Agroecology – A Plant Out of Place

How much yield is enough?

August 28, 2016February 15, 2018 - by Andrew Kniss

Last week, two colleagues and I published a paper in PLOS ONE titled “Commercial crop yields reveal strengths and weaknesses for organic agriculture in the United States.” The article presents an analysis of USDA crop yield data to compare organic and conventional farms in the US. We were pretty careful in the paper not to overstate our conclusions, since our goal was simply to see where organic yields were competitive (or not) with conventional crop yields. I explain more about …

As consumers shift to non-GMO sugar, farmers may be forced to abandon environmental and social gains

May 12, 2016February 15, 2018 - by Andrew Kniss

Dan Charles at NPR has recently done two interesting pieces about sugar production. In the first, he uses sugar as a proxy to look at the environmental costs and trade-offs of growing food in different places. It makes for an interesting comparison because there are two completely different crops (sugarcane and sugarbeet) that can be grown to produce the exact same product, refined sugar. The two crops have very different climatic needs, pest management requirements, and growing seasons. It is an …

Agroecology / Crops / GMO / Herbicide Resistance / Herbicides / Imported from Control Freaks

Everything in Agriculture is a Trade-Off

March 14, 2016June 7, 2019 - by Andrew Kniss

The idea of trade-offs is familiar to everyone. None of us have unlimited money, time, or energy. We make decisions every single day about how to spend our money, our time, and our energy. Do I buy the red shirt or the blue shirt? Do I watch the football game or go to the concert? Should I ride my bike to work or hope I can find a good parking place? Do I call a plumber or try and fix the sink myself? Do …

How to Make a Natural Weed Killer

January 6, 2016February 15, 2018 - by Andrew Kniss

Well over a year ago, I wrote about a homemade herbicide containing salt, vinegar, and dish soap. “Many of you have probably seen it posted to Facebook or Twitter or Pinterest, or on your favorite home gardening site. One of my favorite descriptions calls it a “magical, natural, weed killing potion.” That particular potion certainly kills weeds, but it isn’t natural (and it certainly isn’t chemical-free). It contains dish soap and vinegar, both of which are synthesized industrially, so it isn’t natural by most definitions of the word. That’s disappointing, …

The role of reflected light quality in crop-weed interactions

December 15, 2015February 15, 2018 - by Andrew Kniss

This post is a slightly edited excerpt from an article we wrote for Reflections magazine. Plants need light – this is one of the first biology lessons children learn in school. Plants convert sunlight into forms of energy the plant can use to grow. Nearly everything humans eat is derived in some way from photosynthesis, whether the tomato picked from a garden or a ribeye steak that once grazed on grass. Sunlight seems like a plentiful enough resource, but there’s …

The cost of preventing herbicide resistance

November 16, 2015February 15, 2018 - by Andrew Kniss

In my last post, I reviewed some recent research that suggests one of the best ways to delay the evolution of herbicide resistant weeds is to use mixtures of effective herbicides. Resistance is initially a very rare trait within a weed species, so the probability that any particular individual plant will be resistant to two herbicides is extremely low. The second herbicide is likely to kill any weeds that are resistant to the first herbicide, and vice versa. The theory behind this practice …

Want to reduce herbicide resistance? Spray more herbicides!

October 27, 2015February 15, 2018 - by Andrew Kniss

A while ago, I wrote a post summarizing the pros and cons of using a regulatory framework to slow the evolution of herbicide resistant weeds. As a part of that post, I suggested there exists a “resistance management paradox.” In a nutshell, to reduce the problem of herbicide resistant weeds, one important strategy may be to actually use more herbicide. From my previous post: “The only way to assuredly prevent herbicide resistance from evolving is never to apply the herbicide; but if we are going to …

Dead plants are probably bad for earthworms

September 5, 2015January 30, 2019 - by Andrew Kniss

I’ve gotten a number of questions recently about a new study titled “Glyphosate-based herbicides reduce the activity and reproduction of earthworms and lead to increased soil nutrient concentrations” that was recently published in the online journal Scientific Reports. Although the title seems pretty straightforward, there are some flaws in the study design that preclude any broad conclusions from this research. I would especially be cautious of making statements like Roundup is “imperiling streams, lakes, [and] aquifers” or that there are “far-reaching consequences of [glyphosate] use in ecosystems” …

Stop saying organic food is less safe, unless you can provide evidence

April 18, 2015February 15, 2018 - by Andrew Kniss

A recent article from Western Producer titled “Canada has a world-class food system” was recently re-posted by the Genetic Literacy Project (GLP). GLP, whose stated mission is to “explore the intersection of DNA research, media and policy to disentangle science from ideology”, commonly aggregates news stories. But when they re-posted this particular article, the headline was changed pretty dramatically, to “WHO study finds thousands of illnesses linked annually to organic foods.” After some criticism in the comments, it was later changed to remove …

Defining Agroecology

May 20, 2014February 15, 2018 - by Andrew Kniss

Agroecology (ag´ rō i kol´ ə jē), n. An ecosystems approach to agriculture. Agroecology. It’s an unfamiliar term to many people. And even people who are actively engaged in some aspect of agroecology sometimes disagree about what it means. I have to admit, even though the term is pretty important to me, I was fairly oblivious (or at the very least, indifferent) to the ambiguity until very recently. But it seems more and more I find myself trying to define …