Comments on: Podcast: Buy Water Rights, Sell Riverina’s Future

By: JBob

JBob — Fri, 07 May 2010 20:31:51 +0000

I’d love to hear more about exactly how we can use irrigation water to reduce our dependence on such water. We can use it to establish trees, and we can use it to increase biomass production and hence soil organic matter. Any other ways?

And while we’re on the topic of using “artificial” inputs to improve our soil situation, I will mention that more and more I’m using synthetic nitrogen to similary boost biomass production. I planted legumes (leucaena, desmanthus) first and for 2 years I waited and watched and waited as the trees were set back by a flood and then a hard freeze. Then recently I put out ammonium sulfate at 40lbs/acre every month or so, I saw that you get a MUCH quicker improvement with the NH4SO4. I’ve read that earthworms and microbes aren’t damaged much at such low application rates.

I know synthetic fertilizers are anathema to the permaculture group (rightly so in most cases) and dependent on cheap oil, but isn’t there also some principle about “making hay while the sun shines,” too?

By: Nick Huggins

Nick Huggins — Sat, 01 May 2010 21:47:10 +0000

Thank you all for your comments and feed back.
Please stay tuned for more on this topic. This was just the tip of what is to come from this project in Wagga wagga, NSW.
Within the next 2 weeks I will be writing about the project in detail, looking at the swales, and yes photos of the springs popping out of the ground to follow up on Geoff Lawton work almost 12 months ago and looking at the amazing results.

By: Geoff Lawton

Geoff Lawton — Fri, 30 Apr 2010 20:59:45 +0000

Swales moderate water flow in catchments and greatly reduce floods and droughts, creating a constant high quality water flow which is more life enriched.

The one effect in all of this accounting of the enhanced water cycles in a catchment that is usually missed out is the massive increase in condensation.

The ability to rapidly reforest with swales in a way that is beneficial to a productive landscape creating stability and poly cultural productivity can also increase precipitation by up to 80% of the rainfall volume in arid climates. This is the condensation harvest of air moisture when it is NOT raining, but you have to have a large condensation surface area for this to be achieve and trees are the ultimate achievers of this.

It is useful to research this see http://www.rainforestinfo.org.au/good_wood/trees_gs.htm

TREES: Guardians of the Earth by Bill Mollison*

By: Wayne Bossert

Wayne Bossert — Fri, 30 Apr 2010 13:29:40 +0000

Tim:

Thank you for the extra detail – this explains the water budget better. I had thought (assumed) two things: 1) someone was already using the surface runoff and 2) that there was also groundwater irrigation taking place. While I see your points and the benefit of the swales, I still have to believe that surface water runoff out of the area has to be reduced if it is to be intercepted by the swales for all the benefits you describe and made available for more plant transpiration. My main point was asking if anyone else was using, or had rights to, this runoff. if not, then the described efforts are all positive to the area of interest, as the article is stating, and without negative impacts to others down stream. Again, thank you for the explanation. Very interesting work.

By: Jimmy Y

Jimmy Y — Fri, 30 Apr 2010 03:43:54 +0000

A photo of the springs popping out of the ground would have been nice.

By: Tim Auld

Tim Auld — Fri, 30 Apr 2010 00:25:47 +0000

Wayne,

The purpose of a swale is to intercept and infiltrate surface runoff, so they do not necessarily consume imported water. Efficient irrigation (such as drip) is still used to establish trees.

The increase in humus from systems like this increases the soil’s water holding capacity. The result is less water loss from surface runoff, subsurface drainage and evaporation. For the same amount of rainfall there is progressively more available for plant transpiration.

Nutrient availability is improved due to higher cation exchange capacity as well as increased fungal activity. This results in higher yield without additional irrigation and fertilisation.

By: Wayne Bossert

Wayne Bossert — Thu, 29 Apr 2010 20:39:49 +0000

I have to wonder if anyone else has been using the water that will soon end up in the swales (to recharge the shallow groundwater?) and restore this area’s production. If so, are they expected to be pleased about this? I’m also wondering how the area can “..use less irrigation water as each year passes while still growing ever more productive.” This seems impossible to me as more production always equals more consumptive water use. I think that if old production levels are kept, or reduced a little bit, then the irrigation efficiency gains can be used elsewhere justifiably, but any more production’s consumptive draw on the water supply has to limit the available supply somewhere, sometime. Interesting approach to be sure. More details in the article may have explained these water concerns.

By: Tim Auld

Tim Auld — Thu, 29 Apr 2010 02:53:55 +0000

Great work, Nick! When you mentioned trees cycling water I was hoping you might say something about deforestation being a contributing cause of drought. Willie Smits' project in Borneo proved that the presence of trees increases rainfall (by about 25% in that case). Is it any wonder that after clearing much of Australia we are experiencing some of the worst droughts in history?

By: Rob

Rob — Wed, 28 Apr 2010 22:25:19 +0000

Great interview Nick, I am glad to be leaving Australia, knowing she is in good hands! When I return in two years I expect the whole country will be swaled and every farm will be under 25% tree cover.

Keep up the good work!