There was an article published recently that traced the melting of glaciers in the US over the last 50 years. This study showed, pretty convincingly, that the glaciers are, indeed, melting, and melting rapidly. Meanwhile, in our atmosphere, levels of carbon dioxide from humans burning fossil fuel are increasing in a manner roughly correlated to the increase in temperature that’s melting the glaciers. But is the carbon dioxide actually causing the warming? Believe it or not this is still an area of discussion among scientist, and the answer isn’t as simple as many newspapers make it out to be. Almost all of the scientists that you care to talk to, even those skeptical of the role of carbon dioxide in global warming, admit that increasing carbon dioxide is going to cause a net increase in global temperature. But there is a decent amount of research out there showing that solar and geothermal activity (in other words things that we can’t control) may cause anywhere from 15 to 75% of the warming that we’re seeing. To be honest, based on what I’ve read (and I’m no climate scientist), I tend to side with those who believe that global warming is mostly caused by human releases of carbon dioxide, but I also think that to accept that theory as proven is a mistake.
In my humble opinion we’re missing the more compelling reason to reduce our emissions of carbon dioxide (besides the fact that we’re running out of fossil fuels of course). Plants. Most people simply assume that, temperature increases aside, increasing carbon dioxide in the atmosphere is going to be good for plants, and that’s just not the case. True, some plants, like Canadian thistle and many other weeds, love the increase in carbon dioxide, but other plants, such as many grasses, just don’t respond to it that well. The ironic thing is that, for those plants that respond strongly to CO2, nutrients like nitrogen and potassium are taken up quickly from the soil (as you’d expect with a rapidly growing plant) and then, as the nutrients in the soil run out, the growth of the plant is drastically reduced. In other words, CO2 causes unfertilized soils to become more rapidly depleted. So what does this all mean? It means that as we increase CO2 levels in the atmosphere we’re changing the world’s ecosystem, including the fields that grow our crops. Indeed, we’re actually adjusting the atmosphere to alter which plants are most appropriate for certain situations. There are even those who argue that, because of our CO2 emissions, we’re encouraging invasive plants to take over our native forests because these plants tend to be able to handle high CO2 (and high temperatures) better than the plants that are already there.
To me this is the more important reason to reduce our carbon footprint.
Part of the problem with being a professor is that companies assume that I have a bottomless supply of funds to test their products and that it is, in fact, my duty to do so. And of course they assume that this testing will ultimately find their product useful.
The truth is that I do love to test things, but I don’t have the funds to do the comprehensive tests that these companies usually want, at least not without them helping out at least a little – and most of them don’t want to spend money on tests! But many times, even if I tell them on the phone that I’m not likely to test what they’re selling they’ll send along a sample anyway, hoping that I’ll be curious enough to give the stuff a shot. And I usually let them because, well, why not?
Anyway, that brings me to this pile of ash that is currently sitting on my floor. A guy from a company (which I will decline to name) called me on the phone and convinced me to accept about 25 pounds of rice hulls that had been burned to ash while being used to fuel something or another (I can’t remember what and there was no note in the box). This ash is supposedly the cat’s meow for helping the media in containers to retain water and this guy wants me to test it. I told this guy that I was unlikely to have time for it, but he was insistent. I guess he thought that if the stuff sat on my floor long enough eventually I’d get curious, open the box, and try it out.
Turns out he was right.
So I get this box full of ash, open it up and am immediately hit in the face with black dust which I wisely (and accidentally) inhale. Lovely. Then I take out the MSDS sheet (Material Safety Data Sheet – required for most chemicals) and read about the problems with this product. It turns out this stuff contains crystalline silica (no surprise there, rice hulls are full on silicon), which can cause a rapid onset of silicoses as well as being a cancer hazard (crystalline silica is a known carcinogen if it’s inhaled).
Now I don’t want to blow the danger of this stuff out of proportion. I have little doubt that my exposure to it wasn’t enough to do anything terrible to me (just as I’m pretty sure that the two packs of cigarettes or so that I smoked during college aren’t going to eventually lead to lung cancer). And I’m all in favor of using industrial byproducts for other purposes whenever possible. But my goodness, this stuff is ash! It just flies into the air! I just can’t see how, even with the recommended protection, nursery workers could avoid inhaling this stuff on a daily basis if they were using it to pot up plants (perlite is pretty bad – but this stuff is worse) — which just seems like a heck of a bad idea. In terms of the ability of this stuff to hold water….well, I put some into a plastic container with some water which the ash absorbed none of. All that said, it might be possible that this stuff helps container media to hold more water, but for an unintended reason. This ash is extremely fine. When we mixed it with container media it quickly found its way into all of the pore spaces between the media particles making the media more like clay than media. This did potentially increase the media’s ability to retain water, but decreased its ability to hold air – which is not a good thing for young roots. So the quick and easy summary is that rice hull ash is not the best idea for containers.