Glyphosate is one of the world's most popular weed killer. It's a broad spectrum herbicide; particularly useful for broadleaf weeds and grasses.

It was developed by Monsanto under the trade name Roundup. Monsanto's patent expired in 2000 and it's found under many different brand names now, most cheaper than Monsanto's. The chances are if you buy a commercial broad spectrum weed killer from your local hardware or gardening store, it will contain glyphosate.

While there are so many brands containing the chemical, Monsanto still makes a killing from Roundup; not just in sales of the herbicide, but from "Roundup Ready" crops. These are genetically engineered plants that are tolerant to glyphosate; meaning that a farmer can spray Roundup among these crops without harming them.

As you can imagine through having such crops, a *lot* of glyphosate is used each year. According to the USGS, agricultural use of glyphosate skyrocketed from less than 11,000 tons in 1992 to more than 88,000 tons in 2007. No doubt, that latter figure has increased since 2007.

Glyphosate is often marketed as being safe and reasonably environmentally friendly in that it supposedly breaks down very quickly.

While more earth friendly weed killers are around made from common household ingredients, they are more suited to the average garden rather than large chunks of land or commercial agriculture purposes.

Modern agriculture is heavily dependent on glyphosate ...and even I am to a degree. There's no doubt it does its job very well. Where the doubts are lay in what else it may be doing.

The majority of my chunk of Australia is pretty much weed free and doesn't require herbicide as the bush takes care of itself along with a bit of a helping hand with manual weed pulling. Unfortunately, I have a few acres where I swear every weed species on the planet exists. 

Over a couple of years of staged and very targeted low-level glyphosate usage, I was making headway and reduced the need for glyphosate to practically nil. One of the worst droughts in Australia's history helped as well - it was one of the few positives of what was an otherwise dire situation.

Then the floods came, which wiped out some of the natives in the rehabilitated area that didn't like getting their feet wet. The waters also swept down weed seeds from other properties that did and weed seed that had lay dormant in that area for years also jumped at its chance. I was back to square one. I will never forget the day I visited the area to see a carpet of green had sprung up pretty much overnight - 99% of it weeds. 

It's events like this that have provided me a very small taste of what some farmers battle and gave me a greater appreciation of the challenges they face in making a living from the land while trying to keep the environment in mind.

I grudgingly started hitting this problematic patch with glyphosate again, somewhat reassured that a) it wouldn't be forever and b) glyphosate was the lesser of the herbicide evils.

Or is it?

We've already been hearing about weeds becoming resistant to the herbicide and I had also heard rumblings that this product may not be so safe after all - and might be significantly more persistent and pervasive than I believed. Those rumblings have been building in recent weeks in Australia.

Veteran American plant pathologist, Dr Don Huber, has linked glyphosate to the increasing severity of crop diseases, caused by a binding of minerals such as copper, zinc and manganese to the herbicide, making them unavailable for plants and thus susceptible to certain problems. Dr. Huber says it can also kill some beneficial microbes while allowing others to thrive and also believes it could be associated with animal infertility problems.

Others claim glyphosate does not break down quickly and takes up to 6 months to do so.

According to two new USGS studies released in August 2011, glyphosate was frequently detected in surface waters, rain and air in agricultural areas of the Mississippi River watershed. In the air and rain? Hmm. A little unsettling. The author of the study said very little is known about glyphosate's long term effects on the environment.

In amongst this flurry of news hitting Australian rural journals over the last few months have been reports countering all this, stating some of these concerns are unfounded.

To confuse things further, US microbioligist Dr. Bob Kremer says glyphosate promotes complex reactions among soil organisms and not enough is understood about these interactions to provide specific management advice

Who do we believe? I guess what it boils down to is of course not to use the stuff if it isn't necessary - it's a poison after all and a synthesized one at that.

Sometimes I am tempted just to let the weeds do their thing as I believe the bush will win out in the end. A few years back I read a fascinating book by Peter Andrews on a concept called Natural Sequence Farming, where he used weeds to help rehabilitate his property. Peter's theory was the weeds were growing as conditions weren't right for natives or desirable pasture species. By letting the weeds grow in some areas, it restored the conditions to a point when the native species could then take over. I've also read other studies where people have used selected relatively non-invasive or useful weeds to crowd out other more aggressive and damaging weeds.

It's all fascinating stuff, however, if I tried it, things would certainly get worse before they get better. That's a risk I would be happy to take if it were just my own block, but I have my neighbors' blocks to think of too; not to mention my legal obligation to carry out weed control.

If there is a more earth friendly herbicide out there, I'd sure like to know about it - but with so much conflicting information about anything connected with Big Agriculture, I'm not sure what can be trusted.
 
My situation is just the tip of the iceberg, not even a drop in the glyphosate bucket in this country; but it hasn't escaped me that while I'm knocking down weeds in this small area with the stuff, I really have no idea what else I may be doing. For all I know after reading all I have in recent times, I could just be making conditions more suited to weed growth by making it less suitable for native species.
 
Why we have a product so readily available for so long yet the science still doesn't appear to be settled is a little frightening.