As mentioned in other posts, I am working on an unusual project in the desert and apart from turf types etc. I am looking for an accuarate method of measuring soil moisture availability to the plant.
Perhaps something that could recognise the plants needs and so automajikly apply the correct amount of water required by the plant ?
wow that sounds impressive is there such thing?
I remember a company working on such a device.
Ah sounds like a good idea peter.
Something to controll and monitor the moisture content before heat stress shows, and in hotter climates protein deneturation.
On the other hand it'd have to be used sensible as here in the UK some do panic and 'reach for the button' of the irrigation system too often (it's far too easy!) thus causing many problems we have on our courses we see today.
To an 'experienced' sports turf manager he doesn't read too much into evapo transpiration rates and 'how much water is lost or transpired' as it isn't a coincedence that the UK's best golf courses are maintained to a dry and a 'lean and mean' philosiphy in regards to water management.
Some have even abolished use of 'pop up irrigation' and rely on hand syringing problematic areas of the golf course.
I can see it being a very usefull, almost essentail tool but could be very dangerous in the wrong hands by being far too over catious!
I've been interested in something that can measure moisture in soils for a while and it'd be be ideal to have something to measure soil moisture suction againgst soil moisture content as moisture content is tied up with the particle size distribution so a certain amount of variability occurs which depends on the density and it's pore size distribution.
I think the problem though with monitoring suction is the difficulty of getting something robust enough to leave under a wicket that doesn't get smashed by mechanical operations - tensionmeteres are great but fragile.
Also it's difficult to get reactive devices that measure much beyond 0.8 - 0.1 bar tension which is fine in the moist but no good once clay shrinks and dries.
Spectrum in the US manufacture some pretty handy and rugged units tht can measure gravimetric and volumetric moisture content
Anthony I note your comments about measuring beyond 0.8-0.1 bar tension but if teh soil shrinks and cracks it is generally really to dry for plants I would imagine?
As said the pore size distribution effects just about everything such as how much moisture held, irrigation, drainage, rolling, shrinkage etc etc.
With cricket soils ones that are heavier are more difficult for plants to tap into for moisture as pores are in the residual phase (0.2 microns) so moisture is too tightly held and crops cannot access it - this is why heavier clay soils can be 70 or 80% saturated but still be too dry for plants to survive.
Pores in the storage stage (mesopores) are ok for plant take up as moisture is absorbed by clay skins and available for root hair absorbance ie hold water againgst gravity.
From the above above suggests why heavier clay soils dry quicker than lighter ones - ofcourse the internal structure plays a huge part in all the above.
AA I agree with everything you say..but that is my point...If this is the case with heavier clay soils whats is the point in measuring the moisture content in this case. Once it cracks it is gettign dry and teh only means of measuring this accurately would be "in house" gravimetrically
I understand where your coming from - soils in the residual pore class never release moisture due to the strong suction created by smaller pores (by rolling for example or using heavy clay mediums) unless samples are baked in an oven.
So i agree in that testing of moisture would be realy difficult in the micropore or residual class but It'd be interesting to dabble with such things there's been loads of stuff done over here at cranfield university on micelle minerology and pores size distribution.
wow what are you guys on about?? lol
Im just here to look at Francesca Cumani again!!!
Ah yes a far more interesting topic
I've particulary been interested in moisture content in soils when rolling and one which achieves the maximum attainable BD from only a few repetitions ie small 'cute' phases of consolidation and manipulation by rolling.
Many things count such as temperature, humidity, OM, shearing stress,minerology, PSD etc.
From our trials here in the england there's been some very interesting results from such tests which certainly changes the way in which we do things.
In virtualy all cases the compressive limit is reached after only about six passes during any one rolling session as any more is negligeable in terms of increasing density and it's manipulative effect (or compression effect) on soils.
With this we are saying that the most contact area occurs during any 'initial' pass of any traffic and then becomes less and less, from then on untill no more compressive effect occurs during the session.
Moisture determines the attainable max BD when rolling and BD determines the attainable moisture in a soil as the two are so strongly linked.
These rolling tests has been carried out with different soils and different dominant phylosillicate minerals.
If any one wants any further info on the 'rolling' trials then email me at firstname.lastname@example.org
How's the project coming along peter?
How's the project coming along peter?
I am not sure what irrigation system you have but Toro now have something that could be what you are after (that is if they are selling it where you are)
Check out this website as I am also heading down that road with the Toro SitePro Central Irrigation.
But failing that you could always manually measure the moisture to help you identify problem areas with a something like this http://www.ictinternational.com.au/mpkit.htm
That is what I am doing at the moment then making adjustments to the Irrigation central.
Hope this helps,
You can also have a look at the UgMO system... it's pretty much the same as the Toro Turfguard.
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