Archive for July, 2013

Dumber than dumb

July 31, 2013

Here’s another one of those dumb articles by a so-called ‘environment reporter’ who simply doesn’t have the background knowledge or the brains to think deeply about what he’s writing.

Can you see the problems with the scenario?

1) Algae need sunlight, CO2 and water to grow. If the tanks containing the algae are sealed, that means no sunlight, right?

2) Using the CO2 emissions from the power station to grow algae and then converting that algae into biodiesel to fuel cars, puts that same CO2 back into the atmosphere via the car exhaust when it’s burned. It’s really just extending the exhaust pipe of the power station. The algae would be better returned to the soil where the carbon should be stored.

3) Power station emissions contain a lot more than just CO2. Oxides of nitrogen and sulphur and toxic mercury, to name a few. How’s the algae going to like that?

What annoys me about this type of reporting is that it sounds good to the layperson without the background knowledge to see the flaws in the idea. So the average man in the street gets the idea that all is OK and we can resume BAU (business as usual) without any worries.

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The Volterra Principle

July 30, 2013

I’ve been cleaning up my hard disk, deleting old files and so on and I found this piece I’d written some years ago for an environmental education display on local plants, so thought I’d reproduce it here. It’s one of the reasons why I find ecology such a fascinating science.

 

The Volterra Principle: why you shouldn’t use pesticides in your garden

Do you use pesticides in your garden? Judging by the number of insecticide sprays available in garden centres and supermarkets, most people do.

The book Silent Spring by Rachel Carson appeared first in 1962 and has been credited with being the catalyst that started the environment movement throughout the world. It documents the wholesale use of insecticides and pesticides which was common at that time and points out the long-term effects on wildlife and humans. If you haven’t read it, there’s probably a copy in your local library. It should certainly put you off using pesticides for ever.

The following is a very interesting excerpt from The Machinery of Nature by American ecologist Paul Ehrlich:

“If predator and prey populations are more or less in balance with one another and if an environmental change raises the death rates in both predator and prey populations, there will be a disproportionate decline in the number of predators.

This result is known as the Volterra Principle. It predicts what will happen, all else being equal, after an application of a broad-spectrum pesticide (one that kills many species of insects) to a farmer’s field in which herbivorous insects are being eaten by predatory insects. The surviving prey, whose death rate in the aftermath of the pesticide is now lower due to the absence of predators, will suffer less than the surviving predators, which cannot find sufficient prey to increase their birthrate quickly. The population of prey (the pests) will thus recover from the pesticide much more rapidly than the predators and build up a larger population than was previously present. Thus an even-handed assult on a predator-prey system will tend to promote the prey and suppress the predators—in this case making the pest problem worse.”

In simple terms, what does this mean?

Suppose you have a rose bush which is being attacked by aphids. More than likely, a predatory insect such as a ladybird or a lacewing, will be feeding on the aphids at the same time. Because of the way predator-prey systems work, there will always be more prey than predators, i.e. more aphids than ladybirds or lacewings. (By the same token, there will always be more rose bush than aphids.) A bit of thought will see why this is the case. If the system was ‘top-heavy’ i.e. hundreds of ladybirds, dozens of aphids and very little rose bush, then each predator would quickly eat all the prey and then starve to death. Balanced systems are ‘bottom heavy’ and work the other way—they wouldn’t be balanced if they didn’t.

Suppose on your rose bush, prey and predators exist in the ratio 100:1 i.e. 100 aphids to 1 ladybird. There might be 1000 aphids, in which case there would be 10 ladybirds. Along you come with your ‘Bugoff’ spray and douse the whole bush with insecticide. Suppose that 90% of all insects, both ladybirds and aphids, are killed. That means 100 aphids will survive but only 1 ladybird. The 100 aphids will quickly build up their numbers again but the single ladybird wont.

So, an even-handed attack on pests in your garden can do more harm than good. The very thing we shouldn’t do is upset the natural balances; they have evolved over countless millions of years and they must be maintained for the health and survival of all species. The cost of allowing the natural balances to survive is very small. We must simply accept that a small amount of damage to our garden plants is an inevitable consequence of the natural world we live in, and not rush for the spray every time we see a hole in a leaf.

Another thing to consider is that some of the insects which survive the poison may well have an inbuilt resistance to it and this will be bred into successive generations. Eventually the poison may have very little effect.

By growing local plants in our gardens, we restore the naturally-balanced ecosystems that used to exist in our local areas. There are very few problems with pests in such a garden. It is well worth putting up with a few chewed leaves for the bonus of having a diversity of birds, butterflies, insects, lizards and frogs in the garden.

Good things I’ve read this week

July 27, 2013

*Michael Pollan: Some of my best friends are germs.

Food writer Michael Pollan is always good value. He recently had his gut flora sequenced in order to find out which microbial species he shares his body with. It’s a long article but well worth reading to the end.

“Here were the names of the hundreds of bacterial species that call me home. In sheer numbers, these microbes and their genes dwarf us. It turns out that we are only 10 percent human: for every human cell that is intrinsic to our body, there are about 10 resident microbes — including commensals (generally harmless freeloaders) and mutualists (favor traders) and, in only a tiny number of cases, pathogens. To the extent that we are bearers of genetic information, more than 99 percent of it is microbial. And it appears increasingly likely that this “second genome,” as it is sometimes called, exerts an influence on our health as great and possibly even greater than the genes we inherit from our parents. But while your inherited genes are more or less fixed, it may be possible to reshape, even cultivate, your second genome.”

Who would have thought that—

“Fecal transplants,” which involve installing a healthy person’s microbiota into a sick person’s gut, have been shown to effectively treat an antibiotic-resistant intestinal pathogen named C. difficile, which kills 14,000 Americans each year.

Yuk—but amazing!

Or that babies born by caesarean section may not have acquired  the necessary microbial flora usually picked up in the normal birth process—

“Most of the microbes that make up a baby’s gut community are acquired during birth — a microbially rich and messy process that exposes the baby to a whole suite of maternal microbes. Babies born by Caesarean, however, a comparatively sterile procedure, do not acquire their mother’s vaginal and intestinal microbes at birth. Their initial gut communities more closely resemble that of their mother’s (and father’s) skin, which is less than ideal and may account for higher rates of allergy, asthma and autoimmune problems in C-section babies: not having been seeded with the optimal assortment of microbes at birth, their immune systems may fail to develop properly.”

*Whole Health Source: ancestral nutrition & health

This is a fascinating blog I found recently and I’ve been ploughing steadily through the articles. The author conducts research on obesity and the regulation of body fat by the brain. He’s just completed a series of posts on the genetics of obesity—is it in our genes, or is it what we eat, or a bit of both?

*Energy and the economy—basic principles &  feedback loops

Gail Tverberg writes the blog Our Finite World, which is mainly about peak oil and energy issues, with a bit of finance thrown in for good measure. This latest post explains why an understanding of energy is vital to understanding the current human predicament.

“We live in an economic world. Economic models that were developed years ago were created based on observations of how the economy seemed to work at the time. As time goes on, it is becoming clear that early economists missed important connections. The most important of these is the role of energy and its connection to the economy. It takes energy to make anything, from a piece of steel to a loaf of bread. It takes energy to transport anything. Humans need energy in the form of food to continue to live. Clearly, energy should have a place in economic models.”

Hibernation

July 21, 2013

A while between posts I know, but I’ve been hibernating. Sitting by the fire watching the grey skies and the rain coming down and longing for the longer, warmer days of spring/summer and the time for sowing seeds, planting out seedlings and watching tomatoes fruit and ripen. Even the Girls are hibernating; there have been no eggs from Cheeky and Lady since late December and none from Molly since early March. Their combs and wattles are redder than they were, so I’m hoping. Maybe an egg is what I need to dispel the winter blues and prove that spring is really coming.

Anyway, three seed catalogues came in during the last fortnight; from Edens, Green Harvest and Phoenix.

From Edens I got Sweet Basil, Wild Bergamot, Broccoletti, Capsicum Cherrytime (this variety did well for me last year), Chervil (I believe it goes well with egg dishes) and Red-veined Sorrel. I’m growing the ordinary green sorrel and hope the red-veined variety will add  a touch of colour.

From Green Harvest I got Mixed Basil, Borlotti Beans (I’m going to try growing beans for drying for the first time), Redbor Kale, Onion Mini Purplette, Golden Purslane, Silver Beet Red Ruby and Yellow Crookneck Squash.

From Phoenix came Bergamot (the ordinary one, not the wild), more Chervil (I forgot and doubled up), Wild Rocket (I grew this years ago and liked it better than the normal garden variety), Cumin and some unusual fruiting trees and shrubs from the northern hemisphere—Bunchberry, Chinese Date, Salal, Sand Pear and Saskatoon. Phoenix is a good source of unusual seeds. I remember seeing Chinese Date in Louis Glowinski’s Melbourne garden many years ago. It was a huge tree, covered in fruits (Glowinski is the author of The Complete Book of Fruit Growing in Australia).

This is saskatoon, with edible blue berries:

saskatoon_berries

The leaves of oca died back and I harvested a small crop of tubers:

oca

Small, because I didn’t sow many last spring. There’ll be enough for pickling and nibbles. I’ve been growing the pink variety and will be ordering the cream variety from Yelwek Farm in Tassie, where I bought potato onions and garlic earlier in the year.

I started sowing tomatoes on the 1st of July and most are coming up now. I’ve planted three seeds per small pot and will thin to the strongest seedling when they’re bigger. They’re inside in a sunny window, but not on the heat mat which I usually use. That’s in another window with cuttings on it. I was surprised that they germinated just as quickly without bottom heat as with it.  Twelve days is about what it’s taking.

When I thin to the strongest seedling I’ll take mini cuttings. I wrote about doing this here, here and here. It’s a great way to get extra plants without waiting for seeds to germinate.

This mandarin is fruiting well:

wednesday 007

It’s a variety called Japanese Seedless. It’s not exactly sweet, but then not exactly sour either and it’s easy to peel. I also have an Imperial Mandarin which is a healthy-looking bush, but the fruit are always tiny and don’t have that lovely typical mandarin flavour of shop-bought Imperials. I have read that the Imperial doesn’t do well in Melbourne, so maybe it’s not anything I’m doing wrong, just the nature of the beast.