Water Recycling

[Clinton1]

Flood irrigation seems such a dumb dumb idea.

I seem to remember that cotton farmers in Qld were getting 70% efficiency through flood irrigation (I was doing research at the time and came across a Co-op Research mob's papers)... which meant that it competed on underground drip irrigation very, very well... at the time.
At the time, sub-surface drip systems were achieving 98% efficiency, surface drippers 90% and overhead irrigation was @ 70 - 80%.

The trouble was that underground systems require very significant 'per Ha' installation investment, and at the time were delivering up to 15% per Ha yield loss!

A 15% yield loss for some of the most competitive farmers in the world, in a totally unsubsidised production market, meant that you'd install sub-surface drippers and then go broke in 2 years.
Of course you could just by cotton produced eleswhere... heavily subsidised and which isn't really competitive and is very 'environmentally unfriendly'.
Hell, some Latin/South American cotton producers pay so little the workers have to garden, after hours, to be able to eat!

Now the complexities of underground drip systems are being slowly worked out and it seems to be out competing furrow flood in most cases... both in amount applied per hectare (the easy bit) and in yields per hectare (the difficult part).

Simply put, the new technology had to be integrated into the farming system and had to be studied carefully to work out how to actually make it cost effective and produce better yields.

Funnily enough, continued research into flood irrigation has meant that 'best practice' gets flood irrigation to 98% (and higher) efficiency.
Next step is to conquer the issue of 'on farm storage evaporation' in a cost effective way.

So, my mate banana farmer near Tully (like all farmers) will be scratching his head and doing the sums to reduce the bore pump running time and if that means he converts to buried trickle tape over the existing combination "on ground micro sprinklers and drippers" then he will.
However the information for this will come from the CRC (Co-op Research Centre) that he funds through a levy 'per carton' of bananas and which is also funded through DPI and CSIRO funding.

When he installs sub-surface irrigation, it is going to cost him $1600 - $5000 per hectare, depending on the model used and how much of his existing infrastructure needs to be changed.
He runs 76 Ha of bananas, so that is a minimum of $121, 600.00 investment... and at a $2 per carton average profit, 60,800 cartons or 45 semi trailers leaving the farm to pay for it. That is a very significant investment for a life span of only 6 years.

He pulls about 625 bunches of bananas off each Hectare per 9 months... the paddock goes for 8 cycles of 9 months (6 years) before needing to be replanted. In replanting the sub-surface tape will be ripped out and ruined.
About 2 cartons per bunch = the full production of 48 hectares over 9 months to pay for 6 years of @5% water saving and 5% less pump running time. Its difficult to have that happen cost effectivly.
Easily paid for... if the farmers can levy the cost onto the consumer, which hasn't happened yet and I can't see consumers being willing for it to happen.

Farm irrigation is a complex issue... well beyond the understanding of me, and dare I say it... beyond the understanding of non-farmers, simply because we are not involved and are not aware of the issues.

Suffice to say, the forces to effect change are in place... but change comes at a cost and with time.
In a heavily regulated and unsubsidised market such as the Aust argiculture market, change comes as it can be afforded.

Change will occur within its own time, and my old mate in Tully is reading things like this, this and this and making changes as and when he can.
He's no-ones fool, and no amount of whinging or 'bright ideas' from enviros and greenies (like me) do him any good... he's the one paying the levy to get the research done to make the change.

[Studley 2436]

The flood irrigation used in the 70's and 80's in the Riverland was just trenches with water running down to the bottom. Hard to know how much water got into the soil, it is all sandy stuff there, and it just seemed to be running past everything.

Studley

[astrid]

I never water my garden, thus trees have deep roots and even european trees are fine

I never wash the car

only wash the boy twice per week

have front loader washing machine

my last water bill was over the limit?

meanwhile my neighbours have pools, and dont try to tell me there filling with a bucket.

until the gov has the guts to really restrict water use and deny pool permits etc.
then I'll do what I'm doing and no more.

Astrid

[woodbe]

Clinton,

Flood irrigation 70% efficient? Compared to what?

I think the measure might be for getting water to the roots of the plant or something, not efficient use of water. Efficient use of water doesn't include pouring it on the ground and allowing it to evaporate. I've heard similar stuff quoted about how efficient our rice and cotton farmers are, and I'm sure we lead the world, but the point is that these are hugely water intensive crops and with all due respect to the farmers who work hard at growing it, Australia has better things to do with the water.

Total Australian rice exports totalled 268000 tonnes, valued at $171 million over the past 12 months. This figure is considerably lower than the usual $400...

http://www.nff.org.au/commodities-rice.html

n terms of the value and volume of Australian cotton exports, in 2004-05 raw cotton brought in $770 million (420 kilo tonnes) and cottonseed $55 million ...

http://www.nff.org.au/commodities-cotton.html

Still, I could be wrong, but it sure looks like we as a nation are exporting our precious water overseas by making cotton and rice with it. And yes, there are lots of other problems with water, this is just one of them IMHO.

woodbe