let me tell you something, there’s no such thing as “might” flash flood after heavy drought, no matter what your soil composition. Once the ground goes hard pan, be aware at all times of where you’re at and what the weather is doing, especially upstream.
Corpses have trouble drinking compares to living beings.
The cup on the left is being held up by the grass, so the water pours out. And the cup on the right makes a seal with the dirt, so no air can replace the water. But then the middle cup fucks up my whole theory.
This isn't scientific at all. The cups in the grass will allow air in and water out, while the cup on the dry patch will have a more effective seal against the ground, trapping the water inside for a longer time. EDIT: The point that's being demonstrated is in fact true. Moist soil absorbs water much better than dry soil, but this demonstration is a very poorly executed example of this fact.
Better demo would be using a glass/plexiglass tank with soil in different states, like regularly watered, moist but not saturated and dried out completely. So no grass is in the way letting air in and water out.
But it gets the job done, and makes it easy to understand the concept.
I'm going to believe a meteorologist rather than a bunch of dumb fuck redditors, sorry bros
Everyone over here like "It isn't accurate wwwwah" It's accurate enough to show what basically happens. It's showing there's a difference, not writing a dissertation, jesus.
I often wet the ground first then come back and soak it for just this reason.
John McPhee writes about the San Gabriel Mountains runoff in The Control of Nature. The soil following a fire makes water bead up.
Lol, I did this with my 8-9 year old elementary classroom. Predict, Observe, Explain. The dry dirt soaked up the least and I tricked them all. Muahahah. Edit: I had the dirt in the cup and then they put the water in. You can submerge chunks of dry dirt and it'll stay dry in the middle even after 5 minutes, it absorbed almost nothing.
rent an aerator from home depot or lowes and poke holes in your lawn to enhance its ability to soak up water
I notice this when watering my plants if I've been away, it's almost like dry soil is hydrophobic
couldn’t areas going through severe droughts just run empty bore shots in open fields to create a tunnel of sorts to help avoid flash flooding ?
The dead grass is flatter than the green grass, it forms a better seal around the plastic cup, this is a factor that is being overlooked. A lot of the water from the first two cups is travelling sideways, not downwards, because of a bad seal
maybe a dumb observation but if you have a thick grass water will escape to the sides not into the ground. the flatter the surface the more sealed the cup is
I'm sure the gaps at the bottom of the cup caused by grass has absolutely nothing to do with it. Yes the dry dirt is hard packed, but the other 2 cups don't have the same seal to the ground. Instead, he should have all 3 surfaces flat and free of grass - just dirt.
It doesn’t quite demonstrate what it says it does: the grass on the left and in the middle prevent the glass from making a good seal, so the water is spreading out on the ground. The baked soil on the right does make a seal, and yes, there’s a resistant layer on top that prevents water from being absorbed very quickly. If you did the same experiment but removed the grass first, the difference is speed between the three options would be much lower, but still pretty different. (source: I do timed percolation tests in various kinds of soil for determining soil quality for agriculture.)
Experiment is worthless. Should’ve used Brawndo. It’s what plants crave.
You must’ve gotten a major in Idiocracy
Well California...wish I could say it was nice knowing you
Wow this is actually super cool, I would have somehow expected the opposite
Same. But it makes sense when you think about it. The ground is hard; no matter how "thirsty" the soil may be, it's difficult for hard soil to absorb water. I've seen it with potted plants: normally, the soil stays soft from watering it everyday and the water gets absorbed immediately, but if I've just come home from a trip and it's near dying, I have to be careful as I water it because the soil is dry and hard and the water will pool up in the pot as it takes longer to absorb it.
Credit/Source: @UniofReading
So we need to wet the grass first, got ya.
u/savevideo
Wow, a picture or in this case video really is worth a thousand words. Many years ago one of our offices is Las Vegas had to close down because of flash flooding due to a very small amount of rain compared to our daily thunderstorms in Florida. I made a joke about how little rain they got yet had flooding…I now feel very silly. Great video.
I seriously did not know this.
HI IM GONNA PRETEND THIS IS COMMON KNOWLEDGE BECAUSE I LEARNED IT FIRSTHAND WHILST GROWING CANNABIS *SOIL/MEDIUMS BECOME EXTREMELY HYDROPHOBIC AFTER DRYING OUT TOO MUCH, YOU CAN DAMAGE YOUR ROOTS VERY BADLY AND UPROOT THEM TO A DEGREE FROM THIS.*
This is obviously totally true but I feel like this experiment had a bit of error that could have been corrected. The well watered ground has healthy grass in it. That grass stands up and creates an air pocket around the edges of the cup letting it run out pretty quickly, not just soak into the ground. The dead grass on the dry ground doesn't hold the edges of the cup up so it has to soak into the ground to escape.
whether we like it or not, we are now all students at the university of fuck around and find out
That “after heatwave” is the “normal” where I live.
Very. Cool. But also would be funny if he left the cup there long enough to fully empty and they got a circle of greenery to bamboozle the locals.
This happens in Australia a lot. All over Australia.
More incentive for farmers to reduce their use of tillage and grow more perennial/cover crops. The roots act as channels to improve water infiltration, helping the whole system become more drought resistant. The continuous canopy also keeps the soil surface cooler and softer, aiding even more in water infiltration.
Woohoo My home town has finally been mentioned on Reddit . I feel complete.