11 May 2008

'The Joy of Soil Science' 'More Joy of Soil Science@

....In summary, it would appear th
at the lowly earthworm and still lowlier soil nematodes respond to increases in the air's CO2 content, via a number of plant-mediated phenomena, in ways that further enhance the positive effects of atmospheric CO2 enrichment on plant growth and development, while at the same time helping to sequester more carbon more securely in the soil and thereby reducing the potential for CO2-induced global warming.
Worm Man

Socialists in Australia argue not about what they think of the SWP but undertake serious discussions about soil science...this is a reason to be cheerful

I have pasted this in from Dave Riley's blog comments...if people are debating soil science there is hope...essentially worm bin compost has huge potential however low nutrient soils can be very ecologically important as well.

An important debate....I am king of the compost in Winkfield, Windsor by the way...my neighbours are giving me their grass clippings and the compost is cooking nicely.

I just have to kill the puta madre slugs...no easy task...any way look at the debate in Australia below

On May 09, Dave Riley said...
I agree. There has to be ecological logic to the landscape RE-design.

As well as protecting habitat we need to enlarge the native flora corridors. But in , I guess most,intensely farmed districts soil degradation & exotic invasion is such that a lot of that aspiration will be almost utopian.

You just have to fly over the East Coast of Australia to get a sense of the massive loss. As for the Murray Darling Basin....!

My view -- at least for the moment -- is that if farmers are going to farm the land then we have to establish certain parameters that protect them and their income as well as the environment. We also have to take great swathes of land out of food and fibre production for the regrowth of natural habitat.

The problem is that to do that we have to ask farmers to produce differently with less land and, to some significantly degree, more productively while being more sustainable.

Tall order.

I think that is sure to be a massive economic and social headache as in effect we have to completely redesign the rural landscape and its utilisation. And do that with the cooperation of farmers.

If you check out The Carbon Coalition -- assuming the science is correct -- you can see the problem with such a shift. There has to be financial return -- otherwise it won't happen.

And these farmers are calling for a carbon trading scheme!

While it may be practicable to take degraded rural land out of production, reforest riparian ecosystems, and guarantee produce prices -- the contradiction is likely to be that we have to repopulate the countryside and make farming more labour intensive.

So in region after region there would need to be a range of experimental model projects to prove that such a shift is viable.We'd also have to deal with the challenge of a buy back or land nationalisation (of the big corps) scheme -- while guaranteeing working farmers land tenure.

As for the live stock industry -- if we cannot establish a viable anti-fart campaign for ruminants then we'd need to massively cut stock numbers. Thats' what? An industry farming something like 100 million sheep and 80 million cattle.

So the concept of the 'free range' herd/flock may have to be dropped as livestock are more actively integrated with mixed farming approaches as we shave back their numbers.

Reducing beef consumption may be one key element for instance. Do that and the economies of the outback begin to collapse...

If you take a sample such as the Murray Darling basin -- obviously an emergency situation already exists there -- we'd have to consider a massive almost militarised program of aggressive reforestation born up by thousands of people recruited to plant trees.

We could mobilise school students and the like and make it a national focus. It could be a marker of the changes more generally to come. But we'd need to do it that way to protect future food supplies and save the river systems which are dying.

But planting trees may not be the panacea it's cracked up to be especially in areas of salination. We may have to remodel the land somewhat to drain salt away as well as look to other sources of water catchment than by draining the main tributaries. If we decide that a sustainable flow down the Darling or whatever is so many percentiles more than is currently the case that water has to come from somewhere. The irony is , I guess, that because of run off, deforestration and erosion maybe more water runs into the river systems after good rain than previously despite the fact that the ecology is under so much duress.

So I imagine that "carbon farming" makes a lot of sense in that context as part of the landscape. And in all areas any reforestration program has to proceed , I guess, by a staged process of planting first colonizer species(eg: local wattles) before fostering in other natives.

On May 09, Ben Courtice said...
Of course we must use vermiculture etc to build up the soils in farmland. And in some areas (e.g. New England tableland perhaps) that may have had rich and deep humus before European invasion we could consider programs to re-enrich soils maybe (I'm no expert either, I'm just guessing). The organic farming model has far less impact than chemical industrial farming.

However, my only point is that weed eradication and native re-vegetation projects are required on a large scale, and it is desirable to reclaim some existing farmland for this just to re-establish sufficient habitat for the growing number of threatened species (and threatened ecosystems, in fact).

On May 07, Dave Riley said...
Soil ecology is complex I agree and I'm not about to know much about it. But the problem is being driven by the reality of climate change and how that relates to agricultural production and soil sequestration.

Technically you could convert "soil" to any thing -- offering various attributes-- by the addition of any amount of biological material and fiddling with the local ecology.

The introduction of cloved hoofed animals has had a major, and disastrous, impact on Australian soils and it seems to me that even there if we are to farm them it "may" be preferable to change the soil (and pasture)to suit their impact and 'weight' otherwise you have to consider banning them from the landscape altogether (ESP with more droughts likely).

Weeds are a massive problem and I'm amazed how much effort is required to weed, say, one river valley using any number of tactics as part of full time eradication programs.

While I'm all for a sort of Land Care emergency program with a mobilisation of huge numbers of workers in the effort, to some degree we have to accept that we're stuck with the changes that have already happened and "perch" our new soil attributes and requirements on top of that.

Mark Diesendorf has some interesting commentary for instance about sustainable bio-energy production in regard to already existing soils and tandem with food production (eg: Western Australian malee) using local flora and agricultural biomass..

I'm not sure that we can harness the flora and fauna for food consumption as broadly as some have suggested. Acacia seeds -- yes. More kangaroo perhaps.And its preferable to eat macedonian nuts to the demanding almond... But the reality is that the sort of farming we need for sustainability won't require all the space that is now utilised.

Inasmuch as this relates to worms -- Australian worms aren't very useful in agriculture in the same way as they have limited capacity to help grow the larder. So the worms you know (in your backyard or on the vegey farm)are in fact, European or African in origin in the same way that the many grasses and weeds are exotic.

So it's a bit of a false god to talk about returning all the landscape to an absolute native eco-systems.

So if you wanted to use the soil to sequest carbon and foster sustainable production then you are talking about the soil that is being intensely farmed for food or fibre and weigh that up with the gains you can attain even though the end product ecosystem won't be indigenous.

On May 07, Ben Courtice said...
If you want to "invigorate the extremely poor nature of Australian soils" be warned that on a broad enough scale this would threaten to really disrupt the native ecosystems which are highly specialised in dealing with said poor soils. I know of a place on the East coast of Tasmania where scrub forest grows on soil that is so barren virtually nothing farm-like would take root. Defined agricultural areas, sure, but Australian soils have already been irreparably damaged in at least two ways since European invasion: firstly, massive topsoil loss caused by the introduction of hooved livestock; and secondly, massive invasion of green, leafy foreign weeds which already change the soil composition as they grow and take over from natives. I read not long ago that in native re-vegetation projects landcare workers have even used heavy sugar application on the soil. This stimulates soil bacteria growth, which bacteria use up a lot of the available nitrogen, starving the introduced species for a period of a couple of months until some natives can be established in the friendlier nitrogen-depleted soil.

On May 07, Worm Man said...
CO2 Science -- the Worm Digest..But the good news doesn't end there. As Jongmans et al. (2003) point out, "the rate of organic matter decomposition can be decreased in worm casts compared to bulk soil aggregates (Martin, 1991; Haynes and Fraser, 1998)." Hence, on the basis of these studies and their own micro-morphological investigation of structural development and organic matter distribution in two calcareous marine loam soils on which pear trees had been grown for 45 years (one of which soils exhibited little to no earthworm activity and one of which exhibited high earthworm activity, due to different levels of heavy metal contamination of the soils as a consequence of the prior use of different amounts of fungicides), they concluded that "earthworms play an important role in the intimate mixing of organic residues and fine mineral soil particles and the formation of organic matter-rich micro-aggregates and can, therefore, contribute to physical protection of organic matter, thereby slowing down organic matter turnover and increasing the soil's potential for carbon sequestration." Put more simply, atmospheric CO2 enrichment that stimulates the activity of earthworms also leads to more -- and more secure -- sequestration of carbon in earth's soils, thereby reducing the potential for CO2-induced global warming.

But there's still more to the story of CO2 and worms. In an intriguing research paper published in Soil Biology & Biochemsitry, Cole et al. (2002) report that "in the peatlands of northern England, which are classified as blanket peat, it has been suggested that the potential effects of global warming on carbon and nutrient dynamics will be related to the activities of dominant soil fauna, and especially enchytraeid worms." In harmony with these ideas, Cole et al. say they "hypothesized" that warming would lead to increased enchytraeid worm activity, which would lead to higher grazing pressure on microbes in the soil; and since enchytraeid grazing has been observed to enhance microbial activity (Cole et al., 2000), they further hypothesized that more carbon would be liberated in dissolved organic form, "supporting the view that global warming will increase carbon loss from blanket peat ecosystems."

....In summary, it would appear that the lowly earthworm and still lowlier soil nematodes respond to increases in the air's CO2 content, via a number of plant-mediated phenomena, in ways that further enhance the positive effects of atmospheric CO2 enrichment on plant growth and development, while at the same time helping to sequester more carbon more securely in the soil and thereby reducing the potential for CO2-induced global warming.

Not a bad day's work for something some of us only use as bait for catching fish

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