Andrew McGuire

Cryptic Species, Agriculture, and Confirmation Bias

Posted by Andrew McGuire | May 31, 2018
Australian minnows under water

Australian minnows, or Mountain Galaxias, part of a 15-species cryptic hyper-complex. Photo: CC http://fishesofaustralia.net.au/home/species/3677

Imagine this. You are an avid fisherman in south-eastern Australia. You relish getting away to the many lakes in the nearby mountains. Each lake is a bit different, different surroundings, different fishing holes, but you always see the same minnows, or perhaps two species as you heard a ranger say at a campfire talk, “based on expert taxonomic assessment.” You call them brown minnows, some call them mountain galaxias. They seem common, normal; but we see not as a minnow sees, but with human eyes and thoughts.

In 2012, a group of Aussie scientists (Adams et al. 2014) made a discovery: the minnows from the different lakes that look the same to you, are actually 15 distinct species. What was thought to be one or two species before, even by simple DNA tests, became 15 species with more comprehensive genetic testing (“involving multi-locus nDNA markers”). Organisms such as these minnows, which look very similar, even identical by most standards, but are different species are called cryptic species. A group of these is called a cryptic complex of species. Because of the high number of minnow species, this case is raised to the “hyper-cryptic complex” status. Read more »

Regenerative Agriculture: Solid Principles, Extraordinary Claims

Posted by Andrew McGuire | April 4, 2018

What is regenerative agriculture? Why is it different from sustainable agriculture? And how do I reconcile what practitioners of this system are claiming with the scientific evidence? These were all going through my mind when, a couple weeks ago at an advisory committee meeting of the WSU Center for Sustaining Agriculture and Natural Resources, we watched a YouTube video of Gabe Brown’s TEDx talk in Grand Forks, North Dakota. Brown farms near Bismarck, ND, and has become the American face of regenerative agriculture in the past decade. Here is what I learned. Read more »

Green Manures, The Other GM crops

Posted by Andrew McGuire | March 13, 2018

logo that reads Green Manures with yellow arcs, green triangles pointing upward and brown triangles pointing downwardGreen manures have a lot in common with the other kind of GM crops (GMOs), though there are also some differences. Both green manures and GM crops produce pesticides in their plant cells, yet green manures are completely unregulated. Both are “unnatural” uses of crops, yet nobody argues about green manures. Conventional farmers use green manures, but unlike GM crops, so do organic farmers. Green manures require tillage, but GM crops make no-till easier. Monsanto and other multinational seed companies do not produce GM green manure crops, but they should.

If brown manures are livestock-processed crop biomass, then green manures are their raw, unprocessed predecessors. A green manure is a cover crop that is tilled into the soil while still green. Unlike brown manures, the biomass is grown in place and is used in place with no transport costs. Read more »

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Cover crop monocultures continue to best mixtures; 2017 Update

Posted by Andrew McGuire | December 12, 2017

About a year ago I declared in a post, “Cover crop best bet is monoculture, not mix.” It stirred up quite a few comments and discussion, but no scientific evidence that countered my assertion. Nevertheless, research continues, so I have followed results as they have been published over the last year. Here is an update.

rectangular field plots of different cover crops

Is research finding any benefits of cover crop mixtures? Photo: A. McGuire.

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There is not enough manure (or compost) to sustain agriculture

Posted by Andrew McGuire | October 18, 2017

There is not enough manure. Not enough to supply nutrients to our crops, not enough to maintain our soils. Those were the conclusions in my last two posts, but before we see what this means for agriculture, let’s look to other organic amendments. Is there enough of any of them?

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Can manure sustain soils?

Posted by Andrew McGuire | September 19, 2017

Once you start asking questions, innocence is gone. -Mary Astor

How much manure do you need to spread to maintain your soil’s organic matter? Photo: werktuigendagen via Wikimedia Commons

My first question about manure, “Can Manure Supply Nitrogen and Phosphorus to Agriculture?” was answered here. But manure is more than nutrients. The bulk of manure is organic material, the carbon that the primary-producer feed crop took from the air and built into organic molecules (hence the name “organic”). When added to the soil, some of this manure bulk ends up as soil organic matter.

Organic matter is a small but crucial portion of soil. If we can maintain a soil’s organic matter levels, we have gone a long way in maintaining soil health and function. Can manure do this? Can manure sustain soils?
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Can Manure Supply Nitrogen and Phosphorus to Agriculture?

Posted by Andrew McGuire | September 7, 2017

Once you start asking questions, innocence is gone. -Mary Astor

Manure, whether fresh, old, or composted, is often declared to be a key component of sustainable agriculture. In countless trials, researchers have found multiple benefits of manure application (Haynes and Naidu 1998), and so manure use is promoted as a solution in discussions of sustainable agriculture topics including: soil fertility, soil health, organic farmingregenerative farming, carbon sequestration, and renewable resources.

However, I have questions. Not about the actual spreading of manure, or calculating application rates, but about manure’s role in sustaining agriculture. Is manure a sustainable source of nutrients? Is manure a sustainable organic soil amendment, able to build soil organic matter, store carbon in the soil, and so assist in reducing greenhouse gases? When is manure application a sustainable practice?

In my next few posts, I will answer these questions with the hope of finding manure’s true role in sustaining agriculture. First, let’s look at the nutrient-supplying potential of manure. It all starts with figuring out where manure comes from. Read more »

Cover crop best bet is monoculture, not mix

Posted by Andrew McGuire | December 21, 2016
Can you see 17 species in this cover crop mix? Photo: A. McGuire.

Can you see 17 species in this cover crop mix? Photo: A. McGuire.

Cover crops are great. If I thought I could get away with it, I would just grow cover crops in my garden. They protect the soil, feed microbes, build soil structure, add root channels, and support beneficial insects. I think they look cool too. When cover crop mixtures got popular a few years ago, I got excited and grew a 17 species mix. It looked really cool, I mean, diverse, with all sorts of seeds that became all sorts of plants.  I took pictures, showed my kids, and even had a neighborhood open garden event! (Well, maybe not that last one) Then I grew some vegetables after the cover crop. They did OK. Just OK. I wanted it to be the best tomato/squash/cucumber/lettuce crop ever, but I could not tell the difference between these vegetables and those I had grown after many previous un-biodiverse cover crops. Recent research results may explain this. Read more »

Comparing effects of herbicides, fertilizers, and tillage on the soil

Posted by Andrew McGuire | December 8, 2016
Is this better than an herbicide for the soil? Photo: United Soybean Board.

Is this better than an herbicide for the soil? Photo: United Soybean Board.

In a past post, I argued for the use of an herbicide instead of tillage to kill a soil-building cover crop. My post was mostly observation of the damage of tillage on the soil as compared to the lack of damage, at least visually, from the herbicide. But others suggested that herbicides may not be as benign in the soil as I portrayed them. Here is the latest science on the topic.

A series of reviews have been published on the effects of herbicides on the soil, starting with Bunemann et al. in 2006. They concluded, “The herbicides generally had no major effects on soil organisms.” More recently, a review by Rose et al. (2016) found, “Overall, the majority of papers reported negligible impacts of herbicides on soil microbial communities and beneficial soil functions when applied at recommended field-application rates.” Read more »

Crop rotation: In praise of deliberate, sequenced disruption of natural systems

Posted by Andrew McGuire | December 1, 2016

For years, researchers have been looking to polycultures, biodiversity in space, as a way to improve agriculture (Trenbath 1974; Tilman et al. 1997; Cardinale et al. 2011; Finney and Kaye 2016). Behind this research is the idea that nature is the best model for agriculture. Because we find that nature is generally a polyculture, we should mimic this biodiversity on the farm. Natural is now viewed as the best option. Today, however, I want to commend a most unnatural practice, crop rotation.

The unnatural, disruptive transition of wheat monoculture to bean monoculture – good for agriculture

The unnatural, disruptive transition of wheat monoculture to bean monoculture – good for agriculture

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Contact Andrew McGuire

Email: andrew.mcguire@wsu.edu