We tried growing garlic last year, with some success, but I had the feeling that if we’d prepared the ground a bit better the bulbs might have been larger, so this year we decided to try adding green manure to the soil a month or so before planting the garlic.  With this in mind we planted the bed up with lemongrass about three months ago.

Before reading further you need to understand that on our place “soil” is mostly a concept.  We live in rugged sandstone country and what passes for natural soil is mostly rocky gravel with sand and (perhaps) some humic material.  If we want good soil we have to make it.

Another source of complexity is that because of the depredations of possums, wallabies and bandicoots we need to grow most of our vegetables behind fences topped off with a strand of electric tape.  It wasn’t always like this.  For the first six or seven years we seemed to have a rock-solid agreement with the wildlife (apart from the parrots) that if we didn’t eat their food, they wouldn’t eat ours.  However over the course of a year, and strangely it was a very wet year when there was plenty of natural food for the wildlife, they suddenly decided that our vegetable were infinitely preferable to bush tucker.

Anyway, this is a long-winded way of getting to the point that there are few things we can grow unprotected, but these include all the onion-garlic group, lemongrass, turmeric, ginger, and citrus.  So, in order to be economical with the fenced area, the garlic gets grown ‘in the open’.  This pretty much means that it goes into a terraced garden bed behind a rock wall, which tends to make the whole thing “well drained”, particularly if there isn’t much humic material in the soil to start with.  Hence one of the attractions of green manuring, and the choice of lemongrass as one of the components of the green manure – nothing was going to graze it off.

The functions of green manure are said to include

• increasing the percentage of organic matter in the soil, and thereby improving water infiltration and retention, aeration and enhancing other desirable soil characteristics, including soil structure;
• promoting a more varied and healthy soil biota; and
• adding nutrient resources that deep-rooted green manure crops bring up from deep in the soil (but lemongrass is shallow-rooted).

Here’s the harvest of lemongrass from what will be the garlic bed.  It was densely planted three months before we cut it in the middle of March.  About half of the crop we gave away to friends in the Indonesian community here – it’s a staple of many Indonesian dishes – which is the material in the buckets and pots on the bank.  The heap in the middle is for the green manure, and the lemongrass still growing on the left of the photo gives an idea of the size of the plants we harvested.  The bed in the foreground is where the green manure, and later the garlic, will go.

I also wondered whether the aromatic oils in the lemongrass might have a useful effect in inhibiting soil pests like nematodes, but I couldn’t find anything on this.  In fact I couldn’t find anything at all on lemongrass as a green manure.

We also decided to add the fresh green growth from the pigeon peas.  Pigeon peas (Cajanus cajan) are an evergreen perennial legume shrub that grows to more than two metres in good conditions.  Cath Manuel has an informative short article on pigeon peas over at Soil to Supper, and there’s even more detail on the Tropical Permaculture site.  Both recommend them as a mulch or soil improver, and NSW Agriculture says they are an excellent rotation crop for building up soil nitrogen and breaking weed and disease cycles.  Pigeon pea hosts the VAM fungus which allows the plant to access phosphorous and zinc in the soil, and presumably this is incorporated into the plant, adding to its usefulness as a green manure.

The other ingredient in our green manure mix was mulberry stems and leaves.  We coppice mulberries rather than growing them as trees, for two reasons.  First, the variety we have tends to grow straight up.  No amount of pruning or shaping seems to be able to persuade it to grow as a relatively low spreading tree that one could easily harvest fruit from.  Second, ultimately we will mainly want the leaves as a food supplement for poultry.  We learned from our good friend Thanongsi, who runs a successful demonstration sustainable agriculture farm in central Laos, that he finds he does not have to provide any supplements to goats or poultry that are given mulberry leaves as a component of their fodder.  So presumably these nutritional supplements are going to be incorporated into the green manure.

Here are our green manure ingredients ready for mulching.

In the background is the lemongrass, the heap in the foreground is the pigeon pea, and on the right is the mulberry.  It is important to use only the green and sappy ends of the branches for green manure, to make sure that it breaks down quickly and easily in the soil.  Of course the blades of the lemongrass are typically coarse and hard, but when finely mulched and combined with the other ingredients should break down readily.  One advantage of the mix of ingredients is that when combined it isn’t so “wet” that it will choke up the chipper/mulcher (seen in the background of the photo above).  I’d highly recommend this machine from Greenfields.  It has a very sturdy direct drive from the motor to the chipper blades (rather than a belt-drive which would need regular adjustment) and can chip green branches up to 50mm diameter without even dropping the revs.  We’ve chipped everything less than 50mm in diameter from about ten full-sized trees with this machine, as well as a lot of prunings, and it is still on it’s first set of blades (which can be re-sharpened, but haven’t needed it yet).

Here’s the mulched ingredients on the bed, ready for spreading and digging in, after which it will be watered and covered with a thick barley straw mulch for the next month.  You can see the “shorn” pigeon pea bushes in the background – they hardly look like they’ve been touched.

I’ll let you know what it looks like when we dig it over to plant the garlic (which was ordered today from GreenHarvest).

Having trouble convincing your friends that we need to take global warming seriously?

Do they think that human induced climate change is some whacko left wing, eco-nut conspiracy?

Maybe they’d listen to a staid pillar of the establishment like PriceWaterhouse Cooper on the topic?

Stop banging your head against a brick wall – point them to the PWC website at:

 http://www.pwc.co.uk/sustainability-climate-change/publications/low-carbon-economy-index-overview.jhtml

Here’s what PwC say:

We use the carbon intensity for countries as a measure of progress towards a low carbon economy. The carbon intensity of an economy is the emissions per unit of GDP and is affected by a country’s fuel mix, energy efficiency and the composition of the economy (i.e. extent of activity in carbon-intensive sectors).

It’s time to plan for a warmer world. The annual Low Carbon Economy Index centres on one core statistic: the rate of change of global carbon intensity. This year we estimated that the required improvement in global carbon intensity to meet a 2^°C warming target has risen to 5.1% a year, from now to 2050. We have passed a critical threshold – not once since World War 2 has the world achieved that rate of decarbonisation, but the task now confronting us is to achieve it for 39 consecutive years.

The 2011 rate of improvement in carbon intensity was 0.7%, giving an average rate of decarbonisation of 0.8% a year since 2000. If the world continues to decarbonise at the rate since the turn of the millennium, there will be an emissions gap of approximately 12 gigatonnes of carbon dioxide (GtCO2) by 2020, 30 GtCO2 by 2030 and nearly 70 GtCO2 by 2050, as compared to our 2-degree scenario.

Even doubling our current rate of decarbonisation, would still lead to emissions consistent with 6 degrees of warming by the end of the century. To give ourselves a more than 50% chance of avoiding 2 degrees will require a six-fold improvement in our rate of decarbonisation.

In the emerging markets, where the E7 are now emitting more than the G7, improvements in carbon intensity have largely stalled, with strong GDP growth closely coupled with rapid emissions growth. Meanwhile the policy context for carbon capture and storage (CCS) and nuclear, critical technologies for low carbon energy generation, remains uncertain. Government support for renewable energy technologies is also being scaled back. As negotiators convene every year to attempt to agree a global deal, carbon emissions continue to rise in most parts of the world.

Business leaders have been asking for clarity in political ambition on climate change. Now one thing is clear: businesses, governments and communities across the world need to plan for a warming world – not just 2^°C, but 4^°C, or even 6^°C.

If you need more detail you can download the pdf of PwC’s report Too Late for Two Degrees: Low carbon economy index 2012.

One of the key characteristics of a sustainable system is resilience.  A good working definition of resilience is ‘a built-in ability to avoid or recover from an impact or disturbance’.  In the natural world (I’m including vegetable growing as part of the natural world, bit of a stretch perhaps) resilience can be manifested at many scales, from the overall system right down to individual species.

In food production systems we should always be striving for resilience, and this becomes more significant as we begin to bear the brunt of climate change.  The fundamental weakness of agro-industrial systems of food production is that they have sacrificed resilience in the quest for greater short-term profits.

You might recall that some time ago I referred to my experiment in restricting pumpkin vines to around one square metre, after advice that they would be likely to be as productive if confined by pruning to that small area as they would  be if allowed to “free range”.  Because free range pumpkins take up such a lot of space I’m keen to prove that the “area restricted” approach works.

Unfortunately I didn’t reckon with the impact of heatwaves (or, more accurately, I didn’t respond quickly enough when we experienced a major heatwave over the last few weeks, with temperatures up to 38 degC. and quite low humidity).

Here’s what it does to a pumpkin vine:

Not pretty, and not boding well for a plentiful harvest.

This vine was planted in the corner of the mulched area under a lime tree, and has been more or less restricted to one square metre (it’s probably more like 1.5×1.5m now).  Another part of the vine scrambled across the mulched area directly under the tree.  Here’s what it looked like at the time the above photo was taken:

Strangely enough, even where it isn’t directly under the shade of the lime tree it isn’t sunburnt.  Maybe having the majority of it in shade gave the whole runner some greater resilience.

Lesson:  have structures ready for hanging shading material, so that it can be installed when there is the first hint of unusually high temperatures.  That’s another kind of resilience – being ready to respond to inclement situations so as to avoid negative impacts.

It’s not that I wasn’t aware of this kind of impact, just that we haven’t had really hot weather for four or five years, so I had taken my eye off the ball.  No excuse, I’ve been following Scarecrow’s Garden for a long time and, being in the mid-north of South Australia, she has many strategies for dealing with hot weather.

I’m not sure exactly how this relates to sustainability, but I have a gut feeling that it does.  But the real reason I’m posting this is that it is such a simple, straightforward answer to the crap arguments made endlessly (and mindlessly) by the US gun lobby.

It’s from White Coat Underground, one of my daily fixes of common sense and sanity in an all too often crazy world.  I won’t rehash the gun lobby’s arguments – if you don’t know them already they’ll soon be coming to a TV news, newspaper, magazine, web site near you.  Over to White Coat Underground:

Guns have never played a part in the maintenance of a democracy in the US. Gun ownership in the colonies, which existed for more than a century before the revolution perhaps made it easier to form an army to oppose the Brits, but really, without the external support of France, without the distances involved, the war would have lasted much longer. The colonies were, fundamentally, un-rulable and the real question was how much blood would have to be spilled to prove it.

The civil war, in which a large number of Americans rebelled against what they saw as an unjust government killed people—lots of people. It destroyed large swaths of the country. And the war was not won because Unionists kept guns at home, but because the industrial north could manufacture sophisticated weapons in large numbers.

The so-called disarming of the population feared by the gun-nuts isn’t happening, and if it did (we can only hope), it wouldn’t change our form of government, wouldn’t change our ability to resist tyranny from home or abroad. If the US government really wanted to become a dictatorship (unlikely to ever happen), disarming the population wouldn’t even be necessary. The navy could simply drop a JDAM on people they didn’t like.

But we do have constitutional protections against dictatorship, and they’ve worked for centuries. We have a tripartite government with checks and balances, [and] we have a military that is forbidden from intervening domestically.

More strength to the forces for gun control in the US.

It has occurred to me in the last few days that one of the aspects of trying to live as sustainable a life as possible is that one is often challenged by people along the lines of “Well, your efforts are all well and good, but what good do they really do when ….?” and cite some “statistic” or “fact” that in their mind challenges the whole point of trying to live sustainably.

Maybe one thing this blog can do is to provide answers to some of these challenges.

A good one arose in the days following the recent Tasmanian bushfires.  I’ll let the Philip Gibbons from the Australian National University tell the story as he did for The Conversation on January 10:

Fact check: do bushfires emit more carbon than burning coal?

By Philip Gibbons, Australian National University

“Indeed I guess there’ll be more CO₂ emissions from these fires than there will be from coal-fired power stations for decades.” – acting Opposition leader, Warren Truss, January 9, 2013

On Wednesday, leader of the National Party and acting Opposition Leader, Warren Truss claimed carbon emissions from the current bushfires are equivalent to decades of carbon emissions from coal-fired power.

The current bushfires are so large that the statement by Warren Truss seems plausible.

This spurred me to do some research to find out.

Coal-fired power stations in Australia emit around 200 million tonnes of CO₂ per year. This does not include emissions from our coal exports.

Around 30 tonnes of CO₂ per forested hectare were emitted by the Black Saturday Fires in 2009.

Bushfires this year have so far burned around 130,000ha of forest, so have emitted nearly 4 million tonnes of CO₂.

So, the bushfires this year have emitted an amount of CO₂ equivalent to 2% of Australia’s annual emissions from coal-fired power.

The current bushfires must burn an area of forest greater than Tasmania to generate CO₂ emissions equivalent to a year of burning coal for electricity.

And the current bushfires must burn an area of forest the size of New South Wales to generate CO₂ emissions equivalent to a decade of burning coal for electricity.

However, the carbon emitted from bushfires is not permanent. Eucalypt forest regenerates after fire, and will quickly begin to sequester from the atmosphere the carbon that has been lost from the current bushfires.

The same cannot be said of coal-fired power stations.

Read more about the relationship between bushfires and emissions.

Philip Gibbons receives funding from the Australian Government, the Government of the Australian Capital Territory and the Australian Research Council.

This article was originally published at: