infiltration doesn't work

Just a thought..... one I've been thinking for a while, but probably talking nonsense.

What effect does atmospheric pressure have on infiltration?

Take this past week, we had 5 days of foggy dank wet days, but over those 5 days we didn't actually have much rainful.
By day 5, even on a normally reasonably free draining farm, the quad was marking the ground quite badly.
I carry a small spade on the bike so dung some holes and the water was just sitting in the top 2/3", completely sopping!
The soil below was damp and there was nothing obvious to stop the water moving down.

Roll on day 6 and we get 31mm of heavy rain in about 12hrs, of course we see some fair run off.
The rain is followed by a high and clear skys.
Now after that amount of rain, surely we should be marking the fields worse then ever??
But come the next morning (yesterday) the previously sopping wet 2/3" of top soil has disappeared and the profile is equally damp through the profile and I'm marking the ground less than any point in the last week


🤔🤔🤔🤔🤔
Evaporation might be a big influence.
 

cows r us

Member
BASE UK Member
Location
Buckinghamshire
Obviously it does work. What I mean is that trying to achieve infiltration doesn't work. Or rather, it doesn't here.

I've read all[1] the books, seen talks about how Gabe Brown et al just get all the rainwater to infiltrate away in 5 minutes, and how valuable every drop of that water is, and I regret spending so much time and money thinking I could achieve the same thing.

Dig down a foot or two anywhere here and you find solid clay, which water can't infiltrate. We dug infiltration test holes when we replacing the septic system some years ago and the water didn't run away.

I've spent three years moving sheep and cattle around every day or two, and the fields are worse than they were before I started. It's like the _soil_ layer has improved, but all that means is that when it rains for days and days (and days) on end, I have a much bigger sponge sitting on top of the impermeable clay, so the fields are just so much wetter than before. Then even if it stops raining for a couple of days the fields don't dry out at all, because it's all just sitting in the soil.

The only way to improve anything is drainage. (Trying to achieve) infiltration is hopeless.

[1] obviously not all the books in the world. I was moving fences around too much for _all_ the books in the world.
I think you need to look at your soils profile. As you said if you have good infiltration in the top foot but it cant go any deeper then it's not much help. Look to see how deep the clay layer is. If its possible to grow deeper rooting plants that can put roots down through the clay and out into a layer of soil that that can allow water to get away then that maybe an option as it will help open up pores through the clay layer.
If like some of mine the clay goes on forever then the only option is drains back filled with stone. Expensive but essential.
 

awkward

Member
Location
kerry ireland
You can't expect ground to stay dry if excess water can't get away, infiltration is the capacity of soil to take and hold its capacity but when that is exceded we must let it go, I would clear boundary drains,and if you need to retain moisture later in year have a way to block the drains.
 

N.Yorks.

Member
Screenshot 2021-01-26 at 10.46.01.png

This is just the annual rainfall which seems to be consistently climbing from around 1980. That is just the background but the rainfall comes in big falls just when you don't want it.......
DEFRA etc will know this and some of their ELMS policies (I'm guessing) will be soil and soil nutrient preservation, run-off reduction and probably speed of drainage reduction. Obvious trade off is going to be drainage for production versus drainage slowing, the two not often being compatable.
Policies won't fit all land and local climate scenarios.
 

awkward

Member
Location
kerry ireland
Making
View attachment 936670
This is just the annual rainfall which seems to be consistently climbing from around 1980. That is just the background but the rainfall comes in big falls just when you don't want it.......
DEFRA etc will know this and some of their ELMS policies (I'm guessing) will be soil and soil nutrient preservation, run-off reduction and probably speed of drainage reduction. Obvious trade off is going to be drainage for production versus drainage slowing, the two not often being compatable.
Policies won't fit all land and local climate scenarios.
This i think good drainage is important in order to create capacity within soil at times of deluge,
 

The Ruminant

Member
Livestock Farmer
Location
Hertfordshire
Just a thought..... one I've been thinking for a while, but probably talking nonsense.

What effect does atmospheric pressure have on infiltration?

Take this past week, we had 5 days of foggy dank wet days, but over those 5 days we didn't actually have much rainful.
By day 5, even on a normally reasonably free draining farm, the quad was marking the ground quite badly.
I carry a small spade on the bike so dung some holes and the water was just sitting in the top 2/3", completely sopping!
The soil below was damp and there was nothing obvious to stop the water moving down.

Roll on day 6 and we get 31mm of heavy rain in about 12hrs, of course we see some fair run off.
The rain is followed by a high and clear skys.
Now after that amount of rain, surely we should be marking the fields worse then ever??
But come the next morning (yesterday) the previously sopping wet 2/3" of top soil has disappeared and the profile is equally damp through the profile and I'm marking the ground less than any point in the last week


🤔🤔🤔🤔🤔
I’ve never noticed this until you pointed it out, but I think you may be on to something there! It makes sense too - Mercury, used to measure atmospheric pressure (c.30” is normal at sea level) has been observed between 27” and 33” depending on high and low air pressure. This is a big difference and would “press” water into the ground
 

holwellcourtfarm

Member
Livestock Farmer
I’ve never noticed this until you pointed it out, but I think you may be on to something there! It makes sense too - Mercury, used to measure atmospheric pressure (c.30” is normal at sea level) has been observed between 27” and 33” depending on high and low air pressure. This is a big difference and would “press” water into the ground
Low atmospheric pressure is behind most of the biggest dangerous "tidal" surges of the last century. It can raise the surface level around the UK by several metres. Why wouldn't it similarly affect groundwater?
 

cows r us

Member
BASE UK Member
Location
Buckinghamshire
I asked this question too a soil physicist the other day. He told me that the pressure difference is too small to affect the ground water level. He said the observation is probably because high pressure also means lower humidity in the air and therefor higher evaporation rates.
 

martian

DD Moderator
BASE UK Member
Location
N Herts
I asked this question too a soil physicist the other day. He told me that the pressure difference is too small to affect the ground water level. He said the observation is probably because high pressure also means lower humidity in the air and therefor higher evaporation rates.
I'm not convinced that many soil experts know that much about soil...I've sat on committees where experts have talked rubbish about their own specialities and have no real understanding about the whole picture. There's soil physicists, soil chemists and soil biologists who all think inside their own boxes. I like the idea that there is a tidal movement in the soil whereby the moon heaves the water up and down twice a day, which flushes CO2 out and draws fresh oxygen it to prime the soil biological systems. It won't work if the ground is waterlogged of course and it may be fantasy anyway. But I can't believe that if atmospheric pressure can affect a tower of mercury in a barometer then it can't move water in a network of capillaries in a well structured soil.
 

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