Water Holding Capacity of Soil

[SilliamWhale]

Wheels
Tyres
Cultivation

THESE ARE THE CAUSES OF COMPACTION

Cultivation isn't strictly speaking a cause of compaction. Its the destroying the soil structure by cultivation that causes the compaction - there is a difference because if people say "cultivation causes compaction" its a slightly different thing. Personally I find if you have the structure then the wheels and tyres aren't so bad ie once a year a 140hp tractor and a drill etc is ok - do that two or three times in a short space of time and its different

 

[Kiwi Pete]

Cultivation isn't strictly speaking a cause of compaction. Its the destroying the soil structure by cultivation that causes the compaction - there is a difference because if people say "cultivation causes compaction" its a slightly different thing. Personally I find if you have the structure then the wheels and tyres aren't so bad ie once a year a 140hp tractor and a drill etc is ok - do that two or three times in a short space of time and its different

As the old man used to say about soil: "if it's "a big chocolate sponge" then what can you actually do to it that will make it a better sponge? Come back to me when you work it out, boyo"
I think the answer is, look at it but don't touch it

 

[Blaithin]

Animals do NOT cause compaction, but help relieve it if managed - if they manage themselves, they cannot.

They absolutely can if they’re managed the right/wrong way.

 

[Kiwi Pete]

They absolutely can if they’re managed the right/wrong way.

That's right, it's really that human management element - similar to the distinction Will made ^^^^^

Water is probably just as responsible, in some ways, but it's almost similar to the climate change debate and a whole host of other "let us blame this on that" subjects, cows are the least of our worries, but also a convenient scapegoat

 

[Farmer Roy]

How’s this for infiltration rates on heavy clay

1 1/2” hose on a fire fighter pump, watering trees, about 400 litres at this stage & just being soaked up by the soil

 

[Farmer Roy]

Watering a favourite old orange tree on sandy soil, I had to throttle the water right back as it was just running away, not soaking in

 

[Farmer Roy]

Here’s an example of a non wetting sand repelling water - my heavy clays absorb huge amounts of water, the sand it just pools on top of . . .

 

[Farmer Roy]

Non wetting sand

 

[mikep]

Enjoying this but....... I think everyone only really talks from their own perspective and experience which is understandable but can lead to 'systems' which dont work everywhere. Our soils, climate and farming system are so varied that no one way can ever be valid everywhere.
To me the most missunderstood part of soil structure is the role silt plays. People say heavy clay is dificult and so it is but when you start to mix some silt in it gets pretty messy. If your soil is OK for PH and in good heart the small clay particles floculate and form a fairly good structure. Silt on the other hand wont it's free to do whatever it wants in the particle state and this means silt can rise up in wet conditions and remain on the soil surface, conversely it can be washed down with rain, drains never run clear as there is always silt on the move.
What this means is that the state of the soil is not fixed and this can explain the unpredictable nature of silty clay soils. One example some of my permanent pasture which has been down for at least 40 yrs and hasn't suffered from mechanical damage is wetter in winter than my arable. The soil gets soft when it gets wet and the hooves make small depressions that are waterproof as they have been 'puddled'. These small puddles keep the surface wet and squidgy and the animals soon start to tread more grass than they eat so it's home time. You need rough grazing to keep them out here in the winter or very spread out. The arable doesn't suffer from this so the surface drains quickly and although slimy lets the water away. Any deer or horse tracks show the same effect of puddling though. So I always think silt is the joker in the pack and most of the reason that even seemingly similar soils act differently.

 

[Cece]

Have any of you measured soil organic matter before you started rotational grazing or hpg..

 

[farmerm]

in the “wheat belt” regions of Western Australia, there are big areas of “non wetting” sands. Literally - sandy soils that repel water & don’t let it soak in. It just pools on the surface - it is due to the presence of organic waxes from the breakdown of the original vegetation, or something like that, caused largely by land clearing & cultivation in the past . . . Those farmers have developed a number of techniques to overcome this, including zero till, planting in deep furrows to collect & hold moisture, spreading clay over the surface, in-furrow injection of surfactants / wetting agents into the row at planting, re introducing livestock ( mainly sheep over there ) into arable lands. Constantly refining & adapting their methods . . .
Over here, on degraded lighter & sandy soils, I have seen the very same thing, caused by these organic waxy compounds . . .

In contrast, the best infiltration I have ever seen is out here on the ( heavy clay ) floodplain after an extended dry period. We had a flood & I was able to get around & in front of the water, as it was slowly spreading out across the plain. Upstream was completely underwater, I was standing on dry ground watching the water approach. You could literally hear it gurgling down into the soil, filling the profile, then it would move forward another few metres & just disappear into the ground again, until it filled it up & then moved forward again. It was pretty awesome to watch . . .

I see water repellency occur regularly in potato ridges formed during a hot dry spell. Seen growers send staff to throw 25mm irrigation at it, virtually all of it gets shed and then when the grower walks the field a few days later they cant work out why the ridge is dust dry

 

[Lowland1]

in the “wheat belt” regions of Western Australia, there are big areas of “non wetting” sands. Literally - sandy soils that repel water & don’t let it soak in. It just pools on the surface - it is due to the presence of organic waxes from the breakdown of the original vegetation, or something like that, caused largely by land clearing & cultivation in the past . . . Those farmers have developed a number of techniques to overcome this, including zero till, planting in deep furrows to collect & hold moisture, spreading clay over the surface, in-furrow injection of surfactants / wetting agents into the row at planting, re introducing livestock ( mainly sheep over there ) into arable lands. Constantly refining & adapting their methods . . .
Over here, on degraded lighter & sandy soils, I have seen the very same thing, caused by these organic waxy compounds . . .

In contrast, the best infiltration I have ever seen is out here on the ( heavy clay ) floodplain after an extended dry period. We had a flood & I was able to get around & in front of the water, as it was slowly spreading out across the plain. Upstream was completely underwater, I was standing on dry ground watching the water approach. You could literally hear it gurgling down into the soil, filling the profile, then it would move forward another few metres & just disappear into the ground again, until it filled it up & then moved forward again. It was pretty awesome to watch . . .

Part of their problem has been caused by a build up of organic matter which because of a mixture of no till and low rainfall does not break down. When i worked in this area we burnt our straw usually by fire harrowing dragging a set of harrows until they filled with straw then setting it alight then driving like mad in a circle trying to keep ahead of the blaze. I digress but of the methods they are now using ploughing is one as is the use of discordon or top down type implements to get rid of the organic matter.

 

[Kiwi Pete]

Have any of you measured soil organic matter before you started rotational grazing or hpg..

Kind of. We measure ours annually courtesy of a couple of interested research facilities, but it was rotationally grazed historically since around 1875

 

[bactosoil]

just to throw into the discussion bio-clogging , just like plague , can form in as little as 20 mins and can change a permeable soil to impermiable in that time and all to do with biological imbalance

 

[Samcowman]

Kind of. We measure ours annually courtesy of a couple of interested research facilities, but it was rotationally grazed historically since around 1875

What are the results saying so far Pete?